using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
namespace SqlSugar
{
    public class DeleteBuilder : IDMLBuilder
    {
        #region Fields
        private List<string> _WhereInfos;
        #endregion

        #region Common Properties
        public EntityInfo EntityInfo { get; set; }
        public SqlSugarClient Context { get; set; }
        public ILambdaExpressions LambdaExpressions { get; set; }
        public List<SugarParameter> Parameters { get; set; }
        public StringBuilder sql { get; set; }
        public ISqlBuilder Builder { get; set; }
        public string TableWithString { get; set; }
        public virtual List<string> WhereInfos
        {
            get
            {
                _WhereInfos = UtilMethods.IsNullReturnNew(_WhereInfos);
                return _WhereInfos;
            }
            set { _WhereInfos = value; }
        }
        public virtual List<object> BigDataInValues { get; set; }
        public virtual string BigDataFiled { get;  set; }
        #endregion

        #region Sql Template
        public string SqlTemplate
        {
            get
            {
                return "DELETE FROM {0}{1}";
            }
        }
        public string WhereInTemplate
        {
            get
            {
                return "{0} IN ({1})";
            }
        }
        public string WhereInOrTemplate
        {
            get
            {
                return "OR";
            }
        }
        public string WhereInAndTemplate
        {
            get
            {
                return "AND";
            }
        }
        public string WhereInEqualTemplate
        {
            get
            {
                return Builder.SqlTranslationLeft+"{0}"+Builder.SqlTranslationRight+"=N'{1}'";
            }
        }
        public string WhereInAreaTemplate
        {
            get
            {
                return "({0})";
            }
        }
        #endregion

        #region Get Sql
        public virtual string GetTableNameString
        {
            get
            {
                var result = Builder.GetTranslationTableName(EntityInfo.EntityName);
                result += UtilConstants.Space;
                if (this.TableWithString.HasValue())
                {
                    result += TableWithString + UtilConstants.Space;
                }
                return result;
            }
        }
        public virtual string GetWhereString
        {
            get
            {
                if (_WhereInfos == null || _WhereInfos.Count == 0) return null;
                string whereString = null;
                var i = 0;
                foreach (var item in _WhereInfos)
                {
                    var isFirst = i == 0;
                    whereString += isFirst ? "WHERE " : "AND ";
                    whereString += (item + UtilConstants.Space);
                    ++i;
                }
                return whereString;
            }
        }

        #endregion

        #region Public methods
        public virtual void Clear()
        {
        }
        public virtual string ToSqlString()
        {
            if (this.BigDataInValues.IsNullOrEmpty())
            {
                return string.Format(SqlTemplate, GetTableNameString, GetWhereString);
            }
            else//big data
            {
                var whereString = GetWhereString;
                var sql = string.Format(SqlTemplate, GetTableNameString, whereString);
                sql += whereString.IsNullOrEmpty() ? " WHERE " : " AND ";
                var batchDeleteSql = new StringBuilder();
                var pageSize = 1000;
                var pageIndex = 1;
                var totalRecord = this.BigDataInValues.Count;
                var pageCount = (totalRecord + pageSize - 1) / pageSize;
                while (pageCount >= pageIndex)
                {
                    var inValues = this.BigDataInValues.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList();
                    batchDeleteSql.Append(sql+string.Format(WhereInTemplate,BigDataFiled,inValues.ToArray().ToJoinSqlInVals()));
                    batchDeleteSql.Append(";");
                    pageIndex++;
                }
                return batchDeleteSql.ToString();
            }
        }
        public virtual ExpressionResult GetExpressionValue(Expression expression, ResolveExpressType resolveType)
        {
            var resolveExpress = this.LambdaExpressions;
            this.LambdaExpressions.Clear();
            resolveExpress.MappingColumns = Context.MappingColumns;
            resolveExpress.MappingTables = Context.MappingTables;
            resolveExpress.IgnoreComumnList = Context.IgnoreColumns;
            resolveExpress.SqlFuncServices = Context.CurrentConnectionConfig.ConfigureExternalServices?.SqlFuncServices;
            resolveExpress.InitMappingInfo = Context.InitMppingInfo;
            resolveExpress.RefreshMapping = () =>
            {
                resolveExpress.MappingColumns = Context.MappingColumns;
                resolveExpress.MappingTables = Context.MappingTables;
                resolveExpress.IgnoreComumnList = Context.IgnoreColumns;
                resolveExpress.SqlFuncServices = Context.CurrentConnectionConfig.ConfigureExternalServices?.SqlFuncServices;
            };
            resolveExpress.Resolve(expression, resolveType);
            if (this.Parameters == null)
                this.Parameters = new List<SugarParameter>();
            this.Parameters.AddRange(resolveExpress.Parameters);
            var result = resolveExpress.Result;
            return result;
        }
        #endregion
    }
}