/**
 * Copyright 2017-present, Facebook, Inc. All rights reserved.
 *
 * This source code is licensed under the license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * Messenger Platform Quick Start Tutorial
 *
 * This is the completed code for the Messenger Platform quick start tutorial
 *
 * https://developers.facebook.com/docs/messenger-platform/getting-started/quick-start/
 *
 * To run this code, you must do the following:
 *
 * 1. Deploy this code to a server running Node.js
 * 2. Run `npm install`
 * 3. Update the VERIFY_TOKEN
 * 4. Add your PAGE_ACCESS_TOKEN to your environment vars
 *
 */

'use strict';

// Customize Verify token
const VERIFY_TOKEN = "LG8YBDVaU0Wg47n7VUns66666g";

// User Token
const User_ACCESS_TOKEN = 'EAAJRQcUfZCWIBAOhi8TQZBpFmLWXK5xWFDoR1toWPiGAXdtrWaCR8JDoLtNesjSZAtGkWxseUsoy6nrlqZAgh45jzvZAOYBnJnaj4vizOPWpKd9OrxcZBdXzvJXlPaBXuTc2FYdimRfalAMUmWxMKAwiCGr119Mv7Ic8FA2LDFpmcZAZBhBZBtSZBu';

// Messenger TOKEN: 正式
const PAGE_ACCESS_TOKEN = 'EAAJRQcUfZCWIBAEsL2HcuOaB5mmqw8yOiZCmnvleDGNGS8p3d6EZAcZAaDjIZCZC7zLaZBl6taZAJAfDYw4qzKeELZA5xalFZCSaq4VUZAWDHmHfWVLn64blwZAjwjHZBGvxahZCp4OZB7z8ZBJbHgTvUV0uHW1IrXZBdslZA361srODwVMOC94dQpFbyIGfj6SNYx988slmgZD';
const APIURL = 'https://graph.facebook.com/v3.2/';
// 社團ID
const GROUPID = "202061134174478";

// Imports dependencies and set up http server
const request = require('request');
const express = require('express');
const body_parser = require('body-parser');
const cors = require('cors');
const app = express().use(body_parser.json()); // creates express http server
const corsOptions = {
    origin: [
        'https://www.origtek.com',
        'http://localhost:3000',
        'https://www.origtek.com:3001',
    ],
    methods: 'GET,HEAD,PUT,PATCH,POST,DELETE,OPTIONS',
    allowedHeaders: ['Content-Type', 'Authorization'],
};

app.use(cors(corsOptions));


// 讀取記錄檔案
var recordIDs = {};
saveAndLoadPSID();

// Sets server port and logs message on success
app.listen(process.env.PORT || 3000, () => console.log('webhook is listening'));

// Accepts POST requests at /webhook endpoint
app.post('/webhook', (req, res) => {
    // Parse the request body from the POST
    let body = req.body;

    // Check the webhook event is from a Page subscription
    if (body.object === 'page') {

        body.entry.forEach(function (entry) {

            // Gets the body of the webhook event
            let webhook_event = entry.messaging[0];
            console.log(webhook_event);

            recordIDs
            // Get the sender PSID
            let sender_psid = webhook_event.sender.id;
            // let fullnamekeys = Object.keys(recordIDs)
            lookupUser(sender_psid);
            console.log('Sender ID: ' + sender_psid);

            // Check if the event is a message or postback and
            // pass the event to the appropriate handler function
            // if (webhook_event.message) {
            //     handleMessage(sender_psid, webhook_event.message);
            // } else if (webhook_event.postback) {
            //     handlePostback(sender_psid, webhook_event.postback);
            // }

        });
        // Return a '200 OK' response to all events
        res.status(200).send('EVENT_RECEIVED');

    } else {
        // Return a '404 Not Found' if event is not from a page subscription
        res.sendStatus(404);
    }

});

// Accepts GET requests at the /webhook endpoint
app.get('/webhook', (req, res) => {
    // Parse params from the webhook verification request
    let mode = req.query['hub.mode'];
    let token = req.query['hub.verify_token'];
    let challenge = req.query['hub.challenge'];
    let getRecords = req.query['getRecords'];
    // Check if a token and mode were sent
    if (mode && token) {
        // Check the mode and token sent are correct
        if (mode === 'subscribe' && token === VERIFY_TOKEN) {
            let recipientID = req.query['recipient'];
            let msgText = req.query['reply'];
            let fullname = req.query['fullname'];

            if (getRecords) {
                challenge = JSON.stringify(recordIDs)
                res.status(200).send(challenge);
            }
            else if (recipientID && msgText) {
                callSendAPI(recipientID, { "text": msgText });
            }
            else if (fullname && msgText) {
                let userInfo = getUserInfoByName(fullname);
                if (userInfo) {
                    callSendAPI(userInfo.id, { "text": msgText });
                    res.status(200).send("send");
                }
                else {
                    res.status(200).send("No Matched Data");
                }
            }
            else {

                // Respond with 200 OK and challenge token from the request
                console.log('WEBHOOK_VERIFIED');
                res.status(200).send(challenge);
            }


        } else {
            // Responds with '403 Forbidden' if verify tokens do not match
            res.sendStatus(403);
        }
    }
});

