ShowEasy/EuroTran/WebApp/Scripts/plugins/fullcalendar/fullcalendar.js

/*!
 * FullCalendar v3.1.0
 * Docs & License: http://fullcalendar.io/
 * (c) 2016 Adam Shaw
 */

(function (factory) {
    if (typeof define === 'function' && define.amd) {
        define(['jquery', 'moment'], factory);
    }
    else if (typeof exports === 'object') { // Node/CommonJS
        module.exports = factory(require('jquery'), require('moment'));
    }
    else {
        factory(jQuery, moment);
    }
})(function ($, moment) {
    ;;

    var FC = $.fullCalendar = {
        version: "3.1.0",
        internalApiVersion: 7
    };
    var fcViews = FC.views = {};

    $.fn.fullCalendar = function (options) {
        var args = Array.prototype.slice.call(arguments, 1); // for a possible method call
        var res = this; // what this function will return (this jQuery object by default)

        this.each(function (i, _element) { // loop each DOM element involved
            var element = $(_element);
            var calendar = element.data('fullCalendar'); // get the existing calendar object (if any)
            var singleRes; // the returned value of this single method call

            // a method call
            if (typeof options === 'string') {
                if (calendar && $.isFunction(calendar[options])) {
                    singleRes = calendar[options].apply(calendar, args);
                    if (!i) {
                        res = singleRes; // record the first method call result
                    }
                    if (options === 'destroy') { // for the destroy method, must remove Calendar object data
                        element.removeData('fullCalendar');
                    }
                }
            }
            // a new calendar initialization
            else if (!calendar) { // don't initialize twice
                calendar = new Calendar(element, options);
                element.data('fullCalendar', calendar);
                calendar.render();
            }
        });

        return res;
    };

    var complexOptions = [ // names of options that are objects whose properties should be combined
        'header',
        'footer',
        'buttonText',
        'buttonIcons',
        'themeButtonIcons'
    ];

    // Merges an array of option objects into a single object
    function mergeOptions(optionObjs) {
        return mergeProps(optionObjs, complexOptions);
    }

    ;;

    // exports
    FC.intersectRanges = intersectRanges;
    FC.applyAll = applyAll;
    FC.debounce = debounce;
    FC.isInt = isInt;
    FC.htmlEscape = htmlEscape;
    FC.cssToStr = cssToStr;
    FC.proxy = proxy;
    FC.capitaliseFirstLetter = capitaliseFirstLetter;

    /* FullCalendar-specific DOM Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    // Given the scrollbar widths of some other container, create borders/margins on rowEls in order to match the left
    // and right space that was offset by the scrollbars. A 1-pixel border first, then margin beyond that.
    function compensateScroll(rowEls, scrollbarWidths) {
        if (scrollbarWidths.left) {
            rowEls.css({
                'border-left-width': 1,
                'margin-left': scrollbarWidths.left - 1
            });
        }
        if (scrollbarWidths.right) {
            rowEls.css({
                'border-right-width': 1,
                'margin-right': scrollbarWidths.right - 1
            });
        }
    }

    // Undoes compensateScroll and restores all borders/margins
    function uncompensateScroll(rowEls) {
        rowEls.css({
            'margin-left': '',
            'margin-right': '',
            'border-left-width': '',
            'border-right-width': ''
        });
    }

    // Make the mouse cursor express that an event is not allowed in the current area
    function disableCursor() {
        $('body').addClass('fc-not-allowed');
    }

    // Returns the mouse cursor to its original look
    function enableCursor() {
        $('body').removeClass('fc-not-allowed');
    }

    // Given a total available height to fill, have `els` (essentially child rows) expand to accomodate.
    // By default, all elements that are shorter than the recommended height are expanded uniformly, not considering
    // any other els that are already too tall. if `shouldRedistribute` is on, it considers these tall rows and
    // reduces the available height.
    function distributeHeight(els, availableHeight, shouldRedistribute) {
        // *FLOORING NOTE*: we floor in certain places because zoom can give inaccurate floating-point dimensions,
        // and it is better to be shorter than taller, to avoid creating unnecessary scrollbars.

        var minOffset1 = Math.floor(availableHeight / els.length); // for non-last element
        var minOffset2 = Math.floor(availableHeight - minOffset1 * (els.length - 1)); // for last element *FLOORING NOTE*
        var flexEls = []; // elements that are allowed to expand. array of DOM nodes
        var flexOffsets = []; // amount of vertical space it takes up
        var flexHeights = []; // actual css height
        var usedHeight = 0;

        undistributeHeight(els); // give all elements their natural height

        // find elements that are below the recommended height (expandable).
        // important to query for heights in a single first pass (to avoid reflow oscillation).
        els.each(function (i, el) {
            var minOffset = i === els.length - 1 ? minOffset2 : minOffset1;
            var naturalOffset = $(el).outerHeight(true);

            if (naturalOffset < minOffset) {
                flexEls.push(el);
                flexOffsets.push(naturalOffset);
                flexHeights.push($(el).height());
            }
            else {
                // this element stretches past recommended height (non-expandable). mark the space as occupied.
                usedHeight += naturalOffset;
            }
        });

        // readjust the recommended height to only consider the height available to non-maxed-out rows.
        if (shouldRedistribute) {
            availableHeight -= usedHeight;
            minOffset1 = Math.floor(availableHeight / flexEls.length);
            minOffset2 = Math.floor(availableHeight - minOffset1 * (flexEls.length - 1)); // *FLOORING NOTE*
        }

        // assign heights to all expandable elements
        $(flexEls).each(function (i, el) {
            var minOffset = i === flexEls.length - 1 ? minOffset2 : minOffset1;
            var naturalOffset = flexOffsets[i];
            var naturalHeight = flexHeights[i];
            var newHeight = minOffset - (naturalOffset - naturalHeight); // subtract the margin/padding

            if (naturalOffset < minOffset) { // we check this again because redistribution might have changed things
                $(el).height(newHeight);
            }
        });
    }

    // Undoes distrubuteHeight, restoring all els to their natural height
    function undistributeHeight(els) {
        els.height('');
    }

    // Given `els`, a jQuery set of <td> cells, find the cell with the largest natural width and set the widths of all the
    // cells to be that width.
    // PREREQUISITE: if you want a cell to take up width, it needs to have a single inner element w/ display:inline
    function matchCellWidths(els) {
        var maxInnerWidth = 0;

        els.find('> *').each(function (i, innerEl) {
            var innerWidth = $(innerEl).outerWidth();
            if (innerWidth > maxInnerWidth) {
                maxInnerWidth = innerWidth;
            }
        });

        maxInnerWidth++; // sometimes not accurate of width the text needs to stay on one line. insurance

        els.width(maxInnerWidth);

        return maxInnerWidth;
    }

    // Given one element that resides inside another,
    // Subtracts the height of the inner element from the outer element.
    function subtractInnerElHeight(outerEl, innerEl) {
        var both = outerEl.add(innerEl);
        var diff;

        // effin' IE8/9/10/11 sometimes returns 0 for dimensions. this weird hack was the only thing that worked
        both.css({
            position: 'relative', // cause a reflow, which will force fresh dimension recalculation
            left: -1 // ensure reflow in case the el was already relative. negative is less likely to cause new scroll
        });
        diff = outerEl.outerHeight() - innerEl.outerHeight(); // grab the dimensions
        both.css({ position: '', left: '' }); // undo hack

        return diff;
    }

    /* Element Geom Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    FC.getOuterRect = getOuterRect;
    FC.getClientRect = getClientRect;
    FC.getContentRect = getContentRect;
    FC.getScrollbarWidths = getScrollbarWidths;

    // borrowed from https://github.com/jquery/jquery-ui/blob/1.11.0/ui/core.js#L51
    function getScrollParent(el) {
        var position = el.css('position'),
            scrollParent = el.parents().filter(function () {
                var parent = $(this);
                return (/(auto|scroll)/).test(
                    parent.css('overflow') + parent.css('overflow-y') + parent.css('overflow-x')
                );
            }).eq(0);

        return position === 'fixed' || !scrollParent.length ? $(el[0].ownerDocument || document) : scrollParent;
    }

    // Queries the outer bounding area of a jQuery element.
    // Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
    // Origin is optional.
    function getOuterRect(el, origin) {
        var offset = el.offset();
        var left = offset.left - (origin ? origin.left : 0);
        var top = offset.top - (origin ? origin.top : 0);

        return {
            left: left,
            right: left + el.outerWidth(),
            top: top,
            bottom: top + el.outerHeight()
        };
    }

    // Queries the area within the margin/border/scrollbars of a jQuery element. Does not go within the padding.
    // Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
    // Origin is optional.
    // NOTE: should use clientLeft/clientTop, but very unreliable cross-browser.
    function getClientRect(el, origin) {
        var offset = el.offset();
        var scrollbarWidths = getScrollbarWidths(el);
        var left = offset.left + getCssFloat(el, 'border-left-width') + scrollbarWidths.left - (origin ? origin.left : 0);
        var top = offset.top + getCssFloat(el, 'border-top-width') + scrollbarWidths.top - (origin ? origin.top : 0);

        return {
            left: left,
            right: left + el[0].clientWidth, // clientWidth includes padding but NOT scrollbars
            top: top,
            bottom: top + el[0].clientHeight // clientHeight includes padding but NOT scrollbars
        };
    }

    // Queries the area within the margin/border/padding of a jQuery element. Assumed not to have scrollbars.
    // Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
    // Origin is optional.
    function getContentRect(el, origin) {
        var offset = el.offset(); // just outside of border, margin not included
        var left = offset.left + getCssFloat(el, 'border-left-width') + getCssFloat(el, 'padding-left') -
            (origin ? origin.left : 0);
        var top = offset.top + getCssFloat(el, 'border-top-width') + getCssFloat(el, 'padding-top') -
            (origin ? origin.top : 0);

        return {
            left: left,
            right: left + el.width(),
            top: top,
            bottom: top + el.height()
        };
    }

    // Returns the computed left/right/top/bottom scrollbar widths for the given jQuery element.
    // NOTE: should use clientLeft/clientTop, but very unreliable cross-browser.
    function getScrollbarWidths(el) {
        var leftRightWidth = el.innerWidth() - el[0].clientWidth; // the paddings cancel out, leaving the scrollbars
        var widths = {
            left: 0,
            right: 0,
            top: 0,
            bottom: el.innerHeight() - el[0].clientHeight // the paddings cancel out, leaving the bottom scrollbar
        };

        if (getIsLeftRtlScrollbars() && el.css('direction') == 'rtl') { // is the scrollbar on the left side?
            widths.left = leftRightWidth;
        }
        else {
            widths.right = leftRightWidth;
        }

        return widths;
    }

    // Logic for determining if, when the element is right-to-left, the scrollbar appears on the left side

    var _isLeftRtlScrollbars = null;

    function getIsLeftRtlScrollbars() { // responsible for caching the computation
        if (_isLeftRtlScrollbars === null) {
            _isLeftRtlScrollbars = computeIsLeftRtlScrollbars();
        }
        return _isLeftRtlScrollbars;
    }

    function computeIsLeftRtlScrollbars() { // creates an offscreen test element, then removes it
        var el = $('<div><div/></div>')
            .css({
                position: 'absolute',
                top: -1000,
                left: 0,
                border: 0,
                padding: 0,
                overflow: 'scroll',
                direction: 'rtl'
            })
            .appendTo('body');
        var innerEl = el.children();
        var res = innerEl.offset().left > el.offset().left; // is the inner div shifted to accommodate a left scrollbar?
        el.remove();
        return res;
    }

    // Retrieves a jQuery element's computed CSS value as a floating-point number.
    // If the queried value is non-numeric (ex: IE can return "medium" for border width), will just return zero.
    function getCssFloat(el, prop) {
        return parseFloat(el.css(prop)) || 0;
    }

    /* Mouse / Touch Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    FC.preventDefault = preventDefault;

    // Returns a boolean whether this was a left mouse click and no ctrl key (which means right click on Mac)
    function isPrimaryMouseButton(ev) {
        return ev.which == 1 && !ev.ctrlKey;
    }

    function getEvX(ev) {
        if (ev.pageX !== undefined) {
            return ev.pageX;
        }
        var touches = ev.originalEvent.touches;
        if (touches) {
            return touches[0].pageX;
        }
    }

    function getEvY(ev) {
        if (ev.pageY !== undefined) {
            return ev.pageY;
        }
        var touches = ev.originalEvent.touches;
        if (touches) {
            return touches[0].pageY;
        }
    }

    function getEvIsTouch(ev) {
        return /^touch/.test(ev.type);
    }

    function preventSelection(el) {
        el.addClass('fc-unselectable')
            .on('selectstart', preventDefault);
    }

    // Stops a mouse/touch event from doing it's native browser action
    function preventDefault(ev) {
        ev.preventDefault();
    }

    // attach a handler to get called when ANY scroll action happens on the page.
    // this was impossible to do with normal on/off because 'scroll' doesn't bubble.
    // http://stackoverflow.com/a/32954565/96342
    // returns `true` on success.
    function bindAnyScroll(handler) {
        if (window.addEventListener) {
            window.addEventListener('scroll', handler, true); // useCapture=true
            return true;
        }
        return false;
    }

    // undoes bindAnyScroll. must pass in the original function.
    // returns `true` on success.
    function unbindAnyScroll(handler) {
        if (window.removeEventListener) {
            window.removeEventListener('scroll', handler, true); // useCapture=true
            return true;
        }
        return false;
    }

    /* General Geometry Utils
    ----------------------------------------------------------------------------------------------------------------------*/

    FC.intersectRects = intersectRects;

    // Returns a new rectangle that is the intersection of the two rectangles. If they don't intersect, returns false
    function intersectRects(rect1, rect2) {
        var res = {
            left: Math.max(rect1.left, rect2.left),
            right: Math.min(rect1.right, rect2.right),
            top: Math.max(rect1.top, rect2.top),
            bottom: Math.min(rect1.bottom, rect2.bottom)
        };

        if (res.left < res.right && res.top < res.bottom) {
            return res;
        }
        return false;
    }

    // Returns a new point that will have been moved to reside within the given rectangle
    function constrainPoint(point, rect) {
        return {
            left: Math.min(Math.max(point.left, rect.left), rect.right),
            top: Math.min(Math.max(point.top, rect.top), rect.bottom)
        };
    }

    // Returns a point that is the center of the given rectangle
    function getRectCenter(rect) {
        return {
            left: (rect.left + rect.right) / 2,
            top: (rect.top + rect.bottom) / 2
        };
    }

    // Subtracts point2's coordinates from point1's coordinates, returning a delta
    function diffPoints(point1, point2) {
        return {
            left: point1.left - point2.left,
            top: point1.top - point2.top
        };
    }

    /* Object Ordering by Field
    ----------------------------------------------------------------------------------------------------------------------*/

    FC.parseFieldSpecs = parseFieldSpecs;
    FC.compareByFieldSpecs = compareByFieldSpecs;
    FC.compareByFieldSpec = compareByFieldSpec;
    FC.flexibleCompare = flexibleCompare;

    function parseFieldSpecs(input) {
        var specs = [];
        var tokens = [];
        var i, token;

        if (typeof input === 'string') {
            tokens = input.split(/\s*,\s*/);
        }
        else if (typeof input === 'function') {
            tokens = [input];
        }
        else if ($.isArray(input)) {
            tokens = input;
        }

        for (i = 0; i < tokens.length; i++) {
            token = tokens[i];

            if (typeof token === 'string') {
                specs.push(
                    token.charAt(0) == '-' ?
                        { field: token.substring(1), order: -1 } :
                        { field: token, order: 1 }
                );
            }
            else if (typeof token === 'function') {
                specs.push({ func: token });
            }
        }

        return specs;
    }

    function compareByFieldSpecs(obj1, obj2, fieldSpecs) {
        var i;
        var cmp;

        for (i = 0; i < fieldSpecs.length; i++) {
            cmp = compareByFieldSpec(obj1, obj2, fieldSpecs[i]);
            if (cmp) {
                return cmp;
            }
        }

        return 0;
    }

    function compareByFieldSpec(obj1, obj2, fieldSpec) {
        if (fieldSpec.func) {
            return fieldSpec.func(obj1, obj2);
        }
        return flexibleCompare(obj1[fieldSpec.field], obj2[fieldSpec.field]) *
            (fieldSpec.order || 1);
    }

    function flexibleCompare(a, b) {
        if (!a && !b) {
            return 0;
        }
        if (b == null) {
            return -1;
        }
        if (a == null) {
            return 1;
        }
        if ($.type(a) === 'string' || $.type(b) === 'string') {
            return String(a).localeCompare(String(b));
        }
        return a - b;
    }

    /* FullCalendar-specific Misc Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    // Computes the intersection of the two ranges. Will return fresh date clones in a range.
    // Returns undefined if no intersection.
    // Expects all dates to be normalized to the same timezone beforehand.
    // TODO: move to date section?
    function intersectRanges(subjectRange, constraintRange) {
        var subjectStart = subjectRange.start;
        var subjectEnd = subjectRange.end;
        var constraintStart = constraintRange.start;
        var constraintEnd = constraintRange.end;
        var segStart, segEnd;
        var isStart, isEnd;

        if (subjectEnd > constraintStart && subjectStart < constraintEnd) { // in bounds at all?
            if (subjectStart >= constraintStart) {
                segStart = subjectStart.clone();
                isStart = true;
            }
            else {
                segStart = constraintStart.clone();
                isStart = false;
            }

            if (subjectEnd <= constraintEnd) {
                segEnd = subjectEnd.clone();
                isEnd = true;
            }
            else {
                segEnd = constraintEnd.clone();
                isEnd = false;
            }

            return {
                start: segStart,
                end: segEnd,
                isStart: isStart,
                isEnd: isEnd
            };
        }
    }

    /* Date Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    FC.computeIntervalUnit = computeIntervalUnit;
    FC.divideRangeByDuration = divideRangeByDuration;
    FC.divideDurationByDuration = divideDurationByDuration;
    FC.multiplyDuration = multiplyDuration;
    FC.durationHasTime = durationHasTime;

    var dayIDs = ['sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat'];
    var intervalUnits = ['year', 'month', 'week', 'day', 'hour', 'minute', 'second', 'millisecond'];

    // Diffs the two moments into a Duration where full-days are recorded first, then the remaining time.
    // Moments will have their timezones normalized.
    function diffDayTime(a, b) {
        return moment.duration({
            days: a.clone().stripTime().diff(b.clone().stripTime(), 'days'),
            ms: a.time() - b.time() // time-of-day from day start. disregards timezone
        });
    }

    // Diffs the two moments via their start-of-day (regardless of timezone). Produces whole-day durations.
    function diffDay(a, b) {
        return moment.duration({
            days: a.clone().stripTime().diff(b.clone().stripTime(), 'days')
        });
    }

    // Diffs two moments, producing a duration, made of a whole-unit-increment of the given unit. Uses rounding.
    function diffByUnit(a, b, unit) {
        return moment.duration(
            Math.round(a.diff(b, unit, true)), // returnFloat=true
            unit
        );
    }

    // Computes the unit name of the largest whole-unit period of time.
    // For example, 48 hours will be "days" whereas 49 hours will be "hours".
    // Accepts start/end, a range object, or an original duration object.
    function computeIntervalUnit(start, end) {
        var i, unit;
        var val;

        for (i = 0; i < intervalUnits.length; i++) {
            unit = intervalUnits[i];
            val = computeRangeAs(unit, start, end);

            if (val >= 1 && isInt(val)) {
                break;
            }
        }

        return unit; // will be "milliseconds" if nothing else matches
    }

    // Computes the number of units (like "hours") in the given range.
    // Range can be a {start,end} object, separate start/end args, or a Duration.
    // Results are based on Moment's .as() and .diff() methods, so results can depend on internal handling
    // of month-diffing logic (which tends to vary from version to version).
    function computeRangeAs(unit, start, end) {
        if (end != null) { // given start, end
            return end.diff(start, unit, true);
        }
        else if (moment.isDuration(start)) { // given duration
            return start.as(unit);
        }
        else { // given { start, end } range object
            return start.end.diff(start.start, unit, true);
        }
    }

    // Intelligently divides a range (specified by a start/end params) by a duration
    function divideRangeByDuration(start, end, dur) {
        var months;

        if (durationHasTime(dur)) {
            return (end - start) / dur;
        }
        months = dur.asMonths();
        if (Math.abs(months) >= 1 && isInt(months)) {
            return end.diff(start, 'months', true) / months;
        }
        return end.diff(start, 'days', true) / dur.asDays();
    }

    // Intelligently divides one duration by another
    function divideDurationByDuration(dur1, dur2) {
        var months1, months2;

        if (durationHasTime(dur1) || durationHasTime(dur2)) {
            return dur1 / dur2;
        }
        months1 = dur1.asMonths();
        months2 = dur2.asMonths();
        if (
            Math.abs(months1) >= 1 && isInt(months1) &&
            Math.abs(months2) >= 1 && isInt(months2)
        ) {
            return months1 / months2;
        }
        return dur1.asDays() / dur2.asDays();
    }

    // Intelligently multiplies a duration by a number
    function multiplyDuration(dur, n) {
        var months;

        if (durationHasTime(dur)) {
            return moment.duration(dur * n);
        }
        months = dur.asMonths();
        if (Math.abs(months) >= 1 && isInt(months)) {
            return moment.duration({ months: months * n });
        }
        return moment.duration({ days: dur.asDays() * n });
    }

    // Returns a boolean about whether the given duration has any time parts (hours/minutes/seconds/ms)
    function durationHasTime(dur) {
        return Boolean(dur.hours() || dur.minutes() || dur.seconds() || dur.milliseconds());
    }

    function isNativeDate(input) {
        return Object.prototype.toString.call(input) === '[object Date]' || input instanceof Date;
    }

    // Returns a boolean about whether the given input is a time string, like "06:40:00" or "06:00"
    function isTimeString(str) {
        return /^\d+\:\d+(?:\:\d+\.?(?:\d{3})?)?$/.test(str);
    }

    /* Logging and Debug
    ----------------------------------------------------------------------------------------------------------------------*/

    FC.log = function () {
        var console = window.console;

        if (console && console.log) {
            return console.log.apply(console, arguments);
        }
    };

    FC.warn = function () {
        var console = window.console;

        if (console && console.warn) {
            return console.warn.apply(console, arguments);
        }
        else {
            return FC.log.apply(FC, arguments);
        }
    };

    /* General Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    var hasOwnPropMethod = {}.hasOwnProperty;

    // Merges an array of objects into a single object.
    // The second argument allows for an array of property names who's object values will be merged together.
    function mergeProps(propObjs, complexProps) {
        var dest = {};
        var i, name;
        var complexObjs;
        var j, val;
        var props;

        if (complexProps) {
            for (i = 0; i < complexProps.length; i++) {
                name = complexProps[i];
                complexObjs = [];

                // collect the trailing object values, stopping when a non-object is discovered
                for (j = propObjs.length - 1; j >= 0; j--) {
                    val = propObjs[j][name];

                    if (typeof val === 'object') {
                        complexObjs.unshift(val);
                    }
                    else if (val !== undefined) {
                        dest[name] = val; // if there were no objects, this value will be used
                        break;
                    }
                }

                // if the trailing values were objects, use the merged value
                if (complexObjs.length) {
                    dest[name] = mergeProps(complexObjs);
                }
            }
        }

        // copy values into the destination, going from last to first
        for (i = propObjs.length - 1; i >= 0; i--) {
            props = propObjs[i];

            for (name in props) {
                if (!(name in dest)) { // if already assigned by previous props or complex props, don't reassign
                    dest[name] = props[name];
                }
            }
        }

        return dest;
    }

    // Create an object that has the given prototype. Just like Object.create
    function createObject(proto) {
        var f = function () { };
        f.prototype = proto;
        return new f();
    }
    FC.createObject = createObject;

    function copyOwnProps(src, dest) {
        for (var name in src) {
            if (hasOwnProp(src, name)) {
                dest[name] = src[name];
            }
        }
    }

    function hasOwnProp(obj, name) {
        return hasOwnPropMethod.call(obj, name);
    }

    // Is the given value a non-object non-function value?
    function isAtomic(val) {
        return /undefined|null|boolean|number|string/.test($.type(val));
    }

    function applyAll(functions, thisObj, args) {
        if ($.isFunction(functions)) {
            functions = [functions];
        }
        if (functions) {
            var i;
            var ret;
            for (i = 0; i < functions.length; i++) {
                ret = functions[i].apply(thisObj, args) || ret;
            }
            return ret;
        }
    }

    function firstDefined() {
        for (var i = 0; i < arguments.length; i++) {
            if (arguments[i] !== undefined) {
                return arguments[i];
            }
        }
    }

    function htmlEscape(s) {
        return (s + '').replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/'/g, '&#039;')
            .replace(/"/g, '&quot;')
            .replace(/\n/g, '<br />');
    }

    function stripHtmlEntities(text) {
        return text.replace(/&.*?;/g, '');
    }

    // Given a hash of CSS properties, returns a string of CSS.
    // Uses property names as-is (no camel-case conversion). Will not make statements for null/undefined values.
    function cssToStr(cssProps) {
        var statements = [];

        $.each(cssProps, function (name, val) {
            if (val != null) {
                statements.push(name + ':' + val);
            }
        });

        return statements.join(';');
    }

    // Given an object hash of HTML attribute names to values,
    // generates a string that can be injected between < > in HTML
    function attrsToStr(attrs) {
        var parts = [];

        $.each(attrs, function (name, val) {
            if (val != null) {
                parts.push(name + '="' + htmlEscape(val) + '"');
            }
        });

        return parts.join(' ');
    }

    function capitaliseFirstLetter(str) {
        return str.charAt(0).toUpperCase() + str.slice(1);
    }

    function compareNumbers(a, b) { // for .sort()
        return a - b;
    }

    function isInt(n) {
        return n % 1 === 0;
    }

    // Returns a method bound to the given object context.
    // Just like one of the jQuery.proxy signatures, but without the undesired behavior of treating the same method with
    // different contexts as identical when binding/unbinding events.
    function proxy(obj, methodName) {
        var method = obj[methodName];

        return function () {
            return method.apply(obj, arguments);
        };
    }

    // Returns a function, that, as long as it continues to be invoked, will not
    // be triggered. The function will be called after it stops being called for
    // N milliseconds. If `immediate` is passed, trigger the function on the
    // leading edge, instead of the trailing.
    // https://github.com/jashkenas/underscore/blob/1.6.0/underscore.js#L714
    function debounce(func, wait, immediate) {
        var timeout, args, context, timestamp, result;

        var later = function () {
            var last = +new Date() - timestamp;
            if (last < wait) {
                timeout = setTimeout(later, wait - last);
            }
            else {
                timeout = null;
                if (!immediate) {
                    result = func.apply(context, args);
                    context = args = null;
                }
            }
        };

        return function () {
            context = this;
            args = arguments;
            timestamp = +new Date();
            var callNow = immediate && !timeout;
            if (!timeout) {
                timeout = setTimeout(later, wait);
            }
            if (callNow) {
                result = func.apply(context, args);
                context = args = null;
            }
            return result;
        };
    }

    ;;

    /*
    GENERAL NOTE on moments throughout the *entire rest* of the codebase:
    All moments are assumed to be ambiguously-zoned unless otherwise noted,
    with the NOTABLE EXCEOPTION of start/end dates that live on *Event Objects*.
    Ambiguously-TIMED moments are assumed to be ambiguously-zoned by nature.
    */

    var ambigDateOfMonthRegex = /^\s*\d{4}-\d\d$/;
    var ambigTimeOrZoneRegex =
        /^\s*\d{4}-(?:(\d\d-\d\d)|(W\d\d$)|(W\d\d-\d)|(\d\d\d))((T| )(\d\d(:\d\d(:\d\d(\.\d+)?)?)?)?)?$/;
    var newMomentProto = moment.fn; // where we will attach our new methods
    var oldMomentProto = $.extend({}, newMomentProto); // copy of original moment methods

    // tell momentjs to transfer these properties upon clone
    var momentProperties = moment.momentProperties;
    momentProperties.push('_fullCalendar');
    momentProperties.push('_ambigTime');
    momentProperties.push('_ambigZone');

    // Creating
    // -------------------------------------------------------------------------------------------------

    // Creates a new moment, similar to the vanilla moment(...) constructor, but with
    // extra features (ambiguous time, enhanced formatting). When given an existing moment,
    // it will function as a clone (and retain the zone of the moment). Anything else will
    // result in a moment in the local zone.
    FC.moment = function () {
        return makeMoment(arguments);
    };

    // Sames as FC.moment, but forces the resulting moment to be in the UTC timezone.
    FC.moment.utc = function () {
        var mom = makeMoment(arguments, true);

        // Force it into UTC because makeMoment doesn't guarantee it
        // (if given a pre-existing moment for example)
        if (mom.hasTime()) { // don't give ambiguously-timed moments a UTC zone
            mom.utc();
        }

        return mom;
    };

    // Same as FC.moment, but when given an ISO8601 string, the timezone offset is preserved.
    // ISO8601 strings with no timezone offset will become ambiguously zoned.
    FC.moment.parseZone = function () {
        return makeMoment(arguments, true, true);
    };

    // Builds an enhanced moment from args. When given an existing moment, it clones. When given a
    // native Date, or called with no arguments (the current time), the resulting moment will be local.
    // Anything else needs to be "parsed" (a string or an array), and will be affected by:
    //    parseAsUTC - if there is no zone information, should we parse the input in UTC?
    //    parseZone - if there is zone information, should we force the zone of the moment?
    function makeMoment(args, parseAsUTC, parseZone) {
        var input = args[0];
        var isSingleString = args.length == 1 && typeof input === 'string';
        var isAmbigTime;
        var isAmbigZone;
        var ambigMatch;
        var mom;

        if (moment.isMoment(input) || isNativeDate(input) || input === undefined) {
            mom = moment.apply(null, args);
        }
        else { // "parsing" is required
            isAmbigTime = false;
            isAmbigZone = false;

            if (isSingleString) {
                if (ambigDateOfMonthRegex.test(input)) {
                    // accept strings like '2014-05', but convert to the first of the month
                    input += '-01';
                    args = [input]; // for when we pass it on to moment's constructor
                    isAmbigTime = true;
                    isAmbigZone = true;
                }
                else if ((ambigMatch = ambigTimeOrZoneRegex.exec(input))) {
                    isAmbigTime = !ambigMatch[5]; // no time part?
                    isAmbigZone = true;
                }
            }
            else if ($.isArray(input)) {
                // arrays have no timezone information, so assume ambiguous zone
                isAmbigZone = true;
            }
            // otherwise, probably a string with a format

            if (parseAsUTC || isAmbigTime) {
                mom = moment.utc.apply(moment, args);
            }
            else {
                mom = moment.apply(null, args);
            }

            if (isAmbigTime) {
                mom._ambigTime = true;
                mom._ambigZone = true; // ambiguous time always means ambiguous zone
            }
            else if (parseZone) { // let's record the inputted zone somehow
                if (isAmbigZone) {
                    mom._ambigZone = true;
                }
                else if (isSingleString) {
                    mom.utcOffset(input); // if not a valid zone, will assign UTC
                }
            }
        }

        mom._fullCalendar = true; // flag for extended functionality

        return mom;
    }

    // Week Number
    // -------------------------------------------------------------------------------------------------

    // Returns the week number, considering the locale's custom week number calcuation
    // `weeks` is an alias for `week`
    newMomentProto.week = newMomentProto.weeks = function (input) {
        var weekCalc = this._locale._fullCalendar_weekCalc;

        if (input == null && typeof weekCalc === 'function') { // custom function only works for getter
            return weekCalc(this);
        }
        else if (weekCalc === 'ISO') {
            return oldMomentProto.isoWeek.apply(this, arguments); // ISO getter/setter
        }

        return oldMomentProto.week.apply(this, arguments); // local getter/setter
    };

    // Time-of-day
    // -------------------------------------------------------------------------------------------------

    // GETTER
    // Returns a Duration with the hours/minutes/seconds/ms values of the moment.
    // If the moment has an ambiguous time, a duration of 00:00 will be returned.
    //
    // SETTER
    // You can supply a Duration, a Moment, or a Duration-like argument.
    // When setting the time, and the moment has an ambiguous time, it then becomes unambiguous.
    newMomentProto.time = function (time) {
        // Fallback to the original method (if there is one) if this moment wasn't created via FullCalendar.
        // `time` is a generic enough method name where this precaution is necessary to avoid collisions w/ other plugins.
        if (!this._fullCalendar) {
            return oldMomentProto.time.apply(this, arguments);
        }

        if (time == null) { // getter
            return moment.duration({
                hours: this.hours(),
                minutes: this.minutes(),
                seconds: this.seconds(),
                milliseconds: this.milliseconds()
            });
        }
        else { // setter
            this._ambigTime = false; // mark that the moment now has a time

            if (!moment.isDuration(time) && !moment.isMoment(time)) {
                time = moment.duration(time);
            }

            // The day value should cause overflow (so 24 hours becomes 00:00:00 of next day).
            // Only for Duration times, not Moment times.
            var dayHours = 0;
            if (moment.isDuration(time)) {
                dayHours = Math.floor(time.asDays()) * 24;
            }

            // We need to set the individual fields.
            // Can't use startOf('day') then add duration. In case of DST at start of day.
            return this.hours(dayHours + time.hours())
                .minutes(time.minutes())
                .seconds(time.seconds())
                .milliseconds(time.milliseconds());
        }
    };

    // Converts the moment to UTC, stripping out its time-of-day and timezone offset,
    // but preserving its YMD. A moment with a stripped time will display no time
    // nor timezone offset when .format() is called.
    newMomentProto.stripTime = function () {
        if (!this._ambigTime) {
            this.utc(true); // keepLocalTime=true (for keeping *date* value)

            // set time to zero
            this.set({
                hours: 0,
                minutes: 0,
                seconds: 0,
                ms: 0
            });

            // Mark the time as ambiguous. This needs to happen after the .utc() call, which might call .utcOffset(),
            // which clears all ambig flags.
            this._ambigTime = true;
            this._ambigZone = true; // if ambiguous time, also ambiguous timezone offset
        }

        return this; // for chaining
    };

    // Returns if the moment has a non-ambiguous time (boolean)
    newMomentProto.hasTime = function () {
        return !this._ambigTime;
    };

    // Timezone
    // -------------------------------------------------------------------------------------------------

    // Converts the moment to UTC, stripping out its timezone offset, but preserving its
    // YMD and time-of-day. A moment with a stripped timezone offset will display no
    // timezone offset when .format() is called.
    newMomentProto.stripZone = function () {
        var wasAmbigTime;

        if (!this._ambigZone) {
            wasAmbigTime = this._ambigTime;

            this.utc(true); // keepLocalTime=true (for keeping date and time values)

            // the above call to .utc()/.utcOffset() unfortunately might clear the ambig flags, so restore
            this._ambigTime = wasAmbigTime || false;

            // Mark the zone as ambiguous. This needs to happen after the .utc() call, which might call .utcOffset(),
            // which clears the ambig flags.
            this._ambigZone = true;
        }

        return this; // for chaining
    };

    // Returns of the moment has a non-ambiguous timezone offset (boolean)
    newMomentProto.hasZone = function () {
        return !this._ambigZone;
    };

    // implicitly marks a zone
    newMomentProto.local = function (keepLocalTime) {
        // for when converting from ambiguously-zoned to local,
        // keep the time values when converting from UTC -> local
        oldMomentProto.local.call(this, this._ambigZone || keepLocalTime);

        // ensure non-ambiguous
        // this probably already happened via local() -> utcOffset(), but don't rely on Moment's internals
        this._ambigTime = false;
        this._ambigZone = false;

        return this; // for chaining
    };

    // implicitly marks a zone
    newMomentProto.utc = function (keepLocalTime) {
        oldMomentProto.utc.call(this, keepLocalTime);

        // ensure non-ambiguous
        // this probably already happened via utc() -> utcOffset(), but don't rely on Moment's internals
        this._ambigTime = false;
        this._ambigZone = false;

        return this;
    };

    // implicitly marks a zone (will probably get called upon .utc() and .local())
    newMomentProto.utcOffset = function (tzo) {
        if (tzo != null) { // setter
            // these assignments needs to happen before the original zone method is called.
            // I forget why, something to do with a browser crash.
            this._ambigTime = false;
            this._ambigZone = false;
        }

        return oldMomentProto.utcOffset.apply(this, arguments);
    };

    // Formatting
    // -------------------------------------------------------------------------------------------------

    newMomentProto.format = function () {
        if (this._fullCalendar && arguments[0]) { // an enhanced moment? and a format string provided?
            return formatDate(this, arguments[0]); // our extended formatting
        }
        if (this._ambigTime) {
            return oldMomentFormat(this, 'YYYY-MM-DD');
        }
        if (this._ambigZone) {
            return oldMomentFormat(this, 'YYYY-MM-DD[T]HH:mm:ss');
        }
        return oldMomentProto.format.apply(this, arguments);
    };

    newMomentProto.toISOString = function () {
        if (this._ambigTime) {
            return oldMomentFormat(this, 'YYYY-MM-DD');
        }
        if (this._ambigZone) {
            return oldMomentFormat(this, 'YYYY-MM-DD[T]HH:mm:ss');
        }
        return oldMomentProto.toISOString.apply(this, arguments);
    };

    ;;

    // Single Date Formatting
    // -------------------------------------------------------------------------------------------------

    // call this if you want Moment's original format method to be used
    function oldMomentFormat(mom, formatStr) {
        return oldMomentProto.format.call(mom, formatStr); // oldMomentProto defined in moment-ext.js
    }

    // Formats `date` with a Moment formatting string, but allow our non-zero areas and
    // additional token.
    function formatDate(date, formatStr) {
        return formatDateWithChunks(date, getFormatStringChunks(formatStr));
    }

    function formatDateWithChunks(date, chunks) {
        var s = '';
        var i;

        for (i = 0; i < chunks.length; i++) {
            s += formatDateWithChunk(date, chunks[i]);
        }

        return s;
    }

    // addition formatting tokens we want recognized
    var tokenOverrides = {
        t: function (date) { // "a" or "p"
            return oldMomentFormat(date, 'a').charAt(0);
        },
        T: function (date) { // "A" or "P"
            return oldMomentFormat(date, 'A').charAt(0);
        }
    };

    function formatDateWithChunk(date, chunk) {
        var token;
        var maybeStr;

        if (typeof chunk === 'string') { // a literal string
            return chunk;
        }
        else if ((token = chunk.token)) { // a token, like "YYYY"
            if (tokenOverrides[token]) {
                return tokenOverrides[token](date); // use our custom token
            }
            return oldMomentFormat(date, token);
        }
        else if (chunk.maybe) { // a grouping of other chunks that must be non-zero
            maybeStr = formatDateWithChunks(date, chunk.maybe);
            if (maybeStr.match(/[1-9]/)) {
                return maybeStr;
            }
        }

        return '';
    }

    // Date Range Formatting
    // -------------------------------------------------------------------------------------------------
    // TODO: make it work with timezone offset

    // Using a formatting string meant for a single date, generate a range string, like
    // "Sep 2 - 9 2013", that intelligently inserts a separator where the dates differ.
    // If the dates are the same as far as the format string is concerned, just return a single
    // rendering of one date, without any separator.
    function formatRange(date1, date2, formatStr, separator, isRTL) {
        var localeData;

        date1 = FC.moment.parseZone(date1);
        date2 = FC.moment.parseZone(date2);

        localeData = date1.localeData();

        // Expand localized format strings, like "LL" -> "MMMM D YYYY"
        formatStr = localeData.longDateFormat(formatStr) || formatStr;
        // BTW, this is not important for `formatDate` because it is impossible to put custom tokens
        // or non-zero areas in Moment's localized format strings.

        separator = separator || ' - ';

        return formatRangeWithChunks(
            date1,
            date2,
            getFormatStringChunks(formatStr),
            separator,
            isRTL
        );
    }
    FC.formatRange = formatRange; // expose

    function formatRangeWithChunks(date1, date2, chunks, separator, isRTL) {
        var unzonedDate1 = date1.clone().stripZone(); // for formatSimilarChunk
        var unzonedDate2 = date2.clone().stripZone(); // "
        var chunkStr; // the rendering of the chunk
        var leftI;
        var leftStr = '';
        var rightI;
        var rightStr = '';
        var middleI;
        var middleStr1 = '';
        var middleStr2 = '';
        var middleStr = '';

        // Start at the leftmost side of the formatting string and continue until you hit a token
        // that is not the same between dates.
        for (leftI = 0; leftI < chunks.length; leftI++) {
            chunkStr = formatSimilarChunk(date1, date2, unzonedDate1, unzonedDate2, chunks[leftI]);
            if (chunkStr === false) {
                break;
            }
            leftStr += chunkStr;
        }

        // Similarly, start at the rightmost side of the formatting string and move left
        for (rightI = chunks.length - 1; rightI > leftI; rightI--) {
            chunkStr = formatSimilarChunk(date1, date2, unzonedDate1, unzonedDate2, chunks[rightI]);
            if (chunkStr === false) {
                break;
            }
            rightStr = chunkStr + rightStr;
        }

        // The area in the middle is different for both of the dates.
        // Collect them distinctly so we can jam them together later.
        for (middleI = leftI; middleI <= rightI; middleI++) {
            middleStr1 += formatDateWithChunk(date1, chunks[middleI]);
            middleStr2 += formatDateWithChunk(date2, chunks[middleI]);
        }

        if (middleStr1 || middleStr2) {
            if (isRTL) {
                middleStr = middleStr2 + separator + middleStr1;
            }
            else {
                middleStr = middleStr1 + separator + middleStr2;
            }
        }

        return leftStr + middleStr + rightStr;
    }

    var similarUnitMap = {
        Y: 'year',
        M: 'month',
        D: 'day', // day of month
        d: 'day', // day of week
        // prevents a separator between anything time-related...
        A: 'second', // AM/PM
        a: 'second', // am/pm
        T: 'second', // A/P
        t: 'second', // a/p
        H: 'second', // hour (24)
        h: 'second', // hour (12)
        m: 'second', // minute
        s: 'second' // second
    };
    // TODO: week maybe?

    // Given a formatting chunk, and given that both dates are similar in the regard the
    // formatting chunk is concerned, format date1 against `chunk`. Otherwise, return `false`.
    function formatSimilarChunk(date1, date2, unzonedDate1, unzonedDate2, chunk) {
        var token;
        var unit;

        if (typeof chunk === 'string') { // a literal string
            return chunk;
        }
        else if ((token = chunk.token)) {
            unit = similarUnitMap[token.charAt(0)];

            // are the dates the same for this unit of measurement?
            // use the unzoned dates for this calculation because unreliable when near DST (bug #2396)
            if (unit && unzonedDate1.isSame(unzonedDate2, unit)) {
                return oldMomentFormat(date1, token); // would be the same if we used `date2`
                // BTW, don't support custom tokens
            }
        }

        return false; // the chunk is NOT the same for the two dates
        // BTW, don't support splitting on non-zero areas
    }

    // Chunking Utils
    // -------------------------------------------------------------------------------------------------

    var formatStringChunkCache = {};

    function getFormatStringChunks(formatStr) {
        if (formatStr in formatStringChunkCache) {
            return formatStringChunkCache[formatStr];
        }
        return (formatStringChunkCache[formatStr] = chunkFormatString(formatStr));
    }

    // Break the formatting string into an array of chunks
    function chunkFormatString(formatStr) {
        var chunks = [];
        var chunker = /\[([^\]]*)\]|\(([^\)]*)\)|(LTS|LT|(\w)\4*o?)|([^\w\[\(]+)/g; // TODO: more descrimination
        var match;

        while ((match = chunker.exec(formatStr))) {
            if (match[1]) { // a literal string inside [ ... ]
                chunks.push(match[1]);
            }
            else if (match[2]) { // non-zero formatting inside ( ... )
                chunks.push({ maybe: chunkFormatString(match[2]) });
            }
            else if (match[3]) { // a formatting token
                chunks.push({ token: match[3] });
            }
            else if (match[5]) { // an unenclosed literal string
                chunks.push(match[5]);
            }
        }

        return chunks;
    }

    // Misc Utils
    // -------------------------------------------------------------------------------------------------

    // granularity only goes up until day
    // TODO: unify with similarUnitMap
    var tokenGranularities = {
        Y: { value: 1, unit: 'year' },
        M: { value: 2, unit: 'month' },
        W: { value: 3, unit: 'week' },
        w: { value: 3, unit: 'week' },
        D: { value: 4, unit: 'day' }, // day of month
        d: { value: 4, unit: 'day' } // day of week
    };

    // returns a unit string, either 'year', 'month', 'day', or null
    // for the most granular formatting token in the string.
    FC.queryMostGranularFormatUnit = function (formatStr) {
        var chunks = getFormatStringChunks(formatStr);
        var i, chunk;
        var candidate;
        var best;

        for (i = 0; i < chunks.length; i++) {
            chunk = chunks[i];
            if (chunk.token) {
                candidate = tokenGranularities[chunk.token.charAt(0)];
                if (candidate) {
                    if (!best || candidate.value > best.value) {
                        best = candidate;
                    }
                }
            }
        }

        if (best) {
            return best.unit;
        }

        return null;
    };

    ;;

    FC.Class = Class; // export

    // Class that all other classes will inherit from
    function Class() { }

    // Called on a class to create a subclass.
    // Last argument contains instance methods. Any argument before the last are considered mixins.
    Class.extend = function () {
        var len = arguments.length;
        var i;
        var members;

        for (i = 0; i < len; i++) {
            members = arguments[i];
            if (i < len - 1) { // not the last argument?
                mixIntoClass(this, members);
            }
        }

        return extendClass(this, members || {}); // members will be undefined if no arguments
    };

    // Adds new member variables/methods to the class's prototype.
    // Can be called with another class, or a plain object hash containing new members.
    Class.mixin = function (members) {
        mixIntoClass(this, members);
    };

    function extendClass(superClass, members) {
        var subClass;

        // ensure a constructor for the subclass, forwarding all arguments to the super-constructor if it doesn't exist
        if (hasOwnProp(members, 'constructor')) {
            subClass = members.constructor;
        }
        if (typeof subClass !== 'function') {
            subClass = members.constructor = function () {
                superClass.apply(this, arguments);
            };
        }

        // build the base prototype for the subclass, which is an new object chained to the superclass's prototype
        subClass.prototype = createObject(superClass.prototype);

        // copy each member variable/method onto the the subclass's prototype
        copyOwnProps(members, subClass.prototype);

        // copy over all class variables/methods to the subclass, such as `extend` and `mixin`
        copyOwnProps(superClass, subClass);

        return subClass;
    }

    function mixIntoClass(theClass, members) {
        copyOwnProps(members, theClass.prototype);
    }
    ;;

    /*
    Wrap jQuery's Deferred Promise object to be slightly more Promise/A+ compliant.
    With the added non-standard feature of synchronously executing handlers on resolved promises,
    which doesn't always happen otherwise (esp with nested .then handlers!?),
    so, this makes things a lot easier, esp because jQuery 3 changed the synchronicity for Deferred objects.

