/************************************************************

 Client.cs
 CopyRight 2000-2001
 This is a sample program made by Saurabh Nandu.
 E-mail: saurabh@mastercsharp.com
 Website: http://www.mastercsharp.com
 Socket Chat
Compilation:
csc /t:winexe /out:..\ChatServer.exe ServerForm.cs Client.cs

11/September/2001
************************************************************/
using System;
using System.Net.Sockets;
using System.Text;
using System.Collections;

namespace SocketServer
{
	//Public delegates	
	public delegate void ConnectDelegate(object sender, EventArgs e);
	public delegate void DisconnectDelegate(object sender, EventArgs e);
	public delegate void MessageDelegate(object sender, MessageEventArgs e);

	//Custom EventArgs
	public class MessageEventArgs : EventArgs
	{
		private string msg;
		public string Message
		{
			get
			{
				return this.msg;
			}
			set
			{
				this.msg = value;
			}	
		}
	}

	public class Client
	{
		//Events Defination
		public event ConnectDelegate Connected;
		public event DisconnectDelegate Disconnected;
		public event MessageDelegate MessageReceived;
		//Some Variables
		private bool firstTime=true;
		private bool connected=false;
		private byte[] recByte = new byte[1024];
		private StringBuilder myBuilder = new StringBuilder();
		private TcpClient myClient;
		private string userName, clientID;

		public Client(TcpClient myClient)
		{
			this.myClient=myClient;	
		}
		//Connect method used to connect to Client
		public void Connect()
		{
			
			//Assign a new Guid
			this.clientID = Guid.NewGuid().ToString();
			//Start Receiving the Messages
			AsyncCallback GetStreamMsgCallback = new AsyncCallback(GetStreamMsg);
			myClient.GetStream().BeginRead(recByte,0,1024,GetStreamMsgCallback,null);
		}
		
		public string UserName
		{
			get
			{
				return this.userName;
			}
		}

		public string ID
		{
			get
			{
				return this.clientID;
			}
		}

		public void GetStreamMsg(IAsyncResult ar)
		{
			int intCount;
			try
			{
				//Lock the Client Stream
				lock(myClient.GetStream())
				{
					//Receive the Bytes
					intCount = myClient.GetStream().EndRead(ar);
				}
				if(intCount<1)
				{
					//If a value less than 1 received that means that 
					//client disconnected
					myClient.Close();
					//raise the Disconnected Event
					if(Disconnected!=null)
					{	
						EventArgs e = new EventArgs();
						Disconnected(this, e);
					}
				}
				//Send the received message from processing
				BuildText(recByte,0,intCount);
				if(!firstTime)
				{
					//if its not the first time then restart the listen process
					lock(myClient.GetStream())
					{
						AsyncCallback GetStreamMsgCallback = new AsyncCallback(GetStreamMsg);
						myClient.GetStream().BeginRead(recByte,0,1024,GetStreamMsgCallback,null);
					}
				}
			}
			catch
			{
				myClient.Close();
				if(Disconnected!=null)
				{
					EventArgs e = new EventArgs();
					Disconnected(this, e);
				}
			}
		}

		public void Disconnect()
		{
			this.connected=false;
			myClient.Close();
		}
		//Method that takes the Usernam and does some processing
		public void CheckUserName(string userName)
		{
			if(userName.Length>20)
			{
				Send("sorry@Username too long, enter a Username less than 20 Characters!!");
				Disconnect();
				return;
			}
			else if(userName.IndexOf("@")>=0)
			{
				Send("sorry@Invalid Character in Username!!");
				Disconnect();
				return;
			}
			else if(!ClientList.AddClient(userName, this.clientID))
			{
				//Check if the username is duplicate
				Send("sorry@Duplicate Username, try another Username!!");
				Disconnect();
				return;
			}
			else
			{
				//If name is not duplicate then the client is connected
				this.connected =true;
				this.userName =userName;
				//Build the Usernames list and send it to the client
				StringBuilder userList = new StringBuilder();
				userList.Append(this.clientID);
				Hashtable clientTable =ClientList.GetList;
				foreach(DictionaryEntry d in clientTable)
				{
					//Seperate the usernames by a '@'
					userList.Append("@");
					userList.Append(d.Value.ToString());
				}
				//Start the llistening
				lock(myClient.GetStream())
				{
					AsyncCallback GetStreamMsgCallback = new AsyncCallback(GetStreamMsg);
					myClient.GetStream().BeginRead(recByte,0,1024,GetStreamMsgCallback,null);
				}
				//Send the Userlist
				Send(userList.ToString());
				//Raise the Connected Event
				if(Connected!=null)
				{
					EventArgs e = new EventArgs();
					Connected(this, e);
				}
			}
		}
		
		//Method to process the Messages
		public void BuildText(byte[] dataByte, int offset, int count)
		{
			
			for(int i=0; i<count; i++)
			{
				//Check is a line terminator is encountered
				if(dataByte[i]==13)
				{

					if(firstTime)
					{
						//If first time then call the CheckUserName method
						CheckUserName(myBuilder.ToString().Trim());
						firstTime=false;
					}
					else if(MessageReceived!=null&&connected)
					{
						//Else raise the MessageReceived Event 
						//and pass the message along
						MessageEventArgs e = new MessageEventArgs();
						e.Message=(myBuilder.ToString()).Trim();
						MessageReceived(this,e);
					}
					//Clear the StringBuilder
					myBuilder = new System.Text.StringBuilder();
				}
				else
				{
					//Append the Byte to the StringBuilder
					myBuilder.Append(Convert.ToChar(dataByte[i]));
				}
			}
		}

		//Method to send the message
		public void Send(string msg)
		{
			lock(myClient.GetStream())
			{
				System.IO.StreamWriter myWriter = new System.IO.StreamWriter(myClient.GetStream());
				myWriter.Write(msg);
				myWriter.Flush();
			}
		}
	}

	//Class to maintain the Userlist
	public class ClientList
	{
		private static Hashtable clientTable = new Hashtable();

		//Method to add a new user
		public static bool AddClient(string userName, string id)
		{
			lock(clientTable)
			{
				//If username exists return false
				if(clientTable.ContainsValue(userName))
				{
					return false;
				}
				else
				{
					//Or add the username to the list and return true
					clientTable.Add(id,userName);
					return true;
				}
			}
		}

		//Method to remove the user
		public static bool RemoveClient(string userName, string id)
		{
			lock(clientTable)
			{
				if(clientTable.ContainsValue(userName))
				{
					clientTable.Remove(id);
					return true;
				}
				else
				{
					return false;
				}
			}	
		}
		//Property to get the Users list
		public static Hashtable GetList
		{
			get
			{
				return clientTable;
			}
		}
		
	}
}