using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using TrainInfomationProviderService.StationInfo;
using TrainInfomationProviderService.TrainInfo.Entities;

namespace TrainInfomationProviderService.TrainInfo
{
	public class TrainInfoSearchProvider
	{
		#region 单例模式

		static TrainInfoSearchProvider _instance;
		static readonly object _lockObject = new object();

		public static TrainInfoSearchProvider Instance
		{
			get
			{
				if (_instance == null)
				{
					lock (_lockObject)
					{
						if (_instance == null)
						{
							_instance = new TrainInfoSearchProvider();
						}
					}
				}

				return _instance;
			}
		}

		#endregion

		/// <summary>
		/// 是否已就绪
		/// </summary>
		public bool IsReady { get; private set; }

		public IndexStorage Storage { get; private set; }

		public Dictionary<string, HashSet<string>> SameStationInfo { get; set; }

		private TrainInfoSearchProvider()
		{
		}

		public void Init()
		{
			Trace.TraceInformation("[TRAIN_INFO_SEARCH_PROVIDER] 正在创建车站-车次信息索引对象");
			Storage = TrainInfoManager.Instance.IndexStorage;
			Trace.TraceInformation("[TRAIN_INFO_SEARCH_PROVIDER] 完成创建车站-车次信息索引对象");
			IsReady = true;
		}

		public List<TrainLineSegment> FindDirectTrains(ref DateTime date, string from, string to)
		{
			TrainInfoStorage infoStorage = null;
			var minDate = DateTime.Now.Date;
			while (date >= minDate)
			{
				infoStorage = Storage.TrainInfoStorages.GetValue(date.ToString("yyyy-MM-dd"));
				if (infoStorage == null)
					date = date.AddDays(-1);
				else break;
			}
			var result = new List<TrainLineSegment>();
			if (infoStorage == null)
				return result;

			for (var i = 0; i < infoStorage.Trains.Count; i++)
			{
				var train = infoStorage.Trains[i];
				var stf = FindStop(train, from);
				if (stf == null)
					continue;

				var stt = FindStop(train, to);
				if (stt == null)
					continue;

				if (stf.Index >= stt.Index)
					continue;

				result.Add(new TrainLineSegment(train, stf, stt, date));
			}

			return result;
		}

		public TrainTransitOnceResultCollection FindOnceTransitTrains(DateTime date, string from, string to, TrainTransitSearchOptions options)
		{
			TrainInfoStorage infoStorage = null;
			var minDate = DateTime.Now.Date;
			while (date >= minDate)
			{
				infoStorage = Storage.TrainInfoStorages.GetValue(date.ToString("yyyy-MM-dd"));
				if (infoStorage == null)
					date = date.AddDays(-1);
				else break;
			}
			if (infoStorage == null)
				return null;
			var result = new TrainTransitOnceResultCollection(date, options, from, to);


			//发车经过车站
			var fromStations = GetSameStations(from);
			var toStations = GetSameStations(to);
			var fromTrains = fromStations.Select(s => infoStorage.StationLeftTrainData.GetValue(s)).ExceptNull().SelectMany(s => s).ToArray();
			var toTrains = toStations.Select(s => infoStorage.StationArriveTrainData.GetValue(s)).ExceptNull().SelectMany(s => s).ToArray();

			foreach (var fromTrain in fromTrains)
			{
				var startStop = FindStop(fromTrain, from);
				foreach (var fstop in fromTrain.TrainStops.SkipWhile(x => startStop != x).Skip(1).Where(s => s != null && !string.IsNullOrEmpty(s.Code)))
				{
					foreach (var toTrain in toTrains)
					{
						var toStop = FindStop(toTrain, to);
						foreach (var tStop in toTrain.TrainStops.TakeWhile(x => toStop != x).Where(s => s != null && !string.IsNullOrEmpty(s.Code)))
						{
							if (fstop.Code == tStop.Code)
							{
								var firstTrain = new TrainLineSegment(fromTrain, startStop, fstop, date);
								var secondTrain = new TrainLineSegment(toTrain, tStop, toStop, firstTrain.ArriveTime);
								//一个中转点
								var line = new TrainTransitOnceResult(
									firstTrain,
									secondTrain,
									date
									);
								result.Add(line);
								break;
							}
							if (IsStopInclude(fstop.Code, tStop.Code))
							{
								var firstTrain = new TrainLineSegment(fromTrain, startStop, fstop, date);
								var secondTrain = new TrainLineSegment(toTrain, tStop, toStop, firstTrain.ArriveTime);
								//一个中转点
								var line = new TrainTransitOnceResult(
									firstTrain,
									secondTrain,
									date,
									true
									);
								result.Add(line);
								break;
							}
						}
					}
				}
			}
			result.SecondaryAnalyze();

			return result;
		}

		HashSet<string> GetSameStations(string code)
		{
			var map = SameStationManager.SameStationMap;
			if (map != null)
			{
				var hash = map.GetValue(code);
				if (hash != null)
					return hash;
			}

			return new HashSet<string>() { code };
		}

		bool IsStopInclude(string code1, string code2)
		{

			var map = SameStationManager.SameStationMap;
			if (map == null)
				return false;

			var set = map.GetValue(code1);

			return set != null && set.Contains(code2);
		}

		TrainStop FindStop(Train train, string code)
		{
			if (train == null || train.TrainStopMap == null)
				return null;

			var stop = train.TrainStopMap.GetValue(code);
			if (stop != null)
				return stop;

			var map = SameStationManager.SameStationMap;
			if (map == null)
				return null;

			var hash = map.GetValue(code);
			if (hash == null)
				return null;

			foreach (var s in hash)
			{
				stop = train.TrainStopMap.GetValue(s);
				if (stop != null)
					return stop;
			}

			return null;
		}
	}
}