using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using System.Web.Caching;
using System.Web.Hosting;
using FSLib.Network.Http;
using Newtonsoft.Json;
using TrainInfomationProviderService.TrainInfo.Entities;

namespace TrainInfomationProviderService.TrainInfo
{
	public class TrainInfoManager
	{
		private static readonly object _lockObject = new object();
		private static TrainInfoManager _stationManager;

		public static TrainInfoManager Instance
		{
			get
			{
				if (_stationManager == null)
				{
					lock (_lockObject)
					{
						if (_stationManager == null)
						{
							_stationManager = new TrainInfoManager();
						}
					}
				}

				return _stationManager;
			}
		}

		/// <summary>
		/// 创建 <see cref="TrainInfoManager" />  的新实例(StationManager)
		/// </summary>
		protected TrainInfoManager()
		{
			Trace.TraceInformation("[TAININFOMANGER] 车站管理器对象已新建");
		}

		private string _dataFilePath;

		/// <summary>
		/// 仓库
		/// </summary>
		public IndexStorage Storage
		{
			get
			{
				if (RunTimeContext.IsWeb)
				{
					return HostingEnvironment.Cache["_12306trains"] as IndexStorage;
				}
				return _storage;
			}
		}

		public void Init()
		{
			Trace.TraceInformation("[TAININFOMANGER] 正在初始化");

			_dataFilePath = PathUtility.Combine(RunTimeContext.DataStorageRoot, "trains.json");
			Trace.TraceInformation("[TAININFOMANGER] 目标缓存文件路径：{0}", _dataFilePath);

			if (RunTimeContext.IsWeb)
			{
				Trace.TraceInformation("[TAININFOMANGER] WEB模式");

				InitWeb();
			}
			else
			{
				Trace.TraceInformation("[TAININFOMANGER] 服务模式");
				InitService();
			}
		}


		#region web环境

		/// <summary>
		/// web环境初始化
		/// </summary>
		void InitWeb()
		{
			Trace.TraceInformation("[TAININFOMANGER] 初始化WEB模式");
			LoadCache();
		}

		void LoadCache()
		{
			Trace.TraceInformation("[TAININFOMANGER] 正在检查缓存刷新");
			_storage = null;
			if (File.Exists(_dataFilePath))
			{
				Trace.TraceInformation("[TAININFOMANGER] 正在加载缓存");
				_storage = JsonConvert.DeserializeObject<IndexStorage>(File.ReadAllText(_dataFilePath));
				Trace.TraceInformation("[TAININFOMANGER] 缓存加载完成");
			}

			if (Storage != null)
			{
				Trace.TraceInformation("[TAININFOMANGER] 正在加入HttpRuntime缓存");
				HostingEnvironment.Cache.Add("_12306trains", Storage, new CacheDependency(_dataFilePath),
					Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.High,
					(_1, _2, _3) =>
					{
						Trace.TraceInformation("[TAININFOMANGER] HttpRuntime缓存已被清除，原因：{0}，正在重新加载", _3);
						LoadCache();
					});
				Trace.TraceInformation("[TAININFOMANGER] HttpRuntime缓存加入完成");
			}
		}


		#endregion

		#region 服务模式

		private Timer _checkStationTimer;
		private IndexStorage _storage;

#if DEBUG
		private bool _ininitalized = true;
#else
		private bool _ininitalized = false;
#endif

		/// <summary>
		/// 服务模式初始化
		/// </summary>
		void InitService()
		{
			if (_dataFilePath.AsFileInfo().Exists)
			{
				Trace.TraceInformation("[TAININFOMANGER] 正在加载文件缓存数据");
				_storage = JsonConvert.DeserializeObject<IndexStorage>(File.ReadAllText(_dataFilePath));
				Trace.TraceInformation("[TAININFOMANGER] 文件缓存数据加载完成");
			}
			else
			{
				_storage = new IndexStorage();
			}
			var lastestVersion = GetLatestVersionFromWeb();
			var needUpdate = _storage == null || _storage.Version < lastestVersion;
			Trace.TraceInformation("[TAININFOMANGER] 最新版本：{0}", lastestVersion);

			if (needUpdate || !_ininitalized)
			{
				Trace.TraceInformation("[TAININFOMANGER] 正在刷新缓存");
				RefreshTrainInfo(lastestVersion);
				Trace.TraceInformation("[TAININFOMANGER] 缓存数据已刷新");
			}
			_ininitalized = true;
			_checkStationTimer = new Timer(_ => CheckTrainVersion(), null, new TimeSpan(0, 30, 0), Timeout.InfiniteTimeSpan);
		}

		void RefreshTrainInfo(int version)
		{
			Trace.TraceInformation("[TAININFOMANGER] 正在刷新车次信息");
			var loader = new WebDataProvider();
			try
			{
				Storage.Version = version;
				loader.LoadTrainInfo(Storage);
			}
			catch (Exception ex)
			{
				Trace.TraceError("TAININFOMANGER] 车次信息更新出错：{0}", ex);
			}

			//Storage = new TrainInfoStorage();
			Trace.TraceInformation("[TAININFOMANGER] 车次信息分析完成，车站。正在缓存车站信息");

			//save
			File.WriteAllText(_dataFilePath, JsonConvert.SerializeObject(Storage));
			Trace.TraceInformation("[TAININFOMANGER] 车站信息缓存完成。目标文件 {0}", _dataFilePath);
		}

		void CheckTrainVersion()
		{
			var lastestVersion = GetLatestVersionFromWeb();
			if (Storage == null || Storage.Version < lastestVersion)
			{
				RefreshTrainInfo(lastestVersion);
			}
			_checkStationTimer.Change(new TimeSpan(0, 30, 0), Timeout.InfiniteTimeSpan);
		}

		/// <summary>
		/// 从网络加载最新的版本号
		/// </summary>
		/// <returns></returns>
		public int GetLatestVersionFromWeb()
		{
			var ctx = new HttpClient().Create<string>(HttpMethod.Get, "https://kyfw.12306.cn/otn/queryTrainInfo/init", "https://kyfw.12306.cn/otn/queryTrainInfo/init").Send();
			if (!ctx.IsValid())
				return 0;

			var version = (int)(Regex.Match(ctx.Result, @"train_list\.js\?scriptVersion=([\d\.]+)").GetGroupValue(1).ToSingle() * 100000);

			return version;
		}


		#endregion

	}
}