using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using Aitex.Core.RT.DataCenter;
using Aitex.Core.RT.DBCore;
using Aitex.Core.RT.IOCore;
using Aitex.Core.RT.Log;
using Aitex.Core.RT.SCCore;
using Aitex.Core.Util;
using MECF.Framework.Common.Equipment;
using ThreadState = System.Threading.ThreadState;

namespace Aitex.Core.RT.DataCollection.HighPerformance
{

    public class DataTraceManager : Singleton<DataTraceManager>
    {
        #region Variables

        private readonly object _syncRoot = new();
        private readonly int _dataRecorderInterval;
        private readonly int _dataRecorderCacheSize;
        private readonly int _dataRecorderCachePeriodMs;
        private string[] _dataTableCategory = { ModuleName.System.ToString() };
        private readonly Dictionary<string, Func<object>> _dataGetters = new();
        private readonly R_TRIG _rTrigPersistThreadError = new();
        private readonly CancellationTokenSource _ctsDataRecorderThread;
        private readonly CancellationToken _ctDataRecorderThread;
        private Dictionary<string, DataTraceCache> _dictDataRecCachePerDataTable;
        private DateTime _datePrefixTableName;

        private readonly Thread _threadCache;
        private readonly Thread _threadPersist;

        private bool isAllowTraceAOHopping = false;
        private bool isAllowTraceDOHopping = false;
        
        #endregion

        #region Constructors

        public DataTraceManager()
        {
            _dataRecorderInterval = (SC.ContainsItem("System.DataRecorderInterval")
                ? SC.GetValue<int>("System.DataCollectionInterval")
                : 1000);

            _dataRecorderCacheSize = (SC.ContainsItem("System.DataRecorderCacheSize")
                ? SC.GetValue<int>("System.DataRecorderCacheSize")
                : DataTraceCache.MIN_CACHE_SIZE);

            _dataRecorderCachePeriodMs = (SC.ContainsItem("System.DataRecorderCachePeriod")
                ? SC.GetValue<int>("System.DataRecorderCachePeriod")
                : DataTraceCache.MIN_CACHE_PERIOD_MS);

            _ctsDataRecorderThread = new();
            _ctDataRecorderThread = _ctsDataRecorderThread.Token;

            _threadCache = new Thread(CacheThread);
            _threadCache.Name = nameof(CacheThread);
            _threadPersist = new Thread(PersistThread);
            _threadPersist.Name = nameof(PersistThread);
        }

        #endregion

        #region Methods

        /// <summary>
        /// 初始化<see cref="DataTraceManager"/>对象。
        /// </summary>
        /// <param name="dataTableCategory"></param>
        public void Initialize(string[] dataTableCategory)
        {
                    
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.PersistCostMs", () => _statPersistCostMs);
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.PersistInvMs", () => _statPersistInvMs);
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.PersistLines", () => _statPersistLines);
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.PersistCounter", () => _statPersistCnt);
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.PersistErrorCounter", () => _statPersistErrorCnt);
            
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.CacheCostMs", () => _statCacheCostMs);
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.CacheInvMs", () => _statCacheInvMs);
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.CacheCounter", () => _statCacheCnt);

#if CHECK_DATA_TRACE_OVERRUN_ISSUE
            DATA.Subscribe($"{ModuleName.System}.{ModuleName.Diagnosis}.DataTrace.CacheOverrunDuration", () => _statCacheOverrunDuration);
#endif

        const string SC_ALLOW_TRACE_AO_HOPPING = "System.AllowTraceAOHopping";
        const string SC_ALLOW_TRACE_DO_HOPPING = "System.AllowTraceDOHopping";

        isAllowTraceAOHopping = SC.GetValue(SC_ALLOW_TRACE_AO_HOPPING, true);
            SC.RegisterValueChangedCallback(SC_ALLOW_TRACE_AO_HOPPING, o =>
            {
                if(!bool.TryParse(o.ToString(), out isAllowTraceAOHopping))
                    LOG.Error($"Unable to convert value {o} of [{SC_ALLOW_TRACE_AO_HOPPING}] to boolean.");
            });
            
            isAllowTraceDOHopping = SC.GetValue(SC_ALLOW_TRACE_DO_HOPPING, true);
            SC.RegisterValueChangedCallback(SC_ALLOW_TRACE_DO_HOPPING, o =>
            {
                if(!bool.TryParse(o.ToString(), out isAllowTraceDOHopping))
                    LOG.Error($"Unable to convert value {o} of [{SC_ALLOW_TRACE_DO_HOPPING}] to boolean.");
            });
            
