using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Threading;
using System.Threading.Tasks;
using Aitex.Common.Util;
using Aitex.Core.Account;
using Aitex.Core.RT.Event;
using Aitex.Core.RT.Log;
using Aitex.Core.Util;
using Aitex.Core.WCF;
using MECF.Framework.Common.Account.Extends;
using MECF.Framework.Common.Equipment;

namespace MECF.Framework.Common.Account
{
	/// <summary>
	/// 账号管理器。
	/// </summary>
	public class AccountExManager : Singleton<AccountExManager>
	{
		#region Variables

		private readonly string _scAccountTemplateFile = PathManager.GetCfgDir() + "Account//Account.xml";
		private readonly string _scAccountLocalFile = PathManager.GetCfgDir() + "Account//_AccountEx.xml";

		// 旧的_Account.xml文件路径，为兼容已有的账户配置。
		private readonly string _oldAccountXmlFile = PathManager.GetCfgDir() + "Account//_Account.xml";

		private readonly SemaphoreSlim _syncRoot = new SemaphoreSlim(1, 1);

		#endregion

		#region Constructors

		public AccountExManager()
		{

		}

		#endregion

		#region Properties

		/// <summary>
		/// 返回角色加载器。
		/// </summary>
		public RoleLoader RoleLoader { get; private set; }

		#endregion

		#region Methods

		/// <summary>
		/// 初始化当前对象。
		/// </summary>
		/// <param name="enableService"></param>
		/// <exception cref="ApplicationException"></exception>
		public void Initialize(bool enableService)
		{
			if (!File.Exists(_scAccountLocalFile))
			{
				if (File.Exists(_oldAccountXmlFile))
				{
					// 如果已存在_Account.xml，则从_Account.xml创建_AccountEx.xml文件。
					File.Copy(_oldAccountXmlFile, _scAccountLocalFile);
					Thread.Sleep(10);
				}
				else if (File.Exists(_scAccountTemplateFile))
				{
					File.Copy(_scAccountTemplateFile, _scAccountLocalFile);
					Thread.Sleep(10);
				}

				// 模板文件不存在
				throw new ApplicationException("Can not initialize account configuration file, " +
				                               _scAccountTemplateFile);

			}

			// 默认不支持多用户登录。
			CredentialManager.Instance.Initialize(false);

			RoleLoader = new RoleLoader(_scAccountLocalFile);
			RoleLoader.Load();

			if (enableService)
			{
				Singleton<WcfServiceManager>.Instance.Initialize(new Type[1] { typeof(AccountService) });
			}
		}

		/// <summary>
		/// 获取WCF客户端IP信息。
		/// </summary>
		/// <returns></returns>
		private static RemoteEndpointMessageProperty GetCurrentWCFClientEndPoint()
		{
			var context = OperationContext.Current;
			var prop = context.IncomingMessageProperties;
			var endpoint =
				prop[RemoteEndpointMessageProperty.Name] as RemoteEndpointMessageProperty;
			return endpoint;
		}

		/// <summary>
		/// 等待已登录的用户确认是否允许新的登录请求。
		/// </summary>
		/// <param name="userLoggedIn">已登录用户的凭据。</param>
		/// <param name="userRequesting">新用户的登录凭据。</param>
		/// <returns></returns>
		private static async Task<LoginRequestResults> RequestAndWaitLoginConfirmation(Credential userLoggedIn,
			Credential userRequesting)
		{
			// 等待已登录用户响应，返回结果；
			// 1. Rejected，拒绝新的登录请求
			// 2. Logged Out，主动注销，允许新的登录请求
			// 3. Timeout，超时没有响应，保持原用户的登录凭据
			return await Task.Run(async () =>
			{
				// 通知已登录的用户，其它客户端使用该用户名登录，是否允许登录
				EV.PostLoginBySameUser(userLoggedIn.Token, userRequesting);

				var ct = userRequesting.LoginRequestCancellationTokenSource.Token;

				// 等待已登录的凭据被移除（客户端注销）
				var sw = new Stopwatch();
				sw.Start();

				while (true)
				{
					if (userRequesting.State == CredentialState.Confirmed)
					{
						// 客户端已注销，可以放行新的凭据
						CredentialManager.Instance.Grant(userRequesting);
						EV.PostMessage(ModuleName.System.ToString(), EventEnum.UserLoggedIn,
							userLoggedIn.AccountInfo.LoginName);
						return await Task.FromResult(LoginRequestResults.Confirmed);
					}

					if (userRequesting.State == CredentialState.Reject)
					{
						// 已登录用户拒绝了登录请求
						EV.PostInfoLog(ModuleName.System.ToString(),
							$"User {userRequesting.AccountInfo.LoginName}'s login request from {userRequesting.LoginIP}:{userRequesting.LoginPort} is rejected");

						CredentialManager.Instance.RemoveRequesting(userRequesting);
						return await Task.FromResult(LoginRequestResults.Rejected);
					}

					Thread.Sleep(1000);
					ct.ThrowIfCancellationRequested();

					if (sw.Elapsed.TotalSeconds > 30)
						break;