    TODO: write tests and more comments
    */

    function Promise(executor) {
        var deferred = $.Deferred();
        var promise = deferred.promise();

        if (typeof executor === 'function') {
            executor(
                function (value) { // resolve
                    if (Promise.immediate) {
                        promise._value = value;
                    }
                    deferred.resolve(value);
                },
                function () { // reject
                    deferred.reject();
                }
            );
        }

        if (Promise.immediate) {
            var origThen = promise.then;

            promise.then = function (onFulfilled, onRejected) {
                var state = promise.state();

                if (state === 'resolved') {
                    if (typeof onFulfilled === 'function') {
                        return Promise.resolve(onFulfilled(promise._value));
                    }
                }
                else if (state === 'rejected') {
                    if (typeof onRejected === 'function') {
                        onRejected();
                        return promise; // already rejected
                    }
                }

                return origThen.call(promise, onFulfilled, onRejected);
            };
        }

        return promise; // instanceof Promise will break :( TODO: make Promise a real class
    }

    FC.Promise = Promise;

    Promise.immediate = true;

    Promise.resolve = function (value) {
        if (value && typeof value.resolve === 'function') {
            return value.promise();
        }
        if (value && typeof value.then === 'function') {
            return value;
        }
        else {
            var deferred = $.Deferred().resolve(value);
            var promise = deferred.promise();

            if (Promise.immediate) {
                var origThen = promise.then;

                promise._value = value;

                promise.then = function (onFulfilled, onRejected) {
                    if (typeof onFulfilled === 'function') {
                        return Promise.resolve(onFulfilled(value));
                    }
                    return origThen.call(promise, onFulfilled, onRejected);
                };
            }

            return promise;
        }
    };

    Promise.reject = function () {
        return $.Deferred().reject().promise();
    };

    Promise.all = function (inputs) {
        var hasAllValues = false;
        var values;
        var i, input;

        if (Promise.immediate) {
            hasAllValues = true;
            values = [];

            for (i = 0; i < inputs.length; i++) {
                input = inputs[i];

                if (input && typeof input.state === 'function' && input.state() === 'resolved' && ('_value' in input)) {
                    values.push(input._value);
                }
                else if (input && typeof input.then === 'function') {
                    hasAllValues = false;
                    break;
                }
                else {
                    values.push(input);
                }
            }
        }

        if (hasAllValues) {
            return Promise.resolve(values);
        }
        else {
            return $.when.apply($.when, inputs).then(function () {
                return $.when($.makeArray(arguments));
            });
        }
    };

    ;;

    // TODO: write tests and clean up code

    function TaskQueue(debounceWait) {
        var q = []; // array of runFuncs

        function addTask(taskFunc) {
            return new Promise(function (resolve) {
                // should run this function when it's taskFunc's turn to run.
                // responsible for popping itself off the queue.
                var runFunc = function () {
                    Promise.resolve(taskFunc()) // result might be async, coerce to promise
                        .then(resolve) // resolve TaskQueue::push's promise, for the caller. will receive result of taskFunc.
                        .then(function () {
                            q.shift(); // pop itself off

                            // run the next task, if any
                            if (q.length) {
                                q[0]();
                            }
                        });
                };

                // always put the task at the end of the queue, BEFORE running the task
                q.push(runFunc);

                // if it's the only task in the queue, run immediately
                if (q.length === 1) {
                    runFunc();
                }
            });
        }

        this.add = // potentially debounce, for the public method
            typeof debounceWait === 'number' ?
                debounce(addTask, debounceWait) :
                addTask; // if not a number (null/undefined/false), no debounce at all

        this.addQuickly = addTask; // guaranteed no debounce
    }

    FC.TaskQueue = TaskQueue;

    /*
    q = new TaskQueue();

    function work(i) {
        return q.push(function() {
            trigger();
            console.log('work' + i);
        });
    }

    var cnt = 0;

    function trigger() {
        if (cnt < 5) {
            cnt++;
            work(cnt);
        }
    }

    work(9);
    */

    ;;

    var EmitterMixin = FC.EmitterMixin = {
        // jQuery-ification via $(this) allows a non-DOM object to have
        // the same event handling capabilities (including namespaces).

        on: function (types, handler) {
            $(this).on(types, this._prepareIntercept(handler));
            return this; // for chaining
        },

        one: function (types, handler) {
            $(this).one(types, this._prepareIntercept(handler));
            return this; // for chaining
        },

        _prepareIntercept: function (handler) {
            // handlers are always called with an "event" object as their first param.
            // sneak the `this` context and arguments into the extra parameter object
            // and forward them on to the original handler.
            var intercept = function (ev, extra) {
                return handler.apply(
                    extra.context || this,
                    extra.args || []
                );
            };

            // mimick jQuery's internal "proxy" system (risky, I know)
            // causing all functions with the same .guid to appear to be the same.
            // https://github.com/jquery/jquery/blob/2.2.4/src/core.js#L448
            // this is needed for calling .off with the original non-intercept handler.
            if (!handler.guid) {
                handler.guid = $.guid++;
            }
            intercept.guid = handler.guid;

            return intercept;
        },

        off: function (types, handler) {
            $(this).off(types, handler);

            return this; // for chaining
        },

        trigger: function (types) {
            var args = Array.prototype.slice.call(arguments, 1); // arguments after the first

            // pass in "extra" info to the intercept
            $(this).triggerHandler(types, { args: args });

            return this; // for chaining
        },

        triggerWith: function (types, context, args) {
            // `triggerHandler` is less reliant on the DOM compared to `trigger`.
            // pass in "extra" info to the intercept.
            $(this).triggerHandler(types, { context: context, args: args });

            return this; // for chaining
        }
    };

    ;;

    /*
    Utility methods for easily listening to events on another object,
    and more importantly, easily unlistening from them.
    */
    var ListenerMixin = FC.ListenerMixin = (function () {
        var guid = 0;
        var ListenerMixin = {
            listenerId: null,

            /*
            Given an `other` object that has on/off methods, bind the given `callback` to an event by the given name.
            The `callback` will be called with the `this` context of the object that .listenTo is being called on.
            Can be called:
                .listenTo(other, eventName, callback)
            OR
                .listenTo(other, {
                    eventName1: callback1,
                    eventName2: callback2
                })
            */
            listenTo: function (other, arg, callback) {
                if (typeof arg === 'object') { // given dictionary of callbacks
                    for (var eventName in arg) {
                        if (arg.hasOwnProperty(eventName)) {
                            this.listenTo(other, eventName, arg[eventName]);
                        }
                    }
                }
                else if (typeof arg === 'string') {
                    other.on(
                        arg + '.' + this.getListenerNamespace(), // use event namespacing to identify this object
                        $.proxy(callback, this) // always use `this` context
                        // the usually-undesired jQuery guid behavior doesn't matter,
                        // because we always unbind via namespace
                    );
                }
            },

            /*
            Causes the current object to stop listening to events on the `other` object.
            `eventName` is optional. If omitted, will stop listening to ALL events on `other`.
            */
            stopListeningTo: function (other, eventName) {
                other.off((eventName || '') + '.' + this.getListenerNamespace());
            },

            /*
            Returns a string, unique to this object, to be used for event namespacing
            */
            getListenerNamespace: function () {
                if (this.listenerId == null) {
                    this.listenerId = guid++;
                }
                return '_listener' + this.listenerId;
            }
        };
        return ListenerMixin;
    })();
    ;;

    // simple class for toggle a `isIgnoringMouse` flag on delay
    // initMouseIgnoring must first be called, with a millisecond delay setting.
    var MouseIgnorerMixin = {
        isIgnoringMouse: false, // bool
        delayUnignoreMouse: null, // method

        initMouseIgnoring: function (delay) {
            this.delayUnignoreMouse = debounce(proxy(this, 'unignoreMouse'), delay || 1000);
        },

        // temporarily ignore mouse actions on segments
        tempIgnoreMouse: function () {
            this.isIgnoringMouse = true;
            this.delayUnignoreMouse();
        },

        // delayUnignoreMouse eventually calls this
        unignoreMouse: function () {
            this.isIgnoringMouse = false;
        }
    };

    ;;

    /* A rectangular panel that is absolutely positioned over other content
    ------------------------------------------------------------------------------------------------------------------------
    Options:
        - className (string)
        - content (HTML string or jQuery element set)
        - parentEl
        - top
        - left
        - right (the x coord of where the right edge should be. not a "CSS" right)
        - autoHide (boolean)
        - show (callback)
        - hide (callback)
    */

    var Popover = Class.extend(ListenerMixin, {
        isHidden: true,
        options: null,
        el: null, // the container element for the popover. generated by this object
        margin: 10, // the space required between the popover and the edges of the scroll container

        constructor: function (options) {
            this.options = options || {};
        },

        // Shows the popover on the specified position. Renders it if not already
        show: function () {
            if (this.isHidden) {
                if (!this.el) {
                    this.render();
                }
                this.el.show();
                this.position();
                this.isHidden = false;
                this.trigger('show');
            }
        },

        // Hides the popover, through CSS, but does not remove it from the DOM
        hide: function () {
            if (!this.isHidden) {
                this.el.hide();
                this.isHidden = true;
                this.trigger('hide');
            }
        },

        // Creates `this.el` and renders content inside of it
        render: function () {
            var _this = this;
            var options = this.options;

            this.el = $('<div class="fc-popover"/>')
                .addClass(options.className || '')
                .css({
                    // position initially to the top left to avoid creating scrollbars
                    top: 0,
                    left: 0
                })
                .append(options.content)
                .appendTo(options.parentEl);

            // when a click happens on anything inside with a 'fc-close' className, hide the popover
            this.el.on('click', '.fc-close', function () {
                _this.hide();
            });

            if (options.autoHide) {
                this.listenTo($(document), 'mousedown', this.documentMousedown);
            }
        },

        // Triggered when the user clicks *anywhere* in the document, for the autoHide feature
        documentMousedown: function (ev) {
            // only hide the popover if the click happened outside the popover
            if (this.el && !$(ev.target).closest(this.el).length) {
                this.hide();
            }
        },

        // Hides and unregisters any handlers
        removeElement: function () {
            this.hide();

            if (this.el) {
                this.el.remove();
                this.el = null;
            }

            this.stopListeningTo($(document), 'mousedown');
        },

        // Positions the popover optimally, using the top/left/right options
        position: function () {
            var options = this.options;
            var origin = this.el.offsetParent().offset();
            var width = this.el.outerWidth();
            var height = this.el.outerHeight();
            var windowEl = $(window);
            var viewportEl = getScrollParent(this.el);
            var viewportTop;
            var viewportLeft;
            var viewportOffset;
            var top; // the "position" (not "offset") values for the popover
            var left; //

            // compute top and left
            top = options.top || 0;
            if (options.left !== undefined) {
                left = options.left;
            }
            else if (options.right !== undefined) {
                left = options.right - width; // derive the left value from the right value
            }
            else {
                left = 0;
            }

            if (viewportEl.is(window) || viewportEl.is(document)) { // normalize getScrollParent's result
                viewportEl = windowEl;
                viewportTop = 0; // the window is always at the top left
                viewportLeft = 0; // (and .offset() won't work if called here)
            }
            else {
                viewportOffset = viewportEl.offset();
                viewportTop = viewportOffset.top;
                viewportLeft = viewportOffset.left;
            }

            // if the window is scrolled, it causes the visible area to be further down
            viewportTop += windowEl.scrollTop();
            viewportLeft += windowEl.scrollLeft();

            // constrain to the view port. if constrained by two edges, give precedence to top/left
            if (options.viewportConstrain !== false) {
                top = Math.min(top, viewportTop + viewportEl.outerHeight() - height - this.margin);
                top = Math.max(top, viewportTop + this.margin);
                left = Math.min(left, viewportLeft + viewportEl.outerWidth() - width - this.margin);
                left = Math.max(left, viewportLeft + this.margin);
            }

            this.el.css({
                top: top - origin.top,
                left: left - origin.left
            });
        },

        // Triggers a callback. Calls a function in the option hash of the same name.
        // Arguments beyond the first `name` are forwarded on.
        // TODO: better code reuse for this. Repeat code
        trigger: function (name) {
            if (this.options[name]) {
                this.options[name].apply(this, Array.prototype.slice.call(arguments, 1));
            }
        }
    });

    ;;

    /*
    A cache for the left/right/top/bottom/width/height values for one or more elements.
    Works with both offset (from topleft document) and position (from offsetParent).

    options:
    - els
    - isHorizontal
    - isVertical
    */
    var CoordCache = FC.CoordCache = Class.extend({
        els: null, // jQuery set (assumed to be siblings)
        forcedOffsetParentEl: null, // options can override the natural offsetParent
        origin: null, // {left,top} position of offsetParent of els
        boundingRect: null, // constrain cordinates to this rectangle. {left,right,top,bottom} or null
        isHorizontal: false, // whether to query for left/right/width
        isVertical: false, // whether to query for top/bottom/height

        // arrays of coordinates (offsets from topleft of document)
        lefts: null,
        rights: null,
        tops: null,
        bottoms: null,

        constructor: function (options) {
            this.els = $(options.els);
            this.isHorizontal = options.isHorizontal;
            this.isVertical = options.isVertical;
            this.forcedOffsetParentEl = options.offsetParent ? $(options.offsetParent) : null;
        },

        // Queries the els for coordinates and stores them.
        // Call this method before using and of the get* methods below.
        build: function () {
            var offsetParentEl = this.forcedOffsetParentEl;
            if (!offsetParentEl && this.els.length > 0) {
                offsetParentEl = this.els.eq(0).offsetParent();
            }

            this.origin = offsetParentEl ?
                offsetParentEl.offset() :
                null;

            this.boundingRect = this.queryBoundingRect();

            if (this.isHorizontal) {
                this.buildElHorizontals();
            }
            if (this.isVertical) {
                this.buildElVerticals();
            }
        },

        // Destroys all internal data about coordinates, freeing memory
        clear: function () {
            this.origin = null;
            this.boundingRect = null;
            this.lefts = null;
            this.rights = null;
            this.tops = null;
            this.bottoms = null;
        },

        // When called, if coord caches aren't built, builds them
        ensureBuilt: function () {
            if (!this.origin) {
                this.build();
            }
        },

        // Populates the left/right internal coordinate arrays
        buildElHorizontals: function () {
            var lefts = [];
            var rights = [];

            this.els.each(function (i, node) {
                var el = $(node);
                var left = el.offset().left;
                var width = el.outerWidth();

                lefts.push(left);
                rights.push(left + width);
            });

            this.lefts = lefts;
            this.rights = rights;
        },

        // Populates the top/bottom internal coordinate arrays
        buildElVerticals: function () {
            var tops = [];
            var bottoms = [];

            this.els.each(function (i, node) {
                var el = $(node);
                var top = el.offset().top;
                var height = el.outerHeight();

                tops.push(top);
                bottoms.push(top + height);
            });

            this.tops = tops;
            this.bottoms = bottoms;
        },

        // Given a left offset (from document left), returns the index of the el that it horizontally intersects.
        // If no intersection is made, returns undefined.
        getHorizontalIndex: function (leftOffset) {
            this.ensureBuilt();

            var lefts = this.lefts;
            var rights = this.rights;
            var len = lefts.length;
            var i;

            for (i = 0; i < len; i++) {
                if (leftOffset >= lefts[i] && leftOffset < rights[i]) {
                    return i;
                }
            }
        },

        // Given a top offset (from document top), returns the index of the el that it vertically intersects.
        // If no intersection is made, returns undefined.
        getVerticalIndex: function (topOffset) {
            this.ensureBuilt();

            var tops = this.tops;
            var bottoms = this.bottoms;
            var len = tops.length;
            var i;

            for (i = 0; i < len; i++) {
                if (topOffset >= tops[i] && topOffset < bottoms[i]) {
                    return i;
                }
            }
        },

        // Gets the left offset (from document left) of the element at the given index
        getLeftOffset: function (leftIndex) {
            this.ensureBuilt();
            return this.lefts[leftIndex];
        },

        // Gets the left position (from offsetParent left) of the element at the given index
        getLeftPosition: function (leftIndex) {
            this.ensureBuilt();
            return this.lefts[leftIndex] - this.origin.left;
        },

        // Gets the right offset (from document left) of the element at the given index.
        // This value is NOT relative to the document's right edge, like the CSS concept of "right" would be.
        getRightOffset: function (leftIndex) {
            this.ensureBuilt();
            return this.rights[leftIndex];
        },

        // Gets the right position (from offsetParent left) of the element at the given index.
        // This value is NOT relative to the offsetParent's right edge, like the CSS concept of "right" would be.
        getRightPosition: function (leftIndex) {
            this.ensureBuilt();
            return this.rights[leftIndex] - this.origin.left;
        },

        // Gets the width of the element at the given index
        getWidth: function (leftIndex) {
            this.ensureBuilt();
            return this.rights[leftIndex] - this.lefts[leftIndex];
        },

        // Gets the top offset (from document top) of the element at the given index
        getTopOffset: function (topIndex) {
            this.ensureBuilt();
            return this.tops[topIndex];
        },

        // Gets the top position (from offsetParent top) of the element at the given position
        getTopPosition: function (topIndex) {
            this.ensureBuilt();
            return this.tops[topIndex] - this.origin.top;
        },

        // Gets the bottom offset (from the document top) of the element at the given index.
        // This value is NOT relative to the offsetParent's bottom edge, like the CSS concept of "bottom" would be.
        getBottomOffset: function (topIndex) {
            this.ensureBuilt();
            return this.bottoms[topIndex];
        },

        // Gets the bottom position (from the offsetParent top) of the element at the given index.
        // This value is NOT relative to the offsetParent's bottom edge, like the CSS concept of "bottom" would be.
        getBottomPosition: function (topIndex) {
            this.ensureBuilt();
            return this.bottoms[topIndex] - this.origin.top;
        },

        // Gets the height of the element at the given index
        getHeight: function (topIndex) {
            this.ensureBuilt();
            return this.bottoms[topIndex] - this.tops[topIndex];
        },

        // Bounding Rect
        // TODO: decouple this from CoordCache

        // Compute and return what the elements' bounding rectangle is, from the user's perspective.
        // Right now, only returns a rectangle if constrained by an overflow:scroll element.
        // Returns null if there are no elements
        queryBoundingRect: function () {
            var scrollParentEl;

            if (this.els.length > 0) {
                scrollParentEl = getScrollParent(this.els.eq(0));

                if (!scrollParentEl.is(document)) {
                    return getClientRect(scrollParentEl);
                }
            }

            return null;
        },

        isPointInBounds: function (leftOffset, topOffset) {
            return this.isLeftInBounds(leftOffset) && this.isTopInBounds(topOffset);
        },

        isLeftInBounds: function (leftOffset) {
            return !this.boundingRect || (leftOffset >= this.boundingRect.left && leftOffset < this.boundingRect.right);
        },

        isTopInBounds: function (topOffset) {
            return !this.boundingRect || (topOffset >= this.boundingRect.top && topOffset < this.boundingRect.bottom);
        }
    });

    ;;

    /* Tracks a drag's mouse movement, firing various handlers
    ----------------------------------------------------------------------------------------------------------------------*/
    // TODO: use Emitter

    var DragListener = FC.DragListener = Class.extend(ListenerMixin, MouseIgnorerMixin, {
        options: null,
        subjectEl: null,

        // coordinates of the initial mousedown
        originX: null,
        originY: null,

        // the wrapping element that scrolls, or MIGHT scroll if there's overflow.
        // TODO: do this for wrappers that have overflow:hidden as well.
        scrollEl: null,

        isInteracting: false,
        isDistanceSurpassed: false,
        isDelayEnded: false,
        isDragging: false,
        isTouch: false,

        delay: null,
        delayTimeoutId: null,
        minDistance: null,

        handleTouchScrollProxy: null, // calls handleTouchScroll, always bound to `this`

        constructor: function (options) {
            this.options = options || {};
            this.handleTouchScrollProxy = proxy(this, 'handleTouchScroll');
            this.initMouseIgnoring(500);
        },

        // Interaction (high-level)
        // -----------------------------------------------------------------------------------------------------------------

        startInteraction: function (ev, extraOptions) {
            var isTouch = getEvIsTouch(ev);

            if (ev.type === 'mousedown') {
                if (this.isIgnoringMouse) {
                    return;
                }
                else if (!isPrimaryMouseButton(ev)) {
                    return;
                }
                else {
                    ev.preventDefault(); // prevents native selection in most browsers
                }
            }

            if (!this.isInteracting) {
                // process options
                extraOptions = extraOptions || {};
                this.delay = firstDefined(extraOptions.delay, this.options.delay, 0);
                this.minDistance = firstDefined(extraOptions.distance, this.options.distance, 0);
                this.subjectEl = this.options.subjectEl;

                this.isInteracting = true;
                this.isTouch = isTouch;
                this.isDelayEnded = false;
                this.isDistanceSurpassed = false;

                this.originX = getEvX(ev);
                this.originY = getEvY(ev);
                this.scrollEl = getScrollParent($(ev.target));

                this.bindHandlers();
                this.initAutoScroll();
                this.handleInteractionStart(ev);
                this.startDelay(ev);

                if (!this.minDistance) {
                    this.handleDistanceSurpassed(ev);
                }
            }
        },

        handleInteractionStart: function (ev) {
            this.trigger('interactionStart', ev);
        },

        endInteraction: function (ev, isCancelled) {
            if (this.isInteracting) {
                this.endDrag(ev);

                if (this.delayTimeoutId) {
                    clearTimeout(this.delayTimeoutId);
                    this.delayTimeoutId = null;
                }

                this.destroyAutoScroll();
                this.unbindHandlers();

                this.isInteracting = false;
                this.handleInteractionEnd(ev, isCancelled);

                // a touchstart+touchend on the same element will result in the following addition simulated events:
                // mouseover + mouseout + click
                // let's ignore these bogus events
                if (this.isTouch) {
                    this.tempIgnoreMouse();
                }
            }
        },

        handleInteractionEnd: function (ev, isCancelled) {
            this.trigger('interactionEnd', ev, isCancelled || false);
        },

        // Binding To DOM
        // -----------------------------------------------------------------------------------------------------------------

        bindHandlers: function () {
            var _this = this;
            var touchStartIgnores = 1;

            if (this.isTouch) {
                this.listenTo($(document), {
                    touchmove: this.handleTouchMove,
                    touchend: this.endInteraction,
                    touchcancel: this.endInteraction,

                    // Sometimes touchend doesn't fire
                    // (can't figure out why. touchcancel doesn't fire either. has to do with scrolling?)
                    // If another touchstart happens, we know it's bogus, so cancel the drag.
                    // touchend will continue to be broken until user does a shorttap/scroll, but this is best we can do.
                    touchstart: function (ev) {
                        if (touchStartIgnores) { // bindHandlers is called from within a touchstart,
                            touchStartIgnores--; // and we don't want this to fire immediately, so ignore.
                        }
                        else {
                            _this.endInteraction(ev, true); // isCancelled=true
                        }
                    }
                });

                // listen to ALL scroll actions on the page
                if (
                    !bindAnyScroll(this.handleTouchScrollProxy) && // hopefully this works and short-circuits the rest
                    this.scrollEl // otherwise, attach a single handler to this
                ) {
                    this.listenTo(this.scrollEl, 'scroll', this.handleTouchScroll);
                }
            }
            else {
                this.listenTo($(document), {
                    mousemove: this.handleMouseMove,
                    mouseup: this.endInteraction
                });
            }

            this.listenTo($(document), {
                selectstart: preventDefault, // don't allow selection while dragging
                contextmenu: preventDefault // long taps would open menu on Chrome dev tools
            });
        },

        unbindHandlers: function () {
            this.stopListeningTo($(document));

            // unbind scroll listening
            unbindAnyScroll(this.handleTouchScrollProxy);
            if (this.scrollEl) {
                this.stopListeningTo(this.scrollEl, 'scroll');
            }
        },

        // Drag (high-level)
        // -----------------------------------------------------------------------------------------------------------------

        // extraOptions ignored if drag already started
        startDrag: function (ev, extraOptions) {
            this.startInteraction(ev, extraOptions); // ensure interaction began

            if (!this.isDragging) {
                this.isDragging = true;
                this.handleDragStart(ev);
            }
        },

        handleDragStart: function (ev) {
            this.trigger('dragStart', ev);
        },

        handleMove: function (ev) {
            var dx = getEvX(ev) - this.originX;
            var dy = getEvY(ev) - this.originY;
            var minDistance = this.minDistance;
            var distanceSq; // current distance from the origin, squared

            if (!this.isDistanceSurpassed) {
                distanceSq = dx * dx + dy * dy;
                if (distanceSq >= minDistance * minDistance) { // use pythagorean theorem
                    this.handleDistanceSurpassed(ev);
                }
            }

            if (this.isDragging) {
                this.handleDrag(dx, dy, ev);
            }
        },

        // Called while the mouse is being moved and when we know a legitimate drag is taking place
        handleDrag: function (dx, dy, ev) {
            this.trigger('drag', dx, dy, ev);
            this.updateAutoScroll(ev); // will possibly cause scrolling
        },

        endDrag: function (ev) {
            if (this.isDragging) {
                this.isDragging = false;
                this.handleDragEnd(ev);
            }
        },

        handleDragEnd: function (ev) {
            this.trigger('dragEnd', ev);
        },

        // Delay
        // -----------------------------------------------------------------------------------------------------------------

        startDelay: function (initialEv) {
            var _this = this;

            if (this.delay) {
                this.delayTimeoutId = setTimeout(function () {
                    _this.handleDelayEnd(initialEv);
                }, this.delay);
            }
            else {
                this.handleDelayEnd(initialEv);
            }
        },

        handleDelayEnd: function (initialEv) {
            this.isDelayEnded = true;

            if (this.isDistanceSurpassed) {
                this.startDrag(initialEv);
            }
        },

        // Distance
        // -----------------------------------------------------------------------------------------------------------------

        handleDistanceSurpassed: function (ev) {
            this.isDistanceSurpassed = true;

            if (this.isDelayEnded) {
                this.startDrag(ev);
            }
        },

        // Mouse / Touch
        // -----------------------------------------------------------------------------------------------------------------

        handleTouchMove: function (ev) {
            // prevent inertia and touchmove-scrolling while dragging
            if (this.isDragging) {
                ev.preventDefault();
            }

            this.handleMove(ev);
        },

        handleMouseMove: function (ev) {
            this.handleMove(ev);
        },

        // Scrolling (unrelated to auto-scroll)
        // -----------------------------------------------------------------------------------------------------------------

        handleTouchScroll: function (ev) {
            // if the drag is being initiated by touch, but a scroll happens before
            // the drag-initiating delay is over, cancel the drag
            if (!this.isDragging) {
                this.endInteraction(ev, true); // isCancelled=true
            }
        },

        // Utils
        // -----------------------------------------------------------------------------------------------------------------

        // Triggers a callback. Calls a function in the option hash of the same name.
        // Arguments beyond the first `name` are forwarded on.
        trigger: function (name) {
            if (this.options[name]) {
                this.options[name].apply(this, Array.prototype.slice.call(arguments, 1));
            }
            // makes _methods callable by event name. TODO: kill this
            if (this['_' + name]) {
                this['_' + name].apply(this, Array.prototype.slice.call(arguments, 1));
            }
        }
    });

    ;;
    /*
    this.scrollEl is set in DragListener
    */
    DragListener.mixin({
        isAutoScroll: false,

        scrollBounds: null, // { top, bottom, left, right }
        scrollTopVel: null, // pixels per second
        scrollLeftVel: null, // pixels per second
        scrollIntervalId: null, // ID of setTimeout for scrolling animation loop

        // defaults
        scrollSensitivity: 30, // pixels from edge for scrolling to start
        scrollSpeed: 200, // pixels per second, at maximum speed
        scrollIntervalMs: 50, // millisecond wait between scroll increment

        initAutoScroll: function () {
            var scrollEl = this.scrollEl;

            this.isAutoScroll =
                this.options.scroll &&
                scrollEl &&
                !scrollEl.is(window) &&
                !scrollEl.is(document);

            if (this.isAutoScroll) {
                // debounce makes sure rapid calls don't happen
                this.listenTo(scrollEl, 'scroll', debounce(this.handleDebouncedScroll, 100));
            }
        },

        destroyAutoScroll: function () {
            this.endAutoScroll(); // kill any animation loop

            // remove the scroll handler if there is a scrollEl
            if (this.isAutoScroll) {
                this.stopListeningTo(this.scrollEl, 'scroll'); // will probably get removed by unbindHandlers too :(
            }
        },

        // Computes and stores the bounding rectangle of scrollEl
        computeScrollBounds: function () {
            if (this.isAutoScroll) {
                this.scrollBounds = getOuterRect(this.scrollEl);
                // TODO: use getClientRect in future. but prevents auto scrolling when on top of scrollbars
            }
        },

        // Called when the dragging is in progress and scrolling should be updated
        updateAutoScroll: function (ev) {
            var sensitivity = this.scrollSensitivity;
            var bounds = this.scrollBounds;
            var topCloseness, bottomCloseness;
            var leftCloseness, rightCloseness;
            var topVel = 0;
            var leftVel = 0;

            if (bounds) { // only scroll if scrollEl exists
                // compute closeness to edges. valid range is from 0.0 - 1.0
                topCloseness = (sensitivity - (getEvY(ev) - bounds.top)) / sensitivity;
                bottomCloseness = (sensitivity - (bounds.bottom - getEvY(ev))) / sensitivity;
                leftCloseness = (sensitivity - (getEvX(ev) - bounds.left)) / sensitivity;
                rightCloseness = (sensitivity - (bounds.right - getEvX(ev))) / sensitivity;

                // translate vertical closeness into velocity.
                // mouse must be completely in bounds for velocity to happen.
                if (topCloseness >= 0 && topCloseness <= 1) {
                    topVel = topCloseness * this.scrollSpeed * -1; // negative. for scrolling up
                }
                else if (bottomCloseness >= 0 && bottomCloseness <= 1) {
                    topVel = bottomCloseness * this.scrollSpeed;
                }

                // translate horizontal closeness into velocity
                if (leftCloseness >= 0 && leftCloseness <= 1) {
                    leftVel = leftCloseness * this.scrollSpeed * -1; // negative. for scrolling left
                }
                else if (rightCloseness >= 0 && rightCloseness <= 1) {
                    leftVel = rightCloseness * this.scrollSpeed;
                }
            }

            this.setScrollVel(topVel, leftVel);
        },

        // Sets the speed-of-scrolling for the scrollEl
        setScrollVel: function (topVel, leftVel) {
            this.scrollTopVel = topVel;
            this.scrollLeftVel = leftVel;

            this.constrainScrollVel(); // massages into realistic values

            // if there is non-zero velocity, and an animation loop hasn't already started, then START
            if ((this.scrollTopVel || this.scrollLeftVel) && !this.scrollIntervalId) {
                this.scrollIntervalId = setInterval(
                    proxy(this, 'scrollIntervalFunc'), // scope to `this`
                    this.scrollIntervalMs
                );
            }
        },

        // Forces scrollTopVel and scrollLeftVel to be zero if scrolling has already gone all the way
        constrainScrollVel: function () {
            var el = this.scrollEl;

            if (this.scrollTopVel < 0) { // scrolling up?
                if (el.scrollTop() <= 0) { // already scrolled all the way up?
                    this.scrollTopVel = 0;
                }
            }
            else if (this.scrollTopVel > 0) { // scrolling down?
                if (el.scrollTop() + el[0].clientHeight >= el[0].scrollHeight) { // already scrolled all the way down?
                    this.scrollTopVel = 0;
                }
            }

            if (this.scrollLeftVel < 0) { // scrolling left?
                if (el.scrollLeft() <= 0) { // already scrolled all the left?
                    this.scrollLeftVel = 0;
                }
            }
            else if (this.scrollLeftVel > 0) { // scrolling right?
                if (el.scrollLeft() + el[0].clientWidth >= el[0].scrollWidth) { // already scrolled all the way right?
                    this.scrollLeftVel = 0;
                }
            }
        },

        // This function gets called during every iteration of the scrolling animation loop
        scrollIntervalFunc: function () {
            var el = this.scrollEl;
            var frac = this.scrollIntervalMs / 1000; // considering animation frequency, what the vel should be mult'd by

            // change the value of scrollEl's scroll
            if (this.scrollTopVel) {
                el.scrollTop(el.scrollTop() + this.scrollTopVel * frac);
            }
            if (this.scrollLeftVel) {
                el.scrollLeft(el.scrollLeft() + this.scrollLeftVel * frac);
            }

            this.constrainScrollVel(); // since the scroll values changed, recompute the velocities

            // if scrolled all the way, which causes the vels to be zero, stop the animation loop
            if (!this.scrollTopVel && !this.scrollLeftVel) {
                this.endAutoScroll();
            }
        },

        // Kills any existing scrolling animation loop
        endAutoScroll: function () {
            if (this.scrollIntervalId) {
                clearInterval(this.scrollIntervalId);
                this.scrollIntervalId = null;

                this.handleScrollEnd();
            }
        },

        // Get called when the scrollEl is scrolled (NOTE: this is delayed via debounce)
        handleDebouncedScroll: function () {
            // recompute all coordinates, but *only* if this is *not* part of our scrolling animation
            if (!this.scrollIntervalId) {
                this.handleScrollEnd();
            }
        },

        // Called when scrolling has stopped, whether through auto scroll, or the user scrolling
        handleScrollEnd: function () {
        }
    });
    ;;

    /* Tracks mouse movements over a component and raises events about which hit the mouse is over.
    ------------------------------------------------------------------------------------------------------------------------
    options:
    - subjectEl
    - subjectCenter
    */

    var HitDragListener = DragListener.extend({
        component: null, // converts coordinates to hits
        // methods: prepareHits, releaseHits, queryHit

        origHit: null, // the hit the mouse was over when listening started
        hit: null, // the hit the mouse is over
        coordAdjust: null, // delta that will be added to the mouse coordinates when computing collisions

        constructor: function (component, options) {
            DragListener.call(this, options); // call the super-constructor

            this.component = component;
        },

        // Called when drag listening starts (but a real drag has not necessarily began).
        // ev might be undefined if dragging was started manually.
        handleInteractionStart: function (ev) {
            var subjectEl = this.subjectEl;
            var subjectRect;
            var origPoint;
            var point;

            this.computeCoords();

            if (ev) {
                origPoint = { left: getEvX(ev), top: getEvY(ev) };
                point = origPoint;

                // constrain the point to bounds of the element being dragged
                if (subjectEl) {
                    subjectRect = getOuterRect(subjectEl); // used for centering as well
                    point = constrainPoint(point, subjectRect);
                }

                this.origHit = this.queryHit(point.left, point.top);

                // treat the center of the subject as the collision point?
                if (subjectEl && this.options.subjectCenter) {
                    // only consider the area the subject overlaps the hit. best for large subjects.
                    // TODO: skip this if hit didn't supply left/right/top/bottom
                    if (this.origHit) {
                        subjectRect = intersectRects(this.origHit, subjectRect) ||
                            subjectRect; // in case there is no intersection
                    }

                    point = getRectCenter(subjectRect);
                }

                this.coordAdjust = diffPoints(point, origPoint); // point - origPoint
            }
            else {
                this.origHit = null;
                this.coordAdjust = null;
            }

            // call the super-method. do it after origHit has been computed
            DragListener.prototype.handleInteractionStart.apply(this, arguments);
        },

        // Recomputes the drag-critical positions of elements
        computeCoords: function () {
            this.component.prepareHits();
            this.computeScrollBounds(); // why is this here??????
        },

        // Called when the actual drag has started
        handleDragStart: function (ev) {
            var hit;

            DragListener.prototype.handleDragStart.apply(this, arguments); // call the super-method

            // might be different from this.origHit if the min-distance is large
            hit = this.queryHit(getEvX(ev), getEvY(ev));

            // report the initial hit the mouse is over
            // especially important if no min-distance and drag starts immediately
            if (hit) {
                this.handleHitOver(hit);
            }
        },

        // Called when the drag moves
        handleDrag: function (dx, dy, ev) {
            var hit;

            DragListener.prototype.handleDrag.apply(this, arguments); // call the super-method

            hit = this.queryHit(getEvX(ev), getEvY(ev));

            if (!isHitsEqual(hit, this.hit)) { // a different hit than before?
                if (this.hit) {
                    this.handleHitOut();
                }
                if (hit) {
                    this.handleHitOver(hit);
                }
            }
        },

        // Called when dragging has been stopped
        handleDragEnd: function () {
            this.handleHitDone();
            DragListener.prototype.handleDragEnd.apply(this, arguments); // call the super-method
        },

        // Called when a the mouse has just moved over a new hit
        handleHitOver: function (hit) {
            var isOrig = isHitsEqual(hit, this.origHit);

            this.hit = hit;

            this.trigger('hitOver', this.hit, isOrig, this.origHit);
        },

        // Called when the mouse has just moved out of a hit
        handleHitOut: function () {
            if (this.hit) {
                this.trigger('hitOut', this.hit);
                this.handleHitDone();
                this.hit = null;
            }
        },

        // Called after a hitOut. Also called before a dragStop
        handleHitDone: function () {
            if (this.hit) {
                this.trigger('hitDone', this.hit);
            }
        },

        // Called when the interaction ends, whether there was a real drag or not
        handleInteractionEnd: function () {
            DragListener.prototype.handleInteractionEnd.apply(this, arguments); // call the super-method

            this.origHit = null;
            this.hit = null;

            this.component.releaseHits();
        },

        // Called when scrolling has stopped, whether through auto scroll, or the user scrolling
        handleScrollEnd: function () {
            DragListener.prototype.handleScrollEnd.apply(this, arguments); // call the super-method

            this.computeCoords(); // hits' absolute positions will be in new places. recompute
        },

        // Gets the hit underneath the coordinates for the given mouse event
        queryHit: function (left, top) {
            if (this.coordAdjust) {
                left += this.coordAdjust.left;
                top += this.coordAdjust.top;
            }

            return this.component.queryHit(left, top);
        }
    });

    // Returns `true` if the hits are identically equal. `false` otherwise. Must be from the same component.
    // Two null values will be considered equal, as two "out of the component" states are the same.
    function isHitsEqual(hit0, hit1) {
        if (!hit0 && !hit1) {
            return true;
        }

        if (hit0 && hit1) {
            return hit0.component === hit1.component &&
                isHitPropsWithin(hit0, hit1) &&
                isHitPropsWithin(hit1, hit0); // ensures all props are identical
        }

        return false;
    }

    // Returns true if all of subHit's non-standard properties are within superHit
    function isHitPropsWithin(subHit, superHit) {
        for (var propName in subHit) {
            if (!/^(component|left|right|top|bottom)$/.test(propName)) {
                if (subHit[propName] !== superHit[propName]) {
                    return false;
                }
            }
        }
        return true;
    }

    ;;

    /* Creates a clone of an element and lets it track the mouse as it moves
    ----------------------------------------------------------------------------------------------------------------------*/

    var MouseFollower = Class.extend(ListenerMixin, {
        options: null,

        sourceEl: null, // the element that will be cloned and made to look like it is dragging
        el: null, // the clone of `sourceEl` that will track the mouse
        parentEl: null, // the element that `el` (the clone) will be attached to

        // the initial position of el, relative to the offset parent. made to match the initial offset of sourceEl
        top0: null,
        left0: null,

        // the absolute coordinates of the initiating touch/mouse action
        y0: null,
        x0: null,

        // the number of pixels the mouse has moved from its initial position
        topDelta: null,
        leftDelta: null,

        isFollowing: false,
        isHidden: false,
        isAnimating: false, // doing the revert animation?

        constructor: function (sourceEl, options) {
            this.options = options = options || {};
            this.sourceEl = sourceEl;
            this.parentEl = options.parentEl ? $(options.parentEl) : sourceEl.parent(); // default to sourceEl's parent
        },

        // Causes the element to start following the mouse
        start: function (ev) {
            if (!this.isFollowing) {
                this.isFollowing = true;

                this.y0 = getEvY(ev);
                this.x0 = getEvX(ev);
                this.topDelta = 0;
                this.leftDelta = 0;

                if (!this.isHidden) {
                    this.updatePosition();
                }

                if (getEvIsTouch(ev)) {
                    this.listenTo($(document), 'touchmove', this.handleMove);
                }
                else {
                    this.listenTo($(document), 'mousemove', this.handleMove);
                }
            }
        },

        // Causes the element to stop following the mouse. If shouldRevert is true, will animate back to original position.
        // `callback` gets invoked when the animation is complete. If no animation, it is invoked immediately.
        stop: function (shouldRevert, callback) {
            var _this = this;
            var revertDuration = this.options.revertDuration;

            function complete() { // might be called by .animate(), which might change `this` context
                _this.isAnimating = false;
                _this.removeElement();

                _this.top0 = _this.left0 = null; // reset state for future updatePosition calls

                if (callback) {
                    callback();
                }
            }

            if (this.isFollowing && !this.isAnimating) { // disallow more than one stop animation at a time
                this.isFollowing = false;

                this.stopListeningTo($(document));

                if (shouldRevert && revertDuration && !this.isHidden) { // do a revert animation?
                    this.isAnimating = true;
                    this.el.animate({
                        top: this.top0,
                        left: this.left0
                    }, {
                            duration: revertDuration,
                            complete: complete
                        });
                }
                else {
                    complete();
                }
            }
        },

        // Gets the tracking element. Create it if necessary
        getEl: function () {
            var el = this.el;

            if (!el) {
                el = this.el = this.sourceEl.clone()
                    .addClass(this.options.additionalClass || '')
                    .css({
                        position: 'absolute',
                        visibility: '', // in case original element was hidden (commonly through hideEvents())
                        display: this.isHidden ? 'none' : '', // for when initially hidden
                        margin: 0,
                        right: 'auto', // erase and set width instead
                        bottom: 'auto', // erase and set height instead
                        width: this.sourceEl.width(), // explicit height in case there was a 'right' value
                        height: this.sourceEl.height(), // explicit width in case there was a 'bottom' value
                        opacity: this.options.opacity || '',
                        zIndex: this.options.zIndex
                    });

                // we don't want long taps or any mouse interaction causing selection/menus.
                // would use preventSelection(), but that prevents selectstart, causing problems.
                el.addClass('fc-unselectable');

                el.appendTo(this.parentEl);
            }

            return el;
        },

        // Removes the tracking element if it has already been created
        removeElement: function () {
            if (this.el) {
                this.el.remove();
                this.el = null;
            }
        },

        // Update the CSS position of the tracking element
        updatePosition: function () {
            var sourceOffset;
            var origin;

            this.getEl(); // ensure this.el

            // make sure origin info was computed
            if (this.top0 === null) {
                sourceOffset = this.sourceEl.offset();
                origin = this.el.offsetParent().offset();
                this.top0 = sourceOffset.top - origin.top;
                this.left0 = sourceOffset.left - origin.left;
            }

            this.el.css({
                top: this.top0 + this.topDelta,
                left: this.left0 + this.leftDelta
            });
        },

        // Gets called when the user moves the mouse
        handleMove: function (ev) {
            this.topDelta = getEvY(ev) - this.y0;
            this.leftDelta = getEvX(ev) - this.x0;

            if (!this.isHidden) {
                this.updatePosition();
            }
        },

        // Temporarily makes the tracking element invisible. Can be called before following starts
        hide: function () {
            if (!this.isHidden) {
                this.isHidden = true;
                if (this.el) {
                    this.el.hide();
                }
            }
        },

        // Show the tracking element after it has been temporarily hidden
        show: function () {
            if (this.isHidden) {
                this.isHidden = false;
                this.updatePosition();
                this.getEl().show();
            }
        }
    });

    ;;

    /* An abstract class comprised of a "grid" of areas that each represent a specific datetime
    ----------------------------------------------------------------------------------------------------------------------*/

    var Grid = FC.Grid = Class.extend(ListenerMixin, MouseIgnorerMixin, {
        // self-config, overridable by subclasses
        hasDayInteractions: true, // can user click/select ranges of time?

        view: null, // a View object
        isRTL: null, // shortcut to the view's isRTL option

        start: null,
        end: null,

        el: null, // the containing element
        elsByFill: null, // a hash of jQuery element sets used for rendering each fill. Keyed by fill name.