            _dataTableCategory = dataTableCategory;
            _threadCache.Start();
        }

        /// <summary>
        /// 立即缓存所有模组的数据。
        /// </summary>
        public void ImmediateCache(IIOAccessor io = null, CacheDiagnosisInfo diagnosisInfo = null)
        {
            if (io is AOAccessor)
            {
                if (!isAllowTraceAOHopping)
                    return;

                // maybe DB free disk space too low to trace AO hopping
                var obj = DATA.Poll($"{ModuleName.System}.{ModuleName.Diagnosis}.DiskMon.IsDBFreeDiskSpaceLow");
                if (obj is true)
                    return;

            }
            
            if (io is DOAccessor && !isAllowTraceDOHopping)
                return;
            
            if (diagnosisInfo != null)
                Debug.WriteLine($"{diagnosisInfo.Module}.{diagnosisInfo.IoName} changed to {diagnosisInfo.Value}",
                    $"{nameof(DataTraceManager)} - {nameof(ImmediateCache)}");

            lock (_syncRoot)
            {
                _tmrCacheThreadDelay.Stop();
            }

            DoCache();
        }

        #region Background Threads

        private readonly DeviceTimer _tmrPersistDelay = new();
        
        private void PersistThread()
        {
            try
            {
                while (true)
                {
                    _ctDataRecorderThread.ThrowIfCancellationRequested();
                    Thread.Sleep(10);
                    if (!_tmrPersistDelay.IsIdle() && !_tmrPersistDelay.IsTimeout())
                        continue;

                    // next persist will be called 5sec later
                    _tmrPersistDelay.Start(5000);
                    
                    var ret = Persist();
                    
                    // check whether the DB write operation is succeeded
                    _rTrigPersistThreadError.CLK = ret < 0;
                    if (_rTrigPersistThreadError.Q) //  插入数据错误，退出
                    {
                        // DB Write Error
                        LOG.Error(
                            $"{nameof(DataTraceManager)}.{nameof(PersistThread)} Unable to persist the cache.");
                    }
                }
            }
            catch (OperationCanceledException)
            {
                LOG.Info($"{nameof(DataTraceManager)}.{nameof(PersistThread)} terminated.");
            }
            catch (Exception ex)
            {
                LOG.Write(ex, $"{nameof(DataTraceManager)}.{nameof(PersistThread)} terminated unexpectedly，{ex.Message}");
            }
            finally
            {
                try
                {
                    Persist();
                }
                catch (Exception ex)
                {
                    LOG.Write(ex,
                        $"{nameof(DataTraceManager)}.{nameof(PersistThread)} Failed to persist cache when exit the thread, {ex.Message}");
                }
            }
        }

        private readonly DeviceTimer _tmrCacheThreadDelay = new(); 
        private void CacheThread()
        {
            try
            {
                while (true)
                {
                    Thread.Sleep(_dataRecorderInterval);
                    _ctDataRecorderThread.ThrowIfCancellationRequested();
                    CreateCache();
                    _ctDataRecorderThread.ThrowIfCancellationRequested();
                    
                    // start persist thread once the cache instances are built.
                    // note the persist thread must be started before CreateCache() method.
                    if (_threadPersist.ThreadState == ThreadState.Unstarted)
                        _threadPersist.Start();

                    // 开始周期性数据采集
                    while (true)
                    {
                        _ctDataRecorderThread.ThrowIfCancellationRequested();
                        Thread.Sleep(10);
                        
                        // 跨天，退出循环并创建新表
                        if (DateTime.Now.Date != _datePrefixTableName)
                            break;