// 社團操作類型
app.get('/Groups', (req, res) => {
    let mode = req.query['hub.mode'];
    let token = req.query['hub.verify_token'];
    let message = req.query['message'];
    let postID = req.query['postID'];
    if (mode && token) {
        if (mode === 'subscribe' && token === VERIFY_TOKEN) {
            if (message) {
                newPost(message, x => {
                    res.status(x.statusCode).send(x.body);
                });
            }
            else if (postID) {
                getPostComments(postID, x => {
                    res.status(x.statusCode).send(x.body);
                });
            }

        } else {
            res.sendStatus(403);
        }
    }
    else {
        res.sendStatus(400);
    }

    // 取得貼文內容
    function getPostComments(postID, callbackFn) {
        request({
            uri: APIURL + postID, // EX: "https://graph.facebook.com/v3.2/202061134174478_205484600498798?fields=comments",
            qs: {
                fields: 'comments',
                access_token: User_ACCESS_TOKEN
            },
            method: "GET",
        }, (err, res, body) => {
            console.log(res.statusMessage);
            console.log(res.statusCode);
            callbackFn(res);
        });
    }

    // 新增貼文 **一定要有使用者授權才會看到名字 ID
    function newPost(messages, callbackFn) {
        request({
            uri: APIURL + GROUPID + "/feed", //"202061134174478_205484600498798?fields=comments",
            qs: {
                access_token: User_ACCESS_TOKEN
            },
            method: "POST",
            json: {
                message: messages
            }
        }, (err, res, body) => {
            console.log(res.statusMessage);
            console.log(res.statusCode);
            callbackFn(res);
        });
    }
});


function handleMessage(sender_psid, received_message) {
    let response;

    // Checks if the message contains text
    if (received_message.text) {
        // Create the payload for a basic text message, which
        // will be added to the body of our request to the Send API
        response = {
            "text": `You sent the message: "${received_message.text}". Now send me an attachment!`
        }
    } else if (received_message.attachments) {
        // Get the URL of the message attachment
        let attachment_url = received_message.attachments[0].payload.url;
        response = {
            "attachment": {
                "type": "template",
                "payload": {
                    "template_type": "generic",
                    "elements": [{
                        "title": "Is this the right picture?",
                        "subtitle": "Tap a button to answer.",
                        "image_url": attachment_url,
                        "buttons": [
                            {
                                "type": "postback",
                                "title": "Yes!",
                                "payload": "yes",
                            },
                            {
                                "type": "postback",
                                "title": "No!",
                                "payload": "no",
                            }
                        ],
                    }]
                }
            }
        }
    }

    // Send the response message
    callSendAPI(sender_psid, response);
}

function getUserInfoByName(name) {
    if (recordIDs[name]) {
        return recordIDs[name];
    }
}

function handlePostback(sender_psid, received_postback) {
    console.log('ok')
    let response;
    // Get the payload for the postback
    let payload = received_postback.payload;

    // Set the response based on the postback payload
    if (payload === 'yes') {
        response = { "text": "Thanks!" }
    } else if (payload === 'no') {
        response = { "text": "Oops, try sending another image." }
    }
    // Send the message to acknowledge the postback
    callSendAPI(sender_psid, response);
}

// 查詢user資料，需要messenger 權限
function lookupUser(id) {
    request({
        uri: APIURL + id,
        qs: {
            access_token: PAGE_ACCESS_TOKEN
        },
        method: "GET",
    }, (err, res, body) => {
        //debugger;
        let data = JSON.parse(res.body);
        if (!data.error) {
            let fullname = data.first_name + " " + data.last_name;
            if (!recordIDs.hasOwnProperty(fullname)) {
                recordIDs[fullname] = data;
                saveAndLoadPSID();
            }
        }
        if (!err) {
            console.log('message sent!')
        } else {
            console.error("Unable to send message:" + err);
        }
    });
}



function callSendAPI(sender_psid, response) {
    // Construct the message body
    let request_body = {
        "recipient": {
            "id": sender_psid
        },
        "message": {
            "text": response.text
        }
    };
    // Send the HTTP request to the Messenger Platform
    request({
        uri: APIURL + "me/messages",
        qs: {
            access_token: PAGE_ACCESS_TOKEN
        },
        method: "POST",
        json: request_body
    }, (err, res, body) => {
        console.log(res.statusMessage);
        console.log(res.statusCode);
        if (!err) {
            console.log('message sent!')
        } else {
            console.error("Unable to send message:" + err);
        }
    });
}

function saveAndLoadPSID() {
    var fs = require('fs');
    if (isEmpty(recordIDs)) {
        fs.readFile('record.json', 'utf8', function readFileCallback(err, data) {
            if (err) {
                console.log(err);
            } else {
                recordIDs = JSON.parse(data);
            }
        });
    }
    else {
        let data = JSON.stringify(recordIDs);
        fs.writeFile('record.json', data, 'utf8', function (err) {
            console.log(err);
        });
    }

}

function isEmpty(obj) {

    // null and undefined are "empty"
    if (obj == null) return true;

    // Assume if it has a length property with a non-zero value
    // that that property is correct.
    if (obj.length > 0) return false;
    if (obj.length === 0) return true;

    // If it isn't an object at this point
    // it is empty, but it can't be anything *but* empty
    // Is it empty?  Depends on your application.
    if (typeof obj !== "object") return true;

    // Otherwise, does it have any properties of its own?
    // Note that this doesn't handle
    // toString and valueOf enumeration bugs in IE < 9
    for (var key in obj) {
        if (hasOwnProperty.call(obj, key)) return false;
    }

    return true;
}