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

	/// <summary> A private Class for the the peers on the bus.
	/// </summary>
	internal class MyTcpClient : TcpClient
	{
		public IPAddress RemoteAddress
		{
			get
			{
				IPEndPoint ep = (IPEndPoint)Client.RemoteEndPoint;
				return ep.Address;
			}
			
		}
		public int RemotePort
		{
			get
			{
				IPEndPoint ep = (IPEndPoint)Client.RemoteEndPoint;
				return ep.Port;
			}
			
		}
		public MyTcpClient(string host,int port):base(host,port)
		{
		}
		public MyTcpClient(Socket sock)
		{
			Client = sock;
		}
	}
	/// <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 String ApplicationName
		{
			get
			{
				return appName;
			}
			
		}
		internal Int32 ClientKey
		{
			get
			{
				return clientKey;
			}
			
		}
		public ICollection Regexps
		{
			get
			{
				return regexp_text.Values;
			}
			
		}
		internal int AppPort
		{
			get
			{
				return appPort;
			}
			
		}
		public String RemoteAddress
		{
			get
			{
				IPHostEntry hostInfo = Dns.GetHostByAddress(socket.RemoteAddress);
				return hostInfo.HostName;
			}
			
		}
		public int RemotePort
		{
			get
			{
				return socket.RemotePort;
			}
			
		}
		
		/* the protocol magic numbers */
		internal enum MessageType : int 
		{
			Bye = 0, /* end of the peer */
			AddRegexp = 1, /* the peer adds a regexp */
			Msg = 2, /* the peer sends a message */
			Error = 3, /* error message */
			DelRegexp = 4, /* the peer removes one of his regex */
			EndRegexp = 5, /* no more regexp in the handshake */
			StartRegexp = 6, /* avoid race condition in concurrent connexions */
			DirectMsg = 7, /* the peer sends a direct message */
			Die = 8, /* the peer wants us to quit */
			Ping = 9, /* checks the presence of the other */
			Pong = 10  /* checks the presence of the other */
		};
		
		internal const String MESSAGE_TERMINATOR = "\n"; /* the next protocol will use \r */
		internal const String StartArg = "\u0002"; /* begin of arguments */
		internal const String EndArg = "\u0003"; /* end of arguments */
		
		private static int clientSerial = 0; /* an unique ID for each IvyClient */
		
		private Ivy bus;
		private MyTcpClient socket;
		private StreamWriter out_stream;
		private StreamReader in_stream;
		private Hashtable regexp_in;
		private Hashtable regexp_text;
		private int appPort;
		private bool peerCalling;
		private volatile bool running = false;
		private volatile Thread clientThread; // volatile to ensure the quick communication
		private Int32 clientKey;
		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, MyTcpClient socket)
		{
			regexp_in = Hashtable.Synchronized(new Hashtable());
			regexp_text = Hashtable.Synchronized(new Hashtable());
			appName = "Unknown";
			appPort = 0;
			this.bus = bus;
			this.socket = socket;
			clientKey = clientSerial++;
			out_stream = new StreamWriter(socket.GetStream(),System.Text.Encoding.ASCII);
			in_stream = new StreamReader(socket.GetStream(),System.Text.Encoding.ASCII);
			// 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
			send(MessageType.StartRegexp, bus.applicationPort, bus.appName);
			// sends our regexps to the peer
			lock( bus.regexp_out.SyncRoot )
			{
				foreach (Int32 ikey in  bus.regexp_out.Keys )
				{
					sendRegexp(ikey, (String) bus.regexp_out[ikey]);
				}
			}
			send(MessageType.EndRegexp, 0, "");
			// 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  sendRegexp(int id, String regexp)
		{
			send(MessageType.AddRegexp, id, regexp); /* perhaps we should perform some checking here */
		}
		
		internal void  delRegexp(int id)
		{
			send(MessageType.DelRegexp, id, "");
		}
		
		/// <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)
		{
			send(MessageType.DirectMsg, id, 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
			out_stream.Close();
			out_stream = null;
			socket.Close();
			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( regexp_in.SyncRoot )
			{
				IDictionaryEnumerator myEnumerator = regexp_in.GetEnumerator();
				while ( myEnumerator.MoveNext() )
				{
					Regex regexp = (Regex) myEnumerator.Value;
					Match result = regexp.Match(message);
					if (result.Success)
					{
						send(MessageType.Msg, (int)myEnumerator.Key, result);
						count++;
					}
				}
			}
			return count;
		}
		
		internal void  stopListening()
		{
			if (clientThread == null)
				return ;
			// Tell Thread to stop.
			running = false;
			if ( in_stream != null )
				in_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()
		{
			String msg = null;
			try
			{
				traceDebug("Connected from " + RemoteAddress + ":" + RemotePort);
			}
			catch (Exception ie)
			{
				traceDebug("Interrupted while resolving remote hostname");
			}
			traceDebug("Thread started");
			
			bool running = true;
			while (running)
			{
				try
				{
					if ((msg = in_stream.ReadLine()) != null)
					{
						// early stop during readLine()
						if (doping && (pingerThread != null))
							pingerThread.Interrupt();
						if ( msg.Length == 0 )
							Console.Error.WriteLine("Should close");
						newParseMsg(msg);
					}
					else
					{
						traceDebug("readline null ! leaving the thead");
						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;
				}
			}
			in_stream.Close();
			in_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  sendBuffer(String buffer)
		{
			buffer += "\n";
			try
			{
				if ( out_stream != null )
				{
					out_stream.Write(buffer);
					out_stream.Flush();
				}
			}
			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);
				}
			}
		}
		
