using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Common.TextUtil;

namespace NSC.Service
{
    /// <summary>
    /// 功能：会话服务引擎
    /// 作者：王昊昇
    /// 时间：2012.11.8
    /// </summary>
    public class SessionServiceEngine :IDisposable
    {
        /// <summary>
        /// 私有构造
        /// </summary>
        private SessionServiceEngine()
        {
            SessionList = new Dictionary<string, UserSessionInfo>();

            tmr = new System.Timers.Timer();
            tmr.Interval = 60000;
            tmr.Elapsed += new System.Timers.ElapsedEventHandler(tmr_Elapsed);
            tmr.Start();
        }

        /// <summary>
        /// 创建会话服务
        /// </summary>
        /// <returns></returns>
        public static SessionServiceEngine CreateSessionService()
        {
            if (serviceInstance == null)
            {
                serviceInstance = new SessionServiceEngine();
            }

            return serviceInstance;
        }

        static SessionServiceEngine serviceInstance = null;//当前会话服务对象

        Dictionary<string, UserSessionInfo> SessionList = null;//会话列表

        System.Timers.Timer tmr = null;//会话清理计时器

        /// <summary>
        /// 处理过期的会话
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tmr_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            var s = SessionList.Where(p => Common.TextUtil.DateTimeUtil.DateDiff(p.Value.UpdateTime).TotalMinutes > 20);
            foreach (var u in s)
            {
                SessionList.Remove(u.Key);
            }
        }

        /// <summary>
        /// 向会话中添加用户，已存在时更新会话
        /// </summary>
        /// <param name="user">用户会话信息</param>
        public void AddUser(UserSessionInfo user)
        {
            user.LogonTime = DateTime.Now;
            user.UpdateTime = DateTime.Now;

            if (SessionList.ContainsKey(user.IP))
            {
                SessionList.Add(user.IP, user);
            }
            else
            {
                if (SessionList[user.IP].UserName == user.UserName && SessionList[user.IP].UserID == user.UserID)
                {
                    SessionList[user.IP] = new UserSessionInfo() 
                    {
                        AdminLicense = SessionList[user.IP].AdminLicense,
                        ClientSN = SessionList[user.IP].ClientSN,
                        IP = SessionList[user.IP].IP,
                        License = SessionList[user.IP].License,
                        LogonTime = SessionList[user.IP].LogonTime,
                        Port = user.Port,
                        UpdateTime = DateTime.Now,
                        UserName = SessionList[user.IP].UserName
                    };
                }
                else
                {
                    SessionList.Remove(user.IP);
                    SessionList.Add(user.IP, user);
                }
            }
        }

        /// <summary>
        /// 注销指定用户的会话状态
        /// </summary>
        /// <param name="user">用户会话信息</param>
        public void RemoveUser(UserSessionInfo user)
        {
            if(SessionList.ContainsKey(user.IP))
            {
                SessionList.Remove(user.IP);
            }
        }

        /// <summary>
        /// 查找指定用户
        /// </summary>
        /// <param name="userName">用户姓名</param>
        /// <returns>返回找到的会话数据，找不到时抛出System.InvalidOperationException</returns>
        public UserSessionInfo FindUser(string userName)
        {
            return SessionList.First(p => p.Value.UserName == userName).Value;
        }

        /// <summary>
        /// 释放所有资源
        /// </summary>
        public void Dispose()
        {
            tmr.Stop();
            tmr.Dispose();
            SessionList.Clear();
            SessionList = null;
        }
    }
}