        // derived from options
        eventTimeFormat: null,
        displayEventTime: null,
        displayEventEnd: null,

        minResizeDuration: null, // TODO: hack. set by subclasses. minumum event resize duration

        // if defined, holds the unit identified (ex: "year" or "month") that determines the level of granularity
        // of the date areas. if not defined, assumes to be day and time granularity.
        // TODO: port isTimeScale into same system?
        largeUnit: null,

        dayDragListener: null,
        segDragListener: null,
        segResizeListener: null,
        externalDragListener: null,

        constructor: function (view) {
            this.view = view;
            this.isRTL = view.opt('isRTL');
            this.elsByFill = {};

            this.dayDragListener = this.buildDayDragListener();
            this.initMouseIgnoring();
        },

        /* Options
        ------------------------------------------------------------------------------------------------------------------*/

        // Generates the format string used for event time text, if not explicitly defined by 'timeFormat'
        computeEventTimeFormat: function () {
            return this.view.opt('smallTimeFormat');
        },

        // Determines whether events should have their end times displayed, if not explicitly defined by 'displayEventTime'.
        // Only applies to non-all-day events.
        computeDisplayEventTime: function () {
            return true;
        },

        // Determines whether events should have their end times displayed, if not explicitly defined by 'displayEventEnd'
        computeDisplayEventEnd: function () {
            return true;
        },

        /* Dates
        ------------------------------------------------------------------------------------------------------------------*/

        // Tells the grid about what period of time to display.
        // Any date-related internal data should be generated.
        setRange: function (range) {
            this.start = range.start.clone();
            this.end = range.end.clone();

            this.rangeUpdated();
            this.processRangeOptions();
        },

        // Called when internal variables that rely on the range should be updated
        rangeUpdated: function () {
        },

        // Updates values that rely on options and also relate to range
        processRangeOptions: function () {
            var view = this.view;
            var displayEventTime;
            var displayEventEnd;

            this.eventTimeFormat =
                view.opt('eventTimeFormat') ||
                view.opt('timeFormat') || // deprecated
                this.computeEventTimeFormat();

            displayEventTime = view.opt('displayEventTime');
            if (displayEventTime == null) {
                displayEventTime = this.computeDisplayEventTime(); // might be based off of range
            }

            displayEventEnd = view.opt('displayEventEnd');
            if (displayEventEnd == null) {
                displayEventEnd = this.computeDisplayEventEnd(); // might be based off of range
            }

            this.displayEventTime = displayEventTime;
            this.displayEventEnd = displayEventEnd;
        },

        // Converts a span (has unzoned start/end and any other grid-specific location information)
        // into an array of segments (pieces of events whose format is decided by the grid).
        spanToSegs: function (span) {
            // subclasses must implement
        },

        // Diffs the two dates, returning a duration, based on granularity of the grid
        // TODO: port isTimeScale into this system?
        diffDates: function (a, b) {
            if (this.largeUnit) {
                return diffByUnit(a, b, this.largeUnit);
            }
            else {
                return diffDayTime(a, b);
            }
        },

        /* Hit Area
        ------------------------------------------------------------------------------------------------------------------*/

        // Called before one or more queryHit calls might happen. Should prepare any cached coordinates for queryHit
        prepareHits: function () {
        },

        // Called when queryHit calls have subsided. Good place to clear any coordinate caches.
        releaseHits: function () {
        },

        // Given coordinates from the topleft of the document, return data about the date-related area underneath.
        // Can return an object with arbitrary properties (although top/right/left/bottom are encouraged).
        // Must have a `grid` property, a reference to this current grid. TODO: avoid this
        // The returned object will be processed by getHitSpan and getHitEl.
        queryHit: function (leftOffset, topOffset) {
        },

        // Given position-level information about a date-related area within the grid,
        // should return an object with at least a start/end date. Can provide other information as well.
        getHitSpan: function (hit) {
        },

        // Given position-level information about a date-related area within the grid,
        // should return a jQuery element that best represents it. passed to dayClick callback.
        getHitEl: function (hit) {
        },

        /* Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        // Sets the container element that the grid should render inside of.
        // Does other DOM-related initializations.
        setElement: function (el) {
            this.el = el;

            if (this.hasDayInteractions) {
                preventSelection(el);

                this.bindDayHandler('touchstart', this.dayTouchStart);
                this.bindDayHandler('mousedown', this.dayMousedown);
            }

            // attach event-element-related handlers. in Grid.events
            // same garbage collection note as above.
            this.bindSegHandlers();

            this.bindGlobalHandlers();
        },

        bindDayHandler: function (name, handler) {
            var _this = this;

            // attach a handler to the grid's root element.
            // jQuery will take care of unregistering them when removeElement gets called.
            this.el.on(name, function (ev) {
                if (
                    !$(ev.target).is(
                        _this.segSelector + ',' + // directly on an event element
                        _this.segSelector + ' *,' + // within an event element
                        '.fc-more,' + // a "more.." link
                        'a[data-goto]' // a clickable nav link
                    )
                ) {
                    return handler.call(_this, ev);
                }
            });
        },

        // Removes the grid's container element from the DOM. Undoes any other DOM-related attachments.
        // DOES NOT remove any content beforehand (doesn't clear events or call unrenderDates), unlike View
        removeElement: function () {
            this.unbindGlobalHandlers();
            this.clearDragListeners();

            this.el.remove();

            // NOTE: we don't null-out this.el for the same reasons we don't do it within View::removeElement
        },

        // Renders the basic structure of grid view before any content is rendered
        renderSkeleton: function () {
            // subclasses should implement
        },

        // Renders the grid's date-related content (like areas that represent days/times).
        // Assumes setRange has already been called and the skeleton has already been rendered.
        renderDates: function () {
            // subclasses should implement
        },

        // Unrenders the grid's date-related content
        unrenderDates: function () {
            // subclasses should implement
        },

        /* Handlers
        ------------------------------------------------------------------------------------------------------------------*/

        // Binds DOM handlers to elements that reside outside the grid, such as the document
        bindGlobalHandlers: function () {
            this.listenTo($(document), {
                dragstart: this.externalDragStart, // jqui
                sortstart: this.externalDragStart // jqui
            });
        },

        // Unbinds DOM handlers from elements that reside outside the grid
        unbindGlobalHandlers: function () {
            this.stopListeningTo($(document));
        },

        // Process a mousedown on an element that represents a day. For day clicking and selecting.
        dayMousedown: function (ev) {
            if (!this.isIgnoringMouse) {
                this.dayDragListener.startInteraction(ev, {
                    //distance: 5, // needs more work if we want dayClick to fire correctly
                });
            }
        },

        dayTouchStart: function (ev) {
            var view = this.view;
            var selectLongPressDelay = view.opt('selectLongPressDelay');

            // HACK to prevent a user's clickaway for unselecting a range or an event
            // from causing a dayClick.
            if (view.isSelected || view.selectedEvent) {
                this.tempIgnoreMouse();
            }

            if (selectLongPressDelay == null) {
                selectLongPressDelay = view.opt('longPressDelay'); // fallback
            }

            this.dayDragListener.startInteraction(ev, {
                delay: selectLongPressDelay
            });
        },

        // Creates a listener that tracks the user's drag across day elements.
        // For day clicking and selecting.
        buildDayDragListener: function () {
            var _this = this;
            var view = this.view;
            var isSelectable = view.opt('selectable');
            var dayClickHit; // null if invalid dayClick
            var selectionSpan; // null if invalid selection

            // this listener tracks a mousedown on a day element, and a subsequent drag.
            // if the drag ends on the same day, it is a 'dayClick'.
            // if 'selectable' is enabled, this listener also detects selections.
            var dragListener = new HitDragListener(this, {
                scroll: view.opt('dragScroll'),
                interactionStart: function () {
                    dayClickHit = dragListener.origHit; // for dayClick, where no dragging happens
                    selectionSpan = null;
                },
                dragStart: function () {
                    view.unselect(); // since we could be rendering a new selection, we want to clear any old one
                },
                hitOver: function (hit, isOrig, origHit) {
                    if (origHit) { // click needs to have started on a hit
                        // if user dragged to another cell at any point, it can no longer be a dayClick
                        if (!isOrig) {
                            dayClickHit = null;
                        }

                        if (isSelectable) {
                            selectionSpan = _this.computeSelection(
                                _this.getHitSpan(origHit),
                                _this.getHitSpan(hit)
                            );
                            if (selectionSpan) {
                                _this.renderSelection(selectionSpan);
                            }
                            else if (selectionSpan === false) {
                                disableCursor();
                            }
                        }
                    }
                },
                hitOut: function () { // called before mouse moves to a different hit OR moved out of all hits
                    dayClickHit = null;
                    selectionSpan = null;
                    _this.unrenderSelection();
                },
                hitDone: function () { // called after a hitOut OR before a dragEnd
                    enableCursor();
                },
                interactionEnd: function (ev, isCancelled) {
                    if (!isCancelled) {
                        if (
                            dayClickHit &&
                            !_this.isIgnoringMouse // see hack in dayTouchStart
                        ) {
                            view.triggerDayClick(
                                _this.getHitSpan(dayClickHit),
                                _this.getHitEl(dayClickHit),
                                ev
                            );
                        }
                        if (selectionSpan) {
                            // the selection will already have been rendered. just report it
                            view.reportSelection(selectionSpan, ev);
                        }
                    }
                }
            });

            return dragListener;
        },

        // Kills all in-progress dragging.
        // Useful for when public API methods that result in re-rendering are invoked during a drag.
        // Also useful for when touch devices misbehave and don't fire their touchend.
        clearDragListeners: function () {
            this.dayDragListener.endInteraction();

            if (this.segDragListener) {
                this.segDragListener.endInteraction(); // will clear this.segDragListener
            }
            if (this.segResizeListener) {
                this.segResizeListener.endInteraction(); // will clear this.segResizeListener
            }
            if (this.externalDragListener) {
                this.externalDragListener.endInteraction(); // will clear this.externalDragListener
            }
        },

        /* Event Helper
        ------------------------------------------------------------------------------------------------------------------*/
        // TODO: should probably move this to Grid.events, like we did event dragging / resizing

        // Renders a mock event at the given event location, which contains zoned start/end properties.
        // Returns all mock event elements.
        renderEventLocationHelper: function (eventLocation, sourceSeg) {
            var fakeEvent = this.fabricateHelperEvent(eventLocation, sourceSeg);

            return this.renderHelper(fakeEvent, sourceSeg); // do the actual rendering
        },

        // Builds a fake event given zoned event date properties and a segment is should be inspired from.
        // The range's end can be null, in which case the mock event that is rendered will have a null end time.
        // `sourceSeg` is the internal segment object involved in the drag. If null, something external is dragging.
        fabricateHelperEvent: function (eventLocation, sourceSeg) {
            var fakeEvent = sourceSeg ? createObject(sourceSeg.event) : {}; // mask the original event object if possible

            fakeEvent.start = eventLocation.start.clone();
            fakeEvent.end = eventLocation.end ? eventLocation.end.clone() : null;
            fakeEvent.allDay = null; // force it to be freshly computed by normalizeEventDates
            this.view.calendar.normalizeEventDates(fakeEvent);

            // this extra className will be useful for differentiating real events from mock events in CSS
            fakeEvent.className = (fakeEvent.className || []).concat('fc-helper');

            // if something external is being dragged in, don't render a resizer
            if (!sourceSeg) {
                fakeEvent.editable = false;
            }

            return fakeEvent;
        },

        // Renders a mock event. Given zoned event date properties.
        // Must return all mock event elements.
        renderHelper: function (eventLocation, sourceSeg) {
            // subclasses must implement
        },

        // Unrenders a mock event
        unrenderHelper: function () {
            // subclasses must implement
        },

        /* Selection
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of a selection. Will highlight by default but can be overridden by subclasses.
        // Given a span (unzoned start/end and other misc data)
        renderSelection: function (span) {
            this.renderHighlight(span);
        },

        // Unrenders any visual indications of a selection. Will unrender a highlight by default.
        unrenderSelection: function () {
            this.unrenderHighlight();
        },

        // Given the first and last date-spans of a selection, returns another date-span object.
        // Subclasses can override and provide additional data in the span object. Will be passed to renderSelection().
        // Will return false if the selection is invalid and this should be indicated to the user.
        // Will return null/undefined if a selection invalid but no error should be reported.
        computeSelection: function (span0, span1) {
            var span = this.computeSelectionSpan(span0, span1);

            if (span && !this.view.calendar.isSelectionSpanAllowed(span)) {
                return false;
            }

            return span;
        },

        // Given two spans, must return the combination of the two.
        // TODO: do this separation of concerns (combining VS validation) for event dnd/resize too.
        computeSelectionSpan: function (span0, span1) {
            var dates = [span0.start, span0.end, span1.start, span1.end];

            dates.sort(compareNumbers); // sorts chronologically. works with Moments

            return { start: dates[0].clone(), end: dates[3].clone() };
        },

        /* Highlight
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders an emphasis on the given date range. Given a span (unzoned start/end and other misc data)
        renderHighlight: function (span) {
            this.renderFill('highlight', this.spanToSegs(span));
        },

        // Unrenders the emphasis on a date range
        unrenderHighlight: function () {
            this.unrenderFill('highlight');
        },

        // Generates an array of classNames for rendering the highlight. Used by the fill system.
        highlightSegClasses: function () {
            return ['fc-highlight'];
        },

        /* Business Hours
        ------------------------------------------------------------------------------------------------------------------*/

        renderBusinessHours: function () {
        },

        unrenderBusinessHours: function () {
        },

        /* Now Indicator
        ------------------------------------------------------------------------------------------------------------------*/

        getNowIndicatorUnit: function () {
        },

        renderNowIndicator: function (date) {
        },

        unrenderNowIndicator: function () {
        },

        /* Fill System (highlight, background events, business hours)
        --------------------------------------------------------------------------------------------------------------------
        TODO: remove this system. like we did in TimeGrid
        */

        // Renders a set of rectangles over the given segments of time.
        // MUST RETURN a subset of segs, the segs that were actually rendered.
        // Responsible for populating this.elsByFill. TODO: better API for expressing this requirement
        renderFill: function (type, segs) {
            // subclasses must implement
        },

        // Unrenders a specific type of fill that is currently rendered on the grid
        unrenderFill: function (type) {
            var el = this.elsByFill[type];

            if (el) {
                el.remove();
                delete this.elsByFill[type];
            }
        },

        // Renders and assigns an `el` property for each fill segment. Generic enough to work with different types.
        // Only returns segments that successfully rendered.
        // To be harnessed by renderFill (implemented by subclasses).
        // Analagous to renderFgSegEls.
        renderFillSegEls: function (type, segs) {
            var _this = this;
            var segElMethod = this[type + 'SegEl'];
            var html = '';
            var renderedSegs = [];
            var i;

            if (segs.length) {
                // build a large concatenation of segment HTML
                for (i = 0; i < segs.length; i++) {
                    html += this.fillSegHtml(type, segs[i]);
                }

                // Grab individual elements from the combined HTML string. Use each as the default rendering.
                // Then, compute the 'el' for each segment.
                $(html).each(function (i, node) {
                    var seg = segs[i];
                    var el = $(node);

                    // allow custom filter methods per-type
                    if (segElMethod) {
                        el = segElMethod.call(_this, seg, el);
                    }

                    if (el) { // custom filters did not cancel the render
                        el = $(el); // allow custom filter to return raw DOM node

                        // correct element type? (would be bad if a non-TD were inserted into a table for example)
                        if (el.is(_this.fillSegTag)) {
                            seg.el = el;
                            renderedSegs.push(seg);
                        }
                    }
                });
            }

            return renderedSegs;
        },

        fillSegTag: 'div', // subclasses can override

        // Builds the HTML needed for one fill segment. Generic enough to work with different types.
        fillSegHtml: function (type, seg) {
            // custom hooks per-type
            var classesMethod = this[type + 'SegClasses'];
            var cssMethod = this[type + 'SegCss'];

            var classes = classesMethod ? classesMethod.call(this, seg) : [];
            var css = cssToStr(cssMethod ? cssMethod.call(this, seg) : {});

            return '<' + this.fillSegTag +
                (classes.length ? ' class="' + classes.join(' ') + '"' : '') +
                (css ? ' style="' + css + '"' : '') +
                ' />';
        },

        /* Generic rendering utilities for subclasses
        ------------------------------------------------------------------------------------------------------------------*/

        // Computes HTML classNames for a single-day element
        getDayClasses: function (date, noThemeHighlight) {
            var view = this.view;
            var today = view.calendar.getNow();
            var classes = ['fc-' + dayIDs[date.day()]];

            if (
                view.intervalDuration.as('months') == 1 &&
                date.month() != view.intervalStart.month()
            ) {
                classes.push('fc-other-month');
            }

            if (date.isSame(today, 'day')) {
                classes.push('fc-today');

                if (noThemeHighlight !== true) {
                    classes.push(view.highlightStateClass);
                }
            }
            else if (date < today) {
                classes.push('fc-past');
            }
            else {
                classes.push('fc-future');
            }

            return classes;
        }
    });

    ;;

    /* Event-rendering and event-interaction methods for the abstract Grid class
    ----------------------------------------------------------------------------------------------------------------------*/

    Grid.mixin({
        // self-config, overridable by subclasses
        segSelector: '.fc-event-container > *', // what constitutes an event element?

        mousedOverSeg: null, // the segment object the user's mouse is over. null if over nothing
        isDraggingSeg: false, // is a segment being dragged? boolean
        isResizingSeg: false, // is a segment being resized? boolean
        isDraggingExternal: false, // jqui-dragging an external element? boolean
        segs: null, // the *event* segments currently rendered in the grid. TODO: rename to `eventSegs`

        // Renders the given events onto the grid
        renderEvents: function (events) {
            var bgEvents = [];
            var fgEvents = [];
            var i;

            for (i = 0; i < events.length; i++) {
                (isBgEvent(events[i]) ? bgEvents : fgEvents).push(events[i]);
            }

            this.segs = [].concat( // record all segs
                this.renderBgEvents(bgEvents),
                this.renderFgEvents(fgEvents)
            );
        },

        renderBgEvents: function (events) {
            var segs = this.eventsToSegs(events);

            // renderBgSegs might return a subset of segs, segs that were actually rendered
            return this.renderBgSegs(segs) || segs;
        },

        renderFgEvents: function (events) {
            var segs = this.eventsToSegs(events);

            // renderFgSegs might return a subset of segs, segs that were actually rendered
            return this.renderFgSegs(segs) || segs;
        },

        // Unrenders all events currently rendered on the grid
        unrenderEvents: function () {
            this.handleSegMouseout(); // trigger an eventMouseout if user's mouse is over an event
            this.clearDragListeners();

            this.unrenderFgSegs();
            this.unrenderBgSegs();

            this.segs = null;
        },

        // Retrieves all rendered segment objects currently rendered on the grid
        getEventSegs: function () {
            return this.segs || [];
        },

        /* Foreground Segment Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders foreground event segments onto the grid. May return a subset of segs that were rendered.
        renderFgSegs: function (segs) {
            // subclasses must implement
        },

        // Unrenders all currently rendered foreground segments
        unrenderFgSegs: function () {
            // subclasses must implement
        },

        // Renders and assigns an `el` property for each foreground event segment.
        // Only returns segments that successfully rendered.
        // A utility that subclasses may use.
        renderFgSegEls: function (segs, disableResizing) {
            var view = this.view;
            var html = '';
            var renderedSegs = [];
            var i;

            if (segs.length) { // don't build an empty html string
                // build a large concatenation of event segment HTML
                for (i = 0; i < segs.length; i++) {
                    html += this.fgSegHtml(segs[i], disableResizing);
                }

                // Grab individual elements from the combined HTML string. Use each as the default rendering.
                // Then, compute the 'el' for each segment. An el might be null if the eventRender callback returned false.
                $(html).each(function (i, node) {
                    var seg = segs[i];
                    var el = view.resolveEventEl(seg.event, $(node));

                    if (el) {
                        el.data('fc-seg', seg); // used by handlers
                        seg.el = el;
                        renderedSegs.push(seg);
                    }
                });
            }

            return renderedSegs;
        },

        // Generates the HTML for the default rendering of a foreground event segment. Used by renderFgSegEls()
        fgSegHtml: function (seg, disableResizing) {
            // subclasses should implement
        },

        /* Background Segment Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders the given background event segments onto the grid.
        // Returns a subset of the segs that were actually rendered.
        renderBgSegs: function (segs) {
            return this.renderFill('bgEvent', segs);
        },

        // Unrenders all the currently rendered background event segments
        unrenderBgSegs: function () {
            this.unrenderFill('bgEvent');
        },

        // Renders a background event element, given the default rendering. Called by the fill system.
        bgEventSegEl: function (seg, el) {
            return this.view.resolveEventEl(seg.event, el); // will filter through eventRender
        },

        // Generates an array of classNames to be used for the default rendering of a background event.
        // Called by fillSegHtml.
        bgEventSegClasses: function (seg) {
            var event = seg.event;
            var source = event.source || {};

            return ['fc-bgevent'].concat(
                event.className,
                source.className || []
            );
        },

        // Generates a semicolon-separated CSS string to be used for the default rendering of a background event.
        // Called by fillSegHtml.
        bgEventSegCss: function (seg) {
            return {
                'background-color': this.getSegSkinCss(seg)['background-color']
            };
        },

        // Generates an array of classNames to be used for the rendering business hours overlay. Called by the fill system.
        // Called by fillSegHtml.
        businessHoursSegClasses: function (seg) {
            return ['fc-nonbusiness', 'fc-bgevent'];
        },

        /* Business Hours
        ------------------------------------------------------------------------------------------------------------------*/

        // Compute business hour segs for the grid's current date range.
        // Caller must ask if whole-day business hours are needed.
        // If no `businessHours` configuration value is specified, assumes the calendar default.
        buildBusinessHourSegs: function (wholeDay, businessHours) {
            return this.eventsToSegs(
                this.buildBusinessHourEvents(wholeDay, businessHours)
            );
        },

        // Compute business hour *events* for the grid's current date range.
        // Caller must ask if whole-day business hours are needed.
        // If no `businessHours` configuration value is specified, assumes the calendar default.
        buildBusinessHourEvents: function (wholeDay, businessHours) {
            var calendar = this.view.calendar;
            var events;

            if (businessHours == null) {
                // fallback
                // access from calendawr. don't access from view. doesn't update with dynamic options.
                businessHours = calendar.options.businessHours;
            }

            events = calendar.computeBusinessHourEvents(wholeDay, businessHours);

            // HACK. Eventually refactor business hours "events" system.
            // If no events are given, but businessHours is activated, this means the entire visible range should be
            // marked as *not* business-hours, via inverse-background rendering.
            if (!events.length && businessHours) {
                events = [
                    $.extend({}, BUSINESS_HOUR_EVENT_DEFAULTS, {
                        start: this.view.end, // guaranteed out-of-range
                        end: this.view.end,   // "
                        dow: null
                    })
                ];
            }

            return events;
        },

        /* Handlers
        ------------------------------------------------------------------------------------------------------------------*/

        // Attaches event-element-related handlers for *all* rendered event segments of the view.
        bindSegHandlers: function () {
            this.bindSegHandlersToEl(this.el);
        },

        // Attaches event-element-related handlers to an arbitrary container element. leverages bubbling.
        bindSegHandlersToEl: function (el) {
            this.bindSegHandlerToEl(el, 'touchstart', this.handleSegTouchStart);
            this.bindSegHandlerToEl(el, 'touchend', this.handleSegTouchEnd);
            this.bindSegHandlerToEl(el, 'mouseenter', this.handleSegMouseover);
            this.bindSegHandlerToEl(el, 'mouseleave', this.handleSegMouseout);
            this.bindSegHandlerToEl(el, 'mousedown', this.handleSegMousedown);
            this.bindSegHandlerToEl(el, 'click', this.handleSegClick);
        },

        // Executes a handler for any a user-interaction on a segment.
        // Handler gets called with (seg, ev), and with the `this` context of the Grid
        bindSegHandlerToEl: function (el, name, handler) {
            var _this = this;

            el.on(name, this.segSelector, function (ev) {
                var seg = $(this).data('fc-seg'); // grab segment data. put there by View::renderEvents

                // only call the handlers if there is not a drag/resize in progress
                if (seg && !_this.isDraggingSeg && !_this.isResizingSeg) {
                    return handler.call(_this, seg, ev); // context will be the Grid
                }
            });
        },

        handleSegClick: function (seg, ev) {
            var res = this.view.publiclyTrigger('eventClick', seg.el[0], seg.event, ev); // can return `false` to cancel
            if (res === false) {
                ev.preventDefault();
            }
        },

        // Updates internal state and triggers handlers for when an event element is moused over
        handleSegMouseover: function (seg, ev) {
            if (
                !this.isIgnoringMouse &&
                !this.mousedOverSeg
            ) {
                this.mousedOverSeg = seg;
                if (this.view.isEventResizable(seg.event)) {
                    seg.el.addClass('fc-allow-mouse-resize');
                }
                this.view.publiclyTrigger('eventMouseover', seg.el[0], seg.event, ev);
            }
        },

        // Updates internal state and triggers handlers for when an event element is moused out.
        // Can be given no arguments, in which case it will mouseout the segment that was previously moused over.
        handleSegMouseout: function (seg, ev) {
            ev = ev || {}; // if given no args, make a mock mouse event

            if (this.mousedOverSeg) {
                seg = seg || this.mousedOverSeg; // if given no args, use the currently moused-over segment
                this.mousedOverSeg = null;
                if (this.view.isEventResizable(seg.event)) {
                    seg.el.removeClass('fc-allow-mouse-resize');
                }
                this.view.publiclyTrigger('eventMouseout', seg.el[0], seg.event, ev);
            }
        },

        handleSegMousedown: function (seg, ev) {
            var isResizing = this.startSegResize(seg, ev, { distance: 5 });

            if (!isResizing && this.view.isEventDraggable(seg.event)) {
                this.buildSegDragListener(seg)
                    .startInteraction(ev, {
                        distance: 5
                    });
            }
        },

        handleSegTouchStart: function (seg, ev) {
            var view = this.view;
            var event = seg.event;
            var isSelected = view.isEventSelected(event);
            var isDraggable = view.isEventDraggable(event);
            var isResizable = view.isEventResizable(event);
            var isResizing = false;
            var dragListener;
            var eventLongPressDelay;

            if (isSelected && isResizable) {
                // only allow resizing of the event is selected
                isResizing = this.startSegResize(seg, ev);
            }

            if (!isResizing && (isDraggable || isResizable)) { // allowed to be selected?
                eventLongPressDelay = view.opt('eventLongPressDelay');
                if (eventLongPressDelay == null) {
                    eventLongPressDelay = view.opt('longPressDelay'); // fallback
                }

                dragListener = isDraggable ?
                    this.buildSegDragListener(seg) :
                    this.buildSegSelectListener(seg); // seg isn't draggable, but still needs to be selected

                dragListener.startInteraction(ev, { // won't start if already started
                    delay: isSelected ? 0 : eventLongPressDelay // do delay if not already selected
                });
            }

            // a long tap simulates a mouseover. ignore this bogus mouseover.
            this.tempIgnoreMouse();
        },

        handleSegTouchEnd: function (seg, ev) {
            // touchstart+touchend = click, which simulates a mouseover.
            // ignore this bogus mouseover.
            this.tempIgnoreMouse();
        },

        // returns boolean whether resizing actually started or not.
        // assumes the seg allows resizing.
        // `dragOptions` are optional.
        startSegResize: function (seg, ev, dragOptions) {
            if ($(ev.target).is('.fc-resizer')) {
                this.buildSegResizeListener(seg, $(ev.target).is('.fc-start-resizer'))
                    .startInteraction(ev, dragOptions);
                return true;
            }
            return false;
        },

        /* Event Dragging
        ------------------------------------------------------------------------------------------------------------------*/

        // Builds a listener that will track user-dragging on an event segment.
        // Generic enough to work with any type of Grid.
        // Has side effect of setting/unsetting `segDragListener`
        buildSegDragListener: function (seg) {
            var _this = this;
            var view = this.view;
            var calendar = view.calendar;
            var el = seg.el;
            var event = seg.event;
            var isDragging;
            var mouseFollower; // A clone of the original element that will move with the mouse
            var dropLocation; // zoned event date properties

            if (this.segDragListener) {
                return this.segDragListener;
            }

            // Tracks mouse movement over the *view's* coordinate map. Allows dragging and dropping between subcomponents
            // of the view.
            var dragListener = this.segDragListener = new HitDragListener(view, {
                scroll: view.opt('dragScroll'),
                subjectEl: el,
                subjectCenter: true,
                interactionStart: function (ev) {
                    seg.component = _this; // for renderDrag
                    isDragging = false;
                    mouseFollower = new MouseFollower(seg.el, {
                        additionalClass: 'fc-dragging',
                        parentEl: view.el,
                        opacity: dragListener.isTouch ? null : view.opt('dragOpacity'),
                        revertDuration: view.opt('dragRevertDuration'),
                        zIndex: 2 // one above the .fc-view
                    });
                    mouseFollower.hide(); // don't show until we know this is a real drag
                    mouseFollower.start(ev);
                },
                dragStart: function (ev) {
                    if (dragListener.isTouch && !view.isEventSelected(event)) {
                        // if not previously selected, will fire after a delay. then, select the event
                        view.selectEvent(event);
                    }
                    isDragging = true;
                    _this.handleSegMouseout(seg, ev); // ensure a mouseout on the manipulated event has been reported
                    _this.segDragStart(seg, ev);
                    view.hideEvent(event); // hide all event segments. our mouseFollower will take over
                },
                hitOver: function (hit, isOrig, origHit) {
                    var dragHelperEls;

                    // starting hit could be forced (DayGrid.limit)
                    if (seg.hit) {
                        origHit = seg.hit;
                    }

                    // since we are querying the parent view, might not belong to this grid
                    dropLocation = _this.computeEventDrop(
                        origHit.component.getHitSpan(origHit),
                        hit.component.getHitSpan(hit),
                        event
                    );

                    if (dropLocation && !calendar.isEventSpanAllowed(_this.eventToSpan(dropLocation), event)) {
                        disableCursor();
                        dropLocation = null;
                    }

                    // if a valid drop location, have the subclass render a visual indication
                    if (dropLocation && (dragHelperEls = view.renderDrag(dropLocation, seg))) {
                        dragHelperEls.addClass('fc-dragging');
                        if (!dragListener.isTouch) {
                            _this.applyDragOpacity(dragHelperEls);
                        }

                        mouseFollower.hide(); // if the subclass is already using a mock event "helper", hide our own
                    }
                    else {
                        mouseFollower.show(); // otherwise, have the helper follow the mouse (no snapping)
                    }

                    if (isOrig) {
                        dropLocation = null; // needs to have moved hits to be a valid drop
                    }
                },
                hitOut: function () { // called before mouse moves to a different hit OR moved out of all hits
                    view.unrenderDrag(); // unrender whatever was done in renderDrag
                    mouseFollower.show(); // show in case we are moving out of all hits
                    dropLocation = null;
                },
                hitDone: function () { // Called after a hitOut OR before a dragEnd
                    enableCursor();
                },
                interactionEnd: function (ev) {
                    delete seg.component; // prevent side effects

                    // do revert animation if hasn't changed. calls a callback when finished (whether animation or not)
                    mouseFollower.stop(!dropLocation, function () {
                        if (isDragging) {
                            view.unrenderDrag();
                            _this.segDragStop(seg, ev);
                        }

                        if (dropLocation) {
                            // no need to re-show original, will rerender all anyways. esp important if eventRenderWait
                            view.reportEventDrop(event, dropLocation, _this.largeUnit, el, ev);
                        }
                        else {
                            view.showEvent(event);
                        }
                    });
                    _this.segDragListener = null;
                }
            });

            return dragListener;
        },

        // seg isn't draggable, but let's use a generic DragListener
        // simply for the delay, so it can be selected.
        // Has side effect of setting/unsetting `segDragListener`
        buildSegSelectListener: function (seg) {
            var _this = this;
            var view = this.view;
            var event = seg.event;

            if (this.segDragListener) {
                return this.segDragListener;
            }

            var dragListener = this.segDragListener = new DragListener({
                dragStart: function (ev) {
                    if (dragListener.isTouch && !view.isEventSelected(event)) {
                        // if not previously selected, will fire after a delay. then, select the event
                        view.selectEvent(event);
                    }
                },
                interactionEnd: function (ev) {
                    _this.segDragListener = null;
                }
            });

            return dragListener;
        },

        // Called before event segment dragging starts
        segDragStart: function (seg, ev) {
            this.isDraggingSeg = true;
            this.view.publiclyTrigger('eventDragStart', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },

        // Called after event segment dragging stops
        segDragStop: function (seg, ev) {
            this.isDraggingSeg = false;
            this.view.publiclyTrigger('eventDragStop', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },

        // Given the spans an event drag began, and the span event was dropped, calculates the new zoned start/end/allDay
        // values for the event. Subclasses may override and set additional properties to be used by renderDrag.
        // A falsy returned value indicates an invalid drop.
        // DOES NOT consider overlap/constraint.
        computeEventDrop: function (startSpan, endSpan, event) {
            var calendar = this.view.calendar;
            var dragStart = startSpan.start;
            var dragEnd = endSpan.start;
            var delta;
            var dropLocation; // zoned event date properties

            if (dragStart.hasTime() === dragEnd.hasTime()) {
                delta = this.diffDates(dragEnd, dragStart);

                // if an all-day event was in a timed area and it was dragged to a different time,
                // guarantee an end and adjust start/end to have times
                if (event.allDay && durationHasTime(delta)) {
                    dropLocation = {
                        start: event.start.clone(),
                        end: calendar.getEventEnd(event), // will be an ambig day
                        allDay: false // for normalizeEventTimes
                    };
                    calendar.normalizeEventTimes(dropLocation);
                }
                // othewise, work off existing values
                else {
                    dropLocation = pluckEventDateProps(event);
                }

                dropLocation.start.add(delta);
                if (dropLocation.end) {
                    dropLocation.end.add(delta);
                }
            }
            else {
                // if switching from day <-> timed, start should be reset to the dropped date, and the end cleared
                dropLocation = {
                    start: dragEnd.clone(),
                    end: null, // end should be cleared
                    allDay: !dragEnd.hasTime()
                };
            }

            return dropLocation;
        },

        // Utility for apply dragOpacity to a jQuery set
        applyDragOpacity: function (els) {
            var opacity = this.view.opt('dragOpacity');

            if (opacity != null) {
                els.css('opacity', opacity);
            }
        },

        /* External Element Dragging
        ------------------------------------------------------------------------------------------------------------------*/

        // Called when a jQuery UI drag is initiated anywhere in the DOM
        externalDragStart: function (ev, ui) {
            var view = this.view;
            var el;
            var accept;

            if (view.opt('droppable')) { // only listen if this setting is on
                el = $((ui ? ui.item : null) || ev.target);

                // Test that the dragged element passes the dropAccept selector or filter function.
                // FYI, the default is "*" (matches all)
                accept = view.opt('dropAccept');
                if ($.isFunction(accept) ? accept.call(el[0], el) : el.is(accept)) {
                    if (!this.isDraggingExternal) { // prevent double-listening if fired twice
                        this.listenToExternalDrag(el, ev, ui);
                    }
                }
            }
        },

        // Called when a jQuery UI drag starts and it needs to be monitored for dropping
        listenToExternalDrag: function (el, ev, ui) {
            var _this = this;
            var calendar = this.view.calendar;
            var meta = getDraggedElMeta(el); // extra data about event drop, including possible event to create
            var dropLocation; // a null value signals an unsuccessful drag

            // listener that tracks mouse movement over date-associated pixel regions
            var dragListener = _this.externalDragListener = new HitDragListener(this, {
                interactionStart: function () {
                    _this.isDraggingExternal = true;
                },
                hitOver: function (hit) {
                    dropLocation = _this.computeExternalDrop(
                        hit.component.getHitSpan(hit), // since we are querying the parent view, might not belong to this grid
                        meta
                    );

                    if ( // invalid hit?
                        dropLocation &&
                        !calendar.isExternalSpanAllowed(_this.eventToSpan(dropLocation), dropLocation, meta.eventProps)
                    ) {
                        disableCursor();
                        dropLocation = null;
                    }

                    if (dropLocation) {
                        _this.renderDrag(dropLocation); // called without a seg parameter
                    }
                },
                hitOut: function () {
                    dropLocation = null; // signal unsuccessful
                },
                hitDone: function () { // Called after a hitOut OR before a dragEnd
                    enableCursor();
                    _this.unrenderDrag();
                },
                interactionEnd: function (ev) {
                    if (dropLocation) { // element was dropped on a valid hit
                        _this.view.reportExternalDrop(meta, dropLocation, el, ev, ui);
                    }
                    _this.isDraggingExternal = false;
                    _this.externalDragListener = null;
                }
            });

            dragListener.startDrag(ev); // start listening immediately
        },

        // Given a hit to be dropped upon, and misc data associated with the jqui drag (guaranteed to be a plain object),
        // returns the zoned start/end dates for the event that would result from the hypothetical drop. end might be null.
        // Returning a null value signals an invalid drop hit.
        // DOES NOT consider overlap/constraint.
        computeExternalDrop: function (span, meta) {
            var calendar = this.view.calendar;
            var dropLocation = {
                start: calendar.applyTimezone(span.start), // simulate a zoned event start date
                end: null
            };

            // if dropped on an all-day span, and element's metadata specified a time, set it
            if (meta.startTime && !dropLocation.start.hasTime()) {
                dropLocation.start.time(meta.startTime);
            }

            if (meta.duration) {
                dropLocation.end = dropLocation.start.clone().add(meta.duration);
            }

            return dropLocation;
        },

        /* Drag Rendering (for both events and an external elements)
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of an event or external element being dragged.
        // `dropLocation` contains hypothetical start/end/allDay values the event would have if dropped. end can be null.
        // `seg` is the internal segment object that is being dragged. If dragging an external element, `seg` is null.
        // A truthy returned value indicates this method has rendered a helper element.
        // Must return elements used for any mock events.
        renderDrag: function (dropLocation, seg) {
            // subclasses must implement
        },

        // Unrenders a visual indication of an event or external element being dragged
        unrenderDrag: function () {
            // subclasses must implement
        },

        /* Resizing
        ------------------------------------------------------------------------------------------------------------------*/

        // Creates a listener that tracks the user as they resize an event segment.
        // Generic enough to work with any type of Grid.
        buildSegResizeListener: function (seg, isStart) {
            var _this = this;
            var view = this.view;
            var calendar = view.calendar;
            var el = seg.el;
            var event = seg.event;
            var eventEnd = calendar.getEventEnd(event);
            var isDragging;
            var resizeLocation; // zoned event date properties. falsy if invalid resize

            // Tracks mouse movement over the *grid's* coordinate map
            var dragListener = this.segResizeListener = new HitDragListener(this, {
                scroll: view.opt('dragScroll'),
                subjectEl: el,
                interactionStart: function () {
                    isDragging = false;
                },
                dragStart: function (ev) {
                    isDragging = true;
                    _this.handleSegMouseout(seg, ev); // ensure a mouseout on the manipulated event has been reported
                    _this.segResizeStart(seg, ev);
                },
                hitOver: function (hit, isOrig, origHit) {
                    var origHitSpan = _this.getHitSpan(origHit);
                    var hitSpan = _this.getHitSpan(hit);

                    resizeLocation = isStart ?
                        _this.computeEventStartResize(origHitSpan, hitSpan, event) :
                        _this.computeEventEndResize(origHitSpan, hitSpan, event);

                    if (resizeLocation) {
                        if (!calendar.isEventSpanAllowed(_this.eventToSpan(resizeLocation), event)) {
                            disableCursor();
                            resizeLocation = null;
                        }
                        // no change? (FYI, event dates might have zones)
                        else if (
                            resizeLocation.start.isSame(event.start.clone().stripZone()) &&
                            resizeLocation.end.isSame(eventEnd.clone().stripZone())
                        ) {
                            resizeLocation = null;
                        }
                    }

                    if (resizeLocation) {
                        view.hideEvent(event);
                        _this.renderEventResize(resizeLocation, seg);
                    }
                },
                hitOut: function () { // called before mouse moves to a different hit OR moved out of all hits
                    resizeLocation = null;
                    view.showEvent(event); // for when out-of-bounds. show original
                },
                hitDone: function () { // resets the rendering to show the original event
                    _this.unrenderEventResize();
                    enableCursor();
                },
                interactionEnd: function (ev) {
                    if (isDragging) {
                        _this.segResizeStop(seg, ev);
                    }

                    if (resizeLocation) { // valid date to resize to?
                        // no need to re-show original, will rerender all anyways. esp important if eventRenderWait
                        view.reportEventResize(event, resizeLocation, _this.largeUnit, el, ev);
                    }
                    else {
                        view.showEvent(event);
                    }
                    _this.segResizeListener = null;
                }
            });

            return dragListener;
        },

        // Called before event segment resizing starts
        segResizeStart: function (seg, ev) {
            this.isResizingSeg = true;
            this.view.publiclyTrigger('eventResizeStart', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },

        // Called after event segment resizing stops
        segResizeStop: function (seg, ev) {
            this.isResizingSeg = false;
            this.view.publiclyTrigger('eventResizeStop', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },

        // Returns new date-information for an event segment being resized from its start
        computeEventStartResize: function (startSpan, endSpan, event) {
            return this.computeEventResize('start', startSpan, endSpan, event);
        },

        // Returns new date-information for an event segment being resized from its end
        computeEventEndResize: function (startSpan, endSpan, event) {
            return this.computeEventResize('end', startSpan, endSpan, event);
        },

        // Returns new zoned date information for an event segment being resized from its start OR end
        // `type` is either 'start' or 'end'.
        // DOES NOT consider overlap/constraint.
        computeEventResize: function (type, startSpan, endSpan, event) {
            var calendar = this.view.calendar;
            var delta = this.diffDates(endSpan[type], startSpan[type]);
            var resizeLocation; // zoned event date properties
            var defaultDuration;

            // build original values to work from, guaranteeing a start and end
            resizeLocation = {
                start: event.start.clone(),
                end: calendar.getEventEnd(event),
                allDay: event.allDay
            };

            // if an all-day event was in a timed area and was resized to a time, adjust start/end to have times
            if (resizeLocation.allDay && durationHasTime(delta)) {
                resizeLocation.allDay = false;
                calendar.normalizeEventTimes(resizeLocation);
            }

            resizeLocation[type].add(delta); // apply delta to start or end

            // if the event was compressed too small, find a new reasonable duration for it
            if (!resizeLocation.start.isBefore(resizeLocation.end)) {
                defaultDuration =
                    this.minResizeDuration || // TODO: hack
                    (event.allDay ?
                        calendar.defaultAllDayEventDuration :
                        calendar.defaultTimedEventDuration);

                if (type == 'start') { // resizing the start?
                    resizeLocation.start = resizeLocation.end.clone().subtract(defaultDuration);
                }
                else { // resizing the end?
                    resizeLocation.end = resizeLocation.start.clone().add(defaultDuration);
                }
            }

            return resizeLocation;
        },

        // Renders a visual indication of an event being resized.
        // `range` has the updated dates of the event. `seg` is the original segment object involved in the drag.
        // Must return elements used for any mock events.
        renderEventResize: function (range, seg) {
            // subclasses must implement
        },

        // Unrenders a visual indication of an event being resized.
        unrenderEventResize: function () {
            // subclasses must implement
        },

        /* Rendering Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Compute the text that should be displayed on an event's element.
        // `range` can be the Event object itself, or something range-like, with at least a `start`.
        // If event times are disabled, or the event has no time, will return a blank string.
        // If not specified, formatStr will default to the eventTimeFormat setting,
        // and displayEnd will default to the displayEventEnd setting.
        getEventTimeText: function (range, formatStr, displayEnd) {
            if (formatStr == null) {
                formatStr = this.eventTimeFormat;
            }

            if (displayEnd == null) {
                displayEnd = this.displayEventEnd;
            }

            if (this.displayEventTime && range.start.hasTime()) {
                if (displayEnd && range.end) {
                    return this.view.formatRange(range, formatStr);
                }
                else {
                    return range.start.format(formatStr);
                }
            }

            return '';
        },

        // Generic utility for generating the HTML classNames for an event segment's element
        getSegClasses: function (seg, isDraggable, isResizable) {
            var view = this.view;
            var classes = [
                'fc-event',
                seg.isStart ? 'fc-start' : 'fc-not-start',
                seg.isEnd ? 'fc-end' : 'fc-not-end'
            ].concat(this.getSegCustomClasses(seg));

            if (isDraggable) {
                classes.push('fc-draggable');
            }
            if (isResizable) {
                classes.push('fc-resizable');
            }

            // event is currently selected? attach a className.
            if (view.isEventSelected(seg.event)) {
                classes.push('fc-selected');
            }

            return classes;
        },

        // List of classes that were defined by the caller of the API in some way
        getSegCustomClasses: function (seg) {
            var event = seg.event;

            return [].concat(
                event.className, // guaranteed to be an array
                event.source ? event.source.className : []
            );
        },

        // Utility for generating event skin-related CSS properties
        getSegSkinCss: function (seg) {
            return {
                'background-color': this.getSegBackgroundColor(seg),
                'border-color': this.getSegBorderColor(seg),
                color: this.getSegTextColor(seg)
            };
        },

        // Queries for caller-specified color, then falls back to default
        getSegBackgroundColor: function (seg) {
            return seg.event.backgroundColor ||
                seg.event.color ||
                this.getSegDefaultBackgroundColor(seg);
        },

        getSegDefaultBackgroundColor: function (seg) {
            var source = seg.event.source || {};

            return source.backgroundColor ||
                source.color ||
                this.view.opt('eventBackgroundColor') ||
                this.view.opt('eventColor');
        },

        // Queries for caller-specified color, then falls back to default
        getSegBorderColor: function (seg) {
            return seg.event.borderColor ||
                seg.event.color ||
                this.getSegDefaultBorderColor(seg);
        },

        getSegDefaultBorderColor: function (seg) {
            var source = seg.event.source || {};

            return source.borderColor ||
                source.color ||
                this.view.opt('eventBorderColor') ||
                this.view.opt('eventColor');
        },

        // Queries for caller-specified color, then falls back to default
        getSegTextColor: function (seg) {
            return seg.event.textColor ||
                this.getSegDefaultTextColor(seg);
        },

        getSegDefaultTextColor: function (seg) {
            var source = seg.event.source || {};

            return source.textColor ||
                this.view.opt('eventTextColor');
        },

        /* Converting events -> eventRange -> eventSpan -> eventSegs
        ------------------------------------------------------------------------------------------------------------------*/

        // Generates an array of segments for the given single event
        // Can accept an event "location" as well (which only has start/end and no allDay)
        eventToSegs: function (event) {
            return this.eventsToSegs([event]);
        },

        eventToSpan: function (event) {
            return this.eventToSpans(event)[0];
        },

        // Generates spans (always unzoned) for the given event.
        // Does not do any inverting for inverse-background events.
        // Can accept an event "location" as well (which only has start/end and no allDay)
        eventToSpans: function (event) {
            var range = this.eventToRange(event);
            return this.eventRangeToSpans(range, event);
        },

        // Converts an array of event objects into an array of event segment objects.
        // A custom `segSliceFunc` may be given for arbitrarily slicing up events.
        // Doesn't guarantee an order for the resulting array.
        eventsToSegs: function (allEvents, segSliceFunc) {
            var _this = this;
            var eventsById = groupEventsById(allEvents);
            var segs = [];

            $.each(eventsById, function (id, events) {
                var ranges = [];
                var i;

                for (i = 0; i < events.length; i++) {
                    ranges.push(_this.eventToRange(events[i]));
                }

                // inverse-background events (utilize only the first event in calculations)
                if (isInverseBgEvent(events[0])) {
                    ranges = _this.invertRanges(ranges);

                    for (i = 0; i < ranges.length; i++) {
                        segs.push.apply(segs, // append to
                            _this.eventRangeToSegs(ranges[i], events[0], segSliceFunc));
                    }
                }
                // normal event ranges
                else {
                    for (i = 0; i < ranges.length; i++) {
                        segs.push.apply(segs, // append to
                            _this.eventRangeToSegs(ranges[i], events[i], segSliceFunc));
                    }
                }
            });

            return segs;
        },

        // Generates the unzoned start/end dates an event appears to occupy
        // Can accept an event "location" as well (which only has start/end and no allDay)
        eventToRange: function (event) {
            var calendar = this.view.calendar;
            var start = event.start.clone().stripZone();
            var end = (
                event.end ?
                    event.end.clone() :
                    // derive the end from the start and allDay. compute allDay if necessary
                    calendar.getDefaultEventEnd(
                        event.allDay != null ?
                            event.allDay :
                            !event.start.hasTime(),
                        event.start
                    )
            ).stripZone();

            // hack: dynamic locale change forgets to upate stored event localed
            calendar.localizeMoment(start);
            calendar.localizeMoment(end);

            return { start: start, end: end };
        },

        // Given an event's range (unzoned start/end), and the event itself,
        // slice into segments (using the segSliceFunc function if specified)
        eventRangeToSegs: function (range, event, segSliceFunc) {
            var spans = this.eventRangeToSpans(range, event);
            var segs = [];
            var i;

            for (i = 0; i < spans.length; i++) {
                segs.push.apply(segs, // append to
                    this.eventSpanToSegs(spans[i], event, segSliceFunc));
            }

            return segs;
        },

        // Given an event's unzoned date range, return an array of "span" objects.
        // Subclasses can override.
        eventRangeToSpans: function (range, event) {
            return [$.extend({}, range)]; // copy into a single-item array
        },

        // Given an event's span (unzoned start/end and other misc data), and the event itself,
        // slices into segments and attaches event-derived properties to them.
        eventSpanToSegs: function (span, event, segSliceFunc) {
            var segs = segSliceFunc ? segSliceFunc(span) : this.spanToSegs(span);
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                seg.event = event;
                seg.eventStartMS = +span.start; // TODO: not the best name after making spans unzoned
                seg.eventDurationMS = span.end - span.start;
            }

            return segs;
        },

        // Produces a new array of range objects that will cover all the time NOT covered by the given ranges.
        // SIDE EFFECT: will mutate the given array and will use its date references.
        invertRanges: function (ranges) {
            var view = this.view;
            var viewStart = view.start.clone(); // need a copy
            var viewEnd = view.end.clone(); // need a copy
            var inverseRanges = [];
            var start = viewStart; // the end of the previous range. the start of the new range
            var i, range;

            // ranges need to be in order. required for our date-walking algorithm
            ranges.sort(compareRanges);

            for (i = 0; i < ranges.length; i++) {
                range = ranges[i];

                // add the span of time before the event (if there is any)
                if (range.start > start) { // compare millisecond time (skip any ambig logic)
                    inverseRanges.push({
                        start: start,
                        end: range.start
                    });
                }

                start = range.end;
            }

            // add the span of time after the last event (if there is any)
            if (start < viewEnd) { // compare millisecond time (skip any ambig logic)
                inverseRanges.push({
                    start: start,
                    end: viewEnd
                });
            }

            return inverseRanges;
        },

        sortEventSegs: function (segs) {
            segs.sort(proxy(this, 'compareEventSegs'));
        },

        // A cmp function for determining which segments should take visual priority
        compareEventSegs: function (seg1, seg2) {
            return seg1.eventStartMS - seg2.eventStartMS || // earlier events go first
                seg2.eventDurationMS - seg1.eventDurationMS || // tie? longer events go first
                seg2.event.allDay - seg1.event.allDay || // tie? put all-day events first (booleans cast to 0/1)
                compareByFieldSpecs(seg1.event, seg2.event, this.view.eventOrderSpecs);
        }
    });

    /* Utilities
    ----------------------------------------------------------------------------------------------------------------------*/

    function pluckEventDateProps(event) {
        return {
            start: event.start.clone(),
            end: event.end ? event.end.clone() : null,
            allDay: event.allDay // keep it the same
        };
    }
    FC.pluckEventDateProps = pluckEventDateProps;

    function isBgEvent(event) { // returns true if background OR inverse-background
        var rendering = getEventRendering(event);
        return rendering === 'background' || rendering === 'inverse-background';
    }
    FC.isBgEvent = isBgEvent; // export

    function isInverseBgEvent(event) {
        return getEventRendering(event) === 'inverse-background';
    }

    function getEventRendering(event) {
        return firstDefined((event.source || {}).rendering, event.rendering);
    }

    function groupEventsById(events) {
        var eventsById = {};
        var i, event;

        for (i = 0; i < events.length; i++) {
            event = events[i];
            (eventsById[event._id] || (eventsById[event._id] = [])).push(event);
        }

        return eventsById;
    }

    // A cmp function for determining which non-inverted "ranges" (see above) happen earlier
    function compareRanges(range1, range2) {
        return range1.start - range2.start; // earlier ranges go first
    }

    /* External-Dragging-Element Data
    ----------------------------------------------------------------------------------------------------------------------*/

    // Require all HTML5 data-* attributes used by FullCalendar to have this prefix.
    // A value of '' will query attributes like data-event. A value of 'fc' will query attributes like data-fc-event.
    FC.dataAttrPrefix = '';

    // Given a jQuery element that might represent a dragged FullCalendar event, returns an intermediate data structure
    // to be used for Event Object creation.
    // A defined `.eventProps`, even when empty, indicates that an event should be created.
    function getDraggedElMeta(el) {
        var prefix = FC.dataAttrPrefix;
        var eventProps; // properties for creating the event, not related to date/time
        var startTime; // a Duration
        var duration;
        var stick;

        if (prefix) { prefix += '-'; }
        eventProps = el.data(prefix + 'event') || null;

        if (eventProps) {
            if (typeof eventProps === 'object') {
                eventProps = $.extend({}, eventProps); // make a copy
            }
            else { // something like 1 or true. still signal event creation
                eventProps = {};
            }

