/// François-Régis Colin
/// http://www.tls.cena.fr/products/ivy/
/// *
/// (C) CENA
/// *
namespace IvyBus
{
	using System;
	using System.Collections;
	using System.Threading;
	using System.Text;
	using System.IO;
	using System.Net;
	using System.Net.Sockets;
	using System.Configuration;

	/// <summary> A Class for the the peers on the bus.
	/// </summary>
	/// <remarks>
	/// each time a connexion is made with a remote peer, the regexp are exchanged
	/// once ready, a ready message is sent, and then we can send messages, 
	/// die messages, direct messages, add or remove regexps, or quit. A thread is
	/// created for each remote client.
	/// </remarks>
	public class IvyClient
	{
		public class IvyClientPriority : IComparer  
		{

			// Calls CaseInsensitiveComparer.Compare with the parameters reversed.
			int IComparer.Compare( Object x, Object y )  
			{
				IvyClient c1 = (IvyClient)x;
				IvyClient c2 = (IvyClient)y;
				return( c2.clientPriority - c1.clientPriority );
			}

		}

		public String ApplicationName
		{
			get
			{
				return appName;
			}
			
		}
		
		public string[] Regexps
		{
			get
			{
				int i = 0;
				String[] tab = new String[bindings.Count];
				foreach( IvyBindingBase bind in bindings.Values )
					tab[i++] = bind.expression;
				return tab;
			}
			
		}
		internal int AppPort
		{
			get
			{
				return appPort;
			}
			
		}
		public String RemoteAddress
		{
			get
			{
				IPHostEntry hostInfo = Dns.GetHostByAddress(((IPEndPoint)socket.RemoteEndPoint).Address);
				return hostInfo.HostName;
			}
			
		}
		public int RemotePort
		{
			get
			{
				return ((IPEndPoint)socket.RemoteEndPoint).Port;
			}
			
		}
		
		private Ivy bus;
		private Socket socket;
		private IvyStream stream;
		private Hashtable bindings;
		private int appPort;
		private string clientId;	/* an unique ID for each IvyClient */
		private int clientPriority;	/* client priority */
		
		private bool peerCalling;
		private volatile bool running = false;
		private volatile Thread clientThread; // volatile to ensure the quick communication
		private static bool doping = (ConfigurationSettings.AppSettings["IVY_PING"] != null);
		private const int PINGTIMEOUT = 5000;
		private volatile Thread pingerThread;
		
		// protected variables
		internal String appName;
		
		internal IvyClient(Ivy bus, Socket socket, string appname)
		{
			bindings = Hashtable.Synchronized(new Hashtable());
			appName = appname;
			appPort = 0;
			this.bus = bus;
			this.socket = socket;

			socket.SetSocketOption( SocketOptionLevel.Tcp, SocketOptionName.KeepAlive, 1 );
			stream = new IvyStream( socket );

			clientPriority = Ivy.DEFAULT_PRIORITY;

			sendApplicationId();
			
			// sends our ID, whether we initiated the connexion or not
			// the ID is the couple "host name,application Port", the host name
			// information is in the socket itself, the port is not known if we
			// initiate the connexion
			stream.sendMsg(IvyStream.MessageType.StartRegexp, bus.applicationPort, Encoding.ASCII.GetBytes( bus.appName ));
			// sends our regexps to the peer
			lock( bus.bindings.SyncRoot )
			{
				foreach (Ivy.ApplicationBinding bind in  bus.bindings.Values )
				{
					sendBinding(bind);
				}
			}
			stream.sendMsg(IvyStream.MessageType.EndRegexp, 0, Encoding.ASCII.GetBytes(""));
			// spawns a thread to manage the incoming traffic on this
			// socket. We should be ready to receive messages now.
			clientThread = new Thread(new ThreadStart(this.Run));
			clientThread.Name = "Ivy Tcp Client Reader Thread";
			clientThread.Start();
			if (doping)
			{
				pingerThread = new Thread(new ThreadStart(PingerRun));
				pingerThread.Name = "Ivy Pinger Thread";
				pingerThread.Start();
			}
		}
		
