using System;
using System.Collections.Generic;
using System.Threading;
 
namespace ConsoleApplication1
{
  // 客戶(hù)端離線委托
  public delegate void ClientOfflineHandler(ClientInfo client);
 
  // 客戶(hù)端上線委托
  public delegate void ClientOnlineHandler(ClientInfo client);
 
  public class Program
  {
    /// <summary>
    /// 客戶(hù)端離線提示
    /// </summary>
    /// <param name="clientInfo"></param>
    private static void ClientOffline(ClientInfo clientInfo)
    {
      Console.WriteLine(String.Format("客戶(hù)端{(lán)0}離線，離線時(shí)間：\t{1}", clientInfo.ClientID, clientInfo.LastHeartbeatTime));
    }
 
    /// <summary>
    /// 客戶(hù)端上線提示
    /// </summary>
    /// <param name="clientInfo"></param>
    private static void ClientOnline(ClientInfo clientInfo)
    {
      Console.WriteLine(String.Format("客戶(hù)端{(lán)0}上線，上線時(shí)間：\t{1}", clientInfo.ClientID, clientInfo.LastHeartbeatTime));
    }
 
    static void Main()
    {
      // 服務(wù)端
      Server server = new Server();
 
      // 服務(wù)端離線事件
      server.OnClientOffline += ClientOffline;
 
      // 服務(wù)器上線事件
      server.OnClientOnline += ClientOnline;
 
      // 開(kāi)啟服務(wù)器
      server.Start();
 
      // 模擬100個(gè)客戶(hù)端
      Dictionary<Int32, Client> dicClient = new Dictionary<Int32, Client>();
      for (Int32 i = 0; i < 100; i++)
      {
        // 這里傳入server只是為了方便而已
        Client client = new Client(i + 1, server);
        dicClient.Add(i + 1, client);
 
        // 開(kāi)啟客戶(hù)端
        client.Start();
      }
 
      System.Threading.Thread.Sleep(1000);
 
      while (true)
      {
        Console.WriteLine("請(qǐng)輸入要離線的ClientID,輸入0則退出程序:");
        String clientID = Console.ReadLine();
        if (!String.IsNullOrEmpty(clientID))
        {
          Int32 iClientID = 0;
          Int32.TryParse(clientID, out iClientID);
          if (iClientID > 0)
          {
            Client client;
            if (dicClient.TryGetValue(iClientID, out client))
            {
              // 客戶(hù)端離線
              client.Offline = true;
            }
          }
          else
          {
            return;
          }
        }
      }
    }
  }
 
  /// <summary>
  /// 服務(wù)端
  /// </summary>
  public class Server
  {
    public event ClientOfflineHandler OnClientOffline;
    public event ClientOnlineHandler OnClientOnline;
 
    private Dictionary<Int32, ClientInfo> _DicClient;
 
    /// <summary>
    /// 構(gòu)造函數(shù)
    /// </summary>
    public Server()
    {
      _DicClient = new Dictionary<Int32, ClientInfo>(100);      
    }
 
    /// <summary>
    /// 開(kāi)啟服務(wù)端
    /// </summary>
    public void Start()
    {
      // 開(kāi)啟掃描離線線程
      Thread t = new Thread(new ThreadStart(ScanOffline));
      t.IsBackground = true;
      t.Start();
    }
 
    /// <summary>
    /// 掃描離線
    /// </summary>
    private void ScanOffline()
    {
      while (true)
      {
        // 一秒掃描一次
        System.Threading.Thread.Sleep(1000);
 
        lock (_DicClient)
        {
          foreach (Int32 clientID in _DicClient.Keys)
          {
            ClientInfo clientInfo = _DicClient[clientID];
 
            // 如果已經(jīng)離線則不用管
            if (!clientInfo.State)
            {
              continue;
            }
 
            // 判斷最后心跳時(shí)間是否大于3秒
            TimeSpan sp = System.DateTime.Now - clientInfo.LastHeartbeatTime;
            if (sp.Seconds >= 3)
            {
              // 離線，觸發(fā)離線事件
              if (OnClientOffline != null)
              {
                OnClientOffline(clientInfo);
              }
 
              // 修改狀態(tài)
              clientInfo.State = false;
            }
          }
        }
      }
    }
 
    /// <summary>
    /// 接收心跳包
    /// </summary>
    /// <param name="clientID">客戶(hù)端ID</param>
    public void ReceiveHeartbeat(Int32 clientID)
    {
      lock (_DicClient)
      {
        ClientInfo clientInfo;
        if (_DicClient.TryGetValue(clientID, out clientInfo))
        {
          // 如果客戶(hù)端已經(jīng)上線，則更新最后心跳時(shí)間
          clientInfo.LastHeartbeatTime = System.DateTime.Now;
        }
        else
        {
          // 客戶(hù)端不存在，則認(rèn)為是新上線的
          clientInfo = new ClientInfo();
          clientInfo.ClientID = clientID;
          clientInfo.LastHeartbeatTime = System.DateTime.Now;
          clientInfo.State = true;
 
          _DicClient.Add(clientID, clientInfo);
 
          // 觸發(fā)上線事件
          if (OnClientOnline != null)
          {
            OnClientOnline(clientInfo);
          }
        }
      }
    }
  }
 
  /// <summary>
  /// 客戶(hù)端
  /// </summary>
  public class Client
  {
    public Server Server;
    public Int32 ClientID;
    public Boolean Offline;
 
    /// <summary>
    /// 構(gòu)造函數(shù)
    /// </summary>
    /// <param name="clientID"></param>
    /// <param name="server"></param>
    public Client(Int32 clientID, Server server)
    {
      ClientID = clientID;
      Server = server;
      Offline = false;
    }
 
    /// <summary>
    /// 開(kāi)啟客戶(hù)端
    /// </summary>
    public void Start()
    {
      // 開(kāi)啟心跳線程
      Thread t = new Thread(new ThreadStart(Heartbeat));
      t.IsBackground = true;
      t.Start();
    }
 
    /// <summary>
    /// 向服務(wù)器發(fā)送心跳包
    /// </summary>
    private void Heartbeat()
    {
      while (!Offline)
      {
        // 向服務(wù)端發(fā)送心跳包
        Server.ReceiveHeartbeat(ClientID);
         
        System.Threading.Thread.Sleep(1000);
      }
    }
  }
 
  /// <summary>
  /// 客戶(hù)端信息
  /// </summary>
  public class ClientInfo
  {
    // 客戶(hù)端ID
    public Int32 ClientID;
 
    // 最后心跳時(shí)間
    public DateTime LastHeartbeatTime;
 
    // 狀態(tài)
    public Boolean State;
  }
}