            // pluck special-cased date/time properties
            startTime = eventProps.start;
            if (startTime == null) { startTime = eventProps.time; } // accept 'time' as well
            duration = eventProps.duration;
            stick = eventProps.stick;
            delete eventProps.start;
            delete eventProps.time;
            delete eventProps.duration;
            delete eventProps.stick;
        }

        // fallback to standalone attribute values for each of the date/time properties
        if (startTime == null) { startTime = el.data(prefix + 'start'); }
        if (startTime == null) { startTime = el.data(prefix + 'time'); } // accept 'time' as well
        if (duration == null) { duration = el.data(prefix + 'duration'); }
        if (stick == null) { stick = el.data(prefix + 'stick'); }

        // massage into correct data types
        startTime = startTime != null ? moment.duration(startTime) : null;
        duration = duration != null ? moment.duration(duration) : null;
        stick = Boolean(stick);

        return { eventProps: eventProps, startTime: startTime, duration: duration, stick: stick };
    }

    ;;

    /*
    A set of rendering and date-related methods for a visual component comprised of one or more rows of day columns.
    Prerequisite: the object being mixed into needs to be a *Grid*
    */
    var DayTableMixin = FC.DayTableMixin = {
        breakOnWeeks: false, // should create a new row for each week?
        dayDates: null, // whole-day dates for each column. left to right
        dayIndices: null, // for each day from start, the offset
        daysPerRow: null,
        rowCnt: null,
        colCnt: null,
        colHeadFormat: null,

        // Populates internal variables used for date calculation and rendering
        updateDayTable: function () {
            var view = this.view;
            var date = this.start.clone();
            var dayIndex = -1;
            var dayIndices = [];
            var dayDates = [];
            var daysPerRow;
            var firstDay;
            var rowCnt;

            while (date.isBefore(this.end)) { // loop each day from start to end
                if (view.isHiddenDay(date)) {
                    dayIndices.push(dayIndex + 0.5); // mark that it's between indices
                }
                else {
                    dayIndex++;
                    dayIndices.push(dayIndex);
                    dayDates.push(date.clone());
                }
                date.add(1, 'days');
            }

            if (this.breakOnWeeks) {
                // count columns until the day-of-week repeats
                firstDay = dayDates[0].day();
                for (daysPerRow = 1; daysPerRow < dayDates.length; daysPerRow++) {
                    if (dayDates[daysPerRow].day() == firstDay) {
                        break;
                    }
                }
                rowCnt = Math.ceil(dayDates.length / daysPerRow);
            }
            else {
                rowCnt = 1;
                daysPerRow = dayDates.length;
            }

            this.dayDates = dayDates;
            this.dayIndices = dayIndices;
            this.daysPerRow = daysPerRow;
            this.rowCnt = rowCnt;

            this.updateDayTableCols();
        },

        // Computes and assigned the colCnt property and updates any options that may be computed from it
        updateDayTableCols: function () {
            this.colCnt = this.computeColCnt();
            this.colHeadFormat = this.view.opt('columnFormat') || this.computeColHeadFormat();
        },

        // Determines how many columns there should be in the table
        computeColCnt: function () {
            return this.daysPerRow;
        },

        // Computes the ambiguously-timed moment for the given cell
        getCellDate: function (row, col) {
            return this.dayDates[
                this.getCellDayIndex(row, col)
            ].clone();
        },

        // Computes the ambiguously-timed date range for the given cell
        getCellRange: function (row, col) {
            var start = this.getCellDate(row, col);
            var end = start.clone().add(1, 'days');

            return { start: start, end: end };
        },

        // Returns the number of day cells, chronologically, from the first of the grid (0-based)
        getCellDayIndex: function (row, col) {
            return row * this.daysPerRow + this.getColDayIndex(col);
        },

        // Returns the numner of day cells, chronologically, from the first cell in *any given row*
        getColDayIndex: function (col) {
            if (this.isRTL) {
                return this.colCnt - 1 - col;
            }
            else {
                return col;
            }
        },

        // Given a date, returns its chronolocial cell-index from the first cell of the grid.
        // If the date lies between cells (because of hiddenDays), returns a floating-point value between offsets.
        // If before the first offset, returns a negative number.
        // If after the last offset, returns an offset past the last cell offset.
        // Only works for *start* dates of cells. Will not work for exclusive end dates for cells.
        getDateDayIndex: function (date) {
            var dayIndices = this.dayIndices;
            var dayOffset = date.diff(this.start, 'days');

            if (dayOffset < 0) {
                return dayIndices[0] - 1;
            }
            else if (dayOffset >= dayIndices.length) {
                return dayIndices[dayIndices.length - 1] + 1;
            }
            else {
                return dayIndices[dayOffset];
            }
        },

        /* Options
        ------------------------------------------------------------------------------------------------------------------*/

        // Computes a default column header formatting string if `colFormat` is not explicitly defined
        computeColHeadFormat: function () {
            // if more than one week row, or if there are a lot of columns with not much space,
            // put just the day numbers will be in each cell
            if (this.rowCnt > 1 || this.colCnt > 10) {
                return 'ddd'; // "Sat"
            }
            // multiple days, so full single date string WON'T be in title text
            else if (this.colCnt > 1) {
                return this.view.opt('dayOfMonthFormat'); // "Sat 12/10"
            }
            // single day, so full single date string will probably be in title text
            else {
                return 'dddd'; // "Saturday"
            }
        },

        /* Slicing
        ------------------------------------------------------------------------------------------------------------------*/

        // Slices up a date range into a segment for every week-row it intersects with
        sliceRangeByRow: function (range) {
            var daysPerRow = this.daysPerRow;
            var normalRange = this.view.computeDayRange(range); // make whole-day range, considering nextDayThreshold
            var rangeFirst = this.getDateDayIndex(normalRange.start); // inclusive first index
            var rangeLast = this.getDateDayIndex(normalRange.end.clone().subtract(1, 'days')); // inclusive last index
            var segs = [];
            var row;
            var rowFirst, rowLast; // inclusive day-index range for current row
            var segFirst, segLast; // inclusive day-index range for segment

            for (row = 0; row < this.rowCnt; row++) {
                rowFirst = row * daysPerRow;
                rowLast = rowFirst + daysPerRow - 1;

                // intersect segment's offset range with the row's
                segFirst = Math.max(rangeFirst, rowFirst);
                segLast = Math.min(rangeLast, rowLast);

                // deal with in-between indices
                segFirst = Math.ceil(segFirst); // in-between starts round to next cell
                segLast = Math.floor(segLast); // in-between ends round to prev cell

                if (segFirst <= segLast) { // was there any intersection with the current row?
                    segs.push({
                        row: row,

                        // normalize to start of row
                        firstRowDayIndex: segFirst - rowFirst,
                        lastRowDayIndex: segLast - rowFirst,

                        // must be matching integers to be the segment's start/end
                        isStart: segFirst === rangeFirst,
                        isEnd: segLast === rangeLast
                    });
                }
            }

            return segs;
        },

        // Slices up a date range into a segment for every day-cell it intersects with.
        // TODO: make more DRY with sliceRangeByRow somehow.
        sliceRangeByDay: function (range) {
            var daysPerRow = this.daysPerRow;
            var normalRange = this.view.computeDayRange(range); // make whole-day range, considering nextDayThreshold
            var rangeFirst = this.getDateDayIndex(normalRange.start); // inclusive first index
            var rangeLast = this.getDateDayIndex(normalRange.end.clone().subtract(1, 'days')); // inclusive last index
            var segs = [];
            var row;
            var rowFirst, rowLast; // inclusive day-index range for current row
            var i;
            var segFirst, segLast; // inclusive day-index range for segment

            for (row = 0; row < this.rowCnt; row++) {
                rowFirst = row * daysPerRow;
                rowLast = rowFirst + daysPerRow - 1;

                for (i = rowFirst; i <= rowLast; i++) {
                    // intersect segment's offset range with the row's
                    segFirst = Math.max(rangeFirst, i);
                    segLast = Math.min(rangeLast, i);

                    // deal with in-between indices
                    segFirst = Math.ceil(segFirst); // in-between starts round to next cell
                    segLast = Math.floor(segLast); // in-between ends round to prev cell

                    if (segFirst <= segLast) { // was there any intersection with the current row?
                        segs.push({
                            row: row,

                            // normalize to start of row
                            firstRowDayIndex: segFirst - rowFirst,
                            lastRowDayIndex: segLast - rowFirst,

                            // must be matching integers to be the segment's start/end
                            isStart: segFirst === rangeFirst,
                            isEnd: segLast === rangeLast
                        });
                    }
                }
            }

            return segs;
        },

        /* Header Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        renderHeadHtml: function () {
            var view = this.view;

            return '' +
                '<div class="fc-row ' + view.widgetHeaderClass + '">' +
                '<table>' +
                '<thead>' +
                this.renderHeadTrHtml() +
                '</thead>' +
                '</table>' +
                '</div>';
        },

        renderHeadIntroHtml: function () {
            return this.renderIntroHtml(); // fall back to generic
        },

        renderHeadTrHtml: function () {
            return '' +
                '<tr>' +
                (this.isRTL ? '' : this.renderHeadIntroHtml()) +
                this.renderHeadDateCellsHtml() +
                (this.isRTL ? this.renderHeadIntroHtml() : '') +
                '</tr>';
        },

        renderHeadDateCellsHtml: function () {
            var htmls = [];
            var col, date;

            for (col = 0; col < this.colCnt; col++) {
                date = this.getCellDate(0, col);
                htmls.push(this.renderHeadDateCellHtml(date));
            }

            return htmls.join('');
        },

        // TODO: when internalApiVersion, accept an object for HTML attributes
        // (colspan should be no different)
        renderHeadDateCellHtml: function (date, colspan, otherAttrs) {
            var view = this.view;
            var classNames = [
                'fc-day-header',
                view.widgetHeaderClass
            ];

            // if only one row of days, the classNames on the header can represent the specific days beneath
            if (this.rowCnt === 1) {
                classNames = classNames.concat(
                    // includes the day-of-week class
                    // noThemeHighlight=true (don't highlight the header)
                    this.getDayClasses(date, true)
                );
            }
            else {
                classNames.push('fc-' + dayIDs[date.day()]); // only add the day-of-week class
            }

            return '' +
                '<th class="' + classNames.join(' ') + '"' +
                (this.rowCnt === 1 ?
                    ' data-date="' + date.format('YYYY-MM-DD') + '"' :
                    '') +
                (colspan > 1 ?
                    ' colspan="' + colspan + '"' :
                    '') +
                (otherAttrs ?
                    ' ' + otherAttrs :
                    '') +
                '>' +
                // don't make a link if the heading could represent multiple days, or if there's only one day (forceOff)
                view.buildGotoAnchorHtml(
                    { date: date, forceOff: this.rowCnt > 1 || this.colCnt === 1 },
                    htmlEscape(date.format(this.colHeadFormat)) // inner HTML
                ) +
                '</th>';
        },

        /* Background Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        renderBgTrHtml: function (row) {
            return '' +
                '<tr>' +
                (this.isRTL ? '' : this.renderBgIntroHtml(row)) +
                this.renderBgCellsHtml(row) +
                (this.isRTL ? this.renderBgIntroHtml(row) : '') +
                '</tr>';
        },

        renderBgIntroHtml: function (row) {
            return this.renderIntroHtml(); // fall back to generic
        },

        renderBgCellsHtml: function (row) {
            var htmls = [];
            var col, date;

            for (col = 0; col < this.colCnt; col++) {
                date = this.getCellDate(row, col);
                htmls.push(this.renderBgCellHtml(date));
            }

            return htmls.join('');
        },

        renderBgCellHtml: function (date, otherAttrs) {
            var view = this.view;
            var classes = this.getDayClasses(date);

            classes.unshift('fc-day', view.widgetContentClass);

            return '<td class="' + classes.join(' ') + '"' +
                ' data-date="' + date.format('YYYY-MM-DD') + '"' + // if date has a time, won't format it
                (otherAttrs ?
                    ' ' + otherAttrs :
                    '') +
                '></td>';
        },

        /* Generic
        ------------------------------------------------------------------------------------------------------------------*/

        // Generates the default HTML intro for any row. User classes should override
        renderIntroHtml: function () {
        },

        // TODO: a generic method for dealing with <tr>, RTL, intro
        // when increment internalApiVersion
        // wrapTr (scheduler)

        /* Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Applies the generic "intro" and "outro" HTML to the given cells.
        // Intro means the leftmost cell when the calendar is LTR and the rightmost cell when RTL. Vice-versa for outro.
        bookendCells: function (trEl) {
            var introHtml = this.renderIntroHtml();

            if (introHtml) {
                if (this.isRTL) {
                    trEl.append(introHtml);
                }
                else {
                    trEl.prepend(introHtml);
                }
            }
        }
    };

    ;;

    /* A component that renders a grid of whole-days that runs horizontally. There can be multiple rows, one per week.
    ----------------------------------------------------------------------------------------------------------------------*/

    var DayGrid = FC.DayGrid = Grid.extend(DayTableMixin, {
        numbersVisible: false, // should render a row for day/week numbers? set by outside view. TODO: make internal
        bottomCoordPadding: 0, // hack for extending the hit area for the last row of the coordinate grid

        rowEls: null, // set of fake row elements
        cellEls: null, // set of whole-day elements comprising the row's background
        helperEls: null, // set of cell skeleton elements for rendering the mock event "helper"

        rowCoordCache: null,
        colCoordCache: null,

        // Renders the rows and columns into the component's `this.el`, which should already be assigned.
        // isRigid determins whether the individual rows should ignore the contents and be a constant height.
        // Relies on the view's colCnt and rowCnt. In the future, this component should probably be self-sufficient.
        renderDates: function (isRigid) {
            var view = this.view;
            var rowCnt = this.rowCnt;
            var colCnt = this.colCnt;
            var html = '';
            var row;
            var col;

            for (row = 0; row < rowCnt; row++) {
                html += this.renderDayRowHtml(row, isRigid);
            }
            this.el.html(html);

            this.rowEls = this.el.find('.fc-row');
            this.cellEls = this.el.find('.fc-day');

            this.rowCoordCache = new CoordCache({
                els: this.rowEls,
                isVertical: true
            });
            this.colCoordCache = new CoordCache({
                els: this.cellEls.slice(0, this.colCnt), // only the first row
                isHorizontal: true
            });

            // trigger dayRender with each cell's element
            for (row = 0; row < rowCnt; row++) {
                for (col = 0; col < colCnt; col++) {
                    view.publiclyTrigger(
                        'dayRender',
                        null,
                        this.getCellDate(row, col),
                        this.getCellEl(row, col)
                    );
                }
            }
        },

        unrenderDates: function () {
            this.removeSegPopover();
        },

        renderBusinessHours: function () {
            var segs = this.buildBusinessHourSegs(true); // wholeDay=true
            this.renderFill('businessHours', segs, 'bgevent');
        },

        unrenderBusinessHours: function () {
            this.unrenderFill('businessHours');
        },

        // Generates the HTML for a single row, which is a div that wraps a table.
        // `row` is the row number.
        renderDayRowHtml: function (row, isRigid) {
            var view = this.view;
            var classes = ['fc-row', 'fc-week', view.widgetContentClass];

            if (isRigid) {
                classes.push('fc-rigid');
            }

            return '' +
                '<div class="' + classes.join(' ') + '">' +
                '<div class="fc-bg">' +
                '<table>' +
                this.renderBgTrHtml(row) +
                '</table>' +
                '</div>' +
                '<div class="fc-content-skeleton">' +
                '<table>' +
                (this.numbersVisible ?
                    '<thead>' +
                    this.renderNumberTrHtml(row) +
                    '</thead>' :
                    ''
                ) +
                '</table>' +
                '</div>' +
                '</div>';
        },

        /* Grid Number Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        renderNumberTrHtml: function (row) {
            return '' +
                '<tr>' +
                (this.isRTL ? '' : this.renderNumberIntroHtml(row)) +
                this.renderNumberCellsHtml(row) +
                (this.isRTL ? this.renderNumberIntroHtml(row) : '') +
                '</tr>';
        },

        renderNumberIntroHtml: function (row) {
            return this.renderIntroHtml();
        },

        renderNumberCellsHtml: function (row) {
            var htmls = [];
            var col, date;

            for (col = 0; col < this.colCnt; col++) {
                date = this.getCellDate(row, col);
                htmls.push(this.renderNumberCellHtml(date));
            }

            return htmls.join('');
        },

        // Generates the HTML for the <td>s of the "number" row in the DayGrid's content skeleton.
        // The number row will only exist if either day numbers or week numbers are turned on.
        renderNumberCellHtml: function (date) {
            var html = '';
            var classes;
            var weekCalcFirstDoW;

            if (!this.view.dayNumbersVisible && !this.view.cellWeekNumbersVisible) {
                // no numbers in day cell (week number must be along the side)
                return '<td/>'; //  will create an empty space above events :(
            }

            classes = this.getDayClasses(date);
            classes.unshift('fc-day-top');

            if (this.view.cellWeekNumbersVisible) {
                // To determine the day of week number change under ISO, we cannot
                // rely on moment.js methods such as firstDayOfWeek() or weekday(),
                // because they rely on the locale's dow (possibly overridden by
                // our firstDay option), which may not be Monday. We cannot change
                // dow, because that would affect the calendar start day as well.
                if (date._locale._fullCalendar_weekCalc === 'ISO') {
                    weekCalcFirstDoW = 1;  // Monday by ISO 8601 definition
                }
                else {
                    weekCalcFirstDoW = date._locale.firstDayOfWeek();
                }
            }

            html += '<td class="' + classes.join(' ') + '" data-date="' + date.format() + '">';

            if (this.view.cellWeekNumbersVisible && (date.day() == weekCalcFirstDoW)) {
                html += this.view.buildGotoAnchorHtml(
                    { date: date, type: 'week' },
                    { 'class': 'fc-week-number' },
                    date.format('w') // inner HTML
                );
            }

            if (this.view.dayNumbersVisible) {
                html += this.view.buildGotoAnchorHtml(
                    date,
                    { 'class': 'fc-day-number' },
                    date.date() // inner HTML
                );
            }

            html += '</td>';

            return html;
        },

        /* Options
        ------------------------------------------------------------------------------------------------------------------*/

        // Computes a default event time formatting string if `timeFormat` is not explicitly defined
        computeEventTimeFormat: function () {
            return this.view.opt('extraSmallTimeFormat'); // like "6p" or "6:30p"
        },

        // Computes a default `displayEventEnd` value if one is not expliclty defined
        computeDisplayEventEnd: function () {
            return this.colCnt == 1; // we'll likely have space if there's only one day
        },

        /* Dates
        ------------------------------------------------------------------------------------------------------------------*/

        rangeUpdated: function () {
            this.updateDayTable();
        },

        // Slices up the given span (unzoned start/end with other misc data) into an array of segments
        spanToSegs: function (span) {
            var segs = this.sliceRangeByRow(span);
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                if (this.isRTL) {
                    seg.leftCol = this.daysPerRow - 1 - seg.lastRowDayIndex;
                    seg.rightCol = this.daysPerRow - 1 - seg.firstRowDayIndex;
                }
                else {
                    seg.leftCol = seg.firstRowDayIndex;
                    seg.rightCol = seg.lastRowDayIndex;
                }
            }

            return segs;
        },

        /* Hit System
        ------------------------------------------------------------------------------------------------------------------*/

        prepareHits: function () {
            this.colCoordCache.build();
            this.rowCoordCache.build();
            this.rowCoordCache.bottoms[this.rowCnt - 1] += this.bottomCoordPadding; // hack
        },

        releaseHits: function () {
            this.colCoordCache.clear();
            this.rowCoordCache.clear();
        },

        queryHit: function (leftOffset, topOffset) {
            if (this.colCoordCache.isLeftInBounds(leftOffset) && this.rowCoordCache.isTopInBounds(topOffset)) {
                var col = this.colCoordCache.getHorizontalIndex(leftOffset);
                var row = this.rowCoordCache.getVerticalIndex(topOffset);

                if (row != null && col != null) {
                    return this.getCellHit(row, col);
                }
            }
        },

        getHitSpan: function (hit) {
            return this.getCellRange(hit.row, hit.col);
        },

        getHitEl: function (hit) {
            return this.getCellEl(hit.row, hit.col);
        },

        /* Cell System
        ------------------------------------------------------------------------------------------------------------------*/
        // FYI: the first column is the leftmost column, regardless of date

        getCellHit: function (row, col) {
            return {
                row: row,
                col: col,
                component: this, // needed unfortunately :(
                left: this.colCoordCache.getLeftOffset(col),
                right: this.colCoordCache.getRightOffset(col),
                top: this.rowCoordCache.getTopOffset(row),
                bottom: this.rowCoordCache.getBottomOffset(row)
            };
        },

        getCellEl: function (row, col) {
            return this.cellEls.eq(row * this.colCnt + col);
        },

        /* Event Drag Visualization
        ------------------------------------------------------------------------------------------------------------------*/
        // TODO: move to DayGrid.event, similar to what we did with Grid's drag methods

        // Renders a visual indication of an event or external element being dragged.
        // `eventLocation` has zoned start and end (optional)
        renderDrag: function (eventLocation, seg) {
            // always render a highlight underneath
            this.renderHighlight(this.eventToSpan(eventLocation));

            // if a segment from the same calendar but another component is being dragged, render a helper event
            if (seg && seg.component !== this) {
                return this.renderEventLocationHelper(eventLocation, seg); // returns mock event elements
            }
        },

        // Unrenders any visual indication of a hovering event
        unrenderDrag: function () {
            this.unrenderHighlight();
            this.unrenderHelper();
        },

        /* Event Resize Visualization
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of an event being resized
        renderEventResize: function (eventLocation, seg) {
            this.renderHighlight(this.eventToSpan(eventLocation));
            return this.renderEventLocationHelper(eventLocation, seg); // returns mock event elements
        },

        // Unrenders a visual indication of an event being resized
        unrenderEventResize: function () {
            this.unrenderHighlight();
            this.unrenderHelper();
        },

        /* Event Helper
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a mock "helper" event. `sourceSeg` is the associated internal segment object. It can be null.
        renderHelper: function (event, sourceSeg) {
            var helperNodes = [];
            var segs = this.eventToSegs(event);
            var rowStructs;

            segs = this.renderFgSegEls(segs); // assigns each seg's el and returns a subset of segs that were rendered
            rowStructs = this.renderSegRows(segs);

            // inject each new event skeleton into each associated row
            this.rowEls.each(function (row, rowNode) {
                var rowEl = $(rowNode); // the .fc-row
                var skeletonEl = $('<div class="fc-helper-skeleton"><table/></div>'); // will be absolutely positioned
                var skeletonTop;

                // If there is an original segment, match the top position. Otherwise, put it at the row's top level
                if (sourceSeg && sourceSeg.row === row) {
                    skeletonTop = sourceSeg.el.position().top;
                }
                else {
                    skeletonTop = rowEl.find('.fc-content-skeleton tbody').position().top;
                }

                skeletonEl.css('top', skeletonTop)
                    .find('table')
                    .append(rowStructs[row].tbodyEl);

                rowEl.append(skeletonEl);
                helperNodes.push(skeletonEl[0]);
            });

            return ( // must return the elements rendered
                this.helperEls = $(helperNodes) // array -> jQuery set
            );
        },

        // Unrenders any visual indication of a mock helper event
        unrenderHelper: function () {
            if (this.helperEls) {
                this.helperEls.remove();
                this.helperEls = null;
            }
        },

        /* Fill System (highlight, background events, business hours)
        ------------------------------------------------------------------------------------------------------------------*/

        fillSegTag: 'td', // override the default tag name

        // Renders a set of rectangles over the given segments of days.
        // Only returns segments that successfully rendered.
        renderFill: function (type, segs, className) {
            var nodes = [];
            var i, seg;
            var skeletonEl;

            segs = this.renderFillSegEls(type, segs); // assignes `.el` to each seg. returns successfully rendered segs

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                skeletonEl = this.renderFillRow(type, seg, className);
                this.rowEls.eq(seg.row).append(skeletonEl);
                nodes.push(skeletonEl[0]);
            }

            this.elsByFill[type] = $(nodes);

            return segs;
        },

        // Generates the HTML needed for one row of a fill. Requires the seg's el to be rendered.
        renderFillRow: function (type, seg, className) {
            var colCnt = this.colCnt;
            var startCol = seg.leftCol;
            var endCol = seg.rightCol + 1;
            var skeletonEl;
            var trEl;

            className = className || type.toLowerCase();

            skeletonEl = $(
                '<div class="fc-' + className + '-skeleton">' +
                '<table><tr/></table>' +
                '</div>'
            );
            trEl = skeletonEl.find('tr');

            if (startCol > 0) {
                trEl.append('<td colspan="' + startCol + '"/>');
            }

            trEl.append(
                seg.el.attr('colspan', endCol - startCol)
            );

            if (endCol < colCnt) {
                trEl.append('<td colspan="' + (colCnt - endCol) + '"/>');
            }

            this.bookendCells(trEl);

            return skeletonEl;
        }
    });

    ;;

    /* Event-rendering methods for the DayGrid class
    ----------------------------------------------------------------------------------------------------------------------*/

    DayGrid.mixin({
        rowStructs: null, // an array of objects, each holding information about a row's foreground event-rendering

        // Unrenders all events currently rendered on the grid
        unrenderEvents: function () {
            this.removeSegPopover(); // removes the "more.." events popover
            Grid.prototype.unrenderEvents.apply(this, arguments); // calls the super-method
        },

        // Retrieves all rendered segment objects currently rendered on the grid
        getEventSegs: function () {
            return Grid.prototype.getEventSegs.call(this) // get the segments from the super-method
                .concat(this.popoverSegs || []); // append the segments from the "more..." popover
        },

        // Renders the given background event segments onto the grid
        renderBgSegs: function (segs) {
            // don't render timed background events
            var allDaySegs = $.grep(segs, function (seg) {
                return seg.event.allDay;
            });

            return Grid.prototype.renderBgSegs.call(this, allDaySegs); // call the super-method
        },

        // Renders the given foreground event segments onto the grid
        renderFgSegs: function (segs) {
            var rowStructs;

            // render an `.el` on each seg
            // returns a subset of the segs. segs that were actually rendered
            segs = this.renderFgSegEls(segs);

            rowStructs = this.rowStructs = this.renderSegRows(segs);

            // append to each row's content skeleton
            this.rowEls.each(function (i, rowNode) {
                $(rowNode).find('.fc-content-skeleton > table').append(
                    rowStructs[i].tbodyEl
                );
            });

            return segs; // return only the segs that were actually rendered
        },

        // Unrenders all currently rendered foreground event segments
        unrenderFgSegs: function () {
            var rowStructs = this.rowStructs || [];
            var rowStruct;

            while ((rowStruct = rowStructs.pop())) {
                rowStruct.tbodyEl.remove();
            }

            this.rowStructs = null;
        },

        // Uses the given events array to generate <tbody> elements that should be appended to each row's content skeleton.
        // Returns an array of rowStruct objects (see the bottom of `renderSegRow`).
        // PRECONDITION: each segment shoud already have a rendered and assigned `.el`
        renderSegRows: function (segs) {
            var rowStructs = [];
            var segRows;
            var row;

            segRows = this.groupSegRows(segs); // group into nested arrays

            // iterate each row of segment groupings
            for (row = 0; row < segRows.length; row++) {
                rowStructs.push(
                    this.renderSegRow(row, segRows[row])
                );
            }

            return rowStructs;
        },

        // Builds the HTML to be used for the default element for an individual segment
        fgSegHtml: function (seg, disableResizing) {
            var view = this.view;
            var event = seg.event;
            var isDraggable = view.isEventDraggable(event);
            var isResizableFromStart = !disableResizing && event.allDay &&
                seg.isStart && view.isEventResizableFromStart(event);
            var isResizableFromEnd = !disableResizing && event.allDay &&
                seg.isEnd && view.isEventResizableFromEnd(event);
            var classes = this.getSegClasses(seg, isDraggable, isResizableFromStart || isResizableFromEnd);
            var skinCss = cssToStr(this.getSegSkinCss(seg));
            var timeHtml = '';
            var timeText;
            var titleHtml;

            classes.unshift('fc-day-grid-event', 'fc-h-event');

            // Only display a timed events time if it is the starting segment
            if (seg.isStart) {
                timeText = this.getEventTimeText(event);
                if (timeText) {
                    timeHtml = '<span class="fc-time">' + htmlEscape(timeText) + '</span>';
                }
            }

            titleHtml =
                '<span class="fc-title">' +
                (htmlEscape(event.title || '') || '&nbsp;') + // we always want one line of height
                '</span>';

            return '<a tooltips class="' + classes.join(' ') + '"' +
                (event.url ?
                    ' href="' + htmlEscape(event.url) + '"' :
                    ''
                ) +
                (skinCss ?
                    ' style="' + skinCss + '"' :
                    ''
                ) +
                (event.content ?
                    ' title="' + htmlEscape(event.content) + '"' :
                    ''
                ) +
                '>' +
                '<div class="fc-content">' +
                (this.isRTL ?
                    titleHtml + ' ' + timeHtml : // put a natural space in between
                    timeHtml + ' ' + titleHtml   //
                ) +
                '</div>' +
                (isResizableFromStart ?
                    '<div class="fc-resizer fc-start-resizer" />' :
                    ''
                ) +
                (isResizableFromEnd ?
                    '<div class="fc-resizer fc-end-resizer" />' :
                    ''
                ) +
                '</a>';
        },

        // Given a row # and an array of segments all in the same row, render a <tbody> element, a skeleton that contains
        // the segments. Returns object with a bunch of internal data about how the render was calculated.
        // NOTE: modifies rowSegs
        renderSegRow: function (row, rowSegs) {
            var colCnt = this.colCnt;
            var segLevels = this.buildSegLevels(rowSegs); // group into sub-arrays of levels
            var levelCnt = Math.max(1, segLevels.length); // ensure at least one level
            var tbody = $('<tbody/>');
            var segMatrix = []; // lookup for which segments are rendered into which level+col cells
            var cellMatrix = []; // lookup for all <td> elements of the level+col matrix
            var loneCellMatrix = []; // lookup for <td> elements that only take up a single column
            var i, levelSegs;
            var col;
            var tr;
            var j, seg;
            var td;

            // populates empty cells from the current column (`col`) to `endCol`
            function emptyCellsUntil(endCol) {
                while (col < endCol) {
                    // try to grab a cell from the level above and extend its rowspan. otherwise, create a fresh cell
                    td = (loneCellMatrix[i - 1] || [])[col];
                    if (td) {
                        td.attr(
                            'rowspan',
                            parseInt(td.attr('rowspan') || 1, 10) + 1
                        );
                    }
                    else {
                        td = $('<td/>');
                        tr.append(td);
                    }
                    cellMatrix[i][col] = td;
                    loneCellMatrix[i][col] = td;
                    col++;
                }
            }

            for (i = 0; i < levelCnt; i++) { // iterate through all levels
                levelSegs = segLevels[i];
                col = 0;
                tr = $('<tr/>');

                segMatrix.push([]);
                cellMatrix.push([]);
                loneCellMatrix.push([]);

                // levelCnt might be 1 even though there are no actual levels. protect against this.
                // this single empty row is useful for styling.
                if (levelSegs) {
                    for (j = 0; j < levelSegs.length; j++) { // iterate through segments in level
                        seg = levelSegs[j];

                        emptyCellsUntil(seg.leftCol);

                        // create a container that occupies or more columns. append the event element.
                        td = $('<td class="fc-event-container"/>').append(seg.el);
                        if (seg.leftCol != seg.rightCol) {
                            td.attr('colspan', seg.rightCol - seg.leftCol + 1);
                        }
                        else { // a single-column segment
                            loneCellMatrix[i][col] = td;
                        }

                        while (col <= seg.rightCol) {
                            cellMatrix[i][col] = td;
                            segMatrix[i][col] = seg;
                            col++;
                        }

                        tr.append(td);
                    }
                }

                emptyCellsUntil(colCnt); // finish off the row
                this.bookendCells(tr);
                tbody.append(tr);
            }

            return { // a "rowStruct"
                row: row, // the row number
                tbodyEl: tbody,
                cellMatrix: cellMatrix,
                segMatrix: segMatrix,
                segLevels: segLevels,
                segs: rowSegs
            };
        },

        // Stacks a flat array of segments, which are all assumed to be in the same row, into subarrays of vertical levels.
        // NOTE: modifies segs
        buildSegLevels: function (segs) {
            var levels = [];
            var i, seg;
            var j;

            // Give preference to elements with certain criteria, so they have
            // a chance to be closer to the top.
            this.sortEventSegs(segs);

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];

                // loop through levels, starting with the topmost, until the segment doesn't collide with other segments
                for (j = 0; j < levels.length; j++) {
                    if (!isDaySegCollision(seg, levels[j])) {
                        break;
                    }
                }
                // `j` now holds the desired subrow index
                seg.level = j;

                // create new level array if needed and append segment
                (levels[j] || (levels[j] = [])).push(seg);
            }

            // order segments left-to-right. very important if calendar is RTL
            for (j = 0; j < levels.length; j++) {
                levels[j].sort(compareDaySegCols);
            }

            return levels;
        },

        // Given a flat array of segments, return an array of sub-arrays, grouped by each segment's row
        groupSegRows: function (segs) {
            var segRows = [];
            var i;

            for (i = 0; i < this.rowCnt; i++) {
                segRows.push([]);
            }

            for (i = 0; i < segs.length; i++) {
                segRows[segs[i].row].push(segs[i]);
            }

            return segRows;
        }
    });

    // Computes whether two segments' columns collide. They are assumed to be in the same row.
    function isDaySegCollision(seg, otherSegs) {
        var i, otherSeg;

        for (i = 0; i < otherSegs.length; i++) {
            otherSeg = otherSegs[i];

            if (
                otherSeg.leftCol <= seg.rightCol &&
                otherSeg.rightCol >= seg.leftCol
            ) {
                return true;
            }
        }

        return false;
    }

    // A cmp function for determining the leftmost event
    function compareDaySegCols(a, b) {
        return a.leftCol - b.leftCol;
    }

    ;;

    /* Methods relate to limiting the number events for a given day on a DayGrid
    ----------------------------------------------------------------------------------------------------------------------*/
    // NOTE: all the segs being passed around in here are foreground segs

    DayGrid.mixin({
        segPopover: null, // the Popover that holds events that can't fit in a cell. null when not visible
        popoverSegs: null, // an array of segment objects that the segPopover holds. null when not visible

        removeSegPopover: function () {
            if (this.segPopover) {
                this.segPopover.hide(); // in handler, will call segPopover's removeElement
            }
        },

        // Limits the number of "levels" (vertically stacking layers of events) for each row of the grid.
        // `levelLimit` can be false (don't limit), a number, or true (should be computed).
        limitRows: function (levelLimit) {
            var rowStructs = this.rowStructs || [];
            var row; // row #
            var rowLevelLimit;

            for (row = 0; row < rowStructs.length; row++) {
                this.unlimitRow(row);

                if (!levelLimit) {
                    rowLevelLimit = false;
                }
                else if (typeof levelLimit === 'number') {
                    rowLevelLimit = levelLimit;
                }
                else {
                    rowLevelLimit = this.computeRowLevelLimit(row);
                }

                if (rowLevelLimit !== false) {
                    this.limitRow(row, rowLevelLimit);
                }
            }
        },

        // Computes the number of levels a row will accomodate without going outside its bounds.
        // Assumes the row is "rigid" (maintains a constant height regardless of what is inside).
        // `row` is the row number.
        computeRowLevelLimit: function (row) {
            var rowEl = this.rowEls.eq(row); // the containing "fake" row div
            var rowHeight = rowEl.height(); // TODO: cache somehow?
            var trEls = this.rowStructs[row].tbodyEl.children();
            var i, trEl;
            var trHeight;

            function iterInnerHeights(i, childNode) {
                trHeight = Math.max(trHeight, $(childNode).outerHeight());
            }

            // Reveal one level <tr> at a time and stop when we find one out of bounds
            for (i = 0; i < trEls.length; i++) {
                trEl = trEls.eq(i).removeClass('fc-limited'); // reset to original state (reveal)

                // with rowspans>1 and IE8, trEl.outerHeight() would return the height of the largest cell,
                // so instead, find the tallest inner content element.
                trHeight = 0;
                trEl.find('> td > :first-child').each(iterInnerHeights);

                if (trEl.position().top + trHeight > rowHeight) {
                    return i;
                }
            }

            return false; // should not limit at all
        },

        // Limits the given grid row to the maximum number of levels and injects "more" links if necessary.
        // `row` is the row number.
        // `levelLimit` is a number for the maximum (inclusive) number of levels allowed.
        limitRow: function (row, levelLimit) {
            var _this = this;
            var rowStruct = this.rowStructs[row];
            var moreNodes = []; // array of "more" <a> links and <td> DOM nodes
            var col = 0; // col #, left-to-right (not chronologically)
            var levelSegs; // array of segment objects in the last allowable level, ordered left-to-right
            var cellMatrix; // a matrix (by level, then column) of all <td> jQuery elements in the row
            var limitedNodes; // array of temporarily hidden level <tr> and segment <td> DOM nodes
            var i, seg;
            var segsBelow; // array of segment objects below `seg` in the current `col`
            var totalSegsBelow; // total number of segments below `seg` in any of the columns `seg` occupies
            var colSegsBelow; // array of segment arrays, below seg, one for each column (offset from segs's first column)
            var td, rowspan;
            var segMoreNodes; // array of "more" <td> cells that will stand-in for the current seg's cell
            var j;
            var moreTd, moreWrap, moreLink;

            // Iterates through empty level cells and places "more" links inside if need be
            function emptyCellsUntil(endCol) { // goes from current `col` to `endCol`
                while (col < endCol) {
                    segsBelow = _this.getCellSegs(row, col, levelLimit);
                    if (segsBelow.length) {
                        td = cellMatrix[levelLimit - 1][col];
                        moreLink = _this.renderMoreLink(row, col, segsBelow);
                        moreWrap = $('<div/>').append(moreLink);
                        td.append(moreWrap);
                        moreNodes.push(moreWrap[0]);
                    }
                    col++;
                }
            }

            if (levelLimit && levelLimit < rowStruct.segLevels.length) { // is it actually over the limit?
                levelSegs = rowStruct.segLevels[levelLimit - 1];
                cellMatrix = rowStruct.cellMatrix;

                limitedNodes = rowStruct.tbodyEl.children().slice(levelLimit) // get level <tr> elements past the limit
                    .addClass('fc-limited').get(); // hide elements and get a simple DOM-nodes array

                // iterate though segments in the last allowable level
                for (i = 0; i < levelSegs.length; i++) {
                    seg = levelSegs[i];
                    emptyCellsUntil(seg.leftCol); // process empty cells before the segment

                    // determine *all* segments below `seg` that occupy the same columns
                    colSegsBelow = [];
                    totalSegsBelow = 0;
                    while (col <= seg.rightCol) {
                        segsBelow = this.getCellSegs(row, col, levelLimit);
                        colSegsBelow.push(segsBelow);
                        totalSegsBelow += segsBelow.length;
                        col++;
                    }

                    if (totalSegsBelow) { // do we need to replace this segment with one or many "more" links?
                        td = cellMatrix[levelLimit - 1][seg.leftCol]; // the segment's parent cell
                        rowspan = td.attr('rowspan') || 1;
                        segMoreNodes = [];

                        // make a replacement <td> for each column the segment occupies. will be one for each colspan
                        for (j = 0; j < colSegsBelow.length; j++) {
                            moreTd = $('<td class="fc-more-cell"/>').attr('rowspan', rowspan);
                            segsBelow = colSegsBelow[j];
                            moreLink = this.renderMoreLink(
                                row,
                                seg.leftCol + j,
                                [seg].concat(segsBelow) // count seg as hidden too
                            );
                            moreWrap = $('<div/>').append(moreLink);
                            moreTd.append(moreWrap);
                            segMoreNodes.push(moreTd[0]);
                            moreNodes.push(moreTd[0]);
                        }

                        td.addClass('fc-limited').after($(segMoreNodes)); // hide original <td> and inject replacements
                        limitedNodes.push(td[0]);
                    }
                }

                emptyCellsUntil(this.colCnt); // finish off the level
                rowStruct.moreEls = $(moreNodes); // for easy undoing later
                rowStruct.limitedEls = $(limitedNodes); // for easy undoing later
            }
        },

        // Reveals all levels and removes all "more"-related elements for a grid's row.
        // `row` is a row number.
        unlimitRow: function (row) {
            var rowStruct = this.rowStructs[row];

            if (rowStruct.moreEls) {
                rowStruct.moreEls.remove();
                rowStruct.moreEls = null;
            }

            if (rowStruct.limitedEls) {
                rowStruct.limitedEls.removeClass('fc-limited');
                rowStruct.limitedEls = null;
            }
        },

        // Renders an <a> element that represents hidden event element for a cell.
        // Responsible for attaching click handler as well.
        renderMoreLink: function (row, col, hiddenSegs) {
            var _this = this;
            var view = this.view;

            return $('<a class="fc-more"/>')
                .text(
                    this.getMoreLinkText(hiddenSegs.length)
                )
                .on('click', function (ev) {
                    var clickOption = view.opt('eventLimitClick');
                    var date = _this.getCellDate(row, col);
                    var moreEl = $(this);
                    var dayEl = _this.getCellEl(row, col);
                    var allSegs = _this.getCellSegs(row, col);

                    // rescope the segments to be within the cell's date
                    var reslicedAllSegs = _this.resliceDaySegs(allSegs, date);
                    var reslicedHiddenSegs = _this.resliceDaySegs(hiddenSegs, date);

                    if (typeof clickOption === 'function') {
                        // the returned value can be an atomic option
                        clickOption = view.publiclyTrigger('eventLimitClick', null, {
                            date: date,
                            dayEl: dayEl,
                            moreEl: moreEl,
                            segs: reslicedAllSegs,
                            hiddenSegs: reslicedHiddenSegs
                        }, ev);
                    }

                    if (clickOption === 'popover') {
                        _this.showSegPopover(row, col, moreEl, reslicedAllSegs);
                    }
                    else if (typeof clickOption === 'string') { // a view name
                        view.calendar.zoomTo(date, clickOption);
                    }
                });
        },

        // Reveals the popover that displays all events within a cell
        showSegPopover: function (row, col, moreLink, segs) {
            var _this = this;
            var view = this.view;
            var moreWrap = moreLink.parent(); // the <div> wrapper around the <a>
            var topEl; // the element we want to match the top coordinate of
            var options;

            if (this.rowCnt == 1) {
                topEl = view.el; // will cause the popover to cover any sort of header
            }
            else {
                topEl = this.rowEls.eq(row); // will align with top of row
            }

            options = {
                className: 'fc-more-popover',
                content: this.renderSegPopoverContent(row, col, segs),
                parentEl: this.view.el, // attach to root of view. guarantees outside of scrollbars.
                top: topEl.offset().top,
                autoHide: true, // when the user clicks elsewhere, hide the popover
                viewportConstrain: view.opt('popoverViewportConstrain'),
                hide: function () {
                    // kill everything when the popover is hidden
                    // notify events to be removed
                    if (_this.popoverSegs) {
                        var seg;
                        for (var i = 0; i < _this.popoverSegs.length; ++i) {
                            seg = _this.popoverSegs[i];
                            view.publiclyTrigger('eventDestroy', seg.event, seg.event, seg.el);
                        }
                    }
                    _this.segPopover.removeElement();
                    _this.segPopover = null;
                    _this.popoverSegs = null;
                }
            };

            // Determine horizontal coordinate.
            // We use the moreWrap instead of the <td> to avoid border confusion.
            if (this.isRTL) {
                options.right = moreWrap.offset().left + moreWrap.outerWidth() + 1; // +1 to be over cell border
            }
            else {
                options.left = moreWrap.offset().left - 1; // -1 to be over cell border
            }

            this.segPopover = new Popover(options);
            this.segPopover.show();

            // the popover doesn't live within the grid's container element, and thus won't get the event
            // delegated-handlers for free. attach event-related handlers to the popover.
            this.bindSegHandlersToEl(this.segPopover.el);
        },

        // Builds the inner DOM contents of the segment popover
        renderSegPopoverContent: function (row, col, segs) {
            var view = this.view;
            var isTheme = view.opt('theme');
            var title = this.getCellDate(row, col).format(view.opt('dayPopoverFormat'));
            var content = $(
                '<div class="fc-header ' + view.widgetHeaderClass + '">' +
                '<span class="fc-close ' +
                (isTheme ? 'ui-icon ui-icon-closethick' : 'fc-icon fc-icon-x') +
                '"></span>' +
                '<span class="fc-title">' +
                htmlEscape(title) +
                '</span>' +
                '<div class="fc-clear"/>' +
                '</div>' +
                '<div class="fc-body ' + view.widgetContentClass + '">' +
                '<div class="fc-event-container"></div>' +
                '</div>'
            );
            var segContainer = content.find('.fc-event-container');
            var i;

            // render each seg's `el` and only return the visible segs
            segs = this.renderFgSegEls(segs, true); // disableResizing=true
            this.popoverSegs = segs;

            for (i = 0; i < segs.length; i++) {
                // because segments in the popover are not part of a grid coordinate system, provide a hint to any
                // grids that want to do drag-n-drop about which cell it came from
                this.prepareHits();
                segs[i].hit = this.getCellHit(row, col);
                this.releaseHits();

                segContainer.append(segs[i].el);
            }

            return content;
        },

        // Given the events within an array of segment objects, reslice them to be in a single day
        resliceDaySegs: function (segs, dayDate) {
            // build an array of the original events
            var events = $.map(segs, function (seg) {
                return seg.event;
            });

            var dayStart = dayDate.clone();
            var dayEnd = dayStart.clone().add(1, 'days');
            var dayRange = { start: dayStart, end: dayEnd };

            // slice the events with a custom slicing function
            segs = this.eventsToSegs(
                events,
                function (range) {
                    var seg = intersectRanges(range, dayRange); // undefind if no intersection
                    return seg ? [seg] : []; // must return an array of segments
                }
            );

            // force an order because eventsToSegs doesn't guarantee one
            this.sortEventSegs(segs);

            return segs;
        },

        // Generates the text that should be inside a "more" link, given the number of events it represents
        getMoreLinkText: function (num) {
            var opt = this.view.opt('eventLimitText');

            if (typeof opt === 'function') {
                return opt(num);
            }
            else {
                return '+' + num + ' ' + opt;
            }
        },

        // Returns segments within a given cell.
        // If `startLevel` is specified, returns only events including and below that level. Otherwise returns all segs.
        getCellSegs: function (row, col, startLevel) {
            var segMatrix = this.rowStructs[row].segMatrix;
            var level = startLevel || 0;
            var segs = [];
            var seg;

            while (level < segMatrix.length) {
                seg = segMatrix[level][col];
                if (seg) {
                    segs.push(seg);
                }
                level++;
            }

            return segs;
        }
    });

    ;;

    /* A component that renders one or more columns of vertical time slots
    ----------------------------------------------------------------------------------------------------------------------*/
    // We mixin DayTable, even though there is only a single row of days

    var TimeGrid = FC.TimeGrid = Grid.extend(DayTableMixin, {
        slotDuration: null, // duration of a "slot", a distinct time segment on given day, visualized by lines
        snapDuration: null, // granularity of time for dragging and selecting
        snapsPerSlot: null,
        minTime: null, // Duration object that denotes the first visible time of any given day
        maxTime: null, // Duration object that denotes the exclusive visible end time of any given day
        labelFormat: null, // formatting string for times running along vertical axis
        labelInterval: null, // duration of how often a label should be displayed for a slot

        colEls: null, // cells elements in the day-row background
        slatContainerEl: null, // div that wraps all the slat rows
        slatEls: null, // elements running horizontally across all columns
        nowIndicatorEls: null,

        colCoordCache: null,
        slatCoordCache: null,

        constructor: function () {
            Grid.apply(this, arguments); // call the super-constructor

            this.processOptions();
        },

        // Renders the time grid into `this.el`, which should already be assigned.
        // Relies on the view's colCnt. In the future, this component should probably be self-sufficient.
        renderDates: function () {
            this.el.html(this.renderHtml());
            this.colEls = this.el.find('.fc-day');
            this.slatContainerEl = this.el.find('.fc-slats');
            this.slatEls = this.slatContainerEl.find('tr');

            this.colCoordCache = new CoordCache({
                els: this.colEls,
                isHorizontal: true
            });
            this.slatCoordCache = new CoordCache({
                els: this.slatEls,
                isVertical: true
            });

            this.renderContentSkeleton();
        },

        // Renders the basic HTML skeleton for the grid
        renderHtml: function () {
            return '' +
                '<div class="fc-bg">' +
                '<table>' +
                this.renderBgTrHtml(0) + // row=0
                '</table>' +
                '</div>' +
                '<div class="fc-slats">' +
                '<table>' +
                this.renderSlatRowHtml() +
                '</table>' +
                '</div>';
        },