		private void  send(MessageType type, int id, String arg)
		{
			try
			{
				sendBuffer((int)type + " " + id + StartArg + arg);
			}
			catch (IvyException ie)
			{
				Console.Error.WriteLine("received an exception: " + ie.Message);
				Console.Error.WriteLine(ie.StackTrace);
			}
		}
		
		private void  send(MessageType type, Int32 id, Match result)
		{
			String buffer = (int)type + " " + id + StartArg;
			// Start at 1 because group 0 represent entire matching
			 for (int sub = 1; sub < result.Groups.Count; sub++)
			{
				buffer += result.Groups[sub] + EndArg;
			}
			try
			{
				sendBuffer(buffer);
			}
			catch (IvyException ie)
			{
				Console.Error.WriteLine("received an exception: " + ie.Message);
				Console.Error.WriteLine(ie.StackTrace);
			}
		}
		
		private void  newParseMsg(String s)
		{
			int from = 0, to = 0;
			MessageType msgType;
			int msgId;
			while ((to < s.Length) && (s[to] != ' '))
			{
				to++;
			}
			if (to >= s.Length)
				throw new IvyException("protocol error");
			try
			{
				msgType = (MessageType)Int32.Parse(s.Substring(from, (to) - (from)));
			}
			catch (FormatException nfe)
			{
				throw new IvyException("protocol error on msgType");
			}
			from = to + 1;
			while ((to < s.Length) && (s[to] != 2))
			{
				to++;
			}
			if (to >= s.Length)
				throw new IvyException("protocol error");
			try
			{
				msgId = Int32.Parse(s.Substring(from, (to) - (from)));
			}
			catch (FormatException nfe)
			{
				throw new IvyException("protocol error on identifier");
			}
			from = to + 1;
			switch (msgType)
			{
				case MessageType.Die: 
					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, msgId);
					// makes the bus die
					bus.stop();
					try
					{
						close(false);
					}
					catch (IOException ioe)
					{
						throw new IvyException(ioe.Message);
					}
					if ( !dontkillapp )
						Environment.Exit( -1 );
					break;
				
				case MessageType.Bye: 
					// the peer quits
					traceDebug("received bye Message from " + appName);
					// 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);
					}
					break;
				
				case MessageType.AddRegexp: 
					String regexp = s.Substring(from, (s.Length) - (from));
					if (bus.CheckRegexp(regexp))
					{
						try
						{
							lock( regexp_in.SyncRoot )
							{
								regexp_in.Add( msgId, new Regex(regexp,RegexOptions.Compiled|RegexOptions.IgnoreCase));
							}
							lock( regexp_text.SyncRoot )
							{
								regexp_text.Add( msgId, regexp);
							}
						}
						catch (ArgumentException e)
						{
							throw new IvyException("regexp error " + e.Message);
						}
					}
					else
					{
						traceDebug("regexp Warning exp='" + regexp + "' can't match removing from " + appName);
					}
					break;
				
				case MessageType.DelRegexp: 
					lock( regexp_in.SyncRoot )
					{
						regexp_in.Remove(msgId);
					}
					lock( regexp_text )
					{
						regexp_text.Remove( msgId );
					}
					break;
				
				case MessageType.EndRegexp: 
					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);
					break;
				
				case MessageType.Msg: 
					ArrayList v = new ArrayList();
					while (to < s.Length)
					{
						while ((to < s.Length) && (s[to] != 3))
						{
							to++;
						}
						if (to < s.Length)
						{
							v.Add(s.Substring(from, (to) - (from)));
							to++;
							from = to;
						}
					}
					String[] tab = new String[v.Count];
					 for ( int i2 = 0; i2 < v.Count; i2++)
					{
						tab[i2] = (String) v[i2];
						// for developpemnt purposes
						// out.println(" *"+tab[i]+"* "+(tab[i]).length());
					}
					bus.callCallback(this, msgId, tab);
					break;
				
				case MessageType.Pong: 
					String paramPong = s.Substring(from, (s.Length) - (from));
					traceDebug("Ping msg from " + appName + " : " + paramPong);
					break;
				
				case MessageType.Ping: 
					// I receive a ping. I can answer a pong.
					String param = s.Substring(from, (s.Length) - (from));
					traceDebug("Ping msg from " + appName + " : " + param);
					sendPong(param);
					break;
				
				case MessageType.Error: 
					String error = s.Substring(from, (s.Length) - (from));
					traceDebug("Error msg " + msgId + " " + error);
					break;
				
				case MessageType.StartRegexp: 
					appName = s.Substring(from, (s.Length) - (from));
					appPort = msgId;
					if (bus.checkConnected(this))
					{
						try
						{
							close(false);
						}
						catch (IOException ioe)
						{
							throw new IvyException("io " + ioe.Message);
						}
						throw new IvyException("Rare ! A concurrent connect occured");
					}
					break;
				
				case MessageType.DirectMsg: 
					String direct = s.Substring(from, (s.Length) - (from));
					bus.FireDirectMessage(this, msgId, direct);
					break;
				
				default: 
					throw new IvyException("protocol error, unknown message type " + msgType);
				
			}
		}
		
		private void  sendPong(String s)
		{
			send(MessageType.Pong, 0, s);
		}
		public void  sendPing(String s)
		{
			send(MessageType.Ping, 0, s);
		}
		
		private void  sendBye()
		{
			send(MessageType.Bye, 0, "");
		}
		private void  sendBye(String message)
		{
			send(MessageType.Bye, 0, message);
		}
		
		public void  sendDie()
		{
			send(MessageType.Die, 0, "");
		}
		private void  sendDie(String message)
		{
			send(MessageType.Die, 0, 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();
		}
	
	}
}