                        // 立即缓存一次数据
                        DoCache();
                    }
                }
            }
            catch (OperationCanceledException)
            {
                LOG.Info($"{nameof(DataTraceManager)}.{nameof(CacheThread)} terminated.");
            }
            catch (Exception ex)
            {
                LOG.Write(ex, $"{nameof(DataTraceManager)}.{nameof(CacheThread)}线程意外终止，{ex.Message}");
            }
        }
        
        #endregion

        /// <summary>
        /// 扫描<see cref="DataManager"/>，获取所有可记录的数据。
        /// </summary>
        /// <remarks>
        /// 仅数据管理器中注册的数据，且类型为<see cref="bool"/>、<see cref="double"/>、<see cref="float"/>、<see cref="int"/>、<see cref="ushort"/>、<see cref="short"/>的数据支持保存到数据库。
        /// </remarks>>
        private void GetRecordableDataSource()
        {
            var dBRecorderList = DATA.GetDBRecorderList();
            foreach (var item in dBRecorderList)
            {
                if (_dataGetters.ContainsKey(item.Key))
                    continue;

                var getter = item.Value;
                var value = getter.Invoke();
                if (value != null)
                {
                    var type = value.GetType();
                    if(DataTraceHelper.SupportedValueTypes.Contains(type))
                        _dataGetters[item.Key] = getter;
                }
            }
        }

        /// <summary>
        /// 创建数据缓存对象。
        /// </summary>
        private void CreateCache()
        {
            lock (_syncRoot)
            {
                // persist the existing data since the date is changing.
                if (_dictDataRecCachePerDataTable != null)
                    Persist();
                
                GetRecordableDataSource();

                _dictDataRecCachePerDataTable = new();
                Dictionary<string, List<IDataBuffer>> dictDataBufferPerTable = new();

                var defaultModuleName = (_dataTableCategory.Contains(ModuleName.System.ToString())
                    ? ModuleName.System.ToString()
                    : (_dataTableCategory.Contains(ModuleName.System.ToString())
                        ? ModuleName.System.ToString()
                        : _dataTableCategory[0]));


                if (_dataGetters is { Count: > 0 })
                {
                    foreach (var dataName in _dataGetters.Keys)
                    {
                        Type valueType;
                        Func<object> getter;
                        try
                        {
                            // determine the type of the data.
                            getter = _dataGetters[dataName];
                            var value = getter.Invoke();
                            valueType = value.GetType();
                            Debug.Assert(valueType != null, $"Unable to determine the type of DATA item {dataName}");
                        }
                        catch (Exception ex)
                        {
                            LOG.Write(ex, $"Unable to determine the type of DATA item {dataName}, {ex.Message}");
                            Debug.Assert(false, $"Unable to determine the type of DATA item {dataName}");
                            continue;
                        }
                        
                        var isTableAssigned = false;
                        var categoryName = "";
                        foreach (var category in _dataTableCategory)
                        {
                            if (dataName.StartsWith(category + ".") ||
                                dataName.StartsWith("IO." + category + "."))
                            {
                                if (!dictDataBufferPerTable.ContainsKey(category))
                                    dictDataBufferPerTable[category] = [];

                                categoryName = category;
                                isTableAssigned = true;
                                break;
                            }
                        }

                        if (!isTableAssigned)
                        {
                            if (!dictDataBufferPerTable.ContainsKey(defaultModuleName))
                                dictDataBufferPerTable[defaultModuleName] = [];

                            categoryName = defaultModuleName;
                        }
                        
                        // create DataHolder and add to dictDataHolderPerDataTable.
                        var index = dictDataBufferPerTable[categoryName].Count;
                        var type = typeof(DataBuffer<>).MakeGenericType(valueType);
                        var holder = (IDataBuffer)Activator.CreateInstance(type, index, dataName, getter);
                        if (holder == null)
                        {
                            LOG.Error($"Unable to create instance of DataBuffer for {dataName}.");
                            Debug.Assert(holder != null, "Unable to create instance of DataBuffer.");
                        }
                        else
                        {
                            dictDataBufferPerTable[categoryName].Add(holder);
                        }
                        