		/// <summary>  returns the name of the remote agent.
		/// allow an Ivy package class to access the list of regexps at a
		/// given time.
		/// perhaps we should implement a new IvyApplicationListener method to
		/// allow the notification of regexp addition and deletion
		/// </summary>
		internal void  sendApplicationId()
		{
			stream.sendMsg( IvyStream.MessageType.ApplicationId, bus.applicationPriority, Encoding.ASCII.GetBytes( bus.AppId ) ); 
		}
		
		internal void  sendBinding(Ivy.ApplicationBinding bind)
		{
			stream.sendMsg(bind.type == Ivy.BindingType.BindRegexp ? IvyStream.MessageType.AddRegexp: IvyStream.MessageType.AddBinding, bind.key, Encoding.ASCII.GetBytes( bind.regexp )); /* perhaps we should perform some checking here */
		}
		
		internal void  delBinding(Ivy.ApplicationBinding bind)
		{
			stream.sendMsg(bind.type == Ivy.BindingType.BindRegexp ? IvyStream.MessageType.DelRegexp: IvyStream.MessageType.DelBinding, bind.key,  Encoding.ASCII.GetBytes( "" ));
		}
		/// <summary> sends a direct message to the peer
		/// </summary>
		/// <param name='id'>the numeric value provided to the remote client
		/// </param>
		/// <param name='message'>the string that will be match-tested
		/// 
		/// </param>
		public void  sendDirectMsg(int id, string message)
		{
			try 
			{
				stream.sendMsg(IvyStream.MessageType.DirectMsg, id, Encoding.ASCII.GetBytes( message ) );
			}
			catch (IOException e)
			{
				traceDebug("I can't send my message to this client. He probably left");
				// first, I'm not a first class IvyClient any more
				bus.removeClient(this);
				// invokes the Disconnected applicationListeners
				bus.FireClientDisconnected(this);
				try
				{
					close(false);
				}
				catch (IOException ioe)
				{
					throw new IvyException("close failed" + ioe.Message);
				}
			}
		}
		
		/// <summary> closes the connexion to the peer.
		/// </summary>
		/// <param name='notify'>should I send Bye message ?
		/// the thread managing the socket is stopped
		/// 
		/// </param>
		internal void  close(bool notify)
		{
			traceDebug("closing connexion to " + appName);
			if (doping )
			{
				stopPinging();
			}
			if (notify)
				sendBye("hasta la vista");
			stopListening();
			// bus.clientDisconnect(this);
			// in_stream close in the thread
			if ( stream != null )
			{
				stream.Close();
				stream = null;
				//socket.Close(); // pris en charge par stream ( NetWorkStream )
				socket = null;
			}
		}
		
		/// <summary> sends the substrings of a message to the peer for each matching regexp.
		/// </summary>
		/// <param name='message'>the string that will be match-tested
		/// </param>
		/// <returns>the number of messages sent to the peer
		/// 
		/// </returns>
		internal int sendMsg(String message)
		{
			int count = 0;
			
			lock( bindings.SyncRoot )
			{
				IvyBindingSimple.Prepare( message );
				foreach (IvyBindingBase bind in bindings.Values )
				{
					IvyArgument args = bind.Match(message);
					if (args!=null)
					{
						stream.sendMsg(IvyStream.MessageType.Msg, bind.key, args.Serialize());
						count++;
					}
				}
			}
			return count;
		}
		
		internal void  stopListening()
		{
			if (clientThread == null)
				return ;
			// Tell Thread to stop.
			running = false;
			if ( stream != null )
				stream.Close();
			if ( Thread.CurrentThread != clientThread )
			{
				// Wait for Thread to end.
				clientThread.Join();
			}
			
			clientThread = null;
		}
		
		/// <summary> compares two peers the id is the couple (host,service port).
		/// </summary>
		/// <param name='clnt'>the other peer
		/// </param>
		/// <returns>true if the peers are similir. This should not happen, it is bad
		/// © ® (tm)
		/// 
		/// </returns>
		internal bool sameClient(IvyClient clnt)
		{
			return (appPort != 0 && appPort == clnt.appPort) && (RemoteAddress == clnt.RemoteAddress);
		}
		
