// 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.
//
// This program is also distributed with certain software (including
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// as designated in a particular file or component or in included license
// documentation.  The authors of MySQL hereby grant you an
// 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
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// 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.
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using Microsoft.EntityFrameworkCore.Query;
using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
using System;
using System.Collections.Generic;
using System.Reflection;

namespace MySql.EntityFrameworkCore.Query.Internal
{
  internal class MySQLDateTimeMethodTranslator : IMethodCallTranslator
  {
    private readonly Dictionary<MethodInfo, string> _methodInfoDatePartMapping = new Dictionary<MethodInfo, string>
        {
            { typeof(DateTime).GetRuntimeMethod(nameof(DateTime.AddYears), new[] { typeof(int) }), "year" },
            { typeof(DateTime).GetRuntimeMethod(nameof(DateTime.AddMonths), new[] { typeof(int) }), "month" },
            { typeof(DateTime).GetRuntimeMethod(nameof(DateTime.AddDays), new[] { typeof(double) }), "day" },
            { typeof(DateTime).GetRuntimeMethod(nameof(DateTime.AddHours), new[] { typeof(double) }), "hour" },
            { typeof(DateTime).GetRuntimeMethod(nameof(DateTime.AddMinutes), new[] { typeof(double) }), "minute" },
            { typeof(DateTime).GetRuntimeMethod(nameof(DateTime.AddSeconds), new[] { typeof(double) }), "second" },
            { typeof(DateTimeOffset).GetRuntimeMethod(nameof(DateTimeOffset.AddYears), new[] { typeof(int) }), "year" },
            { typeof(DateTimeOffset).GetRuntimeMethod(nameof(DateTimeOffset.AddMonths), new[] { typeof(int) }), "month" },
            { typeof(DateTimeOffset).GetRuntimeMethod(nameof(DateTimeOffset.AddDays), new[] { typeof(double) }), "day" },
            { typeof(DateTimeOffset).GetRuntimeMethod(nameof(DateTimeOffset.AddHours), new[] { typeof(double) }), "hour" },
            { typeof(DateTimeOffset).GetRuntimeMethod(nameof(DateTimeOffset.AddMinutes), new[] { typeof(double) }), "minute" },
            { typeof(DateTimeOffset).GetRuntimeMethod(nameof(DateTimeOffset.AddSeconds), new[] { typeof(double) }), "second" }
        };

    private MySQLSqlExpressionFactory _sqlExpressionFactory;

    public MySQLDateTimeMethodTranslator(ISqlExpressionFactory sqlExpressionFactory)
    {
      _sqlExpressionFactory = (MySQLSqlExpressionFactory)sqlExpressionFactory;
    }

    public virtual SqlExpression Translate(SqlExpression instance, MethodInfo method, IReadOnlyList<SqlExpression> arguments)
    {
      if (_methodInfoDatePartMapping.TryGetValue(method, out var datePart))
      {
        return !datePart.Equals("year")
          && !datePart.Equals("month")
          && arguments[0] is SqlConstantExpression sqlConstant
          && ((double)sqlConstant.Value >= int.MaxValue
            || (double)sqlConstant.Value <= int.MinValue)
            ? null
            : _sqlExpressionFactory.Function(
              "DATE_ADD",
              new[]
              {
                instance,
                _sqlExpressionFactory.ComplexFunctionArgument(new SqlExpression[]
                {
                  _sqlExpressionFactory.Fragment("INTERVAL"),
                  _sqlExpressionFactory.Convert(arguments[0], typeof(int)),
                  _sqlExpressionFactory.Fragment(datePart)
                }, typeof(string))
              },
              instance.Type,
              instance.TypeMapping);
      }

      return null;
    }
  }
}