                    }
                }

                _datePrefixTableName = DateTime.Now.Date;
                foreach (var perTable in dictDataBufferPerTable.Keys)
                {
                    var holders = dictDataBufferPerTable[perTable];
                    var tableName = $"{_datePrefixTableName:yyyyMMdd}.{perTable}";
                    _dictDataRecCachePerDataTable[perTable] =
                        new DataTraceCache(tableName, perTable, holders, minCachePeriodMs: _dataRecorderCachePeriodMs,
                            maxCacheSize: _dataRecorderCacheSize);

                    UpdateTableSchema(tableName, holders);
                }
            }
        }

        private int _statCacheCostMs;
        private int _statCacheInvMs;
        private int _statCacheCnt;

        private int _statCacheOverrunDuration;
        private readonly R_TRIG _rTrigTraceOverrun = new();
        private readonly Stopwatch _swTraceOverrun = new();
        
        private readonly Stopwatch _swCacheCostMsStat = new();
        private readonly Stopwatch _swCacheInvMsStat = new();
        
        /// <summary>
        /// 立即缓存所有模组的数据。
        /// </summary>
        /// <returns></returns>
        private void DoCache()
        {
            lock (_syncRoot)
            {
                if (!_tmrCacheThreadDelay.IsIdle() && !_tmrCacheThreadDelay.IsTimeout())
                    return;
                _tmrCacheThreadDelay.Start(_dataRecorderInterval);
                
                // statistic cache called interval in ms.
                _swCacheInvMsStat.Stop();
                _statCacheInvMs = (int)_swCacheInvMsStat.Elapsed.TotalMilliseconds;

#if CHECK_DATA_TRACE_OVERRUN_ISSUE

                const int OVERRUN_ALARM_THRESHOLD_M = 60; 
                
                // Check data-trace-overrun issue
                _rTrigTraceOverrun.CLK = _statCacheInvMs < 900;
                if (_rTrigTraceOverrun.Q && !_swTraceOverrun.IsRunning)
                {
                    _swTraceOverrun.Restart();
                }
                else if (!_rTrigTraceOverrun.M && _swTraceOverrun.IsRunning)
                {
                    _swTraceOverrun.Stop();
                }

                if (_swTraceOverrun.Elapsed.TotalSeconds > TimeSpan.FromMinutes(OVERRUN_ALARM_THRESHOLD_M).TotalSeconds)
                {
                    _swTraceOverrun.Stop();
                    _rTrigTraceOverrun.RST = true;
                    Debug.Assert(false, "Data-Trace-Overrun Issue Detected",
                        $"The {nameof(DataTraceManager)} continues to trace data at a high frequency " +
                        $"within {OVERRUN_ALARM_THRESHOLD_M} minutes. Please check whether there are any Monitor() " +
                        $"methods running frequently to assign values to DO and AO.");
                }

                _statCacheOverrunDuration = (int)_swTraceOverrun.Elapsed.TotalSeconds;
#endif
                _swCacheCostMsStat.Restart();
                
                // DO调用ForceCache方法可能发生在当前对象初始化之前，此时_dictCachePerModule为null
                if (_dictDataRecCachePerDataTable == null)
                    return;
                
                // 立即缓存一次数据
                foreach (var drc in _dictDataRecCachePerDataTable.Values)
                    drc.Cache();
                
                _swCacheCostMsStat.Stop();
                _statCacheCostMs = (int)_swCacheCostMsStat.Elapsed.TotalMilliseconds;
                        
                _swCacheInvMsStat.Restart();
                _statCacheCnt++;
            }

        }
        
        private readonly Stopwatch _swPersisCostMsStat = new();
        private readonly Stopwatch _swPersisInvMsStat = new();
        private int _statPersistCostMs;
        private int _statPersistInvMs;
        private int _statPersistCnt;
        private int _statPersistErrorCnt;
        private int _statPersistLines;