        // Generates the HTML for the horizontal "slats" that run width-wise. Has a time axis on a side. Depends on RTL.
        renderSlatRowHtml: function () {
            var view = this.view;
            var isRTL = this.isRTL;
            var html = '';
            var slotTime = moment.duration(+this.minTime); // wish there was .clone() for durations
            var slotDate; // will be on the view's first day, but we only care about its time
            var isLabeled;
            var axisHtml;

            // Calculate the time for each slot
            while (slotTime < this.maxTime) {
                slotDate = this.start.clone().time(slotTime);
                isLabeled = isInt(divideDurationByDuration(slotTime, this.labelInterval));

                axisHtml =
                    '<td class="fc-axis fc-time ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '>' +
                    (isLabeled ?
                        '<span>' + // for matchCellWidths
                        htmlEscape(slotDate.format(this.labelFormat)) +
                        '</span>' :
                        ''
                    ) +
                    '</td>';

                html +=
                    '<tr data-time="' + slotDate.format('HH:mm:ss') + '"' +
                    (isLabeled ? '' : ' class="fc-minor"') +
                    '>' +
                    (!isRTL ? axisHtml : '') +
                    '<td class="' + view.widgetContentClass + '"/>' +
                    (isRTL ? axisHtml : '') +
                    "</tr>";

                slotTime.add(this.slotDuration);
            }

            return html;
        },

        /* Options
        ------------------------------------------------------------------------------------------------------------------*/

        // Parses various options into properties of this object
        processOptions: function () {
            var view = this.view;
            var slotDuration = view.opt('slotDuration');
            var snapDuration = view.opt('snapDuration');
            var input;

            slotDuration = moment.duration(slotDuration);
            snapDuration = snapDuration ? moment.duration(snapDuration) : slotDuration;

            this.slotDuration = slotDuration;
            this.snapDuration = snapDuration;
            this.snapsPerSlot = slotDuration / snapDuration; // TODO: ensure an integer multiple?

            this.minResizeDuration = snapDuration; // hack

            this.minTime = moment.duration(view.opt('minTime'));
            this.maxTime = moment.duration(view.opt('maxTime'));

            // might be an array value (for TimelineView).
            // if so, getting the most granular entry (the last one probably).
            input = view.opt('slotLabelFormat');
            if ($.isArray(input)) {
                input = input[input.length - 1];
            }

            this.labelFormat =
                input ||
                view.opt('smallTimeFormat'); // the computed default

            input = view.opt('slotLabelInterval');
            this.labelInterval = input ?
                moment.duration(input) :
                this.computeLabelInterval(slotDuration);
        },

        // Computes an automatic value for slotLabelInterval
        computeLabelInterval: function (slotDuration) {
            var i;
            var labelInterval;
            var slotsPerLabel;

            // find the smallest stock label interval that results in more than one slots-per-label
            for (i = AGENDA_STOCK_SUB_DURATIONS.length - 1; i >= 0; i--) {
                labelInterval = moment.duration(AGENDA_STOCK_SUB_DURATIONS[i]);
                slotsPerLabel = divideDurationByDuration(labelInterval, slotDuration);
                if (isInt(slotsPerLabel) && slotsPerLabel > 1) {
                    return labelInterval;
                }
            }

            return moment.duration(slotDuration); // fall back. clone
        },

        // Computes a default event time formatting string if `timeFormat` is not explicitly defined
        computeEventTimeFormat: function () {
            return this.view.opt('noMeridiemTimeFormat'); // like "6:30" (no AM/PM)
        },

        // Computes a default `displayEventEnd` value if one is not expliclty defined
        computeDisplayEventEnd: function () {
            return true;
        },

        /* Hit System
        ------------------------------------------------------------------------------------------------------------------*/

        prepareHits: function () {
            this.colCoordCache.build();
            this.slatCoordCache.build();
        },

        releaseHits: function () {
            this.colCoordCache.clear();
            // NOTE: don't clear slatCoordCache because we rely on it for computeTimeTop
        },

        queryHit: function (leftOffset, topOffset) {
            var snapsPerSlot = this.snapsPerSlot;
            var colCoordCache = this.colCoordCache;
            var slatCoordCache = this.slatCoordCache;

            if (colCoordCache.isLeftInBounds(leftOffset) && slatCoordCache.isTopInBounds(topOffset)) {
                var colIndex = colCoordCache.getHorizontalIndex(leftOffset);
                var slatIndex = slatCoordCache.getVerticalIndex(topOffset);

                if (colIndex != null && slatIndex != null) {
                    var slatTop = slatCoordCache.getTopOffset(slatIndex);
                    var slatHeight = slatCoordCache.getHeight(slatIndex);
                    var partial = (topOffset - slatTop) / slatHeight; // floating point number between 0 and 1
                    var localSnapIndex = Math.floor(partial * snapsPerSlot); // the snap # relative to start of slat
                    var snapIndex = slatIndex * snapsPerSlot + localSnapIndex;
                    var snapTop = slatTop + (localSnapIndex / snapsPerSlot) * slatHeight;
                    var snapBottom = slatTop + ((localSnapIndex + 1) / snapsPerSlot) * slatHeight;

                    return {
                        col: colIndex,
                        snap: snapIndex,
                        component: this, // needed unfortunately :(
                        left: colCoordCache.getLeftOffset(colIndex),
                        right: colCoordCache.getRightOffset(colIndex),
                        top: snapTop,
                        bottom: snapBottom
                    };
                }
            }
        },

        getHitSpan: function (hit) {
            var start = this.getCellDate(0, hit.col); // row=0
            var time = this.computeSnapTime(hit.snap); // pass in the snap-index
            var end;

            start.time(time);
            end = start.clone().add(this.snapDuration);

            return { start: start, end: end };
        },

        getHitEl: function (hit) {
            return this.colEls.eq(hit.col);
        },

        /* Dates
        ------------------------------------------------------------------------------------------------------------------*/

        rangeUpdated: function () {
            this.updateDayTable();
        },

        // Given a row number of the grid, representing a "snap", returns a time (Duration) from its start-of-day
        computeSnapTime: function (snapIndex) {
            return moment.duration(this.minTime + this.snapDuration * snapIndex);
        },

        // Slices up the given span (unzoned start/end with other misc data) into an array of segments
        spanToSegs: function (span) {
            var segs = this.sliceRangeByTimes(span);
            var i;

            for (i = 0; i < segs.length; i++) {
                if (this.isRTL) {
                    segs[i].col = this.daysPerRow - 1 - segs[i].dayIndex;
                }
                else {
                    segs[i].col = segs[i].dayIndex;
                }
            }

            return segs;
        },

        sliceRangeByTimes: function (range) {
            var segs = [];
            var seg;
            var dayIndex;
            var dayDate;
            var dayRange;

            for (dayIndex = 0; dayIndex < this.daysPerRow; dayIndex++) {
                dayDate = this.dayDates[dayIndex].clone(); // TODO: better API for this?
                dayRange = {
                    start: dayDate.clone().time(this.minTime),
                    end: dayDate.clone().time(this.maxTime)
                };
                seg = intersectRanges(range, dayRange); // both will be ambig timezone
                if (seg) {
                    seg.dayIndex = dayIndex;
                    segs.push(seg);
                }
            }

            return segs;
        },

        /* Coordinates
        ------------------------------------------------------------------------------------------------------------------*/

        updateSize: function (isResize) { // NOT a standard Grid method
            this.slatCoordCache.build();

            if (isResize) {
                this.updateSegVerticals(
                    [].concat(this.fgSegs || [], this.bgSegs || [], this.businessSegs || [])
                );
            }
        },

        getTotalSlatHeight: function () {
            return this.slatContainerEl.outerHeight();
        },

        // Computes the top coordinate, relative to the bounds of the grid, of the given date.
        // A `startOfDayDate` must be given for avoiding ambiguity over how to treat midnight.
        computeDateTop: function (date, startOfDayDate) {
            return this.computeTimeTop(
                moment.duration(
                    date - startOfDayDate.clone().stripTime()
                )
            );
        },

        // Computes the top coordinate, relative to the bounds of the grid, of the given time (a Duration).
        computeTimeTop: function (time) {
            var len = this.slatEls.length;
            var slatCoverage = (time - this.minTime) / this.slotDuration; // floating-point value of # of slots covered
            var slatIndex;
            var slatRemainder;

            // compute a floating-point number for how many slats should be progressed through.
            // from 0 to number of slats (inclusive)
            // constrained because minTime/maxTime might be customized.
            slatCoverage = Math.max(0, slatCoverage);
            slatCoverage = Math.min(len, slatCoverage);

            // an integer index of the furthest whole slat
            // from 0 to number slats (*exclusive*, so len-1)
            slatIndex = Math.floor(slatCoverage);
            slatIndex = Math.min(slatIndex, len - 1);

            // how much further through the slatIndex slat (from 0.0-1.0) must be covered in addition.
            // could be 1.0 if slatCoverage is covering *all* the slots
            slatRemainder = slatCoverage - slatIndex;

            return this.slatCoordCache.getTopPosition(slatIndex) +
                this.slatCoordCache.getHeight(slatIndex) * slatRemainder;
        },

        /* Event Drag Visualization
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of an event being dragged over the specified date(s).
        // A returned value of `true` signals that a mock "helper" event has been rendered.
        renderDrag: function (eventLocation, seg) {
            if (seg) { // if there is event information for this drag, render a helper event
                // returns mock event elements
                // signal that a helper has been rendered
                return this.renderEventLocationHelper(eventLocation, seg);
            }
            else {
                // otherwise, just render a highlight
                this.renderHighlight(this.eventToSpan(eventLocation));
            }
        },

        // Unrenders any visual indication of an event being dragged
        unrenderDrag: function () {
            this.unrenderHelper();
            this.unrenderHighlight();
        },

        /* Event Resize Visualization
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of an event being resized
        renderEventResize: function (eventLocation, seg) {
            return this.renderEventLocationHelper(eventLocation, seg); // returns mock event elements
        },

        // Unrenders any visual indication of an event being resized
        unrenderEventResize: function () {
            this.unrenderHelper();
        },

        /* Event Helper
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a mock "helper" event. `sourceSeg` is the original segment object and might be null (an external drag)
        renderHelper: function (event, sourceSeg) {
            return this.renderHelperSegs(this.eventToSegs(event), sourceSeg); // returns mock event elements
        },

        // Unrenders any mock helper event
        unrenderHelper: function () {
            this.unrenderHelperSegs();
        },

        /* Business Hours
        ------------------------------------------------------------------------------------------------------------------*/

        renderBusinessHours: function () {
            this.renderBusinessSegs(
                this.buildBusinessHourSegs()
            );
        },

        unrenderBusinessHours: function () {
            this.unrenderBusinessSegs();
        },

        /* Now Indicator
        ------------------------------------------------------------------------------------------------------------------*/

        getNowIndicatorUnit: function () {
            return 'minute'; // will refresh on the minute
        },

        renderNowIndicator: function (date) {
            // seg system might be overkill, but it handles scenario where line needs to be rendered
            //  more than once because of columns with the same date (resources columns for example)
            var segs = this.spanToSegs({ start: date, end: date });
            var top = this.computeDateTop(date, date);
            var nodes = [];
            var i;

            // render lines within the columns
            for (i = 0; i < segs.length; i++) {
                nodes.push($('<div class="fc-now-indicator fc-now-indicator-line"></div>')
                    .css('top', top)
                    .appendTo(this.colContainerEls.eq(segs[i].col))[0]);
            }

            // render an arrow over the axis
            if (segs.length > 0) { // is the current time in view?
                nodes.push($('<div class="fc-now-indicator fc-now-indicator-arrow"></div>')
                    .css('top', top)
                    .appendTo(this.el.find('.fc-content-skeleton'))[0]);
            }

            this.nowIndicatorEls = $(nodes);
        },

        unrenderNowIndicator: function () {
            if (this.nowIndicatorEls) {
                this.nowIndicatorEls.remove();
                this.nowIndicatorEls = null;
            }
        },

        /* Selection
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of a selection. Overrides the default, which was to simply render a highlight.
        renderSelection: function (span) {
            if (this.view.opt('selectHelper')) { // this setting signals that a mock helper event should be rendered
                // normally acceps an eventLocation, span has a start/end, which is good enough
                this.renderEventLocationHelper(span);
            }
            else {
                this.renderHighlight(span);
            }
        },

        // Unrenders any visual indication of a selection
        unrenderSelection: function () {
            this.unrenderHelper();
            this.unrenderHighlight();
        },

        /* Highlight
        ------------------------------------------------------------------------------------------------------------------*/

        renderHighlight: function (span) {
            this.renderHighlightSegs(this.spanToSegs(span));
        },

        unrenderHighlight: function () {
            this.unrenderHighlightSegs();
        }
    });

    ;;

    /* Methods for rendering SEGMENTS, pieces of content that live on the view
     ( this file is no longer just for events )
    ----------------------------------------------------------------------------------------------------------------------*/

    TimeGrid.mixin({
        colContainerEls: null, // containers for each column

        // inner-containers for each column where different types of segs live
        fgContainerEls: null,
        bgContainerEls: null,
        helperContainerEls: null,
        highlightContainerEls: null,
        businessContainerEls: null,

        // arrays of different types of displayed segments
        fgSegs: null,
        bgSegs: null,
        helperSegs: null,
        highlightSegs: null,
        businessSegs: null,

        // Renders the DOM that the view's content will live in
        renderContentSkeleton: function () {
            var cellHtml = '';
            var i;
            var skeletonEl;

            for (i = 0; i < this.colCnt; i++) {
                cellHtml +=
                    '<td>' +
                    '<div class="fc-content-col">' +
                    '<div class="fc-event-container fc-helper-container"></div>' +
                    '<div class="fc-event-container"></div>' +
                    '<div class="fc-highlight-container"></div>' +
                    '<div class="fc-bgevent-container"></div>' +
                    '<div class="fc-business-container"></div>' +
                    '</div>' +
                    '</td>';
            }

            skeletonEl = $(
                '<div class="fc-content-skeleton">' +
                '<table>' +
                '<tr>' + cellHtml + '</tr>' +
                '</table>' +
                '</div>'
            );

            this.colContainerEls = skeletonEl.find('.fc-content-col');
            this.helperContainerEls = skeletonEl.find('.fc-helper-container');
            this.fgContainerEls = skeletonEl.find('.fc-event-container:not(.fc-helper-container)');
            this.bgContainerEls = skeletonEl.find('.fc-bgevent-container');
            this.highlightContainerEls = skeletonEl.find('.fc-highlight-container');
            this.businessContainerEls = skeletonEl.find('.fc-business-container');

            this.bookendCells(skeletonEl.find('tr')); // TODO: do this on string level
            this.el.append(skeletonEl);
        },

        /* Foreground Events
        ------------------------------------------------------------------------------------------------------------------*/

        renderFgSegs: function (segs) {
            segs = this.renderFgSegsIntoContainers(segs, this.fgContainerEls);
            this.fgSegs = segs;
            return segs; // needed for Grid::renderEvents
        },

        unrenderFgSegs: function () {
            this.unrenderNamedSegs('fgSegs');
        },

        /* Foreground Helper Events
        ------------------------------------------------------------------------------------------------------------------*/

        renderHelperSegs: function (segs, sourceSeg) {
            var helperEls = [];
            var i, seg;
            var sourceEl;

            segs = this.renderFgSegsIntoContainers(segs, this.helperContainerEls);

            // Try to make the segment that is in the same row as sourceSeg look the same
            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                if (sourceSeg && sourceSeg.col === seg.col) {
                    sourceEl = sourceSeg.el;
                    seg.el.css({
                        left: sourceEl.css('left'),
                        right: sourceEl.css('right'),
                        'margin-left': sourceEl.css('margin-left'),
                        'margin-right': sourceEl.css('margin-right')
                    });
                }
                helperEls.push(seg.el[0]);
            }

            this.helperSegs = segs;

            return $(helperEls); // must return rendered helpers
        },

        unrenderHelperSegs: function () {
            this.unrenderNamedSegs('helperSegs');
        },

        /* Background Events
        ------------------------------------------------------------------------------------------------------------------*/

        renderBgSegs: function (segs) {
            segs = this.renderFillSegEls('bgEvent', segs); // TODO: old fill system
            this.updateSegVerticals(segs);
            this.attachSegsByCol(this.groupSegsByCol(segs), this.bgContainerEls);
            this.bgSegs = segs;
            return segs; // needed for Grid::renderEvents
        },

        unrenderBgSegs: function () {
            this.unrenderNamedSegs('bgSegs');
        },

        /* Highlight
        ------------------------------------------------------------------------------------------------------------------*/

        renderHighlightSegs: function (segs) {
            segs = this.renderFillSegEls('highlight', segs); // TODO: old fill system
            this.updateSegVerticals(segs);
            this.attachSegsByCol(this.groupSegsByCol(segs), this.highlightContainerEls);
            this.highlightSegs = segs;
        },

        unrenderHighlightSegs: function () {
            this.unrenderNamedSegs('highlightSegs');
        },

        /* Business Hours
        ------------------------------------------------------------------------------------------------------------------*/

        renderBusinessSegs: function (segs) {
            segs = this.renderFillSegEls('businessHours', segs); // TODO: old fill system
            this.updateSegVerticals(segs);
            this.attachSegsByCol(this.groupSegsByCol(segs), this.businessContainerEls);
            this.businessSegs = segs;
        },

        unrenderBusinessSegs: function () {
            this.unrenderNamedSegs('businessSegs');
        },

        /* Seg Rendering Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Given a flat array of segments, return an array of sub-arrays, grouped by each segment's col
        groupSegsByCol: function (segs) {
            var segsByCol = [];
            var i;

            for (i = 0; i < this.colCnt; i++) {
                segsByCol.push([]);
            }

            for (i = 0; i < segs.length; i++) {
                segsByCol[segs[i].col].push(segs[i]);
            }

            return segsByCol;
        },

        // Given segments grouped by column, insert the segments' elements into a parallel array of container
        // elements, each living within a column.
        attachSegsByCol: function (segsByCol, containerEls) {
            var col;
            var segs;
            var i;

            for (col = 0; col < this.colCnt; col++) { // iterate each column grouping
                segs = segsByCol[col];

                for (i = 0; i < segs.length; i++) {
                    containerEls.eq(col).append(segs[i].el);
                }
            }
        },

        // Given the name of a property of `this` object, assumed to be an array of segments,
        // loops through each segment and removes from DOM. Will null-out the property afterwards.
        unrenderNamedSegs: function (propName) {
            var segs = this[propName];
            var i;

            if (segs) {
                for (i = 0; i < segs.length; i++) {
                    segs[i].el.remove();
                }
                this[propName] = null;
            }
        },

        /* Foreground Event Rendering Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Given an array of foreground segments, render a DOM element for each, computes position,
        // and attaches to the column inner-container elements.
        renderFgSegsIntoContainers: function (segs, containerEls) {
            var segsByCol;
            var col;

            segs = this.renderFgSegEls(segs); // will call fgSegHtml
            segsByCol = this.groupSegsByCol(segs);

            for (col = 0; col < this.colCnt; col++) {
                this.updateFgSegCoords(segsByCol[col]);
            }

            this.attachSegsByCol(segsByCol, containerEls);

            return segs;
        },

        // Renders the HTML for a single event segment's default rendering
        fgSegHtml: function (seg, disableResizing) {
            var view = this.view;
            var event = seg.event;
            var isDraggable = view.isEventDraggable(event);
            var isResizableFromStart = !disableResizing && seg.isStart && view.isEventResizableFromStart(event);
            var isResizableFromEnd = !disableResizing && seg.isEnd && view.isEventResizableFromEnd(event);
            var classes = this.getSegClasses(seg, isDraggable, isResizableFromStart || isResizableFromEnd);
            var skinCss = cssToStr(this.getSegSkinCss(seg));
            var timeText;
            var fullTimeText; // more verbose time text. for the print stylesheet
            var startTimeText; // just the start time text

            classes.unshift('fc-time-grid-event', 'fc-v-event');

            if (view.isMultiDayEvent(event)) { // if the event appears to span more than one day...
                // Don't display time text on segments that run entirely through a day.
                // That would appear as midnight-midnight and would look dumb.
                // Otherwise, display the time text for the *segment's* times (like 6pm-midnight or midnight-10am)
                if (seg.isStart || seg.isEnd) {
                    timeText = this.getEventTimeText(seg);
                    fullTimeText = this.getEventTimeText(seg, 'LT');
                    startTimeText = this.getEventTimeText(seg, null, false); // displayEnd=false
                }
            } else {
                // Display the normal time text for the *event's* times
                timeText = this.getEventTimeText(event);
                fullTimeText = this.getEventTimeText(event, 'LT');
                startTimeText = this.getEventTimeText(event, null, false); // displayEnd=false
            }

            return '<a tooltips class="' + classes.join(' ') + '"' +
                (event.url ?
                    ' href="' + htmlEscape(event.url) + '"' :
                    ''
                ) +
                (skinCss ?
                    ' style="' + skinCss + '"' :
                    ''
                ) +
                (event.content ?
                    ' title="' + htmlEscape(event.content) + '"' :
                    ''
                ) +
                '>' +
                '<div class="fc-content">' +
                (timeText ?
                    '<div class="fc-time"' +
                    ' data-start="' + htmlEscape(startTimeText) + '"' +
                    ' data-full="' + htmlEscape(fullTimeText) + '"' +
                    '>' +
                    '<span>' + htmlEscape(timeText) + '</span>' +
                    '</div>' :
                    ''
                ) +
                (event.title ?
                    '<div class="fc-title">' +
                    htmlEscape(event.title) +
                    '</div>' :
                    ''
                ) +
                (event.content ?
                    '<div class="fc-content">' +
                    htmlEscape(event.content) +
                    '</div>' :
                    ''
                ) +
                '</div>' +
                '<div class="fc-bg"/>' +
                /* TODO: write CSS for this
                (isResizableFromStart ?
                    '<div class="fc-resizer fc-start-resizer" />' :
                    ''
                    ) +
                */
                (isResizableFromEnd ?
                    '<div class="fc-resizer fc-end-resizer" />' :
                    ''
                ) +
                '</a>';
        },

        /* Seg Position Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Refreshes the CSS top/bottom coordinates for each segment element.
        // Works when called after initial render, after a window resize/zoom for example.
        updateSegVerticals: function (segs) {
            this.computeSegVerticals(segs);
            this.assignSegVerticals(segs);
        },

        // For each segment in an array, computes and assigns its top and bottom properties
        computeSegVerticals: function (segs) {
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                seg.top = this.computeDateTop(seg.start, seg.start);
                seg.bottom = this.computeDateTop(seg.end, seg.start);
            }
        },

        // Given segments that already have their top/bottom properties computed, applies those values to
        // the segments' elements.
        assignSegVerticals: function (segs) {
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                seg.el.css(this.generateSegVerticalCss(seg));
            }
        },

        // Generates an object with CSS properties for the top/bottom coordinates of a segment element
        generateSegVerticalCss: function (seg) {
            return {
                top: seg.top,
                bottom: -seg.bottom // flipped because needs to be space beyond bottom edge of event container
            };
        },

        /* Foreground Event Positioning Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Given segments that are assumed to all live in the *same column*,
        // compute their verical/horizontal coordinates and assign to their elements.
        updateFgSegCoords: function (segs) {
            this.computeSegVerticals(segs); // horizontals relies on this
            this.computeFgSegHorizontals(segs); // compute horizontal coordinates, z-index's, and reorder the array
            this.assignSegVerticals(segs);
            this.assignFgSegHorizontals(segs);
        },

        // Given an array of segments that are all in the same column, sets the backwardCoord and forwardCoord on each.
        // NOTE: Also reorders the given array by date!
        computeFgSegHorizontals: function (segs) {
            var levels;
            var level0;
            var i;

            this.sortEventSegs(segs); // order by certain criteria
            levels = buildSlotSegLevels(segs);
            computeForwardSlotSegs(levels);

            if ((level0 = levels[0])) {
                for (i = 0; i < level0.length; i++) {
                    computeSlotSegPressures(level0[i]);
                }

                for (i = 0; i < level0.length; i++) {
                    this.computeFgSegForwardBack(level0[i], 0, 0);
                }
            }
        },

        // Calculate seg.forwardCoord and seg.backwardCoord for the segment, where both values range
        // from 0 to 1. If the calendar is left-to-right, the seg.backwardCoord maps to "left" and
        // seg.forwardCoord maps to "right" (via percentage). Vice-versa if the calendar is right-to-left.
        //
        // The segment might be part of a "series", which means consecutive segments with the same pressure
        // who's width is unknown until an edge has been hit. `seriesBackwardPressure` is the number of
        // segments behind this one in the current series, and `seriesBackwardCoord` is the starting
        // coordinate of the first segment in the series.
        computeFgSegForwardBack: function (seg, seriesBackwardPressure, seriesBackwardCoord) {
            var forwardSegs = seg.forwardSegs;
            var i;

            if (seg.forwardCoord === undefined) { // not already computed
                if (!forwardSegs.length) {
                    // if there are no forward segments, this segment should butt up against the edge
                    seg.forwardCoord = 1;
                }
                else {
                    // sort highest pressure first
                    this.sortForwardSegs(forwardSegs);

                    // this segment's forwardCoord will be calculated from the backwardCoord of the
                    // highest-pressure forward segment.
                    this.computeFgSegForwardBack(forwardSegs[0], seriesBackwardPressure + 1, seriesBackwardCoord);
                    seg.forwardCoord = forwardSegs[0].backwardCoord;
                }

                // calculate the backwardCoord from the forwardCoord. consider the series
                seg.backwardCoord = seg.forwardCoord -
                    (seg.forwardCoord - seriesBackwardCoord) / // available width for series
                    (seriesBackwardPressure + 1); // # of segments in the series

                // use this segment's coordinates to computed the coordinates of the less-pressurized
                // forward segments
                for (i = 0; i < forwardSegs.length; i++) {
                    this.computeFgSegForwardBack(forwardSegs[i], 0, seg.forwardCoord);
                }
            }
        },

        sortForwardSegs: function (forwardSegs) {
            forwardSegs.sort(proxy(this, 'compareForwardSegs'));
        },

        // A cmp function for determining which forward segment to rely on more when computing coordinates.
        compareForwardSegs: function (seg1, seg2) {
            // put higher-pressure first
            return seg2.forwardPressure - seg1.forwardPressure ||
                // put segments that are closer to initial edge first (and favor ones with no coords yet)
                (seg1.backwardCoord || 0) - (seg2.backwardCoord || 0) ||
                // do normal sorting...
                this.compareEventSegs(seg1, seg2);
        },

        // Given foreground event segments that have already had their position coordinates computed,
        // assigns position-related CSS values to their elements.
        assignFgSegHorizontals: function (segs) {
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                seg.el.css(this.generateFgSegHorizontalCss(seg));

                // if the height is short, add a className for alternate styling
                if (seg.bottom - seg.top < 30) {
                    seg.el.addClass('fc-short');
                }
            }
        },

        // Generates an object with CSS properties/values that should be applied to an event segment element.
        // Contains important positioning-related properties that should be applied to any event element, customized or not.
        generateFgSegHorizontalCss: function (seg) {
            var shouldOverlap = this.view.opt('slotEventOverlap');
            var backwardCoord = seg.backwardCoord; // the left side if LTR. the right side if RTL. floating-point
            var forwardCoord = seg.forwardCoord; // the right side if LTR. the left side if RTL. floating-point
            var props = this.generateSegVerticalCss(seg); // get top/bottom first
            var left; // amount of space from left edge, a fraction of the total width
            var right; // amount of space from right edge, a fraction of the total width

            if (shouldOverlap) {
                // double the width, but don't go beyond the maximum forward coordinate (1.0)
                forwardCoord = Math.min(1, backwardCoord + (forwardCoord - backwardCoord) * 2);
            }

            if (this.isRTL) {
                left = 1 - forwardCoord;
                right = backwardCoord;
            }
            else {
                left = backwardCoord;
                right = 1 - forwardCoord;
            }

            props.zIndex = seg.level + 1; // convert from 0-base to 1-based
            props.left = left * 100 + '%';
            props.right = right * 100 + '%';

            if (shouldOverlap && seg.forwardPressure) {
                // add padding to the edge so that forward stacked events don't cover the resizer's icon
                props[this.isRTL ? 'marginLeft' : 'marginRight'] = 10 * 2; // 10 is a guesstimate of the icon's width
            }

            return props;
        }
    });

    // Builds an array of segments "levels". The first level will be the leftmost tier of segments if the calendar is
    // left-to-right, or the rightmost if the calendar is right-to-left. Assumes the segments are already ordered by date.
    function buildSlotSegLevels(segs) {
        var levels = [];
        var i, seg;
        var j;

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];

            // go through all the levels and stop on the first level where there are no collisions
            for (j = 0; j < levels.length; j++) {
                if (!computeSlotSegCollisions(seg, levels[j]).length) {
                    break;
                }
            }

            seg.level = j;

            (levels[j] || (levels[j] = [])).push(seg);
        }

        return levels;
    }

    // For every segment, figure out the other segments that are in subsequent
    // levels that also occupy the same vertical space. Accumulate in seg.forwardSegs
    function computeForwardSlotSegs(levels) {
        var i, level;
        var j, seg;
        var k;

        for (i = 0; i < levels.length; i++) {
            level = levels[i];

            for (j = 0; j < level.length; j++) {
                seg = level[j];

                seg.forwardSegs = [];
                for (k = i + 1; k < levels.length; k++) {
                    computeSlotSegCollisions(seg, levels[k], seg.forwardSegs);
                }
            }
        }
    }

    // Figure out which path forward (via seg.forwardSegs) results in the longest path until
    // the furthest edge is reached. The number of segments in this path will be seg.forwardPressure
    function computeSlotSegPressures(seg) {
        var forwardSegs = seg.forwardSegs;
        var forwardPressure = 0;
        var i, forwardSeg;

        if (seg.forwardPressure === undefined) { // not already computed
            for (i = 0; i < forwardSegs.length; i++) {
                forwardSeg = forwardSegs[i];

                // figure out the child's maximum forward path
                computeSlotSegPressures(forwardSeg);

                // either use the existing maximum, or use the child's forward pressure
                // plus one (for the forwardSeg itself)
                forwardPressure = Math.max(
                    forwardPressure,
                    1 + forwardSeg.forwardPressure
                );
            }

            seg.forwardPressure = forwardPressure;
        }
    }

    // Find all the segments in `otherSegs` that vertically collide with `seg`.
    // Append into an optionally-supplied `results` array and return.
    function computeSlotSegCollisions(seg, otherSegs, results) {
        results = results || [];

        for (var i = 0; i < otherSegs.length; i++) {
            if (isSlotSegCollision(seg, otherSegs[i])) {
                results.push(otherSegs[i]);
            }
        }

        return results;
    }

    // Do these segments occupy the same vertical space?
    function isSlotSegCollision(seg1, seg2) {
        return seg1.bottom > seg2.top && seg1.top < seg2.bottom;
    }

    ;;

    /* An abstract class from which other views inherit from
    ----------------------------------------------------------------------------------------------------------------------*/

    var View = FC.View = Class.extend(EmitterMixin, ListenerMixin, {
        type: null, // subclass' view name (string)
        name: null, // deprecated. use `type` instead
        title: null, // the text that will be displayed in the header's title

        calendar: null, // owner Calendar object
        options: null, // hash containing all options. already merged with view-specific-options
        el: null, // the view's containing element. set by Calendar

        isDateSet: false,
        isDateRendered: false,
        dateRenderQueue: null,

        isEventsBound: false,
        isEventsSet: false,
        isEventsRendered: false,
        eventRenderQueue: null,

        // range the view is actually displaying (moments)
        start: null,
        end: null, // exclusive

        // range the view is formally responsible for (moments)
        // may be different from start/end. for example, a month view might have 1st-31st, excluding padded dates
        intervalStart: null,
        intervalEnd: null, // exclusive
        intervalDuration: null,
        intervalUnit: null, // name of largest unit being displayed, like "month" or "week"

        isRTL: false,
        isSelected: false, // boolean whether a range of time is user-selected or not
        selectedEvent: null,

        eventOrderSpecs: null, // criteria for ordering events when they have same date/time

        // classNames styled by jqui themes
        widgetHeaderClass: null,
        widgetContentClass: null,
        highlightStateClass: null,

        // for date utils, computed from options
        nextDayThreshold: null,
        isHiddenDayHash: null,

        // now indicator
        isNowIndicatorRendered: null,
        initialNowDate: null, // result first getNow call
        initialNowQueriedMs: null, // ms time the getNow was called
        nowIndicatorTimeoutID: null, // for refresh timing of now indicator
        nowIndicatorIntervalID: null, // "

        constructor: function (calendar, type, options, intervalDuration) {
            this.calendar = calendar;
            this.type = this.name = type; // .name is deprecated
            this.options = options;
            this.intervalDuration = intervalDuration || moment.duration(1, 'day');

            this.nextDayThreshold = moment.duration(this.opt('nextDayThreshold'));
            this.initThemingProps();
            this.initHiddenDays();
            this.isRTL = this.opt('isRTL');

            this.eventOrderSpecs = parseFieldSpecs(this.opt('eventOrder'));

            this.dateRenderQueue = new TaskQueue();
            this.eventRenderQueue = new TaskQueue(this.opt('eventRenderWait'));

            this.initialize();
        },

        // A good place for subclasses to initialize member variables
        initialize: function () {
            // subclasses can implement
        },

        // Retrieves an option with the given name
        opt: function (name) {
            return this.options[name];
        },

        // Triggers handlers that are view-related. Modifies args before passing to calendar.
        publiclyTrigger: function (name, thisObj) { // arguments beyond thisObj are passed along
            var calendar = this.calendar;

            return calendar.publiclyTrigger.apply(
                calendar,
                [name, thisObj || this].concat(
                    Array.prototype.slice.call(arguments, 2), // arguments beyond thisObj
                    [this] // always make the last argument a reference to the view. TODO: deprecate
                )
            );
        },

        // Returns a proxy of the given promise that will be rejected if the given event fires
        // before the promise resolves.
        rejectOn: function (eventName, promise) {
            var _this = this;

            return new Promise(function (resolve, reject) {
                _this.one(eventName, reject);

                function cleanup() {
                    _this.off(eventName, reject);
                }

                promise.then(function (res) { // success
                    cleanup();
                    resolve(res);
                }, function () { // failure
                    cleanup();
                    reject();
                });
            });
        },

        /* Date Computation
        ------------------------------------------------------------------------------------------------------------------*/

        // Updates all internal dates for displaying the given unzoned range.
        setRange: function (range) {
            $.extend(this, range); // assigns every property to this object's member variables
            this.updateTitle();
        },

        // Given a single current unzoned date, produce information about what range to display.
        // Subclasses can override. Must return all properties.
        computeRange: function (date) {
            var intervalUnit = computeIntervalUnit(this.intervalDuration);
            var intervalStart = date.clone().startOf(intervalUnit);
            var intervalEnd = intervalStart.clone().add(this.intervalDuration);
            var start, end;

            // normalize the range's time-ambiguity
            if (/year|month|week|day/.test(intervalUnit)) { // whole-days?
                intervalStart.stripTime();
                intervalEnd.stripTime();
            }
            else { // needs to have a time?
                if (!intervalStart.hasTime()) {
                    intervalStart = this.calendar.time(0); // give 00:00 time
                }
                if (!intervalEnd.hasTime()) {
                    intervalEnd = this.calendar.time(0); // give 00:00 time
                }
            }

            start = intervalStart.clone();
            start = this.skipHiddenDays(start);
            end = intervalEnd.clone();
            end = this.skipHiddenDays(end, -1, true); // exclusively move backwards

            return {
                intervalUnit: intervalUnit,
                intervalStart: intervalStart,
                intervalEnd: intervalEnd,
                start: start,
                end: end
            };
        },

        // Computes the new date when the user hits the prev button, given the current date
        computePrevDate: function (date) {
            return this.massageCurrentDate(
                date.clone().startOf(this.intervalUnit).subtract(this.intervalDuration), -1
            );
        },

        // Computes the new date when the user hits the next button, given the current date
        computeNextDate: function (date) {
            return this.massageCurrentDate(
                date.clone().startOf(this.intervalUnit).add(this.intervalDuration)
            );
        },

        // Given an arbitrarily calculated current date of the calendar, returns a date that is ensured to be completely
        // visible. `direction` is optional and indicates which direction the current date was being
        // incremented or decremented (1 or -1).
        massageCurrentDate: function (date, direction) {
            if (this.intervalDuration.as('days') <= 1) { // if the view displays a single day or smaller
                if (this.isHiddenDay(date)) {
                    date = this.skipHiddenDays(date, direction);
                    date.startOf('day');
                }
            }

            return date;
        },

        /* Title and Date Formatting
        ------------------------------------------------------------------------------------------------------------------*/

        // Sets the view's title property to the most updated computed value
        updateTitle: function () {
            this.title = this.computeTitle();
            this.calendar.setToolbarsTitle(this.title);
        },

        // Computes what the title at the top of the calendar should be for this view
        computeTitle: function () {
            return this.formatRange(
                {
                    // in case intervalStart/End has a time, make sure timezone is correct
                    start: this.calendar.applyTimezone(this.intervalStart),
                    end: this.calendar.applyTimezone(this.intervalEnd)
                },
                this.opt('titleFormat') || this.computeTitleFormat(),
                this.opt('titleRangeSeparator')
            );
        },

        // Generates the format string that should be used to generate the title for the current date range.
        // Attempts to compute the most appropriate format if not explicitly specified with `titleFormat`.
        computeTitleFormat: function () {
            if (this.intervalUnit == 'year') {
                return 'YYYY';
            }
            else if (this.intervalUnit == 'month') {
                return this.opt('monthYearFormat'); // like "September 2014"
            }
            else if (this.intervalDuration.as('days') > 1) {
                return 'll'; // multi-day range. shorter, like "Sep 9 - 10 2014"
            }
            else {
                return 'LL'; // one day. longer, like "September 9 2014"
            }
        },

        // Utility for formatting a range. Accepts a range object, formatting string, and optional separator.
        // Displays all-day ranges naturally, with an inclusive end. Takes the current isRTL into account.
        // The timezones of the dates within `range` will be respected.
        formatRange: function (range, formatStr, separator) {
            var end = range.end;

            if (!end.hasTime()) { // all-day?
                end = end.clone().subtract(1); // convert to inclusive. last ms of previous day
            }

            return formatRange(range.start, end, formatStr, separator, this.opt('isRTL'));
        },

        getAllDayHtml: function () {
            return this.opt('allDayHtml') || htmlEscape(this.opt('allDayText'));
        },

        /* Navigation
        ------------------------------------------------------------------------------------------------------------------*/

        // Generates HTML for an anchor to another view into the calendar.
        // Will either generate an <a> tag or a non-clickable <span> tag, depending on enabled settings.
        // `gotoOptions` can either be a moment input, or an object with the form:
        // { date, type, forceOff }
        // `type` is a view-type like "day" or "week". default value is "day".
        // `attrs` and `innerHtml` are use to generate the rest of the HTML tag.
        buildGotoAnchorHtml: function (gotoOptions, attrs, innerHtml) {
            var date, type, forceOff;
            var finalOptions;

            if ($.isPlainObject(gotoOptions)) {
                date = gotoOptions.date;
                type = gotoOptions.type;
                forceOff = gotoOptions.forceOff;
            }
            else {
                date = gotoOptions; // a single moment input
            }
            date = FC.moment(date); // if a string, parse it

            finalOptions = { // for serialization into the link
                date: date.format('YYYY-MM-DD'),
                type: type || 'day'
            };

            if (typeof attrs === 'string') {
                innerHtml = attrs;
                attrs = null;
            }

            attrs = attrs ? ' ' + attrsToStr(attrs) : ''; // will have a leading space
            innerHtml = innerHtml || '';

            if (!forceOff && this.opt('navLinks')) {
                return '<a' + attrs +
                    ' data-goto="' + htmlEscape(JSON.stringify(finalOptions)) + '">' +
                    innerHtml +
                    '</a>';
            }
            else {
                return '<span' + attrs + '>' +
                    innerHtml +
                    '</span>';
            }
        },

        // Rendering Non-date-related Content
        // -----------------------------------------------------------------------------------------------------------------

        // Sets the container element that the view should render inside of, does global DOM-related initializations,
        // and renders all the non-date-related content inside.
        setElement: function (el) {
            this.el = el;
            this.bindGlobalHandlers();
            this.renderSkeleton();
        },

        // Removes the view's container element from the DOM, clearing any content beforehand.
        // Undoes any other DOM-related attachments.
        removeElement: function () {
            this.unsetDate();
            this.unrenderSkeleton();

            this.unbindGlobalHandlers();

            this.el.remove();
            // NOTE: don't null-out this.el in case the View was destroyed within an API callback.
            // We don't null-out the View's other jQuery element references upon destroy,
            //  so we shouldn't kill this.el either.
        },

        // Renders the basic structure of the view before any content is rendered
        renderSkeleton: function () {
            // subclasses should implement
        },

        // Unrenders the basic structure of the view
        unrenderSkeleton: function () {
            // subclasses should implement
        },

        // Date Setting/Unsetting
        // -----------------------------------------------------------------------------------------------------------------

        setDate: function (date) {
            var isReset = this.isDateSet;

            this.isDateSet = true;
            this.handleDate(date, isReset);
            this.trigger(isReset ? 'dateReset' : 'dateSet', date);
        },

        unsetDate: function () {
            if (this.isDateSet) {
                this.isDateSet = false;
                this.handleDateUnset();
                this.trigger('dateUnset');
            }
        },

        // Date Handling
        // -----------------------------------------------------------------------------------------------------------------

        handleDate: function (date, isReset) {
            var _this = this;

            this.unbindEvents(); // will do nothing if not already bound
            this.requestDateRender(date).then(function () {
                // wish we could start earlier, but setRange/computeRange needs to execute first
                _this.bindEvents(); // will request events
            });
        },

        handleDateUnset: function () {
            this.unbindEvents();
            this.requestDateUnrender();
        },

        // Date Render Queuing
        // -----------------------------------------------------------------------------------------------------------------

        // if date not specified, uses current
        requestDateRender: function (date) {
            var _this = this;

            return this.dateRenderQueue.add(function () {
                return _this.executeDateRender(date);
            });
        },

        requestDateUnrender: function () {
            var _this = this;

            return this.dateRenderQueue.add(function () {
                return _this.executeDateUnrender();
            });
        },

        // Date High-level Rendering
        // -----------------------------------------------------------------------------------------------------------------

        // if date not specified, uses current
        executeDateRender: function (date) {
            var _this = this;

            // if rendering a new date, reset scroll to initial state (scrollTime)
            if (date) {
                this.captureInitialScroll();
            }
            else {
                this.captureScroll(); // a rerender of the current date
            }

            this.freezeHeight();

            return this.executeDateUnrender().then(function () {
                if (date) {
                    _this.setRange(_this.computeRange(date));
                }

                if (_this.render) {
                    _this.render(); // TODO: deprecate
                }

                _this.renderDates();
                _this.updateSize();
                _this.renderBusinessHours(); // might need coordinates, so should go after updateSize()
                _this.startNowIndicator();

                _this.thawHeight();
                _this.releaseScroll();

                _this.isDateRendered = true;
                _this.onDateRender();
                _this.trigger('dateRender');
            });
        },

        executeDateUnrender: function () {
            var _this = this;

            if (_this.isDateRendered) {
                return this.requestEventsUnrender().then(function () {
                    _this.unselect();
                    _this.stopNowIndicator();
                    _this.triggerUnrender();
                    _this.unrenderBusinessHours();
                    _this.unrenderDates();

                    if (_this.destroy) {
                        _this.destroy(); // TODO: deprecate
                    }

                    _this.isDateRendered = false;
                    _this.trigger('dateUnrender');
                });
            }
            else {
                return Promise.resolve();
            }
        },

        // Date Rendering Triggers
        // -----------------------------------------------------------------------------------------------------------------

        onDateRender: function () {
            this.triggerRender();
        },

        // Date Low-level Rendering
        // -----------------------------------------------------------------------------------------------------------------

        // date-cell content only
        renderDates: function () {
            // subclasses should implement
        },

        // date-cell content only
        unrenderDates: function () {
            // subclasses should override
        },

        // Misc view rendering utils
        // -------------------------

        // Signals that the view's content has been rendered
        triggerRender: function () {
            this.publiclyTrigger('viewRender', this, this, this.el);
        },

        // Signals that the view's content is about to be unrendered
        triggerUnrender: function () {
            this.publiclyTrigger('viewDestroy', this, this, this.el);
        },

        // Binds DOM handlers to elements that reside outside the view container, such as the document
        bindGlobalHandlers: function () {
            this.listenTo($(document), 'mousedown', this.handleDocumentMousedown);
            this.listenTo($(document), 'touchstart', this.processUnselect);
        },

        // Unbinds DOM handlers from elements that reside outside the view container
        unbindGlobalHandlers: function () {
            this.stopListeningTo($(document));
        },

        // Initializes internal variables related to theming
        initThemingProps: function () {
            var tm = this.opt('theme') ? 'ui' : 'fc';

            this.widgetHeaderClass = tm + '-widget-header';
            this.widgetContentClass = tm + '-widget-content';
            this.highlightStateClass = tm + '-state-highlight';
        },

        /* Business Hours
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders business-hours onto the view. Assumes updateSize has already been called.
        renderBusinessHours: function () {
            // subclasses should implement
        },

        // Unrenders previously-rendered business-hours
        unrenderBusinessHours: function () {
            // subclasses should implement
        },

        /* Now Indicator
        ------------------------------------------------------------------------------------------------------------------*/

        // Immediately render the current time indicator and begins re-rendering it at an interval,
        // which is defined by this.getNowIndicatorUnit().
        // TODO: somehow do this for the current whole day's background too
        startNowIndicator: function () {
            var _this = this;
            var unit;
            var update;
            var delay; // ms wait value

            if (this.opt('nowIndicator')) {
                unit = this.getNowIndicatorUnit();
                if (unit) {
                    update = proxy(this, 'updateNowIndicator'); // bind to `this`

                    this.initialNowDate = this.calendar.getNow();
                    this.initialNowQueriedMs = +new Date();
                    this.renderNowIndicator(this.initialNowDate);
                    this.isNowIndicatorRendered = true;

                    // wait until the beginning of the next interval
                    delay = this.initialNowDate.clone().startOf(unit).add(1, unit) - this.initialNowDate;
                    this.nowIndicatorTimeoutID = setTimeout(function () {
                        _this.nowIndicatorTimeoutID = null;
                        update();
                        delay = +moment.duration(1, unit);
                        delay = Math.max(100, delay); // prevent too frequent
                        _this.nowIndicatorIntervalID = setInterval(update, delay); // update every interval
                    }, delay);
                }
            }
        },

        // rerenders the now indicator, computing the new current time from the amount of time that has passed
        // since the initial getNow call.
        updateNowIndicator: function () {
            if (this.isNowIndicatorRendered) {
                this.unrenderNowIndicator();
                this.renderNowIndicator(
                    this.initialNowDate.clone().add(new Date() - this.initialNowQueriedMs) // add ms
                );
            }
        },

