/// François-Régis Colin
/// http://www.tls.cena.fr/products/ivy/
/// *
/// (C) CENA
/// *
namespace IvyBus
{
	using System;
	using System.IO;
	using System.Collections;
	using System.Net;
	using System.Net.Sockets;
	using System.Threading;
	using System.Configuration;
	using System.Windows.Forms;
	using System.Globalization;
	using System.Text.RegularExpressions;
	
	/// <summary> The Main bus Class
	/// </summary>
	public class Ivy 
	{
		/* Event handler */
		public delegate void DirectMessageHandler (IvyClient app, int id, string arg );
		public delegate void ClientConnectedHandler (IvyClient app);
		public delegate void ClientDisconnectedHandler (IvyClient app);
		public delegate bool DieHandler (IvyClient app, int id );
		public delegate void ClientAddBindingHandler (IvyClient app, string arg );
		public delegate void ClientRemoveBindingHandler (IvyClient app, string arg );
		
		public delegate void MessageHandler ( IvyClient app, string[] args );
		

		/* Event */
		/// <summary>fires when a new client connect to the bus</summary>
		/// <param name='appcb'>A callback handling the notification of connexions and
		/// disconnections, may be null
		/// 
		/// </param>
		public event ClientConnectedHandler clientConnected;
		/// <summary>fires when a client discconnect from the bus</summary>
		public event ClientDisconnectedHandler clientDisconnected;
		/// <summary>fires when a client receive a direct message from another client</summary>
		public event DirectMessageHandler directMessageReceived;
		/// <summary>fires when somebody ask for killing every client on the bus</summary>
		public event DieHandler dieReceived;
		/// <summary>fires when a client receive a add binding from another client</summary>
		public event ClientAddBindingHandler addBinding;
		/// <summary>fires when a client receive a remove binding from another client</summary>
		public event ClientAddBindingHandler removeBinding;
		

		/// <summary>IvyClients accesses the list of the connected clients</summary>
		public ArrayList IvyClients
		{
			get
			{
				return clients;
			}
			
		}
		public bool Debug
		{
			get
			{
				return debug;
			}
			set
			{
				debug  = value;
			}
			
		}
		/// <summary>ClientNames accesses the name list of the connected clients</summary>
		private string ClientNames
		{
			get
			{
				string s = appName + " clients are: ";
				lock( clients.SyncRoot )
				{
					foreach (IvyClient client in  clients )
					{
						s += client.ApplicationName + " ";
					}
				}
				return s;
			}
			
		}
		/// <summary>AppName the application name</summary>
		public string AppName
		{
			get
			{
				return appName;
			}
			
		}
		public string AppId
		{
			get
			{
				return applicationUniqueId;
			}
			
		}
		public int AppPriority
		{
			set
			{
			applicationPriority = value;
			lock ( clients.SyncRoot )
			{
				foreach (IvyClient client in clients )
				{
					client.sendApplicationId();
				}
			}
			
			}
			get
			{
				return applicationPriority;
			}
			
		}
		///<summary>SentMessageClasses the first word token of sent messages
		///<remarks> optimise the parsing process when sending messages </remarks>
		///</summary>
		public string[] SentMessageClasses
		{
			get
			{
				return sent_messageClasses;
			}
			set
			{
				sent_messageClasses = value;
			}
			
		}
		internal class MyTcpListener : TcpListener
		{
			public MyTcpListener(IPAddress address, int port) : base(address, port)
			{
			}
			public bool IsActive()
			{
				return  this.Active;
			}
		}
		
		///  the name of the application on the bus
		internal string appName;
		/// the protocol version number
		internal const int PROCOCOLVERSION = 4;
		/// the port for the UDP rendez vous, if none is supplied
		internal const int DEFAULT_PORT = 2010;
		// client default priority 
		internal const int DEFAULT_PRIORITY = 100;
		/// the domain for the UDP rendez vous
		internal static readonly string DEFAULT_DOMAIN = "127.255.255.255:" + DEFAULT_PORT;
		internal const string libVersion = "2.0.0";
		
		private bool debug;
		private static int serial = 0; /* an unique ID for each regexp */
		private MyTcpListener app;
		private ArrayList watchers;
		private volatile Thread serverThread; // to ensure quick communication of the end

		internal enum BindingType { BindRegexp, BindSimple };
		internal struct ApplicationBinding               /* Self Applications bindings  */
		{
			internal BindingType type;
			internal Int32 key;
			internal MessageHandler callback;
			internal string regexp;
			internal object[] args;
		}
		
		internal Hashtable bindings;
		private ArrayList clients;
		private string[] sent_messageClasses = null;
		private bool stopped = false;
		internal int applicationