using Dfs.WayneChina.SpsDataCourier.SpsData;
using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using Microsoft.EntityFrameworkCore;
using System.Threading.Tasks;
using System.Timers;
using Microsoft.Extensions.Logging;
using System.Collections.Concurrent;

namespace Dfs.WayneChina.SpsDataCourier
{
    public class DbMonitor
    {
        #region Fields

        private Timer timer;

        private int interval;

        private bool smartFuel05Compatible;

        private Queue<long> sendQueue = new Queue<long>();
        private object syncObj = new object();

        private ConcurrentQueue<long> processedTransQueue = new ConcurrentQueue<long>();

        private string connectionString;

        #endregion

        #region Events

        public event EventHandler<CardTrxEventArgs> OnCardTrxCreated;

        public event EventHandler<EntryFoundEventArgs> OnAccountCreated;
        public event EventHandler<EntryFoundEventArgs> OnAccountUpdated;


        public event EventHandler<EntryFoundEventArgs> OnCardInfoCreated;
        public event EventHandler<EntryFoundEventArgs> OnCardInfoUpdated;
        public event EventHandler<CardChangedEventArgs> OnCardInfoDeleted;

        //账户/卡充值记录，卡扣款记录, card top-up and reductions
        public event EventHandler<EntryFoundEventArgs> OnRechargeCreated;


        //挂失解挂记录, lost card and found card
        public event EventHandler<EntryFoundEventArgs> OnLostCardCreated;
        

        //注销卡, closed/deactivated card
        public event EventHandler<EntryFoundEventArgs> OnClosedCardCreated;

        //基础黑名单卡, black card
        public event EventHandler<EntryFoundEventArgs> OnBaseBlackCardCreated;
        public event EventHandler<CardChangedEventArgs> OnBaseBlackCardDeleted;

        //增量黑名单卡, blacklisted card
        public event EventHandler<EntryFoundEventArgs> OnBlacklistedCardCreated;
        public event EventHandler<EntryFoundEventArgs> OnBlacklistedCardUpdated;
        public event EventHandler<CardChangedEventArgs> OnBlacklistedCardDeleted;


        //减量黑名单卡, released card
        public event EventHandler<EntryFoundEventArgs> OnReleasedCardCreated;
        //Card number in record
        public event EventHandler<CardChangedEventArgs> OnReleasedCardDeleted;

        public event EventHandler<EntryFoundEventArgs> OnGrayInfoCreated;
        public event EventHandler<EntryFoundEventArgs> OnGrayInfoDeleted;

        public event EventHandler<MultipleAccountRecordsEventArgs> OnMultipleAccountsCreated;
        public event EventHandler<MultipleAccountRecordsEventArgs> OnMultipleAccountsUpdated;

        public event EventHandler<MultipleCardRecordsEventArgs> OnMultipleCardsCreated;
        public event EventHandler<MultipleCardRecordsEventArgs> OnMultipleCardsUpdated;

        #endregion

        #region Logger

        NLog.Logger logger = NLog.LogManager.LoadConfiguration("NLog.config").GetLogger("SpsDataCourier");

        #endregion

        #region Constructor

        public DbMonitor(int scanInterval, string connectionString, bool sf05Compatible)
        {
            interval = scanInterval;
            this.connectionString = connectionString;
            smartFuel05Compatible = sf05Compatible;

            timer = new Timer();
            timer.Interval = interval * 1000;
            timer.Elapsed += Timer_Elapsed;
        }

        #endregion

        public void Start()
        {
            logger.Info("Starting database monitor");
            timer.Start();
        }

        public void Stop()
        {
            logger.Info("Stopping database monitor");
            timer.Stop();
        }

        private async void Timer_Elapsed(object sender, ElapsedEventArgs e)
        {
            logger.Debug("Start to scan database");

            await CheckDbAsync();
        }

        public bool AddToQueue(long gid)
        {
            lock (syncObj)
            {
                foreach (var item in sendQueue)
                {
                    logger.Info($"Item in the send queue: {item}");
                }

                if (sendQueue.Contains(gid))
                {
                    logger.Info($"Trying to enqueue gid {gid}, but it's being processed already");
                    return false;
                }

                sendQueue.Enqueue(gid);
                logger.Info($"After check, Gid: {gid} added to queue");

                return true;
            }
        }

        public void ClearFromQueue(TTableaudit tableaudit)
        {
            if(tableaudit.TransCreated != null && tableaudit.TransCreated.Value != 0)
            {
                lock (syncObj)
                {
                    logger.Info($"Removing {tableaudit.TransCreated.Value} from send queue");
                    sendQueue = new Queue<long>(sendQueue.Where(i => i != tableaudit.TransCreated.Value));
                }
            }
        }

        public void ClearFromQueue(long gid)
        {
            lock (syncObj)
            {
                logger.Info($"Removing {gid} from send queue");
                sendQueue = new Queue<long>(sendQueue.Where(i => i != gid));
            }
        }

        public void AddToProcessedQueue(long gid)
        {
            logger.Info($"Adding {gid} to ProcessedQueue");

            if (processedTransQueue.Count > 10)
            {
                long toBeRemoved = 0;
                processedTransQueue.TryDequeue(out toBeRemoved);
                logger.Info($"To be removed from ProcessedQueue: {toBeRemoved}");
            }

            processedTransQueue.Enqueue(gid);
        }

        public bool IsTransAlreadyUploaded(long gid)
        {
            return processedTransQueue.Contains(gid);
        }

        private async Task CheckDbAsync()
        {
            timer.Stop();

            //await CheckDataVersionsAsync();

            try
            {
                using (var context = new SpsDbContext(connectionString))
                {
                    var allRecords = await context.TTableaudit.ToListAsync();

                    // Check the abundance of `deleted`, `created` and `updated` card records or accounts.
                    var deletedCards = allRecords.Where(t => t.CardInfoDeleted != "0");
                    if (deletedCards.Count() > 0)
                        logger.Info($"Deleted cards count: {deletedCards.Count()}");

                    //Remove the 'DeletedCard' records, can't get them anyway...
                    try
                    {
                        context.TTableaudit.RemoveRange(allRecords.Where(t => t.CardInfoDeleted != "0"));
                        await context.SaveChangesAsync();
                    }
                    catch (Exception ex)
                    {
                        logger.Error($"Exception in removing the DELETED CARD records, {ex.ToString()}");
                    }

                    /////////////////////////////////////////////////////
                    
                    //upload all `created` accounts
                    var createdAccounts = allRecords.Where(t => t.AccountCreated != 0);
                    if (createdAccounts.Count() > 0)
                        logger.Info($"Multiple created accounts, count: {createdAccounts.Count()}");

                    if (createdAccounts.Count() > 5)
                    {
                        List<TAcctinfo> createdAccountInfo = new List<TAcctinfo>();
                        foreach (var r in createdAccounts)
                        {
                            var expectedAccountInfo = context.TAcctinfo
                                .AsNoTracking()
                                .FirstOrDefault(a => a.Gid == Convert.ToUInt64(r.AccountCreated.Value));

                            if (expectedAccountInfo != null)
                                createdAccountInfo.Add(expectedAccountInfo);
                        }

                        if (createdAccountInfo.Count > 0)
                        {
                            ProcessMultipleCreatedAccounts(createdAccountInfo, createdAccounts);
                        }
                    }

                    /////////////////////////////////////////////////////

                    //upload all `updated` accounts
                    var updatedAccounts = allRecords.Where(t => t.AccountUpdated != 0);
                    if (updatedAccounts.Count() > 0)
                        logger.Info($"Multiple updated accounts, count: {updatedAccounts.Count()}");

                    if (updatedAccounts.Count() > 5)
                    {
                        List<TAcctinfo> updatedAccountInfo = new List<TAcctinfo>();
                        foreach (var r in updatedAccounts)
                        {
                            var expectedAccountInfo = context.TAcctinfo
                                .AsNoTracking()
                                .FirstOrDefault(a => a.Gid == Convert.ToUInt64(r.AccountUpdated.Value));

                            if (expectedAccountInfo != null)
                                updatedAccountInfo.Add(expectedAccountInfo);
                        }

                        if (updatedAccountInfo.Count > 0)
                        {
                            ProcessMultipleUpdatedAccounts(updatedAccountInfo, updatedAccounts);
                        }
                    }