        // Immediately unrenders the view's current time indicator and stops any re-rendering timers.
        // Won't cause side effects if indicator isn't rendered.
        stopNowIndicator: function () {
            if (this.isNowIndicatorRendered) {
                if (this.nowIndicatorTimeoutID) {
                    clearTimeout(this.nowIndicatorTimeoutID);
                    this.nowIndicatorTimeoutID = null;
                }
                if (this.nowIndicatorIntervalID) {
                    clearTimeout(this.nowIndicatorIntervalID);
                    this.nowIndicatorIntervalID = null;
                }

                this.unrenderNowIndicator();
                this.isNowIndicatorRendered = false;
            }
        },

        // Returns a string unit, like 'second' or 'minute' that defined how often the current time indicator
        // should be refreshed. If something falsy is returned, no time indicator is rendered at all.
        getNowIndicatorUnit: function () {
            // subclasses should implement
        },

        // Renders a current time indicator at the given datetime
        renderNowIndicator: function (date) {
            // subclasses should implement
        },

        // Undoes the rendering actions from renderNowIndicator
        unrenderNowIndicator: function () {
            // subclasses should implement
        },

        /* Dimensions
        ------------------------------------------------------------------------------------------------------------------*/

        // Refreshes anything dependant upon sizing of the container element of the grid
        updateSize: function (isResize) {
            if (isResize) {
                this.captureScroll();
            }

            this.updateHeight(isResize);
            this.updateWidth(isResize);
            this.updateNowIndicator();

            if (isResize) {
                this.releaseScroll();
            }
        },

        // Refreshes the horizontal dimensions of the calendar
        updateWidth: function (isResize) {
            // subclasses should implement
        },

        // Refreshes the vertical dimensions of the calendar
        updateHeight: function (isResize) {
            var calendar = this.calendar; // we poll the calendar for height information

            this.setHeight(
                calendar.getSuggestedViewHeight(),
                calendar.isHeightAuto()
            );
        },

        // Updates the vertical dimensions of the calendar to the specified height.
        // if `isAuto` is set to true, height becomes merely a suggestion and the view should use its "natural" height.
        setHeight: function (height, isAuto) {
            // subclasses should implement
        },

        /* Scroller
        ------------------------------------------------------------------------------------------------------------------*/

        capturedScroll: null,
        capturedScrollDepth: 0,

        captureScroll: function () {
            if (!(this.capturedScrollDepth++)) {
                this.capturedScroll = this.isDateRendered ? this.queryScroll() : {}; // require a render first
                return true; // root?
            }
            return false;
        },

        captureInitialScroll: function (forcedScroll) {
            if (this.captureScroll()) { // root?
                this.capturedScroll.isInitial = true;

                if (forcedScroll) {
                    $.extend(this.capturedScroll, forcedScroll);
                }
                else {
                    this.capturedScroll.isComputed = true;
                }
            }
        },

        releaseScroll: function () {
            var scroll = this.capturedScroll;
            var isRoot = this.discardScroll();

            if (scroll.isComputed) {
                if (isRoot) {
                    // only compute initial scroll if it will actually be used (is the root capture)
                    $.extend(scroll, this.computeInitialScroll());
                }
                else {
                    scroll = null; // scroll couldn't be computed. don't apply it to the DOM
                }
            }

            if (scroll) {
                // we act immediately on a releaseScroll operation, as opposed to captureScroll.
                // if capture/release wraps a render operation that screws up the scroll,
                // we still want to restore it a good state after, regardless of depth.

                if (scroll.isInitial) {
                    this.hardSetScroll(scroll); // outsmart how browsers set scroll on initial DOM
                }
                else {
                    this.setScroll(scroll);
                }
            }
        },

        discardScroll: function () {
            if (!(--this.capturedScrollDepth)) {
                this.capturedScroll = null;
                return true; // root?
            }
            return false;
        },

        computeInitialScroll: function () {
            return {};
        },

        queryScroll: function () {
            return {};
        },

        hardSetScroll: function (scroll) {
            var _this = this;
            var exec = function () { _this.setScroll(scroll); };
            exec();
            setTimeout(exec, 0); // to surely clear the browser's initial scroll for the DOM
        },

        setScroll: function (scroll) {
        },

        /* Height Freezing
        ------------------------------------------------------------------------------------------------------------------*/

        freezeHeight: function () {
            this.calendar.freezeContentHeight();
        },

        thawHeight: function () {
            this.calendar.thawContentHeight();
        },

        // Event Binding/Unbinding
        // -----------------------------------------------------------------------------------------------------------------

        bindEvents: function () {
            var _this = this;

            if (!this.isEventsBound) {
                this.isEventsBound = true;
                this.rejectOn('eventsUnbind', this.requestEvents()).then(function (events) { // TODO: test rejection
                    _this.listenTo(_this.calendar, 'eventsReset', _this.setEvents);
                    _this.setEvents(events);
                });
            }
        },

        unbindEvents: function () {
            if (this.isEventsBound) {
                this.isEventsBound = false;
                this.stopListeningTo(this.calendar, 'eventsReset');
                this.unsetEvents();
                this.trigger('eventsUnbind');
            }
        },

        // Event Setting/Unsetting
        // -----------------------------------------------------------------------------------------------------------------

        setEvents: function (events) {
            var isReset = this.isEventSet;

            this.isEventsSet = true;
            this.handleEvents(events, isReset);
            this.trigger(isReset ? 'eventsReset' : 'eventsSet', events);
        },

        unsetEvents: function () {
            if (this.isEventsSet) {
                this.isEventsSet = false;
                this.handleEventsUnset();
                this.trigger('eventsUnset');
            }
        },

        whenEventsSet: function () {
            var _this = this;

            if (this.isEventsSet) {
                return Promise.resolve(this.getCurrentEvents());
            }
            else {
                return new Promise(function (resolve) {
                    _this.one('eventsSet', resolve);
                });
            }
        },

        // Event Handling
        // -----------------------------------------------------------------------------------------------------------------

        handleEvents: function (events, isReset) {
            this.requestEventsRender(events);
        },

        handleEventsUnset: function () {
            this.requestEventsUnrender();
        },

        // Event Render Queuing
        // -----------------------------------------------------------------------------------------------------------------

        // assumes any previous event renders have been cleared already
        requestEventsRender: function (events) {
            var _this = this;

            return this.eventRenderQueue.add(function () { // might not return a promise if debounced!? bad
                return _this.executeEventsRender(events);
            });
        },

        requestEventsUnrender: function () {
            var _this = this;

            if (this.isEventsRendered) {
                return this.eventRenderQueue.addQuickly(function () {
                    return _this.executeEventsUnrender();
                });
            }
            else {
                return Promise.resolve();
            }
        },

        requestCurrentEventsRender: function () {
            if (this.isEventsSet) {
                this.requestEventsRender(this.getCurrentEvents());
            }
            else {
                return Promise.reject();
            }
        },

        // Event High-level Rendering
        // -----------------------------------------------------------------------------------------------------------------

        executeEventsRender: function (events) {
            var _this = this;

            this.captureScroll();
            this.freezeHeight();

            return this.executeEventsUnrender().then(function () {
                _this.renderEvents(events);

                _this.thawHeight();
                _this.releaseScroll();

                _this.isEventsRendered = true;
                _this.onEventsRender();
                _this.trigger('eventsRender');
            });
        },

        executeEventsUnrender: function () {
            if (this.isEventsRendered) {
                this.onBeforeEventsUnrender();

                this.captureScroll();
                this.freezeHeight();

                if (this.destroyEvents) {
                    this.destroyEvents(); // TODO: deprecate
                }

                this.unrenderEvents();

                this.thawHeight();
                this.releaseScroll();

                this.isEventsRendered = false;
                this.trigger('eventsUnrender');
            }

            return Promise.resolve(); // always synchronous
        },

        // Event Rendering Triggers
        // -----------------------------------------------------------------------------------------------------------------

        // Signals that all events have been rendered
        onEventsRender: function () {
            this.renderedEventSegEach(function (seg) {
                this.publiclyTrigger('eventAfterRender', seg.event, seg.event, seg.el);
            });
            this.publiclyTrigger('eventAfterAllRender');
        },

        // Signals that all event elements are about to be removed
        onBeforeEventsUnrender: function () {
            this.renderedEventSegEach(function (seg) {
                this.publiclyTrigger('eventDestroy', seg.event, seg.event, seg.el);
            });
        },

        // Event Low-level Rendering
        // -----------------------------------------------------------------------------------------------------------------

        // Renders the events onto the view.
        renderEvents: function (events) {
            // subclasses should implement
        },

        // Removes event elements from the view.
        unrenderEvents: function () {
            // subclasses should implement
        },

        // Event Data Access
        // -----------------------------------------------------------------------------------------------------------------

        requestEvents: function () {
            return this.calendar.requestEvents(this.start, this.end);
        },

        getCurrentEvents: function () {
            return this.calendar.getPrunedEventCache();
        },

        // Event Rendering Utils
        // -----------------------------------------------------------------------------------------------------------------

        // Given an event and the default element used for rendering, returns the element that should actually be used.
        // Basically runs events and elements through the eventRender hook.
        resolveEventEl: function (event, el) {
            var custom = this.publiclyTrigger('eventRender', event, event, el);

            if (custom === false) { // means don't render at all
                el = null;
            }
            else if (custom && custom !== true) {
                el = $(custom);
            }

            return el;
        },

        // Hides all rendered event segments linked to the given event
        showEvent: function (event) {
            this.renderedEventSegEach(function (seg) {
                seg.el.css('visibility', '');
            }, event);
        },

        // Shows all rendered event segments linked to the given event
        hideEvent: function (event) {
            this.renderedEventSegEach(function (seg) {
                seg.el.css('visibility', 'hidden');
            }, event);
        },

        // Iterates through event segments that have been rendered (have an el). Goes through all by default.
        // If the optional `event` argument is specified, only iterates through segments linked to that event.
        // The `this` value of the callback function will be the view.
        renderedEventSegEach: function (func, event) {
            var segs = this.getEventSegs();
            var i;

            for (i = 0; i < segs.length; i++) {
                if (!event || segs[i].event._id === event._id) {
                    if (segs[i].el) {
                        func.call(this, segs[i]);
                    }
                }
            }
        },

        // Retrieves all the rendered segment objects for the view
        getEventSegs: function () {
            // subclasses must implement
            return [];
        },

        /* Event Drag-n-Drop
        ------------------------------------------------------------------------------------------------------------------*/

        // Computes if the given event is allowed to be dragged by the user
        isEventDraggable: function (event) {
            return this.isEventStartEditable(event);
        },

        isEventStartEditable: function (event) {
            return firstDefined(
                event.startEditable,
                (event.source || {}).startEditable,
                this.opt('eventStartEditable'),
                this.isEventGenerallyEditable(event)
            );
        },

        isEventGenerallyEditable: function (event) {
            return firstDefined(
                event.editable,
                (event.source || {}).editable,
                this.opt('editable')
            );
        },

        // Must be called when an event in the view is dropped onto new location.
        // `dropLocation` is an object that contains the new zoned start/end/allDay values for the event.
        reportEventDrop: function (event, dropLocation, largeUnit, el, ev) {
            var calendar = this.calendar;
            var mutateResult = calendar.mutateEvent(event, dropLocation, largeUnit);
            var undoFunc = function () {
                mutateResult.undo();
                calendar.reportEventChange();
            };

            this.triggerEventDrop(event, mutateResult.dateDelta, undoFunc, el, ev);
            calendar.reportEventChange(); // will rerender events
        },

        // Triggers event-drop handlers that have subscribed via the API
        triggerEventDrop: function (event, dateDelta, undoFunc, el, ev) {
            this.publiclyTrigger('eventDrop', el[0], event, dateDelta, undoFunc, ev, {}); // {} = jqui dummy
        },

        /* External Element Drag-n-Drop
        ------------------------------------------------------------------------------------------------------------------*/

        // Must be called when an external element, via jQuery UI, has been dropped onto the calendar.
        // `meta` is the parsed data that has been embedded into the dragging event.
        // `dropLocation` is an object that contains the new zoned start/end/allDay values for the event.
        reportExternalDrop: function (meta, dropLocation, el, ev, ui) {
            var eventProps = meta.eventProps;
            var eventInput;
            var event;

            // Try to build an event object and render it. TODO: decouple the two
            if (eventProps) {
                eventInput = $.extend({}, eventProps, dropLocation);
                event = this.calendar.renderEvent(eventInput, meta.stick)[0]; // renderEvent returns an array
            }

            this.triggerExternalDrop(event, dropLocation, el, ev, ui);
        },

        // Triggers external-drop handlers that have subscribed via the API
        triggerExternalDrop: function (event, dropLocation, el, ev, ui) {
            // trigger 'drop' regardless of whether element represents an event
            this.publiclyTrigger('drop', el[0], dropLocation.start, ev, ui);

            if (event) {
                this.publiclyTrigger('eventReceive', null, event); // signal an external event landed
            }
        },

        /* Drag-n-Drop Rendering (for both events and external elements)
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of a event or external-element drag over the given drop zone.
        // If an external-element, seg will be `null`.
        // Must return elements used for any mock events.
        renderDrag: function (dropLocation, seg) {
            // subclasses must implement
        },

        // Unrenders a visual indication of an event or external-element being dragged.
        unrenderDrag: function () {
            // subclasses must implement
        },

        /* Event Resizing
        ------------------------------------------------------------------------------------------------------------------*/

        // Computes if the given event is allowed to be resized from its starting edge
        isEventResizableFromStart: function (event) {
            return this.opt('eventResizableFromStart') && this.isEventResizable(event);
        },

        // Computes if the given event is allowed to be resized from its ending edge
        isEventResizableFromEnd: function (event) {
            return this.isEventResizable(event);
        },

        // Computes if the given event is allowed to be resized by the user at all
        isEventResizable: function (event) {
            var source = event.source || {};

            return firstDefined(
                event.durationEditable,
                source.durationEditable,
                this.opt('eventDurationEditable'),
                event.editable,
                source.editable,
                this.opt('editable')
            );
        },

        // Must be called when an event in the view has been resized to a new length
        reportEventResize: function (event, resizeLocation, largeUnit, el, ev) {
            var calendar = this.calendar;
            var mutateResult = calendar.mutateEvent(event, resizeLocation, largeUnit);
            var undoFunc = function () {
                mutateResult.undo();
                calendar.reportEventChange();
            };

            this.triggerEventResize(event, mutateResult.durationDelta, undoFunc, el, ev);
            calendar.reportEventChange(); // will rerender events
        },

        // Triggers event-resize handlers that have subscribed via the API
        triggerEventResize: function (event, durationDelta, undoFunc, el, ev) {
            this.publiclyTrigger('eventResize', el[0], event, durationDelta, undoFunc, ev, {}); // {} = jqui dummy
        },

        /* Selection (time range)
        ------------------------------------------------------------------------------------------------------------------*/

        // Selects a date span on the view. `start` and `end` are both Moments.
        // `ev` is the native mouse event that begin the interaction.
        select: function (span, ev) {
            this.unselect(ev);
            this.renderSelection(span);
            this.reportSelection(span, ev);
        },

        // Renders a visual indication of the selection
        renderSelection: function (span) {
            // subclasses should implement
        },

        // Called when a new selection is made. Updates internal state and triggers handlers.
        reportSelection: function (span, ev) {
            this.isSelected = true;
            this.triggerSelect(span, ev);
        },

        // Triggers handlers to 'select'
        triggerSelect: function (span, ev) {
            this.publiclyTrigger(
                'select',
                null,
                this.calendar.applyTimezone(span.start), // convert to calendar's tz for external API
                this.calendar.applyTimezone(span.end), // "
                ev
            );
        },

        // Undoes a selection. updates in the internal state and triggers handlers.
        // `ev` is the native mouse event that began the interaction.
        unselect: function (ev) {
            if (this.isSelected) {
                this.isSelected = false;
                if (this.destroySelection) {
                    this.destroySelection(); // TODO: deprecate
                }
                this.unrenderSelection();
                this.publiclyTrigger('unselect', null, ev);
            }
        },

        // Unrenders a visual indication of selection
        unrenderSelection: function () {
            // subclasses should implement
        },

        /* Event Selection
        ------------------------------------------------------------------------------------------------------------------*/

        selectEvent: function (event) {
            if (!this.selectedEvent || this.selectedEvent !== event) {
                this.unselectEvent();
                this.renderedEventSegEach(function (seg) {
                    seg.el.addClass('fc-selected');
                }, event);
                this.selectedEvent = event;
            }
        },

        unselectEvent: function () {
            if (this.selectedEvent) {
                this.renderedEventSegEach(function (seg) {
                    seg.el.removeClass('fc-selected');
                }, this.selectedEvent);
                this.selectedEvent = null;
            }
        },

        isEventSelected: function (event) {
            // event references might change on refetchEvents(), while selectedEvent doesn't,
            // so compare IDs
            return this.selectedEvent && this.selectedEvent._id === event._id;
        },

        /* Mouse / Touch Unselecting (time range & event unselection)
        ------------------------------------------------------------------------------------------------------------------*/
        // TODO: move consistently to down/start or up/end?
        // TODO: don't kill previous selection if touch scrolling

        handleDocumentMousedown: function (ev) {
            if (isPrimaryMouseButton(ev)) {
                this.processUnselect(ev);
            }
        },

        processUnselect: function (ev) {
            this.processRangeUnselect(ev);
            this.processEventUnselect(ev);
        },

        processRangeUnselect: function (ev) {
            var ignore;

            // is there a time-range selection?
            if (this.isSelected && this.opt('unselectAuto')) {
                // only unselect if the clicked element is not identical to or inside of an 'unselectCancel' element
                ignore = this.opt('unselectCancel');
                if (!ignore || !$(ev.target).closest(ignore).length) {
                    this.unselect(ev);
                }
            }
        },

        processEventUnselect: function (ev) {
            if (this.selectedEvent) {
                if (!$(ev.target).closest('.fc-selected').length) {
                    this.unselectEvent();
                }
            }
        },

        /* Day Click
        ------------------------------------------------------------------------------------------------------------------*/

        // Triggers handlers to 'dayClick'
        // Span has start/end of the clicked area. Only the start is useful.
        triggerDayClick: function (span, dayEl, ev) {
            this.publiclyTrigger(
                'dayClick',
                dayEl,
                this.calendar.applyTimezone(span.start), // convert to calendar's timezone for external API
                ev
            );
        },

        /* Date Utils
        ------------------------------------------------------------------------------------------------------------------*/

        // Initializes internal variables related to calculating hidden days-of-week
        initHiddenDays: function () {
            var hiddenDays = this.opt('hiddenDays') || []; // array of day-of-week indices that are hidden
            var isHiddenDayHash = []; // is the day-of-week hidden? (hash with day-of-week-index -> bool)
            var dayCnt = 0;
            var i;

            if (this.opt('weekends') === false) {
                hiddenDays.push(0, 6); // 0=sunday, 6=saturday
            }

            for (i = 0; i < 7; i++) {
                if (
                    !(isHiddenDayHash[i] = $.inArray(i, hiddenDays) !== -1)
                ) {
                    dayCnt++;
                }
            }

            if (!dayCnt) {
                throw 'invalid hiddenDays'; // all days were hidden? bad.
            }

            this.isHiddenDayHash = isHiddenDayHash;
        },

        // Is the current day hidden?
        // `day` is a day-of-week index (0-6), or a Moment
        isHiddenDay: function (day) {
            if (moment.isMoment(day)) {
                day = day.day();
            }
            return this.isHiddenDayHash[day];
        },

        // Incrementing the current day until it is no longer a hidden day, returning a copy.
        // If the initial value of `date` is not a hidden day, don't do anything.
        // Pass `isExclusive` as `true` if you are dealing with an end date.
        // `inc` defaults to `1` (increment one day forward each time)
        skipHiddenDays: function (date, inc, isExclusive) {
            var out = date.clone();
            inc = inc || 1;
            while (
                this.isHiddenDayHash[(out.day() + (isExclusive ? inc : 0) + 7) % 7]
            ) {
                out.add(inc, 'days');
            }
            return out;
        },

        // Returns the date range of the full days the given range visually appears to occupy.
        // Returns a new range object.
        computeDayRange: function (range) {
            var startDay = range.start.clone().stripTime(); // the beginning of the day the range starts
            var end = range.end;
            var endDay = null;
            var endTimeMS;

            if (end) {
                endDay = end.clone().stripTime(); // the beginning of the day the range exclusively ends
                endTimeMS = +end.time(); // # of milliseconds into `endDay`

                // If the end time is actually inclusively part of the next day and is equal to or
                // beyond the next day threshold, adjust the end to be the exclusive end of `endDay`.
                // Otherwise, leaving it as inclusive will cause it to exclude `endDay`.
                if (endTimeMS && endTimeMS >= this.nextDayThreshold) {
                    endDay.add(1, 'days');
                }
            }

            // If no end was specified, or if it is within `startDay` but not past nextDayThreshold,
            // assign the default duration of one day.
            if (!end || endDay <= startDay) {
                endDay = startDay.clone().add(1, 'days');
            }

            return { start: startDay, end: endDay };
        },

        // Does the given event visually appear to occupy more than one day?
        isMultiDayEvent: function (event) {
            var range = this.computeDayRange(event); // event is range-ish

            return range.end.diff(range.start, 'days') > 1;
        }
    });

    ;;

    /*
    Embodies a div that has potential scrollbars
    */
    var Scroller = FC.Scroller = Class.extend({
        el: null, // the guaranteed outer element
        scrollEl: null, // the element with the scrollbars
        overflowX: null,
        overflowY: null,

        constructor: function (options) {
            options = options || {};
            this.overflowX = options.overflowX || options.overflow || 'auto';
            this.overflowY = options.overflowY || options.overflow || 'auto';
        },

        render: function () {
            this.el = this.renderEl();
            this.applyOverflow();
        },

        renderEl: function () {
            return (this.scrollEl = $('<div class="fc-scroller"></div>'));
        },

        // sets to natural height, unlocks overflow
        clear: function () {
            this.setHeight('auto');
            this.applyOverflow();
        },

        destroy: function () {
            this.el.remove();
        },

        // Overflow
        // -----------------------------------------------------------------------------------------------------------------

        applyOverflow: function () {
            this.scrollEl.css({
                'overflow-x': this.overflowX,
                'overflow-y': this.overflowY
            });
        },

        // Causes any 'auto' overflow values to resolves to 'scroll' or 'hidden'.
        // Useful for preserving scrollbar widths regardless of future resizes.
        // Can pass in scrollbarWidths for optimization.
        lockOverflow: function (scrollbarWidths) {
            var overflowX = this.overflowX;
            var overflowY = this.overflowY;

            scrollbarWidths = scrollbarWidths || this.getScrollbarWidths();

            if (overflowX === 'auto') {
                overflowX = (
                    scrollbarWidths.top || scrollbarWidths.bottom || // horizontal scrollbars?
                    // OR scrolling pane with massless scrollbars?
                    this.scrollEl[0].scrollWidth - 1 > this.scrollEl[0].clientWidth
                    // subtract 1 because of IE off-by-one issue
                ) ? 'scroll' : 'hidden';
            }

            if (overflowY === 'auto') {
                overflowY = (
                    scrollbarWidths.left || scrollbarWidths.right || // vertical scrollbars?
                    // OR scrolling pane with massless scrollbars?
                    this.scrollEl[0].scrollHeight - 1 > this.scrollEl[0].clientHeight
                    // subtract 1 because of IE off-by-one issue
                ) ? 'scroll' : 'hidden';
            }

            this.scrollEl.css({ 'overflow-x': overflowX, 'overflow-y': overflowY });
        },

        // Getters / Setters
        // -----------------------------------------------------------------------------------------------------------------

        setHeight: function (height) {
            this.scrollEl.height(height);
        },

        getScrollTop: function () {
            return this.scrollEl.scrollTop();
        },

        setScrollTop: function (top) {
            this.scrollEl.scrollTop(top);
        },

        getClientWidth: function () {
            return this.scrollEl[0].clientWidth;
        },

        getClientHeight: function () {
            return this.scrollEl[0].clientHeight;
        },

        getScrollbarWidths: function () {
            return getScrollbarWidths(this.scrollEl);
        }
    });

    ;;
    function Iterator(items) {
        this.items = items || [];
    }

    /* Calls a method on every item passing the arguments through */
    Iterator.prototype.proxyCall = function (methodName) {
        var args = Array.prototype.slice.call(arguments, 1);
        var results = [];

        this.items.forEach(function (item) {
            results.push(item[methodName].apply(item, args));
        });

        return results;
    };

    ;;

    /* Toolbar with buttons and title
    ----------------------------------------------------------------------------------------------------------------------*/

    function Toolbar(calendar, toolbarOptions) {
        var t = this;

        // exports
        t.setToolbarOptions = setToolbarOptions;
        t.render = render;
        t.removeElement = removeElement;
        t.updateTitle = updateTitle;
        t.activateButton = activateButton;
        t.deactivateButton = deactivateButton;
        t.disableButton = disableButton;
        t.enableButton = enableButton;
        t.getViewsWithButtons = getViewsWithButtons;
        t.el = null; // mirrors local `el`

        // locals
        var el;
        var viewsWithButtons = [];
        var tm;

        // method to update toolbar-specific options, not calendar-wide options
        function setToolbarOptions(newToolbarOptions) {
            toolbarOptions = newToolbarOptions;
        }

        // can be called repeatedly and will rerender
        function render() {
            var sections = toolbarOptions.layout;

            tm = calendar.options.theme ? 'ui' : 'fc';

            if (sections) {
                if (!el) {
                    el = this.el = $("<div class='fc-toolbar " + toolbarOptions.extraClasses + "'/>");
                }
                else {
                    el.empty();
                }
                el.append(renderSection('left'))
                    .append(renderSection('right'))
                    .append(renderSection('center'))
                    .append('<div class="fc-clear"/>');
            }
            else {
                removeElement();
            }
        }

        function removeElement() {
            if (el) {
                el.remove();
                el = t.el = null;
            }
        }

        function renderSection(position) {
            var sectionEl = $('<div class="fc-' + position + '"/>');
            var buttonStr = toolbarOptions.layout[position];

            if (buttonStr) {
                $.each(buttonStr.split(' '), function (i) {
                    var groupChildren = $();
                    var isOnlyButtons = true;
                    var groupEl;

                    $.each(this.split(','), function (j, buttonName) {
                        var customButtonProps;
                        var viewSpec;
                        var buttonClick;
                        var overrideText; // text explicitly set by calendar's constructor options. overcomes icons
                        var defaultText;
                        var themeIcon;
                        var normalIcon;
                        var innerHtml;
                        var classes;
                        var button; // the element

                        if (buttonName == 'title') {
                            groupChildren = groupChildren.add($('<h2>&nbsp;</h2>')); // we always want it to take up height
                            isOnlyButtons = false;
                        }
                        else {
                            if ((customButtonProps = (calendar.options.customButtons || {})[buttonName])) {
                                buttonClick = function (ev) {
                                    if (customButtonProps.click) {
                                        customButtonProps.click.call(button[0], ev);
                                    }
                                };
                                overrideText = ''; // icons will override text
                                defaultText = customButtonProps.text;
                            }
                            else if ((viewSpec = calendar.getViewSpec(buttonName))) {
                                buttonClick = function () {
                                    calendar.changeView(buttonName);
                                };
                                viewsWithButtons.push(buttonName);
                                overrideText = viewSpec.buttonTextOverride;
                                defaultText = viewSpec.buttonTextDefault;
                            }
                            else if (calendar[buttonName]) { // a calendar method
                                buttonClick = function () {
                                    calendar[buttonName]();
                                };
                                overrideText = (calendar.overrides.buttonText || {})[buttonName];
                                defaultText = calendar.options.buttonText[buttonName]; // everything else is considered default
                            }

                            if (buttonClick) {
                                themeIcon =
                                    customButtonProps ?
                                        customButtonProps.themeIcon :
                                        calendar.options.themeButtonIcons[buttonName];

                                normalIcon =
                                    customButtonProps ?
                                        customButtonProps.icon :
                                        calendar.options.buttonIcons[buttonName];

                                if (overrideText) {
                                    innerHtml = htmlEscape(overrideText);
                                }
                                else if (themeIcon && calendar.options.theme) {
                                    innerHtml = "<span class='ui-icon ui-icon-" + themeIcon + "'></span>";
                                }
                                else if (normalIcon && !calendar.options.theme) {
                                    innerHtml = "<span class='fc-icon fc-icon-" + normalIcon + "'></span>";
                                }
                                else {
                                    innerHtml = htmlEscape(defaultText);
                                }

                                classes = [
                                    'fc-' + buttonName + '-button',
                                    tm + '-button',
                                    tm + '-state-default'
                                ];

                                button = $( // type="button" so that it doesn't submit a form
                                    '<button type="button" data-id="' + (buttonName || '') + '" class="' + classes.join(' ') + '">' +
                                    innerHtml +
                                    '</button>'
                                )
                                    .click(function (ev) {
                                        // don't process clicks for disabled buttons
                                        if (!button.hasClass(tm + '-state-disabled')) {
                                            buttonClick(ev);

                                            // after the click action, if the button becomes the "active" tab, or disabled,
                                            // it should never have a hover class, so remove it now.
                                            if (
                                                button.hasClass(tm + '-state-active') ||
                                                button.hasClass(tm + '-state-disabled')
                                            ) {
                                                button.removeClass(tm + '-state-hover');
                                            }
                                        }
                                    })
                                    .mousedown(function () {
                                        // the *down* effect (mouse pressed in).
                                        // only on buttons that are not the "active" tab, or disabled
                                        button
                                            .not('.' + tm + '-state-active')
                                            .not('.' + tm + '-state-disabled')
                                            .addClass(tm + '-state-down');
                                    })
                                    .mouseup(function () {
                                        // undo the *down* effect
                                        button.removeClass(tm + '-state-down');
                                    })
                                    .hover(
                                        function () {
                                            // the *hover* effect.
                                            // only on buttons that are not the "active" tab, or disabled
                                            button
                                                .not('.' + tm + '-state-active')
                                                .not('.' + tm + '-state-disabled')
                                                .addClass(tm + '-state-hover');
                                        },
                                        function () {
                                            // undo the *hover* effect
                                            button
                                                .removeClass(tm + '-state-hover')
                                                .removeClass(tm + '-state-down'); // if mouseleave happens before mouseup
                                        }
                                    );

                                groupChildren = groupChildren.add(button);
                            }
                        }
                    });

                    if (isOnlyButtons) {
                        groupChildren
                            .first().addClass(tm + '-corner-left').end()
                            .last().addClass(tm + '-corner-right').end();
                    }

                    if (groupChildren.length > 1) {
                        groupEl = $('<div/>');
                        if (isOnlyButtons) {
                            groupEl.addClass('fc-button-group');
                        }
                        groupEl.append(groupChildren);
                        sectionEl.append(groupEl);
                    }
                    else {
                        sectionEl.append(groupChildren); // 1 or 0 children
                    }
                });
            }

            return sectionEl;
        }

        function updateTitle(text) {
            if (el) {
                el.find('h2').text(text);
            }
        }

        function activateButton(buttonName) {
            if (el) {
                el.find('.fc-' + buttonName + '-button')
                    .addClass(tm + '-state-active');
            }
        }

        function deactivateButton(buttonName) {
            if (el) {
                el.find('.fc-' + buttonName + '-button')
                    .removeClass(tm + '-state-active');
            }
        }

        function disableButton(buttonName) {
            if (el) {
                el.find('.fc-' + buttonName + '-button')
                    .prop('disabled', true)
                    .addClass(tm + '-state-disabled');
            }
        }

        function enableButton(buttonName) {
            if (el) {
                el.find('.fc-' + buttonName + '-button')
                    .prop('disabled', false)
                    .removeClass(tm + '-state-disabled');
            }
        }

        function getViewsWithButtons() {
            return viewsWithButtons;
        }
    }

    ;;

    var Calendar = FC.Calendar = Class.extend({
        dirDefaults: null, // option defaults related to LTR or RTL
        localeDefaults: null, // option defaults related to current locale
        overrides: null, // option overrides given to the fullCalendar constructor
        dynamicOverrides: null, // options set with dynamic setter method. higher precedence than view overrides.
        options: null, // all defaults combined with overrides
        viewSpecCache: null, // cache of view definitions
        view: null, // current View object
        header: null,
        footer: null,
        loadingLevel: 0, // number of simultaneous loading tasks

        // a lot of this class' OOP logic is scoped within this constructor function,
        // but in the future, write individual methods on the prototype.
        constructor: Calendar_constructor,

        // Subclasses can override this for initialization logic after the constructor has been called
        initialize: function () {
        },

        // Computes the flattened options hash for the calendar and assigns to `this.options`.
        // Assumes this.overrides and this.dynamicOverrides have already been initialized.
        populateOptionsHash: function () {
            var locale, localeDefaults;
            var isRTL, dirDefaults;

            locale = firstDefined( // explicit locale option given?
                this.dynamicOverrides.locale,
                this.overrides.locale
            );
            localeDefaults = localeOptionHash[locale];
            if (!localeDefaults) { // explicit locale option not given or invalid?
                locale = Calendar.defaults.locale;
                localeDefaults = localeOptionHash[locale] || {};
            }

            isRTL = firstDefined( // based on options computed so far, is direction RTL?
                this.dynamicOverrides.isRTL,
                this.overrides.isRTL,
                localeDefaults.isRTL,
                Calendar.defaults.isRTL
            );
            dirDefaults = isRTL ? Calendar.rtlDefaults : {};

            this.dirDefaults = dirDefaults;
            this.localeDefaults = localeDefaults;
            this.options = mergeOptions([ // merge defaults and overrides. lowest to highest precedence
                Calendar.defaults, // global defaults
                dirDefaults,
                localeDefaults,
                this.overrides,
                this.dynamicOverrides
            ]);
            populateInstanceComputableOptions(this.options); // fill in gaps with computed options
        },

        // Gets information about how to create a view. Will use a cache.
        getViewSpec: function (viewType) {
            var cache = this.viewSpecCache;

            return cache[viewType] || (cache[viewType] = this.buildViewSpec(viewType));
        },

        // Given a duration singular unit, like "week" or "day", finds a matching view spec.
        // Preference is given to views that have corresponding buttons.
        getUnitViewSpec: function (unit) {
            var viewTypes;
            var i;
            var spec;

            if ($.inArray(unit, intervalUnits) != -1) {
                // put views that have buttons first. there will be duplicates, but oh well
                viewTypes = this.header.getViewsWithButtons(); // TODO: include footer as well?
                $.each(FC.views, function (viewType) { // all views
                    viewTypes.push(viewType);
                });

                for (i = 0; i < viewTypes.length; i++) {
                    spec = this.getViewSpec(viewTypes[i]);
                    if (spec) {
                        if (spec.singleUnit == unit) {
                            return spec;
                        }
                    }
                }
            }
        },

        // Builds an object with information on how to create a given view
        buildViewSpec: function (requestedViewType) {
            var viewOverrides = this.overrides.views || {};
            var specChain = []; // for the view. lowest to highest priority
            var defaultsChain = []; // for the view. lowest to highest priority
            var overridesChain = []; // for the view. lowest to highest priority
            var viewType = requestedViewType;
            var spec; // for the view
            var overrides; // for the view
            var duration;
            var unit;

            // iterate from the specific view definition to a more general one until we hit an actual View class
            while (viewType) {
                spec = fcViews[viewType];
                overrides = viewOverrides[viewType];
                viewType = null; // clear. might repopulate for another iteration

                if (typeof spec === 'function') { // TODO: deprecate
                    spec = { 'class': spec };
                }

                if (spec) {
                    specChain.unshift(spec);
                    defaultsChain.unshift(spec.defaults || {});
                    duration = duration || spec.duration;
                    viewType = viewType || spec.type;
                }

                if (overrides) {
                    overridesChain.unshift(overrides); // view-specific option hashes have options at zero-level
                    duration = duration || overrides.duration;
                    viewType = viewType || overrides.type;
                }
            }

            spec = mergeProps(specChain);
            spec.type = requestedViewType;
            if (!spec['class']) {
                return false;
            }

            if (duration) {
                duration = moment.duration(duration);
                if (duration.valueOf()) { // valid?
                    spec.duration = duration;
                    unit = computeIntervalUnit(duration);

                    // view is a single-unit duration, like "week" or "day"
                    // incorporate options for this. lowest priority
                    if (duration.as(unit) === 1) {
                        spec.singleUnit = unit;
                        overridesChain.unshift(viewOverrides[unit] || {});
                    }
                }
            }

            spec.defaults = mergeOptions(defaultsChain);
            spec.overrides = mergeOptions(overridesChain);

            this.buildViewSpecOptions(spec);
            this.buildViewSpecButtonText(spec, requestedViewType);

            return spec;
        },

        // Builds and assigns a view spec's options object from its already-assigned defaults and overrides
        buildViewSpecOptions: function (spec) {
            spec.options = mergeOptions([ // lowest to highest priority
                Calendar.defaults, // global defaults
                spec.defaults, // view's defaults (from ViewSubclass.defaults)
                this.dirDefaults,
                this.localeDefaults, // locale and dir take precedence over view's defaults!
                this.overrides, // calendar's overrides (options given to constructor)
                spec.overrides, // view's overrides (view-specific options)
                this.dynamicOverrides // dynamically set via setter. highest precedence
            ]);
            populateInstanceComputableOptions(spec.options);
        },

        // Computes and assigns a view spec's buttonText-related options
        buildViewSpecButtonText: function (spec, requestedViewType) {
            // given an options object with a possible `buttonText` hash, lookup the buttonText for the
            // requested view, falling back to a generic unit entry like "week" or "day"
            function queryButtonText(options) {
                var buttonText = options.buttonText || {};
                return buttonText[requestedViewType] ||
                    // view can decide to look up a certain key
                    (spec.buttonTextKey ? buttonText[spec.buttonTextKey] : null) ||
                    // a key like "month"
                    (spec.singleUnit ? buttonText[spec.singleUnit] : null);
            }

            // highest to lowest priority
            spec.buttonTextOverride =
                queryButtonText(this.dynamicOverrides) ||
                queryButtonText(this.overrides) || // constructor-specified buttonText lookup hash takes precedence
                spec.overrides.buttonText; // `buttonText` for view-specific options is a string

            // highest to lowest priority. mirrors buildViewSpecOptions
            spec.buttonTextDefault =
                queryButtonText(this.localeDefaults) ||
                queryButtonText(this.dirDefaults) ||
                spec.defaults.buttonText || // a single string. from ViewSubclass.defaults
                queryButtonText(Calendar.defaults) ||
                (spec.duration ? this.humanizeDuration(spec.duration) : null) || // like "3 days"
                requestedViewType; // fall back to given view name
        },

        // Given a view name for a custom view or a standard view, creates a ready-to-go View object
        instantiateView: function (viewType) {
            var spec = this.getViewSpec(viewType);

            return new spec['class'](this, viewType, spec.options, spec.duration);
        },

        // Returns a boolean about whether the view is okay to instantiate at some point
        isValidViewType: function (viewType) {
            return Boolean(this.getViewSpec(viewType));
        },

        // Should be called when any type of async data fetching begins
        pushLoading: function () {
            if (!(this.loadingLevel++)) {
                this.publiclyTrigger('loading', null, true, this.view);
            }
        },

        // Should be called when any type of async data fetching completes
        popLoading: function () {
            if (!(--this.loadingLevel)) {
                this.publiclyTrigger('loading', null, false, this.view);
            }
        },

        // Given arguments to the select method in the API, returns a span (unzoned start/end and other info)
        buildSelectSpan: function (zonedStartInput, zonedEndInput) {
            var start = this.moment(zonedStartInput).stripZone();
            var end;

            if (zonedEndInput) {
                end = this.moment(zonedEndInput).stripZone();
            }
            else if (start.hasTime()) {
                end = start.clone().add(this.defaultTimedEventDuration);
            }
            else {
                end = start.clone().add(this.defaultAllDayEventDuration);
            }

            return { start: start, end: end };
        }
    });

    Calendar.mixin(EmitterMixin);

    function Calendar_constructor(element, overrides) {
        var t = this;

        // Exports
        // -----------------------------------------------------------------------------------

        t.render = render;
        t.destroy = destroy;
        t.rerenderEvents = rerenderEvents;
        t.changeView = renderView; // `renderView` will switch to another view
        t.select = select;
        t.unselect = unselect;
        t.prev = prev;
        t.next = next;
        t.prevYear = prevYear;
        t.nextYear = nextYear;
        t.today = today;
        t.gotoDate = gotoDate;
        t.incrementDate = incrementDate;
        t.zoomTo = zoomTo;
        t.getDate = getDate;
        t.getCalendar = getCalendar;
        t.getView = getView;
        t.option = option; // getter/setter method
        t.publiclyTrigger = publiclyTrigger;

        // Options
        // -----------------------------------------------------------------------------------

        t.dynamicOverrides = {};
        t.viewSpecCache = {};
        t.optionHandlers = {}; // for Calendar.options.js
        t.overrides = $.extend({}, overrides); // make a copy

        t.populateOptionsHash(); // sets this.options

        // Locale-data Internals
        // -----------------------------------------------------------------------------------
        // Apply overrides to the current locale's data

        var localeData;

        // Called immediately, and when any of the options change.
        // Happens before any internal objects rebuild or rerender, because this is very core.
        t.bindOptions([
            'locale', 'monthNames', 'monthNamesShort', 'dayNames', 'dayNamesShort', 'firstDay', 'weekNumberCalculation'
        ], function (locale, monthNames, monthNamesShort, dayNames, dayNamesShort, firstDay, weekNumberCalculation) {
            // normalize
            if (weekNumberCalculation === 'iso') {
                weekNumberCalculation = 'ISO'; // normalize
            }

            localeData = createObject( // make a cheap copy
                getMomentLocaleData(locale) // will fall back to en
            );

            if (monthNames) {
                localeData._months = monthNames;
            }
            if (monthNamesShort) {
                localeData._monthsShort = monthNamesShort;
            }
            if (dayNames) {
                localeData._weekdays = dayNames;
            }
            if (dayNamesShort) {
                localeData._weekdaysShort = dayNamesShort;
            }

            if (firstDay == null && weekNumberCalculation === 'ISO') {
                firstDay = 1;
            }
            if (firstDay != null) {
                var _week = createObject(localeData._week); // _week: { dow: # }
                _week.dow = firstDay;
                localeData._week = _week;
            }

            if ( // whitelist certain kinds of input
                weekNumberCalculation === 'ISO' ||
                weekNumberCalculation === 'local' ||
                typeof weekNumberCalculation === 'function'
            ) {
                localeData._fullCalendar_weekCalc = weekNumberCalculation; // moment-ext will know what to do with it
            }

            // If the internal current date object already exists, move to new locale.
            // We do NOT need to do this technique for event dates, because this happens when converting to "segments".
            if (date) {
                localizeMoment(date); // sets to localeData
            }
        });

        // Calendar-specific Date Utilities
        // -----------------------------------------------------------------------------------

        t.defaultAllDayEventDuration = moment.duration(t.options.defaultAllDayEventDuration);
        t.defaultTimedEventDuration = moment.duration(t.options.defaultTimedEventDuration);

        // Builds a moment using the settings of the current calendar: timezone and locale.
        // Accepts anything the vanilla moment() constructor accepts.
        t.moment = function () {
            var mom;

            if (t.options.timezone === 'local') {
                mom = FC.moment.apply(null, arguments);

                // Force the moment to be local, because FC.moment doesn't guarantee it.
                if (mom.hasTime()) { // don't give ambiguously-timed moments a local zone
                    mom.local();
                }
            }
            else if (t.options.timezone === 'UTC') {
                mom = FC.moment.utc.apply(null, arguments); // process as UTC
            }
            else {
                mom = FC.moment.parseZone.apply(null, arguments); // let the input decide the zone
            }

            localizeMoment(mom);

            return mom;
        };

        // Updates the given moment's locale settings to the current calendar locale settings.
        function localizeMoment(mom) {
            mom._locale = localeData;
        }
        t.localizeMoment = localizeMoment;

        // Returns a boolean about whether or not the calendar knows how to calculate
        // the timezone offset of arbitrary dates in the current timezone.
        t.getIsAmbigTimezone = function () {
            return t.options.timezone !== 'local' && t.options.timezone !== 'UTC';
        };

        // Returns a copy of the given date in the current timezone. Has no effect on dates without times.
        t.applyTimezone = function (date) {
            if (!date.hasTime()) {
                return date.clone();
            }

            var zonedDate = t.moment(date.toArray());
            var timeAdjust = date.time() - zonedDate.time();
            var adjustedZonedDate;

            // Safari sometimes has problems with this coersion when near DST. Adjust if necessary. (bug #2396)
            if (timeAdjust) { // is the time result different than expected?
                adjustedZonedDate = zonedDate.clone().add(timeAdjust); // add milliseconds
                if (date.time() - adjustedZonedDate.time() === 0) { // does it match perfectly now?
                    zonedDate = adjustedZonedDate;
                }
            }

            return zonedDate;
        };

        // Returns a moment for the current date, as defined by the client's computer or from the `now` option.
        // Will return an moment with an ambiguous timezone.
        t.getNow = function () {
            var now = t.options.now;
            if (typeof now === 'function') {
                now = now();
            }
            return t.moment(now).stripZone();
        };

        // Get an event's normalized end date. If not present, calculate it from the defaults.
        t.getEventEnd = function (event) {
            if (event.end) {
                return event.end.clone();
            }
            else {
                return t.getDefaultEventEnd(event.allDay, event.start);
            }
        };

        // Given an event's allDay status and start date, return what its fallback end date should be.
        // TODO: rename to computeDefaultEventEnd
        t.getDefaultEventEnd = function (allDay, zonedStart) {
            var end = zonedStart.clone();

            if (allDay) {
                end.stripTime().add(t.defaultAllDayEventDuration);
            }
            else {
                end.add(t.defaultTimedEventDuration);
            }

            if (t.getIsAmbigTimezone()) {
                end.stripZone(); // we don't know what the tzo should be
            }

            return end;
        };

        // Produces a human-readable string for the given duration.
        // Side-effect: changes the locale of the given duration.
        t.humanizeDuration = function (duration) {
            return duration.locale(t.options.locale).humanize();
        };

        // Imports
        // -----------------------------------------------------------------------------------

        EventManager.call(t);

        // Locals
        // -----------------------------------------------------------------------------------

        var _element = element[0];
        var toolbarsManager;
        var header;
        var footer;
        var content;
        var tm; // for making theme classes
        var currentView; // NOTE: keep this in sync with this.view
        var viewsByType = {}; // holds all instantiated view instances, current or not
        var suggestedViewHeight;
        var windowResizeProxy; // wraps the windowResize function
        var ignoreWindowResize = 0;
        var date; // unzoned

        // Main Rendering
        // -----------------------------------------------------------------------------------

        // compute the initial ambig-timezone date
        if (t.options.defaultDate != null) {
            date = t.moment(t.options.defaultDate).stripZone();
        }
        else {
            date = t.getNow(); // getNow already returns unzoned
        }

        function render() {
            if (!content) {
                initialRender();
            }
            else if (elementVisible()) {
                // mainly for the public API
                calcSize();
                renderView();
            }
        }

        function initialRender() {
            element.addClass('fc');

            // event delegation for nav links
            element.on('click.fc', 'a[data-goto]', function (ev) {
                var anchorEl = $(this);
                var gotoOptions = anchorEl.data('goto'); // will automatically parse JSON
                var date = t.moment(gotoOptions.date);
                var viewType = gotoOptions.type;

                // property like "navLinkDayClick". might be a string or a function
                var customAction = currentView.opt('navLink' + capitaliseFirstLetter(viewType) + 'Click');

                if (typeof customAction === 'function') {
                    customAction(date, ev);
                }
                else {
                    if (typeof customAction === 'string') {
                        viewType = customAction;
                    }
                    zoomTo(date, viewType);
                }
            });

            // called immediately, and upon option change
            t.bindOption('theme', function (theme) {
                tm = theme ? 'ui' : 'fc'; // affects a larger scope
                element.toggleClass('ui-widget', theme);
                element.toggleClass('fc-unthemed', !theme);
            });

