using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Reflection.Metadata.Ecma335;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;


using MySqlConnector;


using ServerCore; using ServerBase;


namespace ServerBase;

//=============================================================================================
// MySqlConnector 관련 각종 지원 함수
//
// author : kangms
// 
//=============================================================================================
public static class MySqlConnectorHelper
{
    public static async Task<Result> simpleTryConnectToDb(string connectionString)
    {
        var result = new Result();
        var err_msg = string.Empty;

        using (var db_connector = new MySqlDbConnector())
        {
            var error_cdoe = await db_connector.initMySql(connectionString);
            if (error_cdoe.isFail())
            {
                err_msg = $"Failed to initMySql() !!! : errCode:{error_cdoe} - connectString:{connectionString}";
                result.setFail(error_cdoe, err_msg);
            }
        }

        return result;
    }

    public static async Task<Result> simpleQueryExecuteForReaderAsync( string queryString, Func<MySqlDataReader, ServerErrorCode> readFunc
                                                                     , string connectionString
                                                                     , Int16 queryTimeoutSec = 15
                                                                     , Int16 retryIntervalMSec = 1000, Int16 retryCount = 3 )
    {
        var result = new Result();
        var err_msg = string.Empty;

        using ( var db_connector = new MySqlDbConnector() )
        {
            for(var i = 0; i <= retryCount; i++)
            {
                var error_cdoe = await db_connector.initMySql(connectionString);
                if (error_cdoe.isSuccess())
                {
                    error_cdoe = await db_connector.querySQL(queryString, readFunc);
                    if(error_cdoe.isSuccess())
                    {
                        // 성공하면 즉시 반환 한다 !!!
                        result.setSuccess();
                        return result;
                    }
                }

                // Db와 연결이 끊어진 경우는 재시도 설정에 따라 추가 처리 한다.
                if (ConnectionState.Closed == db_connector.getLastConnectionState())
                {
                    err_msg = $"Failed to retry Open MySql !!! : errCode:{error_cdoe}";
                    result.setFail(error_cdoe, err_msg);

                    if (i > 0)
                    {
                        await Task.Delay(retryIntervalMSec);

                        err_msg = $"Retry Query !!! : retriedCount:{i}, queryString:{queryString} - retryableCount:{retryCount}";
                        Log.getLogger().error(err_msg);
                    }
                }
                // 기타 오류 발생시 실패로 처리 한다.
                else
                {
                    err_msg = $"Failed to simpleQueryExecuteForReaderAsync() !!! : errCode:{error_cdoe}, queryString:{queryString} - retryCount:{retryCount}";
                    Log.getLogger().error(err_msg);
                    result.setFail(error_cdoe, err_msg);
                    break;
                }
            }
        }

        return result;
    }
}