                    /////////////////////////////////////////////////////

                    //upload all `created` cards
                    var createdCards = allRecords.Where(t => t.CardInfoCreated != 0);
                    if (createdCards.Count() > 0)
                        logger.Info($"Multiple created cards count: {createdCards.Count()}");

                    if (createdCards.Count() > 5)
                    {
                        List<TCardinfo> createdCardInfo = new List<TCardinfo>();
                        foreach (var r in createdCards)
                        {
                            var expectedCardInfo = context.TCardinfo
                                .AsNoTracking()
                                .FirstOrDefault(c => c.Gid == Convert.ToUInt64(r.CardInfoCreated.Value));

                            if (expectedCardInfo != null)
                                createdCardInfo.Add(expectedCardInfo);
                        }

                        if (createdCardInfo.Count > 0)
                        {
                            logger.Info($"Found multiple created card info records, count: {createdCardInfo.Count}");

                            ProcessMultipleCreatedCards(createdCardInfo, createdCards);
                        }
                    }

                    /////////////////////////////////////////////////////

                    //upload all `updated` cards
                    var updatedCards = allRecords
                        .Where(t => t.CardInfoUpdated != 0)
                        .Distinct(new GenericComparer<TTableaudit, long>(a => a.CardInfoUpdated.Value));
                    if (updatedCards.Count() > 0)
                    {
                        logger.Info($"Multiple updated cards, count: {updatedCards.Count()}");
                    }

                    if (updatedCards.Count() > 5)
                    {
                        List<TCardinfo> updatedCardInfo = new List<TCardinfo>();
                        foreach (var r in updatedCards)
                        {
                            var expectedCardInfo = context.TCardinfo
                                .AsNoTracking()
                                .FirstOrDefault(c => c.Gid == Convert.ToUInt64(r.CardInfoUpdated.Value));

                            if (expectedCardInfo != null)
                                updatedCardInfo.Add(expectedCardInfo);
                        }

                        if (updatedCardInfo.Count > 0)
                        {
                            ProcessMultipleUpdatedCards(updatedCardInfo, updatedCards);
                        }
                    }

                    ////////////////////////////////////////////////

                    ////////////////////////////////////////////////

                    // Just to refresh here
                    allRecords = await context.TTableaudit.ToListAsync();

                    var deletedCardsCount1 = allRecords.Where(t => t.CardInfoDeleted != "0").Count();
                    if (deletedCardsCount1 > 0)
                        logger.Info($"After refresh, delete cards count: {deletedCardsCount1}");

                    var recordCount = allRecords.Count;

                    if (recordCount > 0)
                    {                        
                        var record = await context.TTableaudit.FirstAsync();

                        if (record.RechargeCreated.HasValue && record.RechargeCreated.Value != 0)
                        {
                            logger.Info($"New recharge or reduction record, Gid: {record.RechargeCreated.Value}");

                            ProcessRecharge(record);
                        }
                        else if (record.CardInfoCreated.HasValue && record.CardInfoCreated.Value != 0)
                        {
                            logger.Info($"New CardInfo record, Gid: {record.CardInfoCreated.Value}");

                            ProcessCardInfoCreated(record);
                        }
                        else if (record.CardInfoUpdated.HasValue && record.CardInfoUpdated.Value != 0)
                        {
                            logger.Info($"CardInfo updated, Gid: {record.CardInfoUpdated.Value}");

                            ProcessCardInfoUpdated(record);
                        }
                        else if (record.CardInfoDeleted != "0")
                        {
                            logger.Info($"CardInfo deleted, CardNo: {record.CardInfoDeleted}");

                            ProcessCardInfoDeleted(record);
                        }
                        else if (record.AccountCreated.HasValue && record.AccountCreated.Value != 0)
                        {
                            logger.Info($"New account created, Gid: {record.AccountCreated.Value}");

                            ProcessAccountCreated(record);
                        }
                        else if (record.AccountUpdated.HasValue && record.AccountUpdated.Value != 0)
                        {
                            logger.Info($"Account updated on GID: {record.AccountUpdated.Value}");

                            ProcessAccountUpdated(record);
                        }
                        else if (record.ClosedCardCreated.HasValue && record.ClosedCardCreated.Value != 0)
                        {
                            logger.Info($"Card closed/deactivated, Gid: {record.ClosedCardCreated.Value}");

                            ProcessClosedCard(record);
                        }
                        else if (record.LostCardCreated.HasValue && record.LostCardCreated.Value != 0)
                        {
                            logger.Info($"Card lost or found registerred, Gid: {record.LostCardCreated.Value}");

                            ProcessLostCardCreated(record);
                        }
                        else if (record.BlacklistedCardCreated.HasValue && record.BlacklistedCardCreated.Value != 0)
                        {
                            logger.Info($"A blacklisted card is registerred, Gid: {record.BlacklistedCardCreated.Value}");

                            ProcessBlacklistedCardCreated(record);
                        }
                        else if (record.BlacklistedCardUpdated.HasValue && record.BlacklistedCardUpdated.Value != 0)
                        {
                            logger.Info($"A card which was registered as LOST CARD is released, Gid: {record.BlacklistedCardUpdated.Value}");

                            ProcessBlacklistedCardUpdated(record);
                        }
                        else if (record.BlacklistedCardDeleted != "0")
                        {
                            logger.Info($"A blacklisted card was deleted, CardNo: {record.BlacklistedCardDeleted}");

                            ProcessBlacklistedCardDeleted(record);
                        }
                        else if (record.ReleasedCardCreated.HasValue && record.ReleasedCardCreated.Value != 0)
                        {
                            logger.Info($"A lost card was found and released, Gid: {record.ReleasedCardCreated.Value}");

                            ProcessReleasedCardCreated(record);
                        }
                        else if (record.ReleasedCardDeleted != "0")
                        {
                            logger.Info($"A released card is deleted, card no: {record.ReleasedCardDeleted}");

                            ProcessReleasedCardDeleted(record);
                        }
                        else if (record.BaseBlackCardCreated.HasValue && record.BaseBlackCardCreated.Value != 0)
                        {
                            logger.Info($"A base black card is created, gid: {record.BaseBlackCardCreated.Value}");
                            ProcessBaseBlackCardCreated(record);
                        }
                        else if (record.BaseBlackCardDeleted != "0")
                        {
                            logger.Info($"A base black card is deleted, card no: {record.BaseBlackCardDeleted}");
                            ProcessBaseBlackCardDeleted(record);
                        }
                        else if (record.TransCreated.HasValue && record.TransCreated.Value != 0)
                        {
                            logger.Info($"Db monitor, found a newly created card transaction, Gid: {record.TransCreated.Value}");

                            lock (syncObj)
                            {
                                var gid = record.TransCreated.Value;

                                if (sendQueue.Contains(gid))
                                {
                                    if ((DateTime.Now - record.OperationTime).TotalSeconds < 30)
                                    {
                                        logger.Info($"Gid: {gid} being processed now");
                                        timer.Start();
                                        return;
                                    }
                                    else
                                    {
                                        logger.Info($"Trans of GID: {gid} was created more than 30 seconds ago!");
                                    }
                                }
                                else
                                {
                                    sendQueue.Enqueue(gid);
                                    logger.Info($"Enqueued: {gid}");
                                }
                            }

                            ProcessCardTransaction(record);

                            lock (syncObj)
                            {
                                if (sendQueue.Count >= 5)
                                {
                                    var dequeuedGid = sendQueue.Dequeue();
                                    logger.Info($"Dequeued: {dequeuedGid}");
                                }
                            }
                        }
                        else if (record.GrayInfoCreated.HasValue && record.GrayInfoCreated.Value != 0)
                        {
                            logger.Info($"A new Gray info created, gid: {record.GrayInfoCreated.Value}");
                            ProcessGrayInfoCreated(record);
                        }
                        else if (record.GrayInfoDeleted != "0")
                        {
                            logger.Info($"A existing Gray info deleted, Card No: {record.GrayInfoDeleted}");
                            ProcessGrayInfoDeleted(record);
                        }
                    }
                    else
                    {
                        logger.Debug("No record found");
                    }
                }

            }
            catch (Exception ex)
            {
                logger.Error(ex);
            }

            timer.Start();
        }

        #region Multiple records handling

        private void ProcessMultipleCreatedAccounts(IEnumerable<TAcctinfo> createdAccountRecords, IEnumerable<TTableaudit> createdAccoutsAudit)
        {
            OnMultipleAccountsCreated?.Invoke(this, new MultipleAccountRecordsEventArgs(createdAccountRecords, createdAccoutsAudit));
        }

        private void ProcessMultipleUpdatedAccounts(IEnumerable<TAcctinfo> updatedAccountRecords, IEnumerable<TTableaudit> updatedAccountsAudit)
        {
            OnMultipleAccountsUpdated?.Invoke(this, new MultipleAccountRecordsEventArgs(updatedAccountRecords, updatedAccountsAudit));
        }