		/// <summary> the code of the thread handling the incoming messages.
		/// </summary>
		private void  Run()
		{
			IvyStream.MessageType type;
			int id;
			byte[] data;
			int length;

			try
			{
				traceDebug("Connected from " + RemoteAddress + ":" + RemotePort);
			}
			catch (Exception ie)
			{
				traceDebug("Interrupted while resolving remote hostname");
			}
			traceDebug("Thread started");
			
			bool running = true;
			while ( running && (stream != null) )
			{
				try
				{
					if ( stream.receiveMsg(out type, out id, out data ) )
					{
						// early stop during readLine()
						if (doping && (pingerThread != null))
							pingerThread.Interrupt();
						DispatchMsg(type, id, data);
					}
					else
					{
						traceDebug("receiveMsg false ! leaving the thread");
						break;
					}
				}
				catch ( ObjectDisposedException e )
				{
					traceDebug( "ivyclient socket closed" );
					running = false;
					break;
				}
				catch (IvyException ie)
				{
					Console.Error.WriteLine( ie.Message );
					Console.Error.WriteLine( ie.StackTrace);
					running = false;
					break;
				}
				catch (SocketException se)
				{
					traceDebug( "ivyclient socket closed" );
					running = false;
					break;
				}
				catch (IOException e)
				{
					if ( e.InnerException is SocketException )
					{
						traceDebug( "ivyclient socket closed" );
					
					}
					else 
					{
						traceDebug("abnormally Disconnected from " + RemoteAddress + ":" + RemotePort);
						Console.Error.WriteLine( e.Message );
						Console.Error.WriteLine( e.StackTrace);
					}
					running = false;
					break;
				}
			}
			if ( stream != null )
			{
				stream.Close();
				stream = null;
			}
			traceDebug("normally Disconnected from " + appName);
			traceDebug("Thread stopped");
			// invokes the Disconnected applicationListeners
			bus.FireClientDisconnected(this);
			// first, I'm not a first class IvyClient any more
			bus.removeClient(this);
			
		}
		
		
		private void recvDie( int id, string arg )
		{
			traceDebug("received die Message from " + appName);
			// first, I'm not a first class IvyClient any more
			bus.removeClient(this);
			// invokes the die applicationListeners
			bool dontkillapp = bus.FireDie(this, id);
			// makes the bus die
			bus.stop();
			try
			{
				close(false);
			}
			catch (IOException ioe)
			{
				throw new IvyException(ioe.Message);
			}
			if ( !dontkillapp )
				Environment.Exit( -1 );
		}
		private void recvBye( int id, string arg )
		{
			// the peer quits
			traceDebug("received bye Message from " + appName + "Raison: "+ arg);
			// first, I'm not a first class IvyClient any more
			bus.removeClient(this);
			// invokes the disconnect applicationListeners
			//bus.FireClientDisconnected(this); done in Running Thread
			try
			{
				close(false);  // will fire diconnected
			}
			catch (IOException ioe)
			{
				throw new IvyException(ioe.Message);
			}
		}
		private void recvAddRegexp( int id, string regexp )
		{
			if (bus.CheckRegexp(regexp))
			{
				try
				{
					IvyBindingRegexp bind  = new IvyBindingRegexp(id,regexp);
					lock( bindings.SyncRoot )
					{
						bindings.Add( id, bind);
					}
					bus.FireClientAddBinding( this, bind.expression );
				}
				catch (ArgumentException e)
				{
					throw new IvyException("regexp error " + e.Message);
				}
			}
			else
			{
				traceDebug("regexp Warning exp='" + regexp + "' can't match removing from " + appName);
			}
		}
		private void recvDelRegexp( int id, string arg )
		{
			lock( bindings.SyncRoot )
			{
				IvyBindingBase bind = (IvyBindingBase) bindings[id];
				bus.FireClientRemoveBinding( this, bind.expression );
				bindings.Remove(id);
			}
					
		}
		private void recvAddBinding( int id, string expression )
		{
			try
			{
				IvyBindingSimple bind = new IvyBindingSimple(id, expression);
				
				lock( bindings.SyncRoot )
				{
					bindings.Add( id, bind);
				}
				bus.FireClientAddBinding( this, bind.expression );
			}
			catch (ArgumentException e)
			{
				throw new IvyException("regexp error " + e.Message);
			}
					
		}
		private void recvDelBinding( int id, string arg )
		{
			lock( bindings.SyncRoot )
			{
				IvyBindingBase bind = (IvyBindingBase) bindings[id];
				bus.FireClientRemoveBinding( this, bind.expression );
				bindings.Remove(id);
			}
		}
		private void recvMsg( int id, byte[] arg )
		{
			bus.callCallback(this, id, arg);		
		}
		private void recvError( int id, string arg )
		{
			traceDebug("Error msg " + id + " " + arg);
		}
		private void recvApplicationId( int id, string arg )
		{
			clientId = arg;
			if ( clientPriority != id )
			{
				clientPriority = id;
				bus.SortClients();
			}
		}
		private void recvEndRegexp( int id, string arg )
		{
			bus.FireClientConnected(this);
			/* 
					* the peer is perhaps not ready to handle this message
					* an assymetric processing should be written
					*/
			if (bus.ready_message != null)
				sendMsg(bus.ready_message);	
		}
		private void recvStartRegexp( int id, string arg )
		{
			appName = arg;
			appPort = id;
			if (bus.checkConnected(this))
			{
				try
				{
					close(false);
				}
				catch (IOException ioe)
				{
					throw new IvyException("io " + ioe.Message);
				}
				throw new IvyException("Rare ! A concurrent connect occured");
			}
					
