FeedEngineWithInterface

namespace MonitoringSystem.Hubs.Engines
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using Idnc.Cache;
    using Idnc.Cache.Contracts;
    using Idnc.Logger;
    using MonitoringSystem.Kafka.Loaders;
    using MonitoringSystem.SelfHost.Data;

    public class KafkaFeed<TCache, TSnapshot> : IKafkaFeed<TCache, TSnapshot>
        where TSnapshot : BetsSnapshot, new()
        where TCache : CacheObject<string, TSnapshot>, new()
    {
        private static readonly Type LoggerName = typeof(KafkaFeed<TCache, TSnapshot>);

        private static readonly TCache _cache;

        private static bool _isRunning;
        private static object _instanceLock;

        public static ICacheLoader<TCache> AggregatedBetsSnapshotCacheLoader { get; private set; }

        public static TSnapshot LastUpdateItem { get; private set; }

        static KafkaFeed()
        {
            _cache = new TCache();
            _instanceLock = new object();

            AggregatedBetsSnapshotCacheLoader = (ICacheLoader<TCache>)KafkaLoadersRegistrar.Instance.GetLoader<TCache>();
            AggregatedBetsSnapshotCacheLoader.Init();

            CacheObject<string, TSnapshot>.CacheUpdated += AggregatedBetsSnapshotCache_CacheUpdated;
        }

        public TSnapshot NewestItem => LastUpdateItem;

        private static void AggregatedBetsSnapshotCache_CacheUpdated(ICacheObject arg1, List<Tuple<TSnapshot, TSnapshot>> arg2)
        {
            try
            {
                //TODO Figure out why this is called every second
                var item = arg2.FirstOrDefault().Item1;
                var offsetTime = DateTime.UtcNow.AddMinutes(-15); //Skip all elements from topic with older than 15min
                if (LastUpdateItem == null)
                {
                    LastUpdateItem = new TSnapshot
                    {
                        EndTime = DateTime.UtcNow.AddMinutes(-5)
                    };
                }

                if (item != null && item.Data.Count > 0
                    && item.EndTime >= offsetTime
                    && item.EndTime > LastUpdateItem?.EndTime)
                {
                    LastUpdateItem = arg2.FirstOrDefault().Item1;
                }
            }
            catch (Exception ex)
            {
                LogManager.Current.GetLogger(LoggerName).Error("Cache Updated Ex:", ex);
            }
        }

        public static void Run()
        {
            if (!_isRunning)
            {
                lock (_instanceLock)
                {
                    try
                    {
                        _isRunning = true;
                    }
                    catch (Exception ex)
                    {
                        LogManager.Current.GetLogger(LoggerName).Error("RUN Ex:", ex);
                    }
                }
            }
        }
    }
}