        /// <summary>
        /// 缓存写入数据库。
        /// </summary>
        /// <returns>插入数据库的行数。-1 表示写入数据库错误。</returns>
        public int Persist()
        {
            var effectedLines = 0;

            lock (_syncRoot)
            {
                // statistic persist called interval in ms.
                _swPersisInvMsStat.Stop();
                _statPersistInvMs = (int)_swPersisInvMsStat.Elapsed.TotalMilliseconds;
                
                // persist data every 5sec
                _swPersisCostMsStat.Restart();

                foreach (var dcc in _dictDataRecCachePerDataTable.Values)
                {
                    var sql = dcc.GetInsertSql();

                    if (!string.IsNullOrEmpty(sql))
                    {
                        try
                        {
                            var num = DB.ExecuteNonQuery(sql);
                            effectedLines += num;
                        }
                        catch (Exception ex)
                        {
                            LOG.Write(ex, $"{ModuleName.System.ToString()}写入数据库发生异常");
                            effectedLines = int.MinValue;
                        }
                    }
                }
                
                _swPersisCostMsStat.Stop();
                _statPersistCostMs = (int)_swPersisCostMsStat.Elapsed.TotalMilliseconds;
            }

            if (effectedLines < 0)
            {
                _statPersistErrorCnt++;
                _statPersistLines = -1;
            }
            else
            {
                _statPersistCnt++;
                _statPersistLines = effectedLines;
            }

            // start to calculate the interval of persist operation
            _swPersisInvMsStat.Restart();
            
            return effectedLines;
        }

        public void Terminate()
        {
            _ctsDataRecorderThread.Cancel();
        }

        private bool UpdateTableSchema(string tblName, IEnumerable<IDataBuffer> holders)
        {
            var cmdText = $"select column_name from information_schema.columns where table_name = '{tblName}';";
            var reader = DB.ExecuteReader(cmdText);
            var sqlExprAddColumn = string.Empty;
            var existedColumns = new List<string>();
            while (reader.Read())
            {
                for (var i = 0; i < reader.FieldCount; i++)
                {
                    existedColumns.Add(reader[i].ToString());
                }
            }

            reader.Close();
            if (existedColumns.Count > 0)
            {
                foreach (var holder in holders)
                {
                    var colName = holder.Name;
                    if (!existedColumns.Contains(colName))
                    {
                        var type = holder.ValueType;
                        if (type == typeof(bool))
                        {
                            sqlExprAddColumn += $"ALTER TABLE \"{tblName}\" ADD COLUMN \"{colName}\" {"Boolean"};";
                        }
                        else if (DataTraceHelper.SupportedValueTypes.Contains(type))
                        {
                            sqlExprAddColumn += $"ALTER TABLE \"{tblName}\" ADD COLUMN \"{colName}\" {"Real"};";
                        }
                    }
                }

                if (!string.IsNullOrEmpty(sqlExprAddColumn))
                {
                    try
                    {
                        DB.ExecuteNonQuery(sqlExprAddColumn);
                    }
                    catch (Exception ex)
                    {
                        LOG.Write(ex);
                        return false;
                    }
                }
            }
            else
            {
                var sqlExprCreateTable = $"CREATE TABLE \"{tblName}\"(Time bigint NOT NULL,";
                foreach (var dataItem in holders)
                {
                    var colName = dataItem.Name;
                    var dataType = dataItem.Read().GetType();
                    if (dataType == typeof(bool))
                    {
                        sqlExprCreateTable += $"\"{colName}\" Boolean,\n";
                    }
                    else if (DataTraceHelper.SupportedValueTypes.Contains(dataType))
                    {
                        sqlExprCreateTable += $"\"{colName}\" Real,\n";
                    }
                }

                sqlExprCreateTable += $"CONSTRAINT \"{tblName}_pkey\" PRIMARY KEY (Time));";
                sqlExprCreateTable += $"GRANT SELECT ON TABLE \"{tblName}\" TO postgres;";
                try
                {
                    DB.ExecuteNonQuery(sqlExprCreateTable);
                }
                catch (Exception ex2)
                {
                    LOG.Write(ex2, "创建数据库表格失败");
                    return false;
                }
            }

            return true;
        }

        #endregion

    }
}