///
/// Copyright (c) 2020 Sensus Slovensko a.s.
///
using System;
using System.Collections.Generic;
using log4net;
using NHibernate;
using Common;
using Events.Entities;
using Results.Entities;

namespace TBF.Rig.Various.StatisticsMonitoring
{
    public class ProcessStatistics : ComponentBase, IOperation, GenericDevices.IStatisticsMonitoring
	{
		private static readonly ILog log = LogManager.GetLogger(typeof(ProcessStatistics));
        public override string ToString() { return string.Format("{0}({1})", ClassName, Cfg.ToString(-1)); }

		readonly StatisticsCfg statisticsCfg;

		int lastBatchNr;


		public ProcessStatistics() {}

		public ProcessStatistics(Generic.IComponentCfg cfg)
			: base(cfg)
		{
			statisticsCfg = cfg as StatisticsCfg;
		}

        public override void Initialize()
        {
            ApplyConfig();
            log.FatalFormat("{0} initialized: {1}", Name, this);
        }

        void ApplyConfig()
        {
        }

        #region Configuration Change Handling

        public static void OnCfgChange(object sender, CfgChangeArgs args)
        {
            if (CfgChangeHandler == null) return;
            try { CfgChangeHandler(sender, args); }
            catch (Exception e) { log.Error("CfgChangeHandler(...) failed", e); }
        }

        public static event EventHandler<CfgChangeArgs> CfgChangeHandler;

        public override void StartChangeHandler()
        {
            CfgChangeHandler += delegate(object sender, CfgChangeArgs args)
            {
                StatisticsCfg newCfg = args.Cfg as StatisticsCfg;
                if (newCfg != null && newCfg.Name.Equals(Name))
                {
                    if (args.Command == CfgChangeCmd.CfgChange)
                    {
                        statisticsCfg.EventSource = newCfg.EventSource;
                        statisticsCfg.iPerlHeadFailureRateThreshold = newCfg.iPerlHeadFailureRateThreshold;

                        ApplyConfig();
                    }
                }
            };
        }

        #endregion Configuration Change Handling


		/// <summary>
		/// Writes the test cycle results into a file
		/// Events:
        ///		Event.StatisticsProcessed
		///		Event.Busy
		/// </summary>
		/// <param name="batch">Results to write into a file</param>
		/// <returns>Reference to the operation</returns>
        public IOperation ProcessStatisticsOp(int lastBatchNr)
		{
            this.lastBatchNr = lastBatchNr;
			return this;
		}


        public void Start()
		{
            Process(lastBatchNr, statisticsCfg);
        }
        public Event Run()
        {
            return Event.StatisticsProcessed;
		}
        public void Stop()
        {
        }

        /// <summary>
        /// Process recent batch results and calculate statistics of iPERL head failures
        /// </summary>
        /// <param name="batchNr">Number of the last saved batch</param>
        void Process(int batchNr, StatisticsCfg statisticsCfg)
        {
            const int RequiredUsages = 10;
            const int MaxBatches = 20;

            float iperlHeadFailureRateThreshold = (float)statisticsCfg.iPerlHeadFailureRateThreshold / 100.0f;

            int completeBatchesProcessed = 0;

            int[] usages = new int[TBF.Data.WMsCount];
            int[] failures = new int[TBF.Data.WMsCount];
            for (int i = 0; i < TBF.Data.WMsCount; i++) usages[i] = failures[i] = 0;

            ///
            /// Read results of recent batches (up to 'MaxBatches')
            /// Take into account only batches where the 1st test in named 'RFID' and
            /// at least one water meter completed all tests.
            ///
            try
            {
                ISession session = Results.DB.CreateSession();

                int usagesMin;
                do
                {
                    usagesMin = 0;
                    IList<Batch> batches = session.QueryOver<Batch>()
                                                  .Where(x => x.Id == batchNr)
                                                  .List();
                    batchNr--;
                    if (batches.Count != 1 || batches[0].TestRslts.Count < 1 || batches[0].TestRslts[0].MethodClass != "TestMethods.iPerlCommunication")
                    {
                        continue;
                    }

                    bool isACompleteBatch = false;
                    foreach (var wm in batches[0].WaterMeters)
                    {
                        int i = wm.WMPosition - 1;
                        if (0 <= i && i < TBF.Data.WMsCount && usages[i] < RequiredUsages && !wm.Disabled && wm.CompletedFromTests())
                        {
                            isACompleteBatch = true;
                            usages[i]++;
                            if (!wm.MeterTestRslts[0].Passed) failures[i]++;
                        }
                    }

                    usagesMin = int.MaxValue;
                    for (int i = 0; i < TBF.Data.WMsCount; i++) if (usagesMin > usages[i]) usagesMin = usages[i];

                    if (isACompleteBatch) completeBatchesProcessed++;
                }
                while ((usagesMin < RequiredUsages) && (batchNr > 0) && (completeBatchesProcessed < MaxBatches));
            }
            catch (Exception exc)
            {
                log.ErrorFormat("Failed to calculate iPERL head usage statistics: {0}", exc.Message);
            }

            ///
            /// Find out whether at lest one event needs to be triggered
            ///
            bool doTriggerEvents = false;
            for (int i = 0; i < TBF.Data.WMsCount; i++)
            {
                if ((usages[i] > 0) && (iperlHeadFailureRateThreshold > 0) && (float)failures[i] / (float)usages[i] >= iperlHeadFailureRateThreshold)
                {
                    doTriggerEvents = true;
                    break;
                }
            }

            if (doTriggerEvents && !string.IsNullOrEmpty(Events.DB.ConnectionString))
            {
                ///
                /// Trigger events
                ///
                try
                {
                    ISession session = Events.DB.CreateSession();
                    Events.DB.LoadSubscribers(session);

                    for (int i = 0; i < TBF.Data.WMsCount; i++)
                    {
                        if ((usages[i] > 0) && (iperlHeadFailureRateThreshold > 0) && (float)failures[i] / (float)usages[i] >= iperlHeadFailureRateThreshold)
                        {
                            TBF.UiBridge.Bridge.TriggerEvent(session,
                                                             statisticsCfg.EventSource,
                                                             EventClass.EquipmentHW,
                                                             Severity.Error,
                                                             string.Format("Príliš veľa chýb hlavice č. {0}", i + 1),
                                                             string.Format("Percento chýb je {0}%", (100 * failures[i]) / usages[i]),
                                                             SubscriberGroup.Metrology | SubscriberGroup.Maintenance | SubscriberGroup.Production);
                        }
                    }
                }
                catch (Exception exc)
                {
                    log.ErrorFormat("Failed to trigger events: source = {0}, message = {1}", statisticsCfg.EventSource, exc.Message);
                }
            }
        }
	}
}