		}
		private void recvDirectMsg( int id, byte[] arg )
		{
			
			bus.FireDirectMessage(this, id, arg );
		}
		private void recvPing( int id, byte[] arg )
		{
			// I receive a ping. I can answer a pong.
			traceDebug("Ping msg from " + appName + " : " + Encoding.ASCII.GetString( arg) );
			sendPong(arg);
		}
		private void recvPong( int id, byte[] arg )
		{
			traceDebug("Ping msg from " + appName + " : " + arg);
		}
		private void  DispatchMsg(IvyStream.MessageType msgType, int msgId, byte[] msgData)
		{
			string strarg = Encoding.ASCII.GetString( msgData );	
			switch (msgType)
			{
				case IvyStream.MessageType.Die: 
					recvDie( msgId, strarg );
					break;
				
				case IvyStream.MessageType.Bye: 
					recvBye(  msgId, strarg );
					break;
				
				case IvyStream.MessageType.AddRegexp: 
					recvAddRegexp( msgId, strarg );
					break;
				
				case IvyStream.MessageType.DelRegexp: 
					recvDelRegexp( msgId, strarg );
					break;
				case IvyStream.MessageType.AddBinding: 
					recvAddBinding( msgId, strarg );
					break;
				
				case IvyStream.MessageType.DelBinding:
					recvDelBinding( msgId, strarg );
					break;
				
				case IvyStream.MessageType.EndRegexp: 
					recvEndRegexp( msgId, strarg );
					break;
				
				case IvyStream.MessageType.Msg: 
					recvMsg( msgId, msgData );
					break;
				
				case IvyStream.MessageType.Pong: 
					recvPong( msgId, msgData );
					break;
				
				case IvyStream.MessageType.Ping: 
					recvPing(  msgId, msgData );
					break;
				
				case IvyStream.MessageType.Error: 
					recvError( msgId, strarg );
					break;
				
				case IvyStream.MessageType.StartRegexp: 
					recvStartRegexp( msgId, strarg );
					break;
				
				case IvyStream.MessageType.DirectMsg:
					recvDirectMsg( msgId, msgData );
					break;
				case IvyStream.MessageType.ApplicationId:
					recvApplicationId( msgId, strarg );
					break;
				default: 
					throw new IvyException("protocol error, unknown message type " + msgType);
				
			}
		}
		
		private void  sendPong(byte[] s)
		{
			stream.sendMsg(IvyStream.MessageType.Pong, 0, s);
		}
		public void  sendPing(string s)
		{
			stream.sendMsg(IvyStream.MessageType.Ping, 0, Encoding.ASCII.GetBytes(s));
		}
		
		private void  sendBye(string message)
		{
			stream.sendMsg(IvyStream.MessageType.Bye, 0, Encoding.ASCII.GetBytes( message ));
		}
		
		public void  sendDie(string message)
		{
			stream.sendMsg(IvyStream.MessageType.Die, 0, Encoding.ASCII.GetBytes( message ) );
		}
		
		
		public override String ToString()
		{
			return "IvyClient " + bus.appName + ":" + appName;
		}
		
		private void  traceDebug(String s)
		{
			if (bus.Debug)
				Console.Out.WriteLine("-->IvyClient " + bus.appName + ":" + appName + "<-- " + s);
		}
		
		internal bool isPinging = false;
		private void  PingerRun()
		{
			isPinging = true;
			traceDebug("Pinger Thread started");
			while (isPinging)
			{
				try
				{
					Thread.Sleep(new TimeSpan(10000 * PINGTIMEOUT));
					sendPing("are you here ?");
				}
				catch (ThreadInterruptedException ie)
				{
				}
			}
			traceDebug("Pinger Thread stopped");
		}
		public virtual void  stopPinging()
		{
			isPinging = false; 
			pingerThread.Interrupt();
		}
	}
}