using Dapper;
using EVCB_OCPP.Domain;
using EVCB_OCPP.Domain.ConnectionFactory;
using EVCB_OCPP.WSServer.Helper;
using Microsoft.Data.SqlClient;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EVCB_OCPP.WSServer.Service
{
    public class BlockingTreePrintService
    {
        public BlockingTreePrintService(ILogger<BlockingTreePrintService> logger,
            ISqlConnectionFactory<MainDBContext> connectionFactory)
        {
            this.logger = logger;
            this.connectionFactory = connectionFactory;
        }

        public async Task PrintDbBlockingTree()
        {
            using var connection = await connectionFactory.CreateAsync();
            var tree = await connection.QueryAsync<TreeStruct>(Command);

            logger.LogCritical("Printing BlockingTree");
            foreach (var data in tree)
            {
                logger.LogCritical($"{data.BlockingTree} {data.Type} {data.LoginName} {data.SourceDatabase} {data.SQLText} {data.CursorSQLText} {data.Database} {data.Schema} {data.Table} {data.WaitResource} {data.Command} {data.Application} {data.HostName} {data.LastBatchTime} ");
            }
        }

        private const string Command = """
                        /*  SQL Blocking Tree w/Cursor info
            Thanks SQL Server Expert JOHNNYBNO 
            */
            IF OBJECT_ID('tempdb..#Blocks') IS NOT NULL
                DROP TABLE #Blocks
            SELECT   spid
                    ,blocked
                    ,REPLACE (REPLACE (st.TEXT, CHAR(10), ' '), CHAR (13), ' ' ) AS batch
            INTO     #Blocks
            FROM     sys.sysprocesses spr
            	CROSS APPLY sys.dm_exec_sql_text(spr.SQL_HANDLE) st;

            WITH BlockingTree (spid, blocking_spid, [level], batch)
            AS
            (
                SELECT   blc.spid
                        ,blc.blocked
                        ,CAST (REPLICATE ('0', 4-LEN (CAST (blc.spid AS VARCHAR))) + CAST (blc.spid AS VARCHAR) AS VARCHAR (1000)) AS [level]
                        ,blc.batch
                FROM    #Blocks blc
                WHERE   (blc.blocked = 0 OR blc.blocked = SPID) AND
            			EXISTS (SELECT * FROM #Blocks blc2 WHERE blc2.BLOCKED = blc.SPID AND blc2.BLOCKED <> blc2.SPID)
                UNION ALL
                SELECT   blc.spid
                        ,blc.blocked
                        ,CAST(bt.[level] + RIGHT (CAST ((1000 + blc.SPID) AS VARCHAR (100)), 4) AS VARCHAR (1000)) AS [level]
                        ,blc.batch
                FROM     #Blocks AS blc
            		INNER JOIN BlockingTree bt 
            			ON	blc.blocked = bt.SPID
                WHERE   blc.blocked > 0 AND
            			blc.blocked <> blc.SPID
            )
            SELECT	N'' + ISNULL(REPLICATE (N'|         ', LEN (LEVEL)/4 - 2),'')
                    + CASE WHEN (LEN(LEVEL)/4 - 1) = 0 THEN '' ELSE '|------  ' END
                    + CAST (bt.SPID AS NVARCHAR (10)) AS BlockingTree
                    ,spr.lastwaittype   AS [Type]
                    ,spr.loginame       AS [LoginName]
                    ,DB_NAME(spr.dbid)  AS [SourceDatabase]
                    ,st.text            AS [SQLText]
            		,CASE WHEN cur.sql_handle IS NULL THEN '' ELSE (SELECT [TEXT] FROM sys.dm_exec_sql_text (cur.sql_handle)) END  AS [CursorSQLText]
                    ,DB_NAME(sli.rsc_dbid)  AS [Database]
            		,OBJECT_SCHEMA_NAME(sli.rsc_objid,sli.rsc_dbid) AS [Schema]
            		,OBJECT_NAME(sli.rsc_objid, sli.rsc_dbid) AS [Table]
                    ,spr.waitresource   AS [WaitResource]
                    ,spr.cmd            AS [Command]
                    ,spr.program_name   AS [Application]
                    ,spr.hostname       AS [HostName]
                    ,spr.last_batch     AS [Last Batch Time]
            FROM BlockingTree bt
            	LEFT OUTER JOIN sys.sysprocesses spr 
            		ON	spr.spid = bt.spid
            	CROSS APPLY sys.dm_exec_sql_text(spr.SQL_HANDLE) st
            	LEFT JOIN sys.dm_exec_cursors(0) cur
            		ON	cur.session_id = spr.spid AND
            			cur.fetch_status != 0
            	JOIN sys.syslockinfo sli
            		ON	sli.req_spid = spr.spid AND
            			sli.rsc_type = 5 AND
            			OBJECT_NAME(sli.rsc_objid, sli.rsc_dbid) IS NOT NULL
            ORDER BY LEVEL ASC
            """;
        private readonly ILogger<BlockingTreePrintService> logger;
        private readonly ISqlConnectionFactory<MainDBContext> connectionFactory;
    }

    public class TreeStruct
    {
        public string BlockingTree { get; set; }
        public string Type { get; set; }
        public string LoginName { get; set; }
        public string SourceDatabase { get; set; }
        public string SQLText { get; set; }
        public string CursorSQLText { get; set; }
        public string Database { get; set; }
        public string Schema { get; set; }
        public string Table { get; set; }
        public string WaitResource { get; set; }
        public string Command { get; set; }
        public string Application { get; set; }
        public string HostName { get; set; }
        public string LastBatchTime { get; set; }

    }
}