        private void ProcessMultipleCreatedCards(IEnumerable<TCardinfo> cardInfoRecords, IEnumerable<TTableaudit> createdCardsAudit)
        {
            OnMultipleCardsCreated?.Invoke(this, new MultipleCardRecordsEventArgs(cardInfoRecords, createdCardsAudit));
        }

        private void ProcessMultipleUpdatedCards(IEnumerable<TCardinfo> cardInfoRecords, IEnumerable<TTableaudit> updatedCardsAudit)
        {
            OnMultipleCardsUpdated?.Invoke(this, new MultipleCardRecordsEventArgs(cardInfoRecords, updatedCardsAudit));
        }

        #endregion

        #region Single record handling

        /////// Card payment record, for Smart fuel 1.0

        private void ProcessCardTransaction(TTableaudit tableAudit)
        {
            OnCardTrxCreated?.Invoke(this, new CardTrxEventArgs(null, tableAudit));
        }


        /////// Account, 2 operations.

        private void ProcessAccountCreated(TTableaudit tableAudit)
        {
            OnAccountCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessAccountUpdated(TTableaudit tableAudit)
        {
            OnAccountUpdated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }


        /////// CardInfo, 3 operations.

        private void ProcessCardInfoCreated(TTableaudit tableAudit)
        {
            OnCardInfoCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessCardInfoUpdated(TTableaudit tableAudit)
        {
            OnCardInfoUpdated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessCardInfoDeleted(TTableaudit tableAudit)
        {
            OnCardInfoDeleted?.Invoke(this, new CardChangedEventArgs(tableAudit.CardInfoDeleted, tableAudit));
        }


        /////// Account and card top-up and reductions, 1 operation.

        private void ProcessRecharge(TTableaudit tableAudit)
        {
            OnRechargeCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }


        /////// Card closed or deactivated, 1 operation.

        private void ProcessClosedCard(TTableaudit tableAudit)
        {
            OnClosedCardCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }


        /////// Lost card and found card, 1 operation.

        private void ProcessLostCardCreated(TTableaudit tableAudit)
        {
            OnLostCardCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }


        /////// Base Blackcard, 2 operations.
        ///
        private void ProcessBaseBlackCardCreated(TTableaudit tableAudit)
        {
            OnBaseBlackCardCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessBaseBlackCardDeleted(TTableaudit tableAudit)
        {
            OnBaseBlackCardDeleted?.Invoke(this, new CardChangedEventArgs(tableAudit.BaseBlackCardDeleted, tableAudit));
        }

        /////// Blacklisted card, 3 operations.

        private void ProcessBlacklistedCardCreated(TTableaudit tableAudit)
        {
            OnBlacklistedCardCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessBlacklistedCardUpdated(TTableaudit tableAudit)
        {
            OnBlacklistedCardUpdated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessBlacklistedCardDeleted(TTableaudit tableAudit)
        {
            OnBlacklistedCardDeleted?.Invoke(this, new CardChangedEventArgs(tableAudit.BlacklistedCardDeleted, tableAudit));
        }


        /////// Released card, 2 operations.
        private void ProcessReleasedCardCreated(TTableaudit tableAudit)
        {
            OnReleasedCardCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessReleasedCardDeleted(TTableaudit tableAudit)
        {
            OnReleasedCardDeleted?.Invoke(this, new CardChangedEventArgs(tableAudit.ReleasedCardDeleted, tableAudit));
        }

        /////// Gray info, 2 operations.
        private void ProcessGrayInfoCreated(TTableaudit tableAudit)
        {
            OnGrayInfoCreated?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        private void ProcessGrayInfoDeleted(TTableaudit tableAudit)
        {
            OnGrayInfoDeleted?.Invoke(this, new EntryFoundEventArgs(tableAudit, tableAudit.OperationTime));
        }

        #endregion

        #region Data versions

        private async Task CheckDataVersionsAsync()
        {
            using (var context = new SpsDbContext(connectionString))
            {
                var versionData = await context.TVersioninfo.ToListAsync();

                foreach (var versionInfo in versionData)
                {
                    logger.Debug($"{versionInfo.Gid}, {versionInfo.VerNo}, {versionInfo.EffTime}, {versionInfo.LoseEffTime}");
                }
            }
        }

        #endregion
    }
}