using FreeSql;
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using FreeSql.Internal.Model;
using FreeSql.Internal.CommonProvider;
using FreeSql.Internal.ObjectPool;
using System.Linq;
using System.Data.Common;
#if MySqlConnector
using MySqlConnector;
#else
using MySql.Data.MySqlClient;
#endif

public static class FreeSqlMySqlConnectorGlobalExtensions
{
    #region ExecuteMySqlBulkCopy

    /// <summary>
    /// 批量更新（更新字段数量超过 2000 时收益大）<para></para>
    /// 实现原理：使用 MySqlBulkCopy 插入临时表，再使用 UPDATE INNER JOIN 联表更新
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="that"></param>
    /// <param name="bulkCopyTimeout"></param>
    /// <returns></returns>
    public static int ExecuteMySqlBulkCopy<T>(this IUpdate<T> that, int? bulkCopyTimeout = null) where T : class
    {
        var update = that as UpdateProvider<T>;
        if (update._source.Any() != true || update._tempPrimarys.Any() == false) return 0;
        var state = ExecuteMySqlBulkCopyState(update);
        return UpdateProvider.ExecuteBulkUpdate(update, state, insert => insert.ExecuteMySqlBulkCopy(bulkCopyTimeout));
    }
    static NativeTuple<string, string, string, string> ExecuteMySqlBulkCopyState<T>(UpdateProvider<T> update) where T : class
    {
        if (update._source.Any() != true) return null;
        var _table = update._table;
        var _tempPrimarys = update._tempPrimarys;
        var _commonUtils = update._commonUtils;
        var _ignore = update._ignore;
        var updateTableName = update._tableRule?.Invoke(_table.DbName) ?? _table.DbName;
        var tempTableName = $"Temp_{Guid.NewGuid().ToString("N")}";
        if (update._connection == null)
        {
            if (update._orm.Ado.TransactionCurrentThread != null)
                update.WithTransaction(update._orm.Ado.TransactionCurrentThread);
        }
        var sb = new StringBuilder();
        sb.Append("CREATE TEMPORARY TABLE ").Append(_commonUtils.QuoteSqlName(tempTableName)).Append(" ( ");
        foreach (var tbcol in _table.ColumnsByPosition)
        {
            sb.Append(" \r\n  ").Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(" ").Append(tbcol.Attribute.DbType);
            sb.Append(",");
        }
        //if (_tempPrimarys.Any())
        //{
        //    sb.Append(" \r\n  PRIMARY KEY (");
        //    foreach (var tbcol in _tempPrimarys) sb.Append(_commonUtils.QuoteSqlName(tbcol.Attribute.Name)).Append(", ");
        //    sb.Remove(sb.Length - 2, 2).Append("),");
        //}
        var sql1 = sb.Remove(sb.Length - 1, 1).Append(" \r\n) Engine=InnoDB;").ToString();

        sb.Clear().Append("UPDATE ").Append(_commonUtils.QuoteSqlName(updateTableName)).Append(" a ")
            .Append(" \r\nINNER JOIN ").Append(_commonUtils.QuoteSqlName(tempTableName)).Append(" b ON ");
        for (var a = 0; a < _tempPrimarys.Length; a++)
        {
            var pkname = _commonUtils.QuoteSqlName(_tempPrimarys[a].Attribute.Name);
            if (a > 0) sb.Append(" AND ");
            sb.Append("b.").Append(pkname).Append(" = a.").Append(pkname);
        }
        sb.Append("\r\n SET ");
        var colidx = 0;
        foreach (var col in _table.Columns.Values)
        {
            if (col.Attribute.IsPrimary) continue;
            if (_tempPrimarys.Any(a => a.CsName == col.CsName)) continue;
            if (col.Attribute.IsIdentity == false && col.Attribute.IsVersion == false && _ignore.ContainsKey(col.Attribute.Name) == false)
            {
                if (colidx > 0) sb.Append(",");
                sb.Append(" \r\n  a.").Append(_commonUtils.QuoteSqlName(col.Attribute.Name)).Append(" = ").Append("b.").Append(_commonUtils.QuoteSqlName(col.Attribute.Name));
                ++colidx;
            }
        }
        var sql2 = sb.ToString();
        sb.Clear();
        var sql3 = $"DROP TABLE {_commonUtils.QuoteSqlName(tempTableName)}";
        return NativeTuple.Create(sql1, sql2, sql3, tempTableName);
    }

    /// <summary>
    /// MySql MySqlCopyBulk 批量插入功能<para></para>
    /// 使用 IgnoreColumns/InsertColumns 设置忽略/指定导入的列<para></para>
    /// 使用 WithConnection/WithTransaction 传入连接/事务对象<para></para>
    /// 提示：若本方法不能满足，请使用 IInsert&lt;T&gt;.ToDataTable 方法得到 DataTable 对象后，自行处理。<para></para>
    /// MySqlCopyBulk 与 insert into t values(..),(..),(..) 性能测试参考：<para></para>
    /// 插入180000行，52列：28,405ms 与 38,481ms，10列：6,504ms 与 11,171ms<para></para>
    /// 插入10000行，52列：1,142ms 与 2,234ms，10列：339ms 与 866ms<para></para>
    /// 插入5000行，52列：657ms 与 1,136ms，10列：257ms 与 366ms<para></para>
    /// 插入2000行，52列：451ms 与 284ms，10列：116ms 与 80ms<para></para>
    /// 插入1000行，52列：435ms 与 239ms，10列：87ms 与 83ms<para></para>
    /// 插入500行，52列：592ms 与 167ms，10列：100ms 与 50ms<para></para>
    /// 插入100行，52列：47ms 与 66ms，10列：16ms 与 24ms<para></para>
    /// 插入50行，52列：22ms 与 30ms，10列：16ms 与 34ms<para></para>
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="that"></param>
    /// <param name="bulkCopyTimeout"></param>
    public static void ExecuteMySqlBulkCopy<T>(this IInsert<T> that, int? bulkCopyTimeout = null) where T : class
    {
        var insert = that as FreeSql.MySql.Curd.MySqlInsert<T>;
        if (insert == null) throw new Exception(CoreStrings.S_Features_Unique("ExecuteMySqlBulkCopy", "MySqlConnector"));

        var dt = that.ToDataTable();
        if (dt.Rows.Count == 0) return;