				}

				// 等待客户端注销超时
				return LoginRequestResults.Timeout;
			});
		}

		/// <summary>
		/// 登录。
		/// </summary>
		/// <param name="userName">用户名</param>
		/// <param name="password">密码</param>
		/// <param name="roleID">角色ID</param>
		/// <param name="clientInfo">发起登录请求的客户端信息</param>
		/// <returns><see cref="LoginRequestResults"/></returns>
		/// <exception cref="TimeoutException"></exception>
		public async Task<LoginResult> Login(string userName, string password, string roleID,
			LoginClientInfo clientInfo)
		{
			var endPoint = GetCurrentWCFClientEndPoint();

			try
			{
				var accountList = RoleLoader.AccountList;

				var matchedAccount = accountList.FirstOrDefault(x => x.LoginName == userName);
				if (matchedAccount == null)
					// 用户不存在
					return await Task.FromResult(new LoginResult(LoginRequestResults.NoMatchUser));

				if (matchedAccount.Password != password)
					// 密码错误
					return await Task.FromResult(new LoginResult(LoginRequestResults.WrongPwd));

				// 查找当前用户的登录角色是否存在
				var matchedRole = matchedAccount.RoleIDs.FirstOrDefault(x => x == roleID);
				if (matchedRole == null)
					// 找不到角色
					return await Task.FromResult(new LoginResult(LoginRequestResults.NoMatchRole));


				// 同一用户名不可重复请求登录。
				var requestingCred =
					CredentialManager.Instance.GetRequestingCredential(userName);

				if (requestingCred != null)
				{
					// 该用户名正在请求登录，拒绝新的登录请求
					return await Task.FromResult(new LoginResult(LoginRequestResults.RequstingLogin));
				}

				// 创建新凭据
				var newCred = new Credential(CredentialManager.GenerateToken(), matchedAccount)
				{
					LoginIP = endPoint.Address,
					LoginPort = endPoint.Port
				};

				// 添加凭据到登录请求列表，Grant时需要请求列表中存在此凭据。
				CredentialManager.Instance.AddRequestingList(newCred);

				if (CredentialManager.Instance.LoggedInCount == 0)
				{
					// 没有用户登录，直接发放凭据
					CredentialManager.Instance.Grant(newCred);
					EV.PostMessage(ModuleName.System.ToString(), EventEnum.UserLoggedIn, userName);
					return await Task.FromResult(new LoginResult(LoginRequestResults.Confirmed, newCred));
				}

				if (CredentialManager.Instance.IsSupportMultiUserLogin)
				{
					// 查找当前请求的用户是否已经登录				
					var loggedCred = CredentialManager.Instance.GetCredential(userName);

					// 支持多用户同时登录
					if (loggedCred == null)
					{
						// 用户未登录，直接放行凭据
						CredentialManager.Instance.Grant(newCred);
						EV.PostMessage(ModuleName.System.ToString(), EventEnum.UserLoggedIn, userName);
						return await Task.FromResult(new LoginResult(LoginRequestResults.Confirmed, newCred));
					}

					var ret = await RequestAndWaitLoginConfirmation(loggedCred, newCred);
					return ret == LoginRequestResults.Confirmed ? new LoginResult(ret, newCred) : new LoginResult(ret);

				}
				else
				{
					if (CredentialManager.Instance.LoggedInCount > 1)
					{
						EV.PostWarningLog(ModuleName.System.ToString(),
							$"{nameof(CredentialManager)} does not support multiple users login but more than one credentials found.");
					}

					var loggedCred = CredentialManager.Instance.GetCredential(userName);

					var ret = await RequestAndWaitLoginConfirmation(loggedCred, newCred);
					return ret == LoginRequestResults.Confirmed ? new LoginResult(ret, newCred) : new LoginResult(ret);
				}
			}
			catch (Exception ex)
			{
				LOG.Error(ex.Message, ex);
				return await Task.FromResult(new LoginResult(LoginRequestResults.Error));
			}
			finally
			{

			}
		}

		/// <summary>
		/// 登录请求发起端取消登录请求。
		/// </summary>
		/// <param name="userName"></param>
		public void CancelLoginRequest(string userName)
		{
			var cred = CredentialManager.Instance.GetRequestingCredential(userName);
			if (cred != null)
			{
				cred.LoginRequestCancellationTokenSource.Cancel();
			}
		}

		public void ConfirmedLoginRequest(Credential requestingCred)
		{
			var cred = CredentialManager.Instance.GetRequestingCredential(requestingCred.Token);
			if (cred != null)
				cred.State = CredentialState.Confirmed;
		}

		public void RejectLoginRequest(Credential requestingCred)
		{
			var cred = CredentialManager.Instance.GetRequestingCredential(requestingCred.Token);
			if (cred != null)
				cred.State = CredentialState.Reject;
		}

		internal void Logout(Guid token)
		{
			var cred = CredentialManager.Instance.GetCredential(token);
			if (cred != null)
			{
				EV.PostMessage(ModuleName.System.ToString(), EventEnum.UserLoggedOff,
					cred.AccountInfo.LoginName);
			}

			CredentialManager.Instance.Remove(token);
		}

		#endregion
	}
}