// Copyright (c) 2020 Oracle and/or its affiliates.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
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// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Connector/NET, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
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//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License, version 2.0, for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
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using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Query;
using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
using MySql.EntityFrameworkCore.Extensions;
using System;
using System.Collections.Generic;
using System.Reflection;

namespace MySql.EntityFrameworkCore.Query.Internal
{
  internal class MySQLDateDiffFunctionsTranslator : IMethodCallTranslator
  {
    private readonly Dictionary<MethodInfo, string> _methodInfoDateDiffMapping
        = new Dictionary<MethodInfo, string>
        {
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffYear),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "YEAR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffYear),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "YEAR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffYear),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "YEAR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffYear),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "YEAR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMonth),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "MONTH"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMonth),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "MONTH"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMonth),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "MONTH"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMonth),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "MONTH"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffDay),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "DAY"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffDay),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "DAY"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffDay),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "DAY"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffDay),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "DAY"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffHour),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "HOUR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffHour),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "HOUR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffHour),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "HOUR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffHour),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "HOUR"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMinute),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "MINUTE"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMinute),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "MINUTE"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMinute),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "MINUTE"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMinute),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "MINUTE"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffSecond),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "SECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffSecond),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "SECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffSecond),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "SECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffSecond),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "SECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMicrosecond),
                        new[] { typeof(DbFunctions), typeof(DateTime), typeof(DateTime) }),
                    "MICROSECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMicrosecond),
                        new[] { typeof(DbFunctions), typeof(DateTime?), typeof(DateTime?) }),
                    "MICROSECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMicrosecond),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset), typeof(DateTimeOffset) }),
                    "MICROSECOND"
                },
                {
                    typeof(MySQLDbFunctionsExtensions).GetRuntimeMethod(
                        nameof(MySQLDbFunctionsExtensions.DateDiffMicrosecond),
                        new[] { typeof(DbFunctions), typeof(DateTimeOffset?), typeof(DateTimeOffset?) }),
                    "MICROSECOND"
                }
        };

    private readonly ISqlExpressionFactory _sqlExpressionFactory;

    public MySQLDateDiffFunctionsTranslator(ISqlExpressionFactory sqlExpressionFactory)
    {
      _sqlExpressionFactory = sqlExpressionFactory;
    }

    public virtual SqlExpression Translate(SqlExpression instance, MethodInfo method, IReadOnlyList<SqlExpression> arguments)
    {
      if (_methodInfoDateDiffMapping.TryGetValue(method, out var datePart))
      {
        var startDate = arguments[1];
        var endDate = arguments[2];
        var typeMapping = ExpressionExtensions.InferTypeMapping(startDate, endDate);

        startDate = _sqlExpressionFactory.ApplyTypeMapping(startDate, typeMapping);
        endDate = _sqlExpressionFactory.ApplyTypeMapping(endDate, typeMapping);

        return _sqlExpressionFactory.Function(
            "TIMESTAMPDIFF",
            new[]
            {
              _sqlExpressionFactory.Fragment(datePart),
              startDate,
              endDate
            },
            typeof(int));
      }

      return null;
    }
  }
}