        Action<MySqlBulkCopy> writeToServer = bulkCopy =>
        {
            if (bulkCopyTimeout.HasValue) bulkCopy.BulkCopyTimeout = bulkCopyTimeout.Value;
            bulkCopy.DestinationTableName = dt.TableName;
            for (int i = 0; i < dt.Columns.Count; i++)
                bulkCopy.ColumnMappings.Add(new MySqlBulkCopyColumnMapping(i, dt.Columns[i].ColumnName));
            bulkCopy.WriteToServer(dt);
        };

        try
        {
            if (insert.InternalConnection == null && insert.InternalTransaction == null)
            {
                if (insert._orm.Ado?.TransactionCurrentThread != null)
                    writeToServer(new MySqlBulkCopy(insert._orm.Ado.TransactionCurrentThread.Connection as MySqlConnection, insert._orm.Ado?.TransactionCurrentThread as MySqlTransaction));
                else
                    using (var conn = insert.InternalOrm.Ado.MasterPool.Get())
                        writeToServer(new MySqlBulkCopy(conn.Value as MySqlConnection));
            }
            else if (insert.InternalTransaction != null)
            {
                writeToServer(new MySqlBulkCopy(insert.InternalTransaction.Connection as MySqlConnection, insert.InternalTransaction as MySqlTransaction));
            }
            else if (insert.InternalConnection != null)
            {
                var conn = insert.InternalConnection as MySqlConnection;
                var isNotOpen = false;
                if (conn.State != System.Data.ConnectionState.Open)
                {
                    isNotOpen = true;
                    conn.Open();
                }
                try
                {
                    writeToServer(new MySqlBulkCopy(conn));
                }
                finally
                {
                    if (isNotOpen)
                        conn.Close();
                }
            }
            else
            {
                throw new NotImplementedException($"ExecuteMySqlBulkCopy {CoreStrings.S_Not_Implemented_FeedBack}");
            }
        }
        finally
        {
            dt.Clear();
        }
    }
#if net40
#else
    public static Task<int> ExecuteMySqlBulkCopyAsync<T>(this IUpdate<T> that, int? bulkCopyTimeout = null, CancellationToken cancellationToken = default) where T : class
    {
        var update = that as UpdateProvider<T>;
        if (update._source.Any() != true || update._tempPrimarys.Any() == false) return Task.FromResult(0);
        var state = ExecuteMySqlBulkCopyState(update);
        return UpdateProvider.ExecuteBulkUpdateAsync(update, state, insert => insert.ExecuteMySqlBulkCopyAsync(bulkCopyTimeout, cancellationToken));
    }
    async public static Task ExecuteMySqlBulkCopyAsync<T>(this IInsert<T> that, int? bulkCopyTimeout = null, CancellationToken cancellationToken = default) where T : class
    {
        var insert = that as FreeSql.MySql.Curd.MySqlInsert<T>;
        if (insert == null) throw new Exception(CoreStrings.S_Features_Unique("ExecuteMySqlBulkCopyAsync", "MySqlConnector"));

        var dt = that.ToDataTable();
        if (dt.Rows.Count == 0) return;

        Func<MySqlBulkCopy, Task> writeToServer = async bulkCopy =>
        {
            if (bulkCopyTimeout.HasValue) bulkCopy.BulkCopyTimeout = bulkCopyTimeout.Value;
            bulkCopy.DestinationTableName = dt.TableName;
            for (int i = 0; i < dt.Columns.Count; i++)
                bulkCopy.ColumnMappings.Add(new MySqlBulkCopyColumnMapping(i, dt.Columns[i].ColumnName));
            await bulkCopy.WriteToServerAsync(dt, cancellationToken);
        };

        try
        {
            if (insert.InternalConnection == null && insert.InternalTransaction == null)
            {
                if (insert._orm.Ado?.TransactionCurrentThread != null)
                    await writeToServer(new MySqlBulkCopy(insert._orm.Ado.TransactionCurrentThread.Connection as MySqlConnection, insert._orm.Ado?.TransactionCurrentThread as MySqlTransaction));
                else
                    using (var conn = insert.InternalOrm.Ado.MasterPool.Get())
                        await writeToServer(new MySqlBulkCopy(conn.Value as MySqlConnection));
            }
            else if (insert.InternalTransaction != null)
            {
                await writeToServer(new MySqlBulkCopy(insert.InternalTransaction.Connection as MySqlConnection, insert.InternalTransaction as MySqlTransaction));
            }
            else if (insert.InternalConnection != null)
            {
                var conn = insert.InternalConnection as MySqlConnection;
                var isNotOpen = false;
                if (conn.State != System.Data.ConnectionState.Open)
                {
                    isNotOpen = true;
                    await conn.OpenAsync(cancellationToken);
                }
                try
                {
                    await writeToServer(new MySqlBulkCopy(conn));
                }
                finally
                {
                    if (isNotOpen)
                        await conn.CloseAsync();
                }
            }
            else
            {
                throw new NotImplementedException($"ExecuteMySqlBulkCopyAsync {CoreStrings.S_Not_Implemented_FeedBack}");
            }
        }
        finally
        {
            dt.Clear();
        }
    }
#endif
    #endregion
}