            // called immediately, and upon option change.
            // HACK: locale often affects isRTL, so we explicitly listen to that too.
            t.bindOptions(['isRTL', 'locale'], function (isRTL) {
                element.toggleClass('fc-ltr', !isRTL);
                element.toggleClass('fc-rtl', isRTL);
            });

            content = $("<div class='fc-view-container'/>").prependTo(element);

            var toolbars = buildToolbars();
            toolbarsManager = new Iterator(toolbars);

            header = t.header = toolbars[0];
            footer = t.footer = toolbars[1];

            renderHeader();
            renderFooter();
            renderView(t.options.defaultView);

            if (t.options.handleWindowResize) {
                windowResizeProxy = debounce(windowResize, t.options.windowResizeDelay); // prevents rapid calls
                $(window).resize(windowResizeProxy);
            }
        }

        function destroy() {
            if (currentView) {
                currentView.removeElement();

                // NOTE: don't null-out currentView/t.view in case API methods are called after destroy.
                // It is still the "current" view, just not rendered.
            }

            toolbarsManager.proxyCall('removeElement');
            content.remove();
            element.removeClass('fc fc-ltr fc-rtl fc-unthemed ui-widget');

            element.off('.fc'); // unbind nav link handlers

            if (windowResizeProxy) {
                $(window).unbind('resize', windowResizeProxy);
            }
        }

        function elementVisible() {
            return element.is(':visible');
        }

        // View Rendering
        // -----------------------------------------------------------------------------------

        // Renders a view because of a date change, view-type change, or for the first time.
        // If not given a viewType, keep the current view but render different dates.
        // Accepts an optional scroll state to restore to.
        function renderView(viewType, forcedScroll) {
            ignoreWindowResize++;

            var needsClearView = currentView && viewType && currentView.type !== viewType;

            // if viewType is changing, remove the old view's rendering
            if (needsClearView) {
                freezeContentHeight(); // prevent a scroll jump when view element is removed
                clearView();
            }

            // if viewType changed, or the view was never created, create a fresh view
            if (!currentView && viewType) {
                currentView = t.view =
                    viewsByType[viewType] ||
                    (viewsByType[viewType] = t.instantiateView(viewType));

                currentView.setElement(
                    $("<div class='fc-view fc-" + viewType + "-view' />").appendTo(content)
                );
                toolbarsManager.proxyCall('activateButton', viewType);
            }

            if (currentView) {
                // in case the view should render a period of time that is completely hidden
                date = currentView.massageCurrentDate(date);

                // render or rerender the view
                if (
                    !currentView.isDateSet ||
                    !( // NOT within interval range signals an implicit date window change
                        date >= currentView.intervalStart &&
                        date < currentView.intervalEnd
                    )
                ) {
                    if (elementVisible()) {
                        if (forcedScroll) {
                            currentView.captureInitialScroll(forcedScroll);
                        }

                        currentView.setDate(date, forcedScroll);

                        if (forcedScroll) {
                            currentView.releaseScroll();
                        }

                        // need to do this after View::render, so dates are calculated
                        // NOTE: view updates title text proactively
                        updateToolbarsTodayButton();
                    }
                }
            }

            if (needsClearView) {
                thawContentHeight();
            }

            ignoreWindowResize--;
        }

        // Unrenders the current view and reflects this change in the Header.
        // Unregsiters the `currentView`, but does not remove from viewByType hash.
        function clearView() {
            toolbarsManager.proxyCall('deactivateButton', currentView.type);
            currentView.removeElement();
            currentView = t.view = null;
        }

        // Destroys the view, including the view object. Then, re-instantiates it and renders it.
        // Maintains the same scroll state.
        // TODO: maintain any other user-manipulated state.
        function reinitView() {
            ignoreWindowResize++;
            freezeContentHeight();

            var viewType = currentView.type;
            var scrollState = currentView.queryScroll();
            clearView();
            calcSize();
            renderView(viewType, scrollState);

            thawContentHeight();
            ignoreWindowResize--;
        }

        // Resizing
        // -----------------------------------------------------------------------------------

        t.getSuggestedViewHeight = function () {
            if (suggestedViewHeight === undefined) {
                calcSize();
            }
            return suggestedViewHeight;
        };

        t.isHeightAuto = function () {
            return t.options.contentHeight === 'auto' || t.options.height === 'auto';
        };

        function updateSize(shouldRecalc) {
            if (elementVisible()) {
                if (shouldRecalc) {
                    _calcSize();
                }

                ignoreWindowResize++;
                currentView.updateSize(true); // isResize=true. will poll getSuggestedViewHeight() and isHeightAuto()
                ignoreWindowResize--;

                return true; // signal success
            }
        }

        function calcSize() {
            if (elementVisible()) {
                _calcSize();
            }
        }

        function _calcSize() { // assumes elementVisible
            var contentHeightInput = t.options.contentHeight;
            var heightInput = t.options.height;

            if (typeof contentHeightInput === 'number') { // exists and not 'auto'
                suggestedViewHeight = contentHeightInput;
            }
            else if (typeof contentHeightInput === 'function') { // exists and is a function
                suggestedViewHeight = contentHeightInput();
            }
            else if (typeof heightInput === 'number') { // exists and not 'auto'
                suggestedViewHeight = heightInput - queryToolbarsHeight();
            }
            else if (typeof heightInput === 'function') { // exists and is a function
                suggestedViewHeight = heightInput() - queryToolbarsHeight();
            }
            else if (heightInput === 'parent') { // set to height of parent element
                suggestedViewHeight = element.parent().height() - queryToolbarsHeight();
            }
            else {
                suggestedViewHeight = Math.round(content.width() / Math.max(t.options.aspectRatio, .5));
            }
        }

        function queryToolbarsHeight() {
            return toolbarsManager.items.reduce(function (accumulator, toolbar) {
                var toolbarHeight = toolbar.el ? toolbar.el.outerHeight(true) : 0; // includes margin
                return accumulator + toolbarHeight;
            }, 0);
        }

        function windowResize(ev) {
            if (
                !ignoreWindowResize &&
                ev.target === window && // so we don't process jqui "resize" events that have bubbled up
                currentView.start // view has already been rendered
            ) {
                if (updateSize(true)) {
                    currentView.publiclyTrigger('windowResize', _element);
                }
            }
        }

        /* Event Rendering
        -----------------------------------------------------------------------------*/

        function rerenderEvents() { // API method. destroys old events if previously rendered.
            if (elementVisible()) {
                t.reportEventChange(); // will re-trasmit events to the view, causing a rerender
            }
        }

        /* Toolbars
        -----------------------------------------------------------------------------*/

        function buildToolbars() {
            return [
                new Toolbar(t, computeHeaderOptions()),
                new Toolbar(t, computeFooterOptions())
            ];
        }

        function computeHeaderOptions() {
            return {
                extraClasses: 'fc-header-toolbar',
                layout: t.options.header
            };
        }

        function computeFooterOptions() {
            return {
                extraClasses: 'fc-footer-toolbar',
                layout: t.options.footer
            };
        }

        // can be called repeatedly and Header will rerender
        function renderHeader() {
            header.setToolbarOptions(computeHeaderOptions());
            header.render();
            if (header.el) {
                element.prepend(header.el);
            }
        }

        // can be called repeatedly and Footer will rerender
        function renderFooter() {
            footer.setToolbarOptions(computeFooterOptions());
            footer.render();
            if (footer.el) {
                element.append(footer.el);
            }
        }

        t.setToolbarsTitle = function (title) {
            toolbarsManager.proxyCall('updateTitle', title);
        };

        function updateToolbarsTodayButton() {
            var now = t.getNow();
            if (now >= currentView.intervalStart && now < currentView.intervalEnd) {
                toolbarsManager.proxyCall('disableButton', 'today');
            }
            else {
                toolbarsManager.proxyCall('enableButton', 'today');
            }
        }

        /* Selection
        -----------------------------------------------------------------------------*/

        // this public method receives start/end dates in any format, with any timezone
        function select(zonedStartInput, zonedEndInput) {
            currentView.select(
                t.buildSelectSpan.apply(t, arguments)
            );
        }

        function unselect() { // safe to be called before renderView
            if (currentView) {
                currentView.unselect();
            }
        }

        /* Date
        -----------------------------------------------------------------------------*/

        function prev() {
            date = currentView.computePrevDate(date);
            renderView();
        }

        function next() {
            date = currentView.computeNextDate(date);
            renderView();
        }

        function prevYear() {
            date.add(-1, 'years');
            renderView();
        }

        function nextYear() {
            date.add(1, 'years');
            renderView();
        }

        function today() {
            date = t.getNow();
            renderView();
        }

        function gotoDate(zonedDateInput) {
            date = t.moment(zonedDateInput).stripZone();
            renderView();
        }

        function incrementDate(delta) {
            date.add(moment.duration(delta));
            renderView();
        }

        // Forces navigation to a view for the given date.
        // `viewType` can be a specific view name or a generic one like "week" or "day".
        function zoomTo(newDate, viewType) {
            var spec;

            viewType = viewType || 'day'; // day is default zoom
            spec = t.getViewSpec(viewType) || t.getUnitViewSpec(viewType);

            date = newDate.clone();
            renderView(spec ? spec.type : null);
        }

        // for external API
        function getDate() {
            return t.applyTimezone(date); // infuse the calendar's timezone
        }

        /* Height "Freezing"
        -----------------------------------------------------------------------------*/

        t.freezeContentHeight = freezeContentHeight;
        t.thawContentHeight = thawContentHeight;

        var freezeContentHeightDepth = 0;

        function freezeContentHeight() {
            if (!(freezeContentHeightDepth++)) {
                content.css({
                    width: '100%',
                    height: content.height(),
                    overflow: 'hidden'
                });
            }
        }

        function thawContentHeight() {
            if (!(--freezeContentHeightDepth)) {
                content.css({
                    width: '',
                    height: '',
                    overflow: ''
                });
            }
        }

        /* Misc
        -----------------------------------------------------------------------------*/

        function getCalendar() {
            return t;
        }

        function getView() {
            return currentView;
        }

        function option(name, value) {
            var newOptionHash;

            if (typeof name === 'string') {
                if (value === undefined) { // getter
                    return t.options[name];
                }
                else { // setter for individual option
                    newOptionHash = {};
                    newOptionHash[name] = value;
                    setOptions(newOptionHash);
                }
            }
            else if (typeof name === 'object') { // compound setter with object input
                setOptions(name);
            }
        }

        function setOptions(newOptionHash) {
            var optionCnt = 0;
            var optionName;

            for (optionName in newOptionHash) {
                t.dynamicOverrides[optionName] = newOptionHash[optionName];
            }

            t.viewSpecCache = {}; // the dynamic override invalidates the options in this cache, so just clear it
            t.populateOptionsHash(); // this.options needs to be recomputed after the dynamic override

            // trigger handlers after this.options has been updated
            for (optionName in newOptionHash) {
                t.triggerOptionHandlers(optionName); // recall bindOption/bindOptions
                optionCnt++;
            }

            // special-case handling of single option change.
            // if only one option change, `optionName` will be its name.
            if (optionCnt === 1) {
                if (optionName === 'height' || optionName === 'contentHeight' || optionName === 'aspectRatio') {
                    updateSize(true); // true = allow recalculation of height
                    return;
                }
                else if (optionName === 'defaultDate') {
                    return; // can't change date this way. use gotoDate instead
                }
                else if (optionName === 'businessHours') {
                    if (currentView) {
                        currentView.unrenderBusinessHours();
                        currentView.renderBusinessHours();
                    }
                    return;
                }
                else if (optionName === 'timezone') {
                    t.rezoneArrayEventSources();
                    t.refetchEvents();
                    return;
                }
            }

            // catch-all. rerender the header and footer and rebuild/rerender the current view
            renderHeader();
            renderFooter();
            viewsByType = {}; // even non-current views will be affected by this option change. do before rerender
            reinitView();
        }

        function publiclyTrigger(name, thisObj) {
            var args = Array.prototype.slice.call(arguments, 2);

            thisObj = thisObj || _element;
            this.triggerWith(name, thisObj, args); // Emitter's method

            if (t.options[name]) {
                return t.options[name].apply(thisObj, args);
            }
        }

        t.initialize();
    }

    ;;
    /*
    Options binding/triggering system.
    */
    Calendar.mixin({
        // A map of option names to arrays of handler objects. Initialized to {} in Calendar.
        // Format for a handler object:
        // {
        //   func // callback function to be called upon change
        //   names // option names whose values should be given to func
        // }
        optionHandlers: null,

        // Calls handlerFunc immediately, and when the given option has changed.
        // handlerFunc will be given the option value.
        bindOption: function (optionName, handlerFunc) {
            this.bindOptions([optionName], handlerFunc);
        },

        // Calls handlerFunc immediately, and when any of the given options change.
        // handlerFunc will be given each option value as ordered function arguments.
        bindOptions: function (optionNames, handlerFunc) {
            var handlerObj = { func: handlerFunc, names: optionNames };
            var i;

            for (i = 0; i < optionNames.length; i++) {
                this.registerOptionHandlerObj(optionNames[i], handlerObj);
            }

            this.triggerOptionHandlerObj(handlerObj);
        },

        // Puts the given handler object into the internal hash
        registerOptionHandlerObj: function (optionName, handlerObj) {
            (this.optionHandlers[optionName] || (this.optionHandlers[optionName] = []))
                .push(handlerObj);
        },

        // Reports that the given option has changed, and calls all appropriate handlers.
        triggerOptionHandlers: function (optionName) {
            var handlerObjs = this.optionHandlers[optionName] || [];
            var i;

            for (i = 0; i < handlerObjs.length; i++) {
                this.triggerOptionHandlerObj(handlerObjs[i]);
            }
        },

        // Calls the callback for a specific handler object, passing in the appropriate arguments.
        triggerOptionHandlerObj: function (handlerObj) {
            var optionNames = handlerObj.names;
            var optionValues = [];
            var i;

            for (i = 0; i < optionNames.length; i++) {
                optionValues.push(this.options[optionNames[i]]);
            }

            handlerObj.func.apply(this, optionValues); // maintain the Calendar's `this` context
        }
    });

    ;;

    Calendar.defaults = {
        titleRangeSeparator: ' \u2013 ', // en dash
        monthYearFormat: 'MMMM YYYY', // required for en. other locales rely on datepicker computable option

        defaultTimedEventDuration: '02:00:00',
        defaultAllDayEventDuration: { days: 1 },
        forceEventDuration: false,
        nextDayThreshold: '09:00:00', // 9am

        // display
        defaultView: 'month',
        aspectRatio: 1.35,
        header: {
            left: 'title',
            center: '',
            right: 'today prev,next'
        },
        weekends: true,
        weekNumbers: false,

        weekNumberTitle: 'W',
        weekNumberCalculation: 'local',

        //editable: false,

        //nowIndicator: false,

        scrollTime: '06:00:00',

        // event ajax
        lazyFetching: true,
        startParam: 'start',
        endParam: 'end',
        timezoneParam: 'timezone',

        timezone: false,

        //allDayDefault: undefined,

        // locale
        isRTL: false,
        buttonText: {
            prev: "prev",
            next: "next",
            prevYear: "prev year",
            nextYear: "next year",
            year: 'year', // TODO: locale files need to specify this
            today: 'today',
            month: 'month',
            week: 'week',
            day: 'day'
        },

        buttonIcons: {
            prev: 'left-single-arrow',
            next: 'right-single-arrow',
            prevYear: 'left-double-arrow',
            nextYear: 'right-double-arrow'
        },

        allDayText: 'all-day',

        // jquery-ui theming
        theme: false,
        themeButtonIcons: {
            prev: 'circle-triangle-w',
            next: 'circle-triangle-e',
            prevYear: 'seek-prev',
            nextYear: 'seek-next'
        },

        //eventResizableFromStart: false,
        dragOpacity: .75,
        dragRevertDuration: 500,
        dragScroll: true,

        //selectable: false,
        unselectAuto: true,

        dropAccept: '*',

        eventOrder: 'title',
        //eventRenderWait: null,

        eventLimit: false,
        eventLimitText: 'more',
        eventLimitClick: 'popover',
        dayPopoverFormat: 'LL',

        handleWindowResize: true,
        windowResizeDelay: 100, // milliseconds before an updateSize happens

        longPressDelay: 1000
    };

    Calendar.englishDefaults = { // used by locale.js
        dayPopoverFormat: 'dddd, MMMM D'
    };

    Calendar.rtlDefaults = { // right-to-left defaults
        header: { // TODO: smarter solution (first/center/last ?)
            left: 'next,prev today',
            center: '',
            right: 'title'
        },
        buttonIcons: {
            prev: 'right-single-arrow',
            next: 'left-single-arrow',
            prevYear: 'right-double-arrow',
            nextYear: 'left-double-arrow'
        },
        themeButtonIcons: {
            prev: 'circle-triangle-e',
            next: 'circle-triangle-w',
            nextYear: 'seek-prev',
            prevYear: 'seek-next'
        }
    };

    ;;

    var localeOptionHash = FC.locales = {}; // initialize and expose

    // TODO: document the structure and ordering of a FullCalendar locale file

    // Initialize jQuery UI datepicker translations while using some of the translations
    // Will set this as the default locales for datepicker.
    FC.datepickerLocale = function (localeCode, dpLocaleCode, dpOptions) {
        // get the FullCalendar internal option hash for this locale. create if necessary
        var fcOptions = localeOptionHash[localeCode] || (localeOptionHash[localeCode] = {});

        // transfer some simple options from datepicker to fc
        fcOptions.isRTL = dpOptions.isRTL;
        fcOptions.weekNumberTitle = dpOptions.weekHeader;

        // compute some more complex options from datepicker
        $.each(dpComputableOptions, function (name, func) {
            fcOptions[name] = func(dpOptions);
        });

        // is jQuery UI Datepicker is on the page?
        if ($.datepicker) {
            // Register the locale data.
            // FullCalendar and MomentJS use locale codes like "pt-br" but Datepicker
            // does it like "pt-BR" or if it doesn't have the locale, maybe just "pt".
            // Make an alias so the locale can be referenced either way.
            $.datepicker.regional[dpLocaleCode] =
                $.datepicker.regional[localeCode] = // alias
                dpOptions;

            // Alias 'en' to the default locale data. Do this every time.
            $.datepicker.regional.en = $.datepicker.regional[''];

            // Set as Datepicker's global defaults.
            $.datepicker.setDefaults(dpOptions);
        }
    };

    // Sets FullCalendar-specific translations. Will set the locales as the global default.
    FC.locale = function (localeCode, newFcOptions) {
        var fcOptions;
        var momOptions;

        // get the FullCalendar internal option hash for this locale. create if necessary
        fcOptions = localeOptionHash[localeCode] || (localeOptionHash[localeCode] = {});

        // provided new options for this locales? merge them in
        if (newFcOptions) {
            fcOptions = localeOptionHash[localeCode] = mergeOptions([fcOptions, newFcOptions]);
        }

        // compute locale options that weren't defined.
        // always do this. newFcOptions can be undefined when initializing from i18n file,
        // so no way to tell if this is an initialization or a default-setting.
        momOptions = getMomentLocaleData(localeCode); // will fall back to en
        $.each(momComputableOptions, function (name, func) {
            if (fcOptions[name] == null) {
                fcOptions[name] = func(momOptions, fcOptions);
            }
        });

        // set it as the default locale for FullCalendar
        Calendar.defaults.locale = localeCode;
    };

    // NOTE: can't guarantee any of these computations will run because not every locale has datepicker
    // configs, so make sure there are English fallbacks for these in the defaults file.
    var dpComputableOptions = {
        buttonText: function (dpOptions) {
            return {
                // the translations sometimes wrongly contain HTML entities
                prev: stripHtmlEntities(dpOptions.prevText),
                next: stripHtmlEntities(dpOptions.nextText),
                today: stripHtmlEntities(dpOptions.currentText)
            };
        },

        // Produces format strings like "MMMM YYYY" -> "September 2014"
        monthYearFormat: function (dpOptions) {
            return dpOptions.showMonthAfterYear ?
                'YYYY[' + dpOptions.yearSuffix + '] MMMM' :
                'MMMM YYYY[' + dpOptions.yearSuffix + ']';
        }
    };

    var momComputableOptions = {
        // Produces format strings like "ddd M/D" -> "Fri 9/15"
        dayOfMonthFormat: function (momOptions, fcOptions) {
            var format = momOptions.longDateFormat('l'); // for the format like "M/D/YYYY"

            // strip the year off the edge, as well as other misc non-whitespace chars
            format = format.replace(/^Y+[^\w\s]*|[^\w\s]*Y+$/g, '');

            if (fcOptions.isRTL) {
                format += ' ddd'; // for RTL, add day-of-week to end
            }
            else {
                format = 'ddd ' + format; // for LTR, add day-of-week to beginning
            }
            return format;
        },

        // Produces format strings like "h:mma" -> "6:00pm"
        mediumTimeFormat: function (momOptions) { // can't be called `timeFormat` because collides with option
            return momOptions.longDateFormat('LT')
                .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
        },

        // Produces format strings like "h(:mm)a" -> "6pm" / "6:30pm"
        smallTimeFormat: function (momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(':mm', '(:mm)')
                .replace(/(\Wmm)$/, '($1)') // like above, but for foreign locales
                .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
        },

        // Produces format strings like "h(:mm)t" -> "6p" / "6:30p"
        extraSmallTimeFormat: function (momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(':mm', '(:mm)')
                .replace(/(\Wmm)$/, '($1)') // like above, but for foreign locales
                .replace(/\s*a$/i, 't'); // convert to AM/PM/am/pm to lowercase one-letter. remove any spaces beforehand
        },

        // Produces format strings like "ha" / "H" -> "6pm" / "18"
        hourFormat: function (momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(':mm', '')
                .replace(/(\Wmm)$/, '') // like above, but for foreign locales
                .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
        },

        // Produces format strings like "h:mm" -> "6:30" (with no AM/PM)
        noMeridiemTimeFormat: function (momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(/\s*a$/i, ''); // remove trailing AM/PM
        }
    };

    // options that should be computed off live calendar options (considers override options)
    // TODO: best place for this? related to locale?
    // TODO: flipping text based on isRTL is a bad idea because the CSS `direction` might want to handle it
    var instanceComputableOptions = {
        // Produces format strings for results like "Mo 16"
        smallDayDateFormat: function (options) {
            return options.isRTL ?
                'D dd' :
                'dd D';
        },

        // Produces format strings for results like "Wk 5"
        weekFormat: function (options) {
            return options.isRTL ?
                'w[ ' + options.weekNumberTitle + ']' :
                '[' + options.weekNumberTitle + ' ]w';
        },

        // Produces format strings for results like "Wk5"
        smallWeekFormat: function (options) {
            return options.isRTL ?
                'w[' + options.weekNumberTitle + ']' :
                '[' + options.weekNumberTitle + ']w';
        }
    };

    function populateInstanceComputableOptions(options) {
        $.each(instanceComputableOptions, function (name, func) {
            if (options[name] == null) {
                options[name] = func(options);
            }
        });
    }

    // Returns moment's internal locale data. If doesn't exist, returns English.
    function getMomentLocaleData(localeCode) {
        return moment.localeData(localeCode) || moment.localeData('en');
    }

    // Initialize English by forcing computation of moment-derived options.
    // Also, sets it as the default.
    FC.locale('en', Calendar.englishDefaults);

    ;;

    FC.sourceNormalizers = [];
    FC.sourceFetchers = [];

    var ajaxDefaults = {
        dataType: 'json',
        cache: false
    };

    var eventGUID = 1;

    function EventManager() { // assumed to be a calendar
        var t = this;

        // exports
        t.requestEvents = requestEvents;
        t.reportEventChange = reportEventChange;
        t.isFetchNeeded = isFetchNeeded;
        t.fetchEvents = fetchEvents;
        t.fetchEventSources = fetchEventSources;
        t.refetchEvents = refetchEvents;
        t.refetchEventSources = refetchEventSources;
        t.getEventSources = getEventSources;
        t.getEventSourceById = getEventSourceById;
        t.addEventSource = addEventSource;
        t.removeEventSource = removeEventSource;
        t.removeEventSources = removeEventSources;
        t.updateEvent = updateEvent;
        t.updateEvents = updateEvents;
        t.renderEvent = renderEvent;
        t.renderEvents = renderEvents;
        t.removeEvents = removeEvents;
        t.clientEvents = clientEvents;
        t.mutateEvent = mutateEvent;
        t.normalizeEventDates = normalizeEventDates;
        t.normalizeEventTimes = normalizeEventTimes;

        // locals
        var stickySource = { events: [] };
        var sources = [stickySource];
        var rangeStart, rangeEnd;
        var pendingSourceCnt = 0; // outstanding fetch requests, max one per source
        var cache = []; // holds events that have already been expanded
        var prunedCache; // like cache, but only events that intersect with rangeStart/rangeEnd

        $.each(
            (t.options.events ? [t.options.events] : []).concat(t.options.eventSources || []),
            function (i, sourceInput) {
                var source = buildEventSource(sourceInput);
                if (source) {
                    sources.push(source);
                }
            }
        );

        function requestEvents(start, end) {
            if (!t.options.lazyFetching || isFetchNeeded(start, end)) {
                return fetchEvents(start, end);
            }
            else {
                return Promise.resolve(prunedCache);
            }
        }

        function reportEventChange() {
            prunedCache = filterEventsWithinRange(cache);
            t.trigger('eventsReset', prunedCache);
        }

        function filterEventsWithinRange(events) {
            var filteredEvents = [];
            var i, event;

            for (i = 0; i < events.length; i++) {
                event = events[i];

                if (
                    event.start.clone().stripZone() < rangeEnd &&
                    t.getEventEnd(event).stripZone() > rangeStart
                ) {
                    filteredEvents.push(event);
                }
            }

            return filteredEvents;
        }

        t.getEventCache = function () {
            return cache;
        };

        t.getPrunedEventCache = function () {
            return prunedCache;
        };

        /* Fetching
        -----------------------------------------------------------------------------*/

        // start and end are assumed to be unzoned
        function isFetchNeeded(start, end) {
            return !rangeStart || // nothing has been fetched yet?
                start < rangeStart || end > rangeEnd; // is part of the new range outside of the old range?
        }

        function fetchEvents(start, end) {
            rangeStart = start;
            rangeEnd = end;
            return refetchEvents();
        }

        // poorly named. fetches all sources with current `rangeStart` and `rangeEnd`.
        function refetchEvents() {
            return fetchEventSources(sources, 'reset');
        }

        // poorly named. fetches a subset of event sources.
        function refetchEventSources(matchInputs) {
            return fetchEventSources(getEventSourcesByMatchArray(matchInputs));
        }

        // expects an array of event source objects (the originals, not copies)
        // `specialFetchType` is an optimization parameter that affects purging of the event cache.
        function fetchEventSources(specificSources, specialFetchType) {
            var i, source;

            if (specialFetchType === 'reset') {
                cache = [];
            }
            else if (specialFetchType !== 'add') {
                cache = excludeEventsBySources(cache, specificSources);
            }

            for (i = 0; i < specificSources.length; i++) {
                source = specificSources[i];

                // already-pending sources have already been accounted for in pendingSourceCnt
                if (source._status !== 'pending') {
                    pendingSourceCnt++;
                }

                source._fetchId = (source._fetchId || 0) + 1;
                source._status = 'pending';
            }

            for (i = 0; i < specificSources.length; i++) {
                source = specificSources[i];
                tryFetchEventSource(source, source._fetchId);
            }

            if (pendingSourceCnt) {
                return new Promise(function (resolve) {
                    t.one('eventsReceived', resolve); // will send prunedCache
                });
            }
            else { // executed all synchronously, or no sources at all
                return Promise.resolve(prunedCache);
            }
        }

        // fetches an event source and processes its result ONLY if it is still the current fetch.
        // caller is responsible for incrementing pendingSourceCnt first.
        function tryFetchEventSource(source, fetchId) {
            _fetchEventSource(source, function (eventInputs) {
                var isArraySource = $.isArray(source.events);
                var i, eventInput;
                var abstractEvent;

                if (
                    // is this the source's most recent fetch?
                    // if not, rely on an upcoming fetch of this source to decrement pendingSourceCnt
                    fetchId === source._fetchId &&
                    // event source no longer valid?
                    source._status !== 'rejected'
                ) {
                    source._status = 'resolved';

                    if (eventInputs) {
                        for (i = 0; i < eventInputs.length; i++) {
                            eventInput = eventInputs[i];

                            if (isArraySource) { // array sources have already been convert to Event Objects
                                abstractEvent = eventInput;
                            }
                            else {
                                abstractEvent = buildEventFromInput(eventInput, source);
                            }

                            if (abstractEvent) { // not false (an invalid event)
                                cache.push.apply( // append
                                    cache,
                                    expandEvent(abstractEvent) // add individual expanded events to the cache
                                );
                            }
                        }
                    }

                    decrementPendingSourceCnt();
                }
            });
        }

        function rejectEventSource(source) {
            var wasPending = source._status === 'pending';

            source._status = 'rejected';

            if (wasPending) {
                decrementPendingSourceCnt();
            }
        }

        function decrementPendingSourceCnt() {
            pendingSourceCnt--;
            if (!pendingSourceCnt) {
                reportEventChange(cache); // updates prunedCache
                t.trigger('eventsReceived', prunedCache);
            }
        }

        function _fetchEventSource(source, callback) {
            var i;
            var fetchers = FC.sourceFetchers;
            var res;

            for (i = 0; i < fetchers.length; i++) {
                res = fetchers[i].call(
                    t, // this, the Calendar object
                    source,
                    rangeStart.clone(),
                    rangeEnd.clone(),
                    t.options.timezone,
                    callback
                );

                if (res === true) {
                    // the fetcher is in charge. made its own async request
                    return;
                }
                else if (typeof res == 'object') {
                    // the fetcher returned a new source. process it
                    _fetchEventSource(res, callback);
                    return;
                }
            }

            var events = source.events;
            if (events) {
                if ($.isFunction(events)) {
                    t.pushLoading();
                    events.call(
                        t, // this, the Calendar object
                        rangeStart.clone(),
                        rangeEnd.clone(),
                        t.options.timezone,
                        function (events) {
                            callback(events);
                            t.popLoading();
                        }
                    );
                }
                else if ($.isArray(events)) {
                    callback(events);
                }
                else {
                    callback();
                }
            } else {
                var url = source.url;
                if (url) {
                    var success = source.success;
                    var error = source.error;
                    var complete = source.complete;

                    // retrieve any outbound GET/POST $.ajax data from the options
                    var customData;
                    if ($.isFunction(source.data)) {
                        // supplied as a function that returns a key/value object
                        customData = source.data();
                    }
                    else {
                        // supplied as a straight key/value object
                        customData = source.data;
                    }

                    // use a copy of the custom data so we can modify the parameters
                    // and not affect the passed-in object.
                    var data = $.extend({}, customData || {});

                    var startParam = firstDefined(source.startParam, t.options.startParam);
                    var endParam = firstDefined(source.endParam, t.options.endParam);
                    var timezoneParam = firstDefined(source.timezoneParam, t.options.timezoneParam);

                    if (startParam) {
                        data[startParam] = rangeStart.format();
                    }
                    if (endParam) {
                        data[endParam] = rangeEnd.format();
                    }
                    if (t.options.timezone && t.options.timezone != 'local') {
                        data[timezoneParam] = t.options.timezone;
                    }

                    t.pushLoading();
                    $.ajax($.extend({}, ajaxDefaults, source, {
                        data: data,
                        success: function (events) {
                            events = events || [];
                            var res = applyAll(success, this, arguments);
                            if ($.isArray(res)) {
                                events = res;
                            }
                            callback(events);
                        },
                        error: function () {
                            applyAll(error, this, arguments);
                            callback();
                        },
                        complete: function () {
                            applyAll(complete, this, arguments);
                            t.popLoading();
                        }
                    }));
                } else {
                    callback();
                }
            }
        }

        /* Sources
        -----------------------------------------------------------------------------*/

        function addEventSource(sourceInput) {
            var source = buildEventSource(sourceInput);
            if (source) {
                sources.push(source);
                fetchEventSources([source], 'add'); // will eventually call reportEventChange
            }
        }

        function buildEventSource(sourceInput) { // will return undefined if invalid source
            var normalizers = FC.sourceNormalizers;
            var source;
            var i;

            if ($.isFunction(sourceInput) || $.isArray(sourceInput)) {
                source = { events: sourceInput };
            }
            else if (typeof sourceInput === 'string') {
                source = { url: sourceInput };
            }
            else if (typeof sourceInput === 'object') {
                source = $.extend({}, sourceInput); // shallow copy
            }

            if (source) {
                // TODO: repeat code, same code for event classNames
                if (source.className) {
                    if (typeof source.className === 'string') {
                        source.className = source.className.split(/\s+/);
                    }
                    // otherwise, assumed to be an array
                }
                else {
                    source.className = [];
                }

                // for array sources, we convert to standard Event Objects up front
                if ($.isArray(source.events)) {
                    source.origArray = source.events; // for removeEventSource
                    source.events = $.map(source.events, function (eventInput) {
                        return buildEventFromInput(eventInput, source);
                    });
                }

                for (i = 0; i < normalizers.length; i++) {
                    normalizers[i].call(t, source);
                }

                return source;
            }
        }

        function removeEventSource(matchInput) {
            removeSpecificEventSources(
                getEventSourcesByMatch(matchInput)
            );
        }

        // if called with no arguments, removes all.
        function removeEventSources(matchInputs) {
            if (matchInputs == null) {
                removeSpecificEventSources(sources, true); // isAll=true
            }
            else {
                removeSpecificEventSources(
                    getEventSourcesByMatchArray(matchInputs)
                );
            }
        }

        function removeSpecificEventSources(targetSources, isAll) {
            var i;

            // cancel pending requests
            for (i = 0; i < targetSources.length; i++) {
                rejectEventSource(targetSources[i]);
            }

            if (isAll) { // an optimization
                sources = [];
                cache = [];
            }
            else {
                // remove from persisted source list
                sources = $.grep(sources, function (source) {
                    for (i = 0; i < targetSources.length; i++) {
                        if (source === targetSources[i]) {
                            return false; // exclude
                        }
                    }
                    return true; // include
                });

                cache = excludeEventsBySources(cache, targetSources);
            }

            reportEventChange();
        }

        function getEventSources() {
            return sources.slice(1); // returns a shallow copy of sources with stickySource removed
        }

        function getEventSourceById(id) {
            return $.grep(sources, function (source) {
                return source.id && source.id === id;
            })[0];
        }

        // like getEventSourcesByMatch, but accepts multple match criteria (like multiple IDs)
        function getEventSourcesByMatchArray(matchInputs) {
            // coerce into an array
            if (!matchInputs) {
                matchInputs = [];
            }
            else if (!$.isArray(matchInputs)) {
                matchInputs = [matchInputs];
            }

            var matchingSources = [];
            var i;

            // resolve raw inputs to real event source objects
            for (i = 0; i < matchInputs.length; i++) {
                matchingSources.push.apply( // append
                    matchingSources,
                    getEventSourcesByMatch(matchInputs[i])
                );
            }

            return matchingSources;
        }

        // matchInput can either by a real event source object, an ID, or the function/URL for the source.
        // returns an array of matching source objects.
        function getEventSourcesByMatch(matchInput) {
            var i, source;

            // given an proper event source object
            for (i = 0; i < sources.length; i++) {
                source = sources[i];
                if (source === matchInput) {
                    return [source];
                }
            }

            // an ID match
            source = getEventSourceById(matchInput);
            if (source) {
                return [source];
            }

            return $.grep(sources, function (source) {
                return isSourcesEquivalent(matchInput, source);
            });
        }

        function isSourcesEquivalent(source1, source2) {
            return source1 && source2 && getSourcePrimitive(source1) == getSourcePrimitive(source2);
        }

        function getSourcePrimitive(source) {
            return (
                (typeof source === 'object') ? // a normalized event source?
                    (source.origArray || source.googleCalendarId || source.url || source.events) : // get the primitive
                    null
            ) ||
                source; // the given argument *is* the primitive
        }

        // util
        // returns a filtered array without events that are part of any of the given sources
        function excludeEventsBySources(specificEvents, specificSources) {
            return $.grep(specificEvents, function (event) {
                for (var i = 0; i < specificSources.length; i++) {
                    if (event.source === specificSources[i]) {
                        return false; // exclude
                    }
                }
                return true; // keep
            });
        }

        /* Manipulation
        -----------------------------------------------------------------------------*/

        // Only ever called from the externally-facing API
        function updateEvent(event) {
            updateEvents([event]);
        }

        // Only ever called from the externally-facing API
        function updateEvents(events) {
            var i, event;

            for (i = 0; i < events.length; i++) {
                event = events[i];

                // massage start/end values, even if date string values
                event.start = t.moment(event.start);
                if (event.end) {
                    event.end = t.moment(event.end);
                }
                else {
                    event.end = null;
                }

                mutateEvent(event, getMiscEventProps(event)); // will handle start/end/allDay normalization
            }

            reportEventChange(); // reports event modifications (so we can redraw)
        }

        // Returns a hash of misc event properties that should be copied over to related events.
        function getMiscEventProps(event) {
            var props = {};

            $.each(event, function (name, val) {
                if (isMiscEventPropName(name)) {
                    if (val !== undefined && isAtomic(val)) { // a defined non-object
                        props[name] = val;
                    }
                }
            });

            return props;
        }

        // non-date-related, non-id-related, non-secret
        function isMiscEventPropName(name) {
            return !/^_|^(id|allDay|start|end)$/.test(name);
        }

        // returns the expanded events that were created
        function renderEvent(eventInput, stick) {
            return renderEvents([eventInput], stick);
        }

        // returns the expanded events that were created
        function renderEvents(eventInputs, stick) {
            var renderedEvents = [];
            var renderableEvents;
            var abstractEvent;
            var i, j, event;

            for (i = 0; i < eventInputs.length; i++) {
                abstractEvent = buildEventFromInput(eventInputs[i]);

                if (abstractEvent) { // not false (a valid input)
                    renderableEvents = expandEvent(abstractEvent);

                    for (j = 0; j < renderableEvents.length; j++) {
                        event = renderableEvents[j];

                        if (!event.source) {
                            if (stick) {
                                stickySource.events.push(event);
                                event.source = stickySource;
                            }
                            cache.push(event);
                        }
                    }

                    renderedEvents = renderedEvents.concat(renderableEvents);
                }
            }

            if (renderedEvents.length) { // any new events rendered?
                reportEventChange();
            }

            return renderedEvents;
        }

        function removeEvents(filter) {
            var eventID;
            var i;

            if (filter == null) { // null or undefined. remove all events
                filter = function () { return true; }; // will always match
            }
            else if (!$.isFunction(filter)) { // an event ID
                eventID = filter + '';
                filter = function (event) {
                    return event._id == eventID;
                };
            }

            // Purge event(s) from our local cache
            cache = $.grep(cache, filter, true); // inverse=true

            // Remove events from array sources.
            // This works because they have been converted to official Event Objects up front.
            // (and as a result, event._id has been calculated).
            for (i = 0; i < sources.length; i++) {
                if ($.isArray(sources[i].events)) {
                    sources[i].events = $.grep(sources[i].events, filter, true);
                }
            }

            reportEventChange();
        }

        function clientEvents(filter) {
            if ($.isFunction(filter)) {
                return $.grep(cache, filter);
            }
            else if (filter != null) { // not null, not undefined. an event ID
                filter += '';
                return $.grep(cache, function (e) {
                    return e._id == filter;
                });
            }
            return cache; // else, return all
        }

        // Makes sure all array event sources have their internal event objects
        // converted over to the Calendar's current timezone.
        t.rezoneArrayEventSources = function () {
            var i;
            var events;
            var j;

            for (i = 0; i < sources.length; i++) {
                events = sources[i].events;
                if ($.isArray(events)) {
                    for (j = 0; j < events.length; j++) {
                        rezoneEventDates(events[j]);
                    }
                }
            }
        };

        function rezoneEventDates(event) {
            event.start = t.moment(event.start);
            if (event.end) {
                event.end = t.moment(event.end);
            }
            backupEventDates(event);
        }

        /* Event Normalization
        -----------------------------------------------------------------------------*/

        // Given a raw object with key/value properties, returns an "abstract" Event object.
        // An "abstract" event is an event that, if recurring, will not have been expanded yet.
        // Will return `false` when input is invalid.
        // `source` is optional
        function buildEventFromInput(input, source) {
            var out = {};
            var start, end;
            var allDay;

            if (t.options.eventDataTransform) {
                input = t.options.eventDataTransform(input);
            }
            if (source && source.eventDataTransform) {
                input = source.eventDataTransform(input);
            }

            // Copy all properties over to the resulting object.
            // The special-case properties will be copied over afterwards.
            $.extend(out, input);

            if (source) {
                out.source = source;
            }

            out._id = input._id || (input.id === undefined ? '_fc' + eventGUID++ : input.id + '');

            if (input.className) {
                if (typeof input.className == 'string') {
                    out.className = input.className.split(/\s+/);
                }
                else { // assumed to be an array
                    out.className = input.className;
                }
            }
            else {
                out.className = [];
            }

            start = input.start || input.date; // "date" is an alias for "start"
            end = input.end;

            // parse as a time (Duration) if applicable
            if (isTimeString(start)) {
                start = moment.duration(start);
            }
            if (isTimeString(end)) {
                end = moment.duration(end);
            }

            if (input.dow || moment.isDuration(start) || moment.isDuration(end)) {
                // the event is "abstract" (recurring) so don't calculate exact start/end dates just yet
                out.start = start ? moment.duration(start) : null; // will be a Duration or null
                out.end = end ? moment.duration(end) : null; // will be a Duration or null
                out._recurring = true; // our internal marker
            }
            else {
                if (start) {
                    start = t.moment(start);
                    if (!start.isValid()) {
                        return false;
                    }
                }

                if (end) {
                    end = t.moment(end);
                    if (!end.isValid()) {
                        end = null; // let defaults take over
                    }
                }

                allDay = input.allDay;
                if (allDay === undefined) { // still undefined? fallback to default
                    allDay = firstDefined(
                        source ? source.allDayDefault : undefined,
                        t.options.allDayDefault
                    );
                    // still undefined? normalizeEventDates will calculate it
                }

                assignDatesToEvent(start, end, allDay, out);
            }

            t.normalizeEvent(out); // hook for external use. a prototype method

            return out;
        }
        t.buildEventFromInput = buildEventFromInput;

        // Normalizes and assigns the given dates to the given partially-formed event object.
        // NOTE: mutates the given start/end moments. does not make a copy.
        function assignDatesToEvent(start, end, allDay, event) {
            event.start = start;
            event.end = end;
            event.allDay = allDay;
            normalizeEventDates(event);
            backupEventDates(event);
        }

        // Ensures proper values for allDay/start/end. Accepts an Event object, or a plain object with event-ish properties.
        // NOTE: Will modify the given object.
        function normalizeEventDates(eventProps) {
            normalizeEventTimes(eventProps);

            if (eventProps.end && !eventProps.end.isAfter(eventProps.start)) {
                eventProps.end = null;
            }

            if (!eventProps.end) {
                if (t.options.forceEventDuration) {
                    eventProps.end = t.getDefaultEventEnd(eventProps.allDay, eventProps.start);
                }
                else {
                    eventProps.end = null;
                }
            }
        }

        // Ensures the allDay property exists and the timeliness of the start/end dates are consistent
        function normalizeEventTimes(eventProps) {
            if (eventProps.allDay == null) {
                eventProps.allDay = !(eventProps.start.hasTime() || (eventProps.end && eventProps.end.hasTime()));
            }

            if (eventProps.allDay) {
                eventProps.start.stripTime();
                if (eventProps.end) {
                    // TODO: consider nextDayThreshold here? If so, will require a lot of testing and adjustment
                    eventProps.end.stripTime();
                }
            }
            else {
                if (!eventProps.start.hasTime()) {
                    eventProps.start = t.applyTimezone(eventProps.start.time(0)); // will assign a 00:00 time
                }
                if (eventProps.end && !eventProps.end.hasTime()) {
                    eventProps.end = t.applyTimezone(eventProps.end.time(0)); // will assign a 00:00 time
                }
            }
        }

        // If the given event is a recurring event, break it down into an array of individual instances.
        // If not a recurring event, return an array with the single original event.
        // If given a falsy input (probably because of a failed buildEventFromInput call), returns an empty array.
        // HACK: can override the recurring window by providing custom rangeStart/rangeEnd (for businessHours).
        function expandEvent(abstractEvent, _rangeStart, _rangeEnd) {
            var events = [];
            var dowHash;
            var dow;
            var i;
            var date;
            var startTime, endTime;
            var start, end;
            var event;

            _rangeStart = _rangeStart || rangeStart;
            _rangeEnd = _rangeEnd || rangeEnd;

            if (abstractEvent) {
                if (abstractEvent._recurring) {
                    // make a boolean hash as to whether the event occurs on each day-of-week
                    if ((dow = abstractEvent.dow)) {
                        dowHash = {};
                        for (i = 0; i < dow.length; i++) {
                            dowHash[dow[i]] = true;
                        }
                    }

                    // iterate through every day in the current range
                    date = _rangeStart.clone().stripTime(); // holds the date of the current day
                    while (date.isBefore(_rangeEnd)) {
                        if (!dowHash || dowHash[date.day()]) { // if everyday, or this particular day-of-week
                            startTime = abstractEvent.start; // the stored start and end properties are times (Durations)
                            endTime = abstractEvent.end; // "
                            start = date.clone();
                            end = null;

                            if (startTime) {
                                start = start.time(startTime);
                            }
                            if (endTime) {
                                end = date.clone().time(endTime);
                            }

                            event = $.extend({}, abstractEvent); // make a copy of the original
                            assignDatesToEvent(
                                start, end,
                                !startTime && !endTime, // allDay?
                                event
                            );
                            events.push(event);
                        }

                        date.add(1, 'days');
                    }
                }
                else {
                    events.push(abstractEvent); // return the original event. will be a one-item array
                }
            }

            return events;
        }
        t.expandEvent = expandEvent;

        /* Event Modification Math
        -----------------------------------------------------------------------------------------*/

        // Modifies an event and all related events by applying the given properties.
        // Special date-diffing logic is used for manipulation of dates.
        // If `props` does not contain start/end dates, the updated values are assumed to be the event's current start/end.
        // All date comparisons are done against the event's pristine _start and _end dates.
        // Returns an object with delta information and a function to undo all operations.
        // For making computations in a granularity greater than day/time, specify largeUnit.
        // NOTE: The given `newProps` might be mutated for normalization purposes.
        function mutateEvent(event, newProps, largeUnit) {
            var miscProps = {};
            var oldProps;
            var clearEnd;
            var startDelta;
            var endDelta;
            var durationDelta;
            var undoFunc;

            // diffs the dates in the appropriate way, returning a duration
            function diffDates(date1, date0) { // date1 - date0
                if (largeUnit) {
                    return diffByUnit(date1, date0, largeUnit);
                }
                else if (newProps.allDay) {
                    return diffDay(date1, date0);
                }
                else {
                    return diffDayTime(date1, date0);
                }
            }

            newProps = newProps || {};

            // normalize new date-related properties
            if (!newProps.start) {
                newProps.start = event.start.clone();
            }
            if (newProps.end === undefined) {
                newProps.end = event.end ? event.end.clone() : null;
            }
            if (newProps.allDay == null) { // is null or undefined?
                newProps.allDay = event.allDay;
            }
            normalizeEventDates(newProps);

            // create normalized versions of the original props to compare against
            // need a real end value, for diffing
            oldProps = {
                start: event._start.clone(),
                end: event._end ? event._end.clone() : t.getDefaultEventEnd(event._allDay, event._start),
                allDay: newProps.allDay // normalize the dates in the same regard as the new properties
            };
            normalizeEventDates(oldProps);

            // need to clear the end date if explicitly changed to null
            clearEnd = event._end !== null && newProps.end === null;

            // compute the delta for moving the start date
            startDelta = diffDates(newProps.start, oldProps.start);

            // compute the delta for moving the end date
            if (newProps.end) {
                endDelta = diffDates(newProps.end, oldProps.end);
                durationDelta = endDelta.subtract(startDelta);
            }
            else {
                durationDelta = null;
            }

            // gather all non-date-related properties
            $.each(newProps, function (name, val) {
                if (isMiscEventPropName(name)) {
                    if (val !== undefined) {
                        miscProps[name] = val;
                    }
                }
            });

            // apply the operations to the event and all related events
            undoFunc = mutateEvents(
                clientEvents(event._id), // get events with this ID
                clearEnd,
                newProps.allDay,
                startDelta,
                durationDelta,
                miscProps
            );

            return {
                dateDelta: startDelta,
                durationDelta: durationDelta,
                undo: undoFunc
            };
        }

        // Modifies an array of events in the following ways (operations are in order):
        // - clear the event's `end`
        // - convert the event to allDay
        // - add `dateDelta` to the start and end
        // - add `durationDelta` to the event's duration
        // - assign `miscProps` to the event
        //
        // Returns a function that can be called to undo all the operations.
        //
        // TODO: don't use so many closures. possible memory issues when lots of events with same ID.
        //
        function mutateEvents(events, clearEnd, allDay, dateDelta, durationDelta, miscProps) {
            var isAmbigTimezone = t.getIsAmbigTimezone();
            var undoFunctions = [];

            // normalize zero-length deltas to be null
            if (dateDelta && !dateDelta.valueOf()) { dateDelta = null; }
            if (durationDelta && !durationDelta.valueOf()) { durationDelta = null; }

            $.each(events, function (i, event) {
                var oldProps;
                var newProps;

                // build an object holding all the old values, both date-related and misc.
                // for the undo function.
                oldProps = {
                    start: event.start.clone(),
                    end: event.end ? event.end.clone() : null,
                    allDay: event.allDay
                };
                $.each(miscProps, function (name) {
                    oldProps[name] = event[name];
                });

                // new date-related properties. work off the original date snapshot.
                // ok to use references because they will be thrown away when backupEventDates is called.
                newProps = {
                    start: event._start,
                    end: event._end,
                    allDay: allDay // normalize the dates in the same regard as the new properties
                };
                normalizeEventDates(newProps); // massages start/end/allDay

                // strip or ensure the end date
                if (clearEnd) {
                    newProps.end = null;
                }
                else if (durationDelta && !newProps.end) { // the duration translation requires an end date
                    newProps.end = t.getDefaultEventEnd(newProps.allDay, newProps.start);
                }

                if (dateDelta) {
                    newProps.start.add(dateDelta);
                    if (newProps.end) {
                        newProps.end.add(dateDelta);
                    }
                }

                if (durationDelta) {
                    newProps.end.add(durationDelta); // end already ensured above
                }

                // if the dates have changed, and we know it is impossible to recompute the
                // timezone offsets, strip the zone.
                if (
                    isAmbigTimezone &&
                    !newProps.allDay &&
                    (dateDelta || durationDelta)
                ) {
                    newProps.start.stripZone();
                    if (newProps.end) {
                        newProps.end.stripZone();
                    }
                }

                $.extend(event, miscProps, newProps); // copy over misc props, then date-related props
                backupEventDates(event); // regenerate internal _start/_end/_allDay

                undoFunctions.push(function () {
                    $.extend(event, oldProps);
                    backupEventDates(event); // regenerate internal _start/_end/_allDay
                });
            });

            return function () {
                for (var i = 0; i < undoFunctions.length; i++) {
                    undoFunctions[i]();
                }
            };
        }
    }

    // hook for external libs to manipulate event properties upon creation.
    // should manipulate the event in-place.
    Calendar.prototype.normalizeEvent = function (event) {
    };

    // Does the given span (start, end, and other location information)
    // fully contain the other?
    Calendar.prototype.spanContainsSpan = function (outerSpan, innerSpan) {
        var eventStart = outerSpan.start.clone().stripZone();
        var eventEnd = this.getEventEnd(outerSpan).stripZone();

        return innerSpan.start >= eventStart && innerSpan.end <= eventEnd;
    };

    // Returns a list of events that the given event should be compared against when being considered for a move to
    // the specified span. Attached to the Calendar's prototype because EventManager is a mixin for a Calendar.
    Calendar.prototype.getPeerEvents = function (span, event) {
        var cache = this.getEventCache();
        var peerEvents = [];
        var i, otherEvent;

        for (i = 0; i < cache.length; i++) {
            otherEvent = cache[i];
            if (
                !event ||
                event._id !== otherEvent._id // don't compare the event to itself or other related [repeating] events
            ) {
                peerEvents.push(otherEvent);
            }
        }

        return peerEvents;
    };

    // updates the "backup" properties, which are preserved in order to compute diffs later on.
    function backupEventDates(event) {
        event._allDay = event.allDay;
        event._start = event.start.clone();
        event._end = event.end ? event.end.clone() : null;
    }

    /* Overlapping / Constraining
    -----------------------------------------------------------------------------------------*/

    // Determines if the given event can be relocated to the given span (unzoned start/end with other misc data)
    Calendar.prototype.isEventSpanAllowed = function (span, event) {
        var source = event.source || {};

        var constraint = firstDefined(
            event.constraint,
            source.constraint,
            this.options.eventConstraint
        );

        var overlap = firstDefined(
            event.overlap,
            source.overlap,
            this.options.eventOverlap
        );

        return this.isSpanAllowed(span, constraint, overlap, event) &&
            (!this.options.eventAllow || this.options.eventAllow(span, event) !== false);
    };

    // Determines if an external event can be relocated to the given span (unzoned start/end with other misc data)
    Calendar.prototype.isExternalSpanAllowed = function (eventSpan, eventLocation, eventProps) {
        var eventInput;
        var event;

        // note: very similar logic is in View's reportExternalDrop
        if (eventProps) {
            eventInput = $.extend({}, eventProps, eventLocation);
            event = this.expandEvent(
                this.buildEventFromInput(eventInput)
            )[0];
        }

        if (event) {
            return this.isEventSpanAllowed(eventSpan, event);
        }
        else { // treat it as a selection
            return this.isSelectionSpanAllowed(eventSpan);
        }
    };

    // Determines the given span (unzoned start/end with other misc data) can be selected.
    Calendar.prototype.isSelectionSpanAllowed = function (span) {
        return this.isSpanAllowed(span, this.options.selectConstraint, this.options.selectOverlap) &&
            (!this.options.selectAllow || this.options.selectAllow(span) !== false);
    };

    // Returns true if the given span (caused by an event drop/resize or a selection) is allowed to exist
    // according to the constraint/overlap settings.
    // `event` is not required if checking a selection.
    Calendar.prototype.isSpanAllowed = function (span, constraint, overlap, event) {
        var constraintEvents;
        var anyContainment;
        var peerEvents;
        var i, peerEvent;
        var peerOverlap;

        // the range must be fully contained by at least one of produced constraint events
        if (constraint != null) {
            // not treated as an event! intermediate data structure
            // TODO: use ranges in the future
            constraintEvents = this.constraintToEvents(constraint);
            if (constraintEvents) { // not invalid
                anyContainment = false;
                for (i = 0; i < constraintEvents.length; i++) {
                    if (this.spanContainsSpan(constraintEvents[i], span)) {
                        anyContainment = true;
                        break;
                    }
                }

                if (!anyContainment) {
                    return false;
                }
            }
        }

        peerEvents = this.getPeerEvents(span, event);

        for (i = 0; i < peerEvents.length; i++) {
            peerEvent = peerEvents[i];

            // there needs to be an actual intersection before disallowing anything
            if (this.eventIntersectsRange(peerEvent, span)) {
                // evaluate overlap for the given range and short-circuit if necessary
                if (overlap === false) {
                    return false;
                }
                // if the event's overlap is a test function, pass the peer event in question as the first param
                else if (typeof overlap === 'function' && !overlap(peerEvent, event)) {
                    return false;
                }

                // if we are computing if the given range is allowable for an event, consider the other event's
                // EventObject-specific or Source-specific `overlap` property
                if (event) {
                    peerOverlap = firstDefined(
                        peerEvent.overlap,
                        (peerEvent.source || {}).overlap
                        // we already considered the global `eventOverlap`
                    );
                    if (peerOverlap === false) {
                        return false;
                    }
                    // if the peer event's overlap is a test function, pass the subject event as the first param
                    if (typeof peerOverlap === 'function' && !peerOverlap(event, peerEvent)) {
                        return false;
                    }
                }
            }
        }

        return true;
    };

    // Given an event input from the API, produces an array of event objects. Possible event inputs:
    // 'businessHours'
    // An event ID (number or string)
    // An object with specific start/end dates or a recurring event (like what businessHours accepts)
    Calendar.prototype.constraintToEvents = function (constraintInput) {
        if (constraintInput === 'businessHours') {
            return this.getCurrentBusinessHourEvents();
        }

        if (typeof constraintInput === 'object') {
            if (constraintInput.start != null) { // needs to be event-like input
                return this.expandEvent(this.buildEventFromInput(constraintInput));
            }
            else {
                return null; // invalid
            }
        }

        return this.clientEvents(constraintInput); // probably an ID
    };

    // Does the event's date range intersect with the given range?
    // start/end already assumed to have stripped zones :(
    Calendar.prototype.eventIntersectsRange = function (event, range) {
        var eventStart = event.start.clone().stripZone();
        var eventEnd = this.getEventEnd(event).stripZone();

        return range.start < eventEnd && range.end > eventStart;
    };

    /* Business Hours
    -----------------------------------------------------------------------------------------*/

    var BUSINESS_HOUR_EVENT_DEFAULTS = {
        id: '_fcBusinessHours', // will relate events from different calls to expandEvent
        start: '09:00',
        end: '17:00',
        dow: [1, 2, 3, 4, 5], // monday - friday
        rendering: 'inverse-background'
        // classNames are defined in businessHoursSegClasses
    };

    // Return events objects for business hours within the current view.
    // Abuse of our event system :(
    Calendar.prototype.getCurrentBusinessHourEvents = function (wholeDay) {
        return this.computeBusinessHourEvents(wholeDay, this.options.businessHours);
    };

    // Given a raw input value from options, return events objects for business hours within the current view.
    Calendar.prototype.computeBusinessHourEvents = function (wholeDay, input) {
        if (input === true) {
            return this.expandBusinessHourEvents(wholeDay, [{}]);
        }
        else if ($.isPlainObject(input)) {
            return this.expandBusinessHourEvents(wholeDay, [input]);
        }
        else if ($.isArray(input)) {
            return this.expandBusinessHourEvents(wholeDay, input, true);
        }
        else {
            return [];
        }
    };

    // inputs expected to be an array of objects.
    // if ignoreNoDow is true, will ignore entries that don't specify a day-of-week (dow) key.
    Calendar.prototype.expandBusinessHourEvents = function (wholeDay, inputs, ignoreNoDow) {
        var view = this.getView();
        var events = [];
        var i, input;

        for (i = 0; i < inputs.length; i++) {
            input = inputs[i];

            if (ignoreNoDow && !input.dow) {
                continue;
            }

            // give defaults. will make a copy
            input = $.extend({}, BUSINESS_HOUR_EVENT_DEFAULTS, input);

            // if a whole-day series is requested, clear the start/end times
            if (wholeDay) {
                input.start = null;
                input.end = null;
            }

            events.push.apply(events, // append
                this.expandEvent(
                    this.buildEventFromInput(input),
                    view.start,
                    view.end
                )
            );
        }

        return events;
    };

    ;;

    /* An abstract class for the "basic" views, as well as month view. Renders one or more rows of day cells.
    ----------------------------------------------------------------------------------------------------------------------*/
    // It is a manager for a DayGrid subcomponent, which does most of the heavy lifting.
    // It is responsible for managing width/height.

    var BasicView = FC.BasicView = View.extend({
        scroller: null,

        dayGridClass: DayGrid, // class the dayGrid will be instantiated from (overridable by subclasses)
        dayGrid: null, // the main subcomponent that does most of the heavy lifting

        dayNumbersVisible: false, // display day numbers on each day cell?
        colWeekNumbersVisible: false, // display week numbers along the side?
        cellWeekNumbersVisible: false, // display week numbers in day cell?

        weekNumberWidth: null, // width of all the week-number cells running down the side

        headContainerEl: null, // div that hold's the dayGrid's rendered date header
        headRowEl: null, // the fake row element of the day-of-week header

        initialize: function () {
            this.dayGrid = this.instantiateDayGrid();

            this.scroller = new Scroller({
                overflowX: 'hidden',
                overflowY: 'auto'
            });
        },

        // Generates the DayGrid object this view needs. Draws from this.dayGridClass
        instantiateDayGrid: function () {
            // generate a subclass on the fly with BasicView-specific behavior
            // TODO: cache this subclass
            var subclass = this.dayGridClass.extend(basicDayGridMethods);

            return new subclass(this);
        },

        // Sets the display range and computes all necessary dates
        setRange: function (range) {
            View.prototype.setRange.call(this, range); // call the super-method

            this.dayGrid.breakOnWeeks = /year|month|week/.test(this.intervalUnit); // do before setRange
            this.dayGrid.setRange(range);
        },

        // Compute the value to feed into setRange. Overrides superclass.
        computeRange: function (date) {
            var range = View.prototype.computeRange.call(this, date); // get value from the super-method

            // year and month views should be aligned with weeks. this is already done for week
            if (/year|month/.test(range.intervalUnit)) {
                range.start.startOf('week');
                range.start = this.skipHiddenDays(range.start);

                // make end-of-week if not already
                if (range.end.weekday()) {
                    range.end.add(1, 'week').startOf('week');
                    range.end = this.skipHiddenDays(range.end, -1, true); // exclusively move backwards
                }
            }

            return range;
        },

        // Renders the view into `this.el`, which should already be assigned
        renderDates: function () {
            this.dayNumbersVisible = this.dayGrid.rowCnt > 1; // TODO: make grid responsible
            if (this.opt('weekNumbers')) {
                if (this.opt('weekNumbersWithinDays')) {
                    this.cellWeekNumbersVisible = true;
                    this.colWeekNumbersVisible = false;
                }
                else {
                    this.cellWeekNumbersVisible = false;
                    this.colWeekNumbersVisible = true;
                };
            }
            this.dayGrid.numbersVisible = this.dayNumbersVisible ||
                this.cellWeekNumbersVisible || this.colWeekNumbersVisible;

            this.el.addClass('fc-basic-view').html(this.renderSkeletonHtml());
            this.renderHead();

            this.scroller.render();
            var dayGridContainerEl = this.scroller.el.addClass('fc-day-grid-container');
            var dayGridEl = $('<div class="fc-day-grid" />').appendTo(dayGridContainerEl);
            this.el.find('.fc-body > tr > td').append(dayGridContainerEl);

            this.dayGrid.setElement(dayGridEl);
            this.dayGrid.renderDates(this.hasRigidRows());
        },

        // render the day-of-week headers
        renderHead: function () {
            this.headContainerEl =
                this.el.find('.fc-head-container')
                    .html(this.dayGrid.renderHeadHtml());
            this.headRowEl = this.headContainerEl.find('.fc-row');
        },

        // Unrenders the content of the view. Since we haven't separated skeleton rendering from date rendering,
        // always completely kill the dayGrid's rendering.
        unrenderDates: function () {
            this.dayGrid.unrenderDates();
            this.dayGrid.removeElement();
            this.scroller.destroy();
        },

        renderBusinessHours: function () {
            this.dayGrid.renderBusinessHours();
        },

        unrenderBusinessHours: function () {
            this.dayGrid.unrenderBusinessHours();
        },

        // Builds the HTML skeleton for the view.
        // The day-grid component will render inside of a container defined by this HTML.
        renderSkeletonHtml: function () {
            return '' +
                '<table>' +
                '<thead class="fc-head">' +
                '<tr>' +
                '<td class="fc-head-container ' + this.widgetHeaderClass + '"></td>' +
                '</tr>' +
                '</thead>' +
                '<tbody class="fc-body">' +
                '<tr>' +
                '<td class="' + this.widgetContentClass + '"></td>' +
                '</tr>' +
                '</tbody>' +
                '</table>';
        },

        // Generates an HTML attribute string for setting the width of the week number column, if it is known
        weekNumberStyleAttr: function () {
            if (this.weekNumberWidth !== null) {
                return 'style="width:' + this.weekNumberWidth + 'px"';
            }
            return '';
        },

        // Determines whether each row should have a constant height
        hasRigidRows: function () {
            var eventLimit = this.opt('eventLimit');
            return eventLimit && typeof eventLimit !== 'number';
        },

        /* Dimensions
        ------------------------------------------------------------------------------------------------------------------*/

        // Refreshes the horizontal dimensions of the view
        updateWidth: function () {
            if (this.colWeekNumbersVisible) {
                // Make sure all week number cells running down the side have the same width.
                // Record the width for cells created later.
                this.weekNumberWidth = matchCellWidths(
                    this.el.find('.fc-week-number')
                );
            }
        },

        // Adjusts the vertical dimensions of the view to the specified values
        setHeight: function (totalHeight, isAuto) {
            var eventLimit = this.opt('eventLimit');
            var scrollerHeight;
            var scrollbarWidths;

            // reset all heights to be natural
            this.scroller.clear();
            uncompensateScroll(this.headRowEl);

            this.dayGrid.removeSegPopover(); // kill the "more" popover if displayed

            // is the event limit a constant level number?
            if (eventLimit && typeof eventLimit === 'number') {
                this.dayGrid.limitRows(eventLimit); // limit the levels first so the height can redistribute after
            }

            // distribute the height to the rows
            // (totalHeight is a "recommended" value if isAuto)
            scrollerHeight = this.computeScrollerHeight(totalHeight);
            this.setGridHeight(scrollerHeight, isAuto);

            // is the event limit dynamically calculated?
            if (eventLimit && typeof eventLimit !== 'number') {
                this.dayGrid.limitRows(eventLimit); // limit the levels after the grid's row heights have been set
            }

            if (!isAuto) { // should we force dimensions of the scroll container?
                this.scroller.setHeight(scrollerHeight);
                scrollbarWidths = this.scroller.getScrollbarWidths();

                if (scrollbarWidths.left || scrollbarWidths.right) { // using scrollbars?
                    compensateScroll(this.headRowEl, scrollbarWidths);

                    // doing the scrollbar compensation might have created text overflow which created more height. redo
                    scrollerHeight = this.computeScrollerHeight(totalHeight);
                    this.scroller.setHeight(scrollerHeight);
                }

                // guarantees the same scrollbar widths
                this.scroller.lockOverflow(scrollbarWidths);
            }
        },

        // given a desired total height of the view, returns what the height of the scroller should be
        computeScrollerHeight: function (totalHeight) {
            return totalHeight -
                subtractInnerElHeight(this.el, this.scroller.el); // everything that's NOT the scroller
        },

        // Sets the height of just the DayGrid component in this view
        setGridHeight: function (height, isAuto) {
            if (isAuto) {
                undistributeHeight(this.dayGrid.rowEls); // let the rows be their natural height with no expanding
            }
            else {
                distributeHeight(this.dayGrid.rowEls, height, true); // true = compensate for height-hogging rows
            }
        },

        /* Scroll
        ------------------------------------------------------------------------------------------------------------------*/

        computeInitialScroll: function () {
            return { top: 0 };
        },

        queryScroll: function () {
            return { top: this.scroller.getScrollTop() };
        },

        setScroll: function (scroll) {
            this.scroller.setScrollTop(scroll.top);
        },

        /* Hit Areas
        ------------------------------------------------------------------------------------------------------------------*/
        // forward all hit-related method calls to dayGrid

        prepareHits: function () {
            this.dayGrid.prepareHits();
        },

        releaseHits: function () {
            this.dayGrid.releaseHits();
        },

        queryHit: function (left, top) {
            return this.dayGrid.queryHit(left, top);
        },

        getHitSpan: function (hit) {
            return this.dayGrid.getHitSpan(hit);
        },

        getHitEl: function (hit) {
            return this.dayGrid.getHitEl(hit);
        },

        /* Events
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders the given events onto the view and populates the segments array
        renderEvents: function (events) {
            this.dayGrid.renderEvents(events);

            this.updateHeight(); // must compensate for events that overflow the row
        },

        // Retrieves all segment objects that are rendered in the view
        getEventSegs: function () {
            return this.dayGrid.getEventSegs();
        },

        // Unrenders all event elements and clears internal segment data
        unrenderEvents: function () {
            this.dayGrid.unrenderEvents();

            // we DON'T need to call updateHeight() because
            // a renderEvents() call always happens after this, which will eventually call updateHeight()
        },

        /* Dragging (for both events and external elements)
        ------------------------------------------------------------------------------------------------------------------*/

        // A returned value of `true` signals that a mock "helper" event has been rendered.
        renderDrag: function (dropLocation, seg) {
            return this.dayGrid.renderDrag(dropLocation, seg);
        },

        unrenderDrag: function () {
            this.dayGrid.unrenderDrag();
        },

        /* Selection
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of a selection
        renderSelection: function (span) {
            this.dayGrid.renderSelection(span);
        },

        // Unrenders a visual indications of a selection
        unrenderSelection: function () {
            this.dayGrid.unrenderSelection();
        }
    });

    // Methods that will customize the rendering behavior of the BasicView's dayGrid
    var basicDayGridMethods = {
        // Generates the HTML that will go before the day-of week header cells
        renderHeadIntroHtml: function () {
            var view = this.view;

            if (view.colWeekNumbersVisible) {
                return '' +
                    '<th class="fc-week-number ' + view.widgetHeaderClass + '" ' + view.weekNumberStyleAttr() + '>' +
                    '<span>' + // needed for matchCellWidths
                    htmlEscape(view.opt('weekNumberTitle')) +
                    '</span>' +
                    '</th>';
            }

            return '';
        },

        // Generates the HTML that will go before content-skeleton cells that display the day/week numbers
        renderNumberIntroHtml: function (row) {
            var view = this.view;
            var weekStart = this.getCellDate(row, 0);

            if (view.colWeekNumbersVisible) {
                return '' +
                    '<td class="fc-week-number" ' + view.weekNumberStyleAttr() + '>' +
                    view.buildGotoAnchorHtml( // aside from link, important for matchCellWidths
                        { date: weekStart, type: 'week', forceOff: this.colCnt === 1 },
                        weekStart.format('w') // inner HTML
                    ) +
                    '</td>';
            }

            return '';
        },

        // Generates the HTML that goes before the day bg cells for each day-row
        renderBgIntroHtml: function () {
            var view = this.view;

            if (view.colWeekNumbersVisible) {
                return '<td class="fc-week-number ' + view.widgetContentClass + '" ' +
                    view.weekNumberStyleAttr() + '></td>';
            }

            return '';
        },

        // Generates the HTML that goes before every other type of row generated by DayGrid.
        // Affects helper-skeleton and highlight-skeleton rows.
        renderIntroHtml: function () {
            var view = this.view;

            if (view.colWeekNumbersVisible) {
                return '<td class="fc-week-number" ' + view.weekNumberStyleAttr() + '></td>';
            }

            return '';
        }
    };

    ;;

    /* A month view with day cells running in rows (one-per-week) and columns
    ----------------------------------------------------------------------------------------------------------------------*/

    var MonthView = FC.MonthView = BasicView.extend({
        // Produces information about what range to display
        computeRange: function (date) {
            var range = BasicView.prototype.computeRange.call(this, date); // get value from super-method
            var rowCnt;

            // ensure 6 weeks
            if (this.isFixedWeeks()) {
                rowCnt = Math.ceil(range.end.diff(range.start, 'weeks', true)); // could be partial weeks due to hiddenDays
                range.end.add(6 - rowCnt, 'weeks');
            }

            return range;
        },

        // Overrides the default BasicView behavior to have special multi-week auto-height logic
        setGridHeight: function (height, isAuto) {
            // if auto, make the height of each row the height that it would be if there were 6 weeks
            if (isAuto) {
                height *= this.rowCnt / 6;
            }

            distributeHeight(this.dayGrid.rowEls, height, !isAuto); // if auto, don't compensate for height-hogging rows
        },

        isFixedWeeks: function () {
            return this.opt('fixedWeekCount');
        }
    });

    ;;

    fcViews.basic = {
        'class': BasicView
    };

    fcViews.basicDay = {
        type: 'basic',
        duration: { days: 1 }
    };

    fcViews.basicWeek = {
        type: 'basic',
        duration: { weeks: 1 }
    };

    fcViews.month = {
        'class': MonthView,
        duration: { months: 1 }, // important for prev/next
        defaults: {
            fixedWeekCount: true
        }
    };
    ;;

    /* An abstract class for all agenda-related views. Displays one more columns with time slots running vertically.
    ----------------------------------------------------------------------------------------------------------------------*/
    // Is a manager for the TimeGrid subcomponent and possibly the DayGrid subcomponent (if allDaySlot is on).
    // Responsible for managing width/height.

    var AgendaView = FC.AgendaView = View.extend({
        scroller: null,

        timeGridClass: TimeGrid, // class used to instantiate the timeGrid. subclasses can override
        timeGrid: null, // the main time-grid subcomponent of this view

        dayGridClass: DayGrid, // class used to instantiate the dayGrid. subclasses can override
        dayGrid: null, // the "all-day" subcomponent. if all-day is turned off, this will be null

        axisWidth: null, // the width of the time axis running down the side

        headContainerEl: null, // div that hold's the timeGrid's rendered date header
        noScrollRowEls: null, // set of fake row elements that must compensate when scroller has scrollbars

        // when the time-grid isn't tall enough to occupy the given height, we render an <hr> underneath
        bottomRuleEl: null,

        initialize: function () {
            this.timeGrid = this.instantiateTimeGrid();

            if (this.opt('allDaySlot')) { // should we display the "all-day" area?
                this.dayGrid = this.instantiateDayGrid(); // the all-day subcomponent of this view
            }

            this.scroller = new Scroller({
                overflowX: 'hidden',
                overflowY: 'auto'
            });
        },

        // Instantiates the TimeGrid object this view needs. Draws from this.timeGridClass
        instantiateTimeGrid: function () {
            var subclass = this.timeGridClass.extend(agendaTimeGridMethods);

            return new subclass(this);
        },

        // Instantiates the DayGrid object this view might need. Draws from this.dayGridClass
        instantiateDayGrid: function () {
            var subclass = this.dayGridClass.extend(agendaDayGridMethods);

            return new subclass(this);
        },

        /* Rendering
        ------------------------------------------------------------------------------------------------------------------*/

        // Sets the display range and computes all necessary dates
        setRange: function (range) {
            View.prototype.setRange.call(this, range); // call the super-method

            this.timeGrid.setRange(range);
            if (this.dayGrid) {
                this.dayGrid.setRange(range);
            }
        },

        // Renders the view into `this.el`, which has already been assigned
        renderDates: function () {
            this.el.addClass('fc-agenda-view').html(this.renderSkeletonHtml());
            this.renderHead();

            this.scroller.render();
            var timeGridWrapEl = this.scroller.el.addClass('fc-time-grid-container');
            var timeGridEl = $('<div class="fc-time-grid" />').appendTo(timeGridWrapEl);
            this.el.find('.fc-body > tr > td').append(timeGridWrapEl);

            this.timeGrid.setElement(timeGridEl);
            this.timeGrid.renderDates();

            // the <hr> that sometimes displays under the time-grid
            this.bottomRuleEl = $('<hr class="fc-divider ' + this.widgetHeaderClass + '"/>')
                .appendTo(this.timeGrid.el); // inject it into the time-grid

            if (this.dayGrid) {
                this.dayGrid.setElement(this.el.find('.fc-day-grid'));
                this.dayGrid.renderDates();

                // have the day-grid extend it's coordinate area over the <hr> dividing the two grids
                this.dayGrid.bottomCoordPadding = this.dayGrid.el.next('hr').outerHeight();
            }

            this.noScrollRowEls = this.el.find('.fc-row:not(.fc-scroller *)'); // fake rows not within the scroller
        },

        // render the day-of-week headers
        renderHead: function () {
            this.headContainerEl =
                this.el.find('.fc-head-container')
                    .html(this.timeGrid.renderHeadHtml());
        },

        // Unrenders the content of the view. Since we haven't separated skeleton rendering from date rendering,
        // always completely kill each grid's rendering.
        unrenderDates: function () {
            this.timeGrid.unrenderDates();
            this.timeGrid.removeElement();

            if (this.dayGrid) {
                this.dayGrid.unrenderDates();
                this.dayGrid.removeElement();
            }

            this.scroller.destroy();
        },

        // Builds the HTML skeleton for the view.
        // The day-grid and time-grid components will render inside containers defined by this HTML.
        renderSkeletonHtml: function () {
            return '' +
                '<table>' +
                '<thead class="fc-head">' +
                '<tr>' +
                '<td class="fc-head-container ' + this.widgetHeaderClass + '"></td>' +
                '</tr>' +
                '</thead>' +
                '<tbody class="fc-body">' +
                '<tr>' +
                '<td class="' + this.widgetContentClass + '">' +
                (this.dayGrid ?
                    '<div class="fc-day-grid"/>' +
                    '<hr class="fc-divider ' + this.widgetHeaderClass + '"/>' :
                    ''
                ) +
                '</td>' +
                '</tr>' +
                '</tbody>' +
                '</table>';
        },

        // Generates an HTML attribute string for setting the width of the axis, if it is known
        axisStyleAttr: function () {
            if (this.axisWidth !== null) {
                return 'style="width:' + this.axisWidth + 'px"';
            }
            return '';
        },

        /* Business Hours
        ------------------------------------------------------------------------------------------------------------------*/

        renderBusinessHours: function () {
            this.timeGrid.renderBusinessHours();

            if (this.dayGrid) {
                this.dayGrid.renderBusinessHours();
            }
        },

        unrenderBusinessHours: function () {
            this.timeGrid.unrenderBusinessHours();

            if (this.dayGrid) {
                this.dayGrid.unrenderBusinessHours();
            }
        },

        /* Now Indicator
        ------------------------------------------------------------------------------------------------------------------*/

        getNowIndicatorUnit: function () {
            return this.timeGrid.getNowIndicatorUnit();
        },

        renderNowIndicator: function (date) {
            this.timeGrid.renderNowIndicator(date);
        },

        unrenderNowIndicator: function () {
            this.timeGrid.unrenderNowIndicator();
        },

        /* Dimensions
        ------------------------------------------------------------------------------------------------------------------*/

        updateSize: function (isResize) {
            this.timeGrid.updateSize(isResize);

            View.prototype.updateSize.call(this, isResize); // call the super-method
        },

        // Refreshes the horizontal dimensions of the view
        updateWidth: function () {
            // make all axis cells line up, and record the width so newly created axis cells will have it
            this.axisWidth = matchCellWidths(this.el.find('.fc-axis'));
        },

        // Adjusts the vertical dimensions of the view to the specified values
        setHeight: function (totalHeight, isAuto) {
            var eventLimit;
            var scrollerHeight;
            var scrollbarWidths;

            // reset all dimensions back to the original state
            this.bottomRuleEl.hide(); // .show() will be called later if this <hr> is necessary
            this.scroller.clear(); // sets height to 'auto' and clears overflow
            uncompensateScroll(this.noScrollRowEls);

            // limit number of events in the all-day area
            if (this.dayGrid) {
                this.dayGrid.removeSegPopover(); // kill the "more" popover if displayed

                eventLimit = this.opt('eventLimit');
                if (eventLimit && typeof eventLimit !== 'number') {
                    eventLimit = AGENDA_ALL_DAY_EVENT_LIMIT; // make sure "auto" goes to a real number
                }
                if (eventLimit) {
                    this.dayGrid.limitRows(eventLimit);
                }
            }

            if (!isAuto) { // should we force dimensions of the scroll container?
                scrollerHeight = this.computeScrollerHeight(totalHeight);
                this.scroller.setHeight(scrollerHeight);
                scrollbarWidths = this.scroller.getScrollbarWidths();

                if (scrollbarWidths.left || scrollbarWidths.right) { // using scrollbars?
                    // make the all-day and header rows lines up
                    compensateScroll(this.noScrollRowEls, scrollbarWidths);

                    // the scrollbar compensation might have changed text flow, which might affect height, so recalculate
                    // and reapply the desired height to the scroller.
                    scrollerHeight = this.computeScrollerHeight(totalHeight);
                    this.scroller.setHeight(scrollerHeight);
                }

                // guarantees the same scrollbar widths
                this.scroller.lockOverflow(scrollbarWidths);

                // if there's any space below the slats, show the horizontal rule.
                // this won't cause any new overflow, because lockOverflow already called.
                if (this.timeGrid.getTotalSlatHeight() < scrollerHeight) {
                    this.bottomRuleEl.show();
                }
            }
        },

        // given a desired total height of the view, returns what the height of the scroller should be
        computeScrollerHeight: function (totalHeight) {
            return totalHeight -
                subtractInnerElHeight(this.el, this.scroller.el); // everything that's NOT the scroller
        },

        /* Scroll
        ------------------------------------------------------------------------------------------------------------------*/

        // Computes the initial pre-configured scroll state prior to allowing the user to change it
        computeInitialScroll: function () {
            var scrollTime = moment.duration(this.opt('scrollTime'));
            var top = this.timeGrid.computeTimeTop(scrollTime);

            // zoom can give weird floating-point values. rather scroll a little bit further
            top = Math.ceil(top);

            if (top) {
                top++; // to overcome top border that slots beyond the first have. looks better
            }

            return { top: top };
        },

        queryScroll: function () {
            return { top: this.scroller.getScrollTop() };
        },

        setScroll: function (scroll) {
            this.scroller.setScrollTop(scroll.top);
        },

        /* Hit Areas
        ------------------------------------------------------------------------------------------------------------------*/
        // forward all hit-related method calls to the grids (dayGrid might not be defined)

        prepareHits: function () {
            this.timeGrid.prepareHits();
            if (this.dayGrid) {
                this.dayGrid.prepareHits();
            }
        },

        releaseHits: function () {
            this.timeGrid.releaseHits();
            if (this.dayGrid) {
                this.dayGrid.releaseHits();
            }
        },

        queryHit: function (left, top) {
            var hit = this.timeGrid.queryHit(left, top);

            if (!hit && this.dayGrid) {
                hit = this.dayGrid.queryHit(left, top);
            }

            return hit;
        },

        getHitSpan: function (hit) {
            // TODO: hit.component is set as a hack to identify where the hit came from
            return hit.component.getHitSpan(hit);
        },

        getHitEl: function (hit) {
            // TODO: hit.component is set as a hack to identify where the hit came from
            return hit.component.getHitEl(hit);
        },

        /* Events
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders events onto the view and populates the View's segment array
        renderEvents: function (events) {
            var dayEvents = [];
            var timedEvents = [];
            var daySegs = [];
            var timedSegs;
            var i;

            // separate the events into all-day and timed
            for (i = 0; i < events.length; i++) {
                if (events[i].allDay) {
                    dayEvents.push(events[i]);
                }
                else {
                    timedEvents.push(events[i]);
                }
            }

            // render the events in the subcomponents
            timedSegs = this.timeGrid.renderEvents(timedEvents);
            if (this.dayGrid) {
                daySegs = this.dayGrid.renderEvents(dayEvents);
            }

            // the all-day area is flexible and might have a lot of events, so shift the height
            this.updateHeight();
        },

        // Retrieves all segment objects that are rendered in the view
        getEventSegs: function () {
            return this.timeGrid.getEventSegs().concat(
                this.dayGrid ? this.dayGrid.getEventSegs() : []
            );
        },

        // Unrenders all event elements and clears internal segment data
        unrenderEvents: function () {
            // unrender the events in the subcomponents
            this.timeGrid.unrenderEvents();
            if (this.dayGrid) {
                this.dayGrid.unrenderEvents();
            }

            // we DON'T need to call updateHeight() because
            // a renderEvents() call always happens after this, which will eventually call updateHeight()
        },

        /* Dragging (for events and external elements)
        ------------------------------------------------------------------------------------------------------------------*/

        // A returned value of `true` signals that a mock "helper" event has been rendered.
        renderDrag: function (dropLocation, seg) {
            if (dropLocation.start.hasTime()) {
                return this.timeGrid.renderDrag(dropLocation, seg);
            }
            else if (this.dayGrid) {
                return this.dayGrid.renderDrag(dropLocation, seg);
            }
        },

        unrenderDrag: function () {
            this.timeGrid.unrenderDrag();
            if (this.dayGrid) {
                this.dayGrid.unrenderDrag();
            }
        },

        /* Selection
        ------------------------------------------------------------------------------------------------------------------*/

        // Renders a visual indication of a selection
        renderSelection: function (span) {
            if (span.start.hasTime() || span.end.hasTime()) {
                this.timeGrid.renderSelection(span);
            }
            else if (this.dayGrid) {
                this.dayGrid.renderSelection(span);
            }
        },

        // Unrenders a visual indications of a selection
        unrenderSelection: function () {
            this.timeGrid.unrenderSelection();
            if (this.dayGrid) {
                this.dayGrid.unrenderSelection();
            }
        }
    });

    // Methods that will customize the rendering behavior of the AgendaView's timeGrid
    // TODO: move into TimeGrid
    var agendaTimeGridMethods = {
        // Generates the HTML that will go before the day-of week header cells
        renderHeadIntroHtml: function () {
            var view = this.view;
            var weekText;

            if (view.opt('weekNumbers')) {
                weekText = this.start.format(view.opt('smallWeekFormat'));

                return '' +
                    '<th class="fc-axis fc-week-number ' + view.widgetHeaderClass + '" ' + view.axisStyleAttr() + '>' +
                    view.buildGotoAnchorHtml( // aside from link, important for matchCellWidths
                        { date: this.start, type: 'week', forceOff: this.colCnt > 1 },
                        htmlEscape(weekText) // inner HTML
                    ) +
                    '</th>';
            }
            else {
                return '<th class="fc-axis ' + view.widgetHeaderClass + '" ' + view.axisStyleAttr() + '></th>';
            }
        },

        // Generates the HTML that goes before the bg of the TimeGrid slot area. Long vertical column.
        renderBgIntroHtml: function () {
            var view = this.view;

            return '<td class="fc-axis ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '></td>';
        },

        // Generates the HTML that goes before all other types of cells.
        // Affects content-skeleton, helper-skeleton, highlight-skeleton for both the time-grid and day-grid.
        renderIntroHtml: function () {
            var view = this.view;

            return '<td class="fc-axis" ' + view.axisStyleAttr() + '></td>';
        }
    };

    // Methods that will customize the rendering behavior of the AgendaView's dayGrid
    var agendaDayGridMethods = {
        // Generates the HTML that goes before the all-day cells
        renderBgIntroHtml: function () {
            var view = this.view;

            return '' +
                '<td class="fc-axis ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '>' +
                '<span>' + // needed for matchCellWidths
                view.getAllDayHtml() +
                '</span>' +
                '</td>';
        },

        // Generates the HTML that goes before all other types of cells.
        // Affects content-skeleton, helper-skeleton, highlight-skeleton for both the time-grid and day-grid.
        renderIntroHtml: function () {
            var view = this.view;

            return '<td class="fc-axis" ' + view.axisStyleAttr() + '></td>';
        }
    };

    ;;

    var AGENDA_ALL_DAY_EVENT_LIMIT = 5;

    // potential nice values for the slot-duration and interval-duration
    // from largest to smallest
    var AGENDA_STOCK_SUB_DURATIONS = [
        { hours: 1 },
        { minutes: 30 },
        { minutes: 15 },
        { seconds: 30 },
        { seconds: 15 }
    ];

    fcViews.agenda = {
        'class': AgendaView,
        defaults: {
            allDaySlot: true,
            slotDuration: '00:30:00',
            minTime: '00:00:00',
            maxTime: '24:00:00',
            slotEventOverlap: true // a bad name. confused with overlap/constraint system
        }
    };

    fcViews.agendaDay = {
        type: 'agenda',
        duration: { days: 1 }
    };

    fcViews.agendaWeek = {
        type: 'agenda',
        duration: { weeks: 1 }
    };
    ;;

    /*
    Responsible for the scroller, and forwarding event-related actions into the "grid"
    */
    var ListView = View.extend({
        grid: null,
        scroller: null,

        initialize: function () {
            this.grid = new ListViewGrid(this);
            this.scroller = new Scroller({
                overflowX: 'hidden',
                overflowY: 'auto'
            });
        },

        setRange: function (range) {
            View.prototype.setRange.call(this, range); // super

            this.grid.setRange(range); // needs to process range-related options
        },

        renderSkeleton: function () {
            this.el.addClass(
                'fc-list-view ' +
                this.widgetContentClass
            );

            this.scroller.render();
            this.scroller.el.appendTo(this.el);

            this.grid.setElement(this.scroller.scrollEl);
        },

        unrenderSkeleton: function () {
            this.scroller.destroy(); // will remove the Grid too
        },

        setHeight: function (totalHeight, isAuto) {
            this.scroller.setHeight(this.computeScrollerHeight(totalHeight));
        },

        computeScrollerHeight: function (totalHeight) {
            return totalHeight -
                subtractInnerElHeight(this.el, this.scroller.el); // everything that's NOT the scroller
        },

        renderEvents: function (events) {
            this.grid.renderEvents(events);
        },

        unrenderEvents: function () {
            this.grid.unrenderEvents();
        },

        isEventResizable: function (event) {
            return false;
        },

        isEventDraggable: function (event) {
            return false;
        }
    });

    /*
    Responsible for event rendering and user-interaction.
    Its "el" is the inner-content of the above view's scroller.
    */
    var ListViewGrid = Grid.extend({
        segSelector: '.fc-list-item', // which elements accept event actions
        hasDayInteractions: false, // no day selection or day clicking

        // slices by day
        spanToSegs: function (span) {
            var view = this.view;
            var dayStart = view.start.clone().time(0); // timed, so segs get times!
            var dayIndex = 0;
            var seg;
            var segs = [];

            while (dayStart < view.end) {
                seg = intersectRanges(span, {
                    start: dayStart,
                    end: dayStart.clone().add(1, 'day')
                });

                if (seg) {
                    seg.dayIndex = dayIndex;
                    segs.push(seg);
                }

                dayStart.add(1, 'day');
                dayIndex++;

                // detect when span won't go fully into the next day,
                // and mutate the latest seg to the be the end.
                if (
                    seg && !seg.isEnd && span.end.hasTime() &&
                    span.end < dayStart.clone().add(this.view.nextDayThreshold)
                ) {
                    seg.end = span.end.clone();
                    seg.isEnd = true;
                    break;
                }
            }

            return segs;
        },

        // like "4:00am"
        computeEventTimeFormat: function () {
            return this.view.opt('mediumTimeFormat');
        },

        // for events with a url, the whole <tr> should be clickable,
        // but it's impossible to wrap with an <a> tag. simulate this.
        handleSegClick: function (seg, ev) {
            var url;

            Grid.prototype.handleSegClick.apply(this, arguments); // super. might prevent the default action

            // not clicking on or within an <a> with an href
            if (!$(ev.target).closest('a[href]').length) {
                url = seg.event.url;
                if (url && !ev.isDefaultPrevented()) { // jsEvent not cancelled in handler
                    window.location.href = url; // simulate link click
                }
            }
        },

        // returns list of foreground segs that were actually rendered
        renderFgSegs: function (segs) {
            segs = this.renderFgSegEls(segs); // might filter away hidden events

            if (!segs.length) {
                this.renderEmptyMessage();
            }
            else {
                this.renderSegList(segs);
            }

            return segs;
        },

        renderEmptyMessage: function () {
            this.el.html(
                '<div class="fc-list-empty-wrap2">' + // TODO: try less wraps
                '<div class="fc-list-empty-wrap1">' +
                '<div class="fc-list-empty">' +
                htmlEscape(this.view.opt('noEventsMessage')) +
                '</div>' +
                '</div>' +
                '</div>'
            );
        },

        // render the event segments in the view
        renderSegList: function (allSegs) {
            var segsByDay = this.groupSegsByDay(allSegs); // sparse array
            var dayIndex;
            var daySegs;
            var i;
            var tableEl = $('<table class="fc-list-table"><tbody/></table>');
            var tbodyEl = tableEl.find('tbody');

            for (dayIndex = 0; dayIndex < segsByDay.length; dayIndex++) {
                daySegs = segsByDay[dayIndex];
                if (daySegs) { // sparse array, so might be undefined
                    // append a day header
                    tbodyEl.append(this.dayHeaderHtml(
                        this.view.start.clone().add(dayIndex, 'days')
                    ));

                    this.sortEventSegs(daySegs);

                    for (i = 0; i < daySegs.length; i++) {
                        tbodyEl.append(daySegs[i].el); // append event row
                    }
                }
            }

            this.el.empty().append(tableEl);
        },

        // Returns a sparse array of arrays, segs grouped by their dayIndex
        groupSegsByDay: function (segs) {
            var segsByDay = []; // sparse array
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                (segsByDay[seg.dayIndex] || (segsByDay[seg.dayIndex] = []))
                    .push(seg);
            }

            return segsByDay;
        },

        // generates the HTML for the day headers that live amongst the event rows
        dayHeaderHtml: function (dayDate) {
            var view = this.view;
            var mainFormat = view.opt('listDayFormat');
            var altFormat = view.opt('listDayAltFormat');

            return '<tr class="fc-list-heading" data-date="' + dayDate.format('YYYY-MM-DD') + '">' +
                '<td class="' + view.widgetHeaderClass + '" colspan="3">' +
                (mainFormat ?
                    view.buildGotoAnchorHtml(
                        dayDate,
                        { 'class': 'fc-list-heading-main' },
                        htmlEscape(dayDate.format(mainFormat)) // inner HTML
                    ) :
                    '') +
                (altFormat ?
                    view.buildGotoAnchorHtml(
                        dayDate,
                        { 'class': 'fc-list-heading-alt' },
                        htmlEscape(dayDate.format(altFormat)) // inner HTML
                    ) :
                    '') +
                '</td>' +
                '</tr>';
        },

        // generates the HTML for a single event row
        fgSegHtml: function (seg) {
            var view = this.view;
            var classes = ['fc-list-item'].concat(this.getSegCustomClasses(seg));
            var bgColor = this.getSegBackgroundColor(seg);
            var event = seg.event;
            var url = event.url;
            var timeHtml;

            if (event.allDay) {
                timeHtml = view.getAllDayHtml();
            }
            else if (view.isMultiDayEvent(event)) { // if the event appears to span more than one day
                if (seg.isStart || seg.isEnd) { // outer segment that probably lasts part of the day
                    timeHtml = htmlEscape(this.getEventTimeText(seg));
                }
                else { // inner segment that lasts the whole day
                    timeHtml = view.getAllDayHtml();
                }
            }
            else {
                // Display the normal time text for the *event's* times
                timeHtml = htmlEscape(this.getEventTimeText(event));
            }

            if (url) {
                classes.push('fc-has-url');
            }

            return '<tr class="' + classes.join(' ') + '">' +
                (this.displayEventTime ?
                    '<td class="fc-list-item-time ' + view.widgetContentClass + '">' +
                    (timeHtml || '') +
                    '</td>' :
                    '') +
                '<td class="fc-list-item-marker ' + view.widgetContentClass + '">' +
                '<span class="fc-event-dot"' +
                (bgColor ?
                    ' style="background-color:' + bgColor + '"' :
                    '') +
                '></span>' +
                '</td>' +
                '<td class="fc-list-item-title ' + view.widgetContentClass + '">' +
                '<a tooltips' + (url ? ' href="' + htmlEscape(url) + '"' : '') + '>' +
                'title: ' + htmlEscape(event.title || '') +
                (event.content ?
                    ': ' + htmlEscape(event.content) :
                    ''
                ) +
                '</a>' +
                '</td>' +
                '</tr>';
        }
    });

    ;;

    fcViews.list = {
        'class': ListView,
        buttonTextKey: 'list', // what to lookup in locale files
        defaults: {
            buttonText: 'list', // text to display for English
            listDayFormat: 'LL', // like "January 1, 2016"
            noEventsMessage: 'No events to display'
        }
    };

    fcViews.listDay = {
        type: 'list',
        duration: { days: 1 },
        defaults: {
            listDayFormat: 'dddd' // day-of-week is all we need. full date is probably in header
        }
    };

    fcViews.listWeek = {
        type: 'list',
        duration: { weeks: 1 },
        defaults: {
            listDayFormat: 'dddd', // day-of-week is more important
            listDayAltFormat: 'LL'
        }
    };

    fcViews.listMonth = {
        type: 'list',
        duration: { month: 1 },
        defaults: {
            listDayAltFormat: 'dddd' // day-of-week is nice-to-have
        }
    };

    fcViews.listYear = {
        type: 'list',
        duration: { year: 1 },
        defaults: {
            listDayAltFormat: 'dddd' // day-of-week is nice-to-have
        }
    };

    ;;

    return FC; // export for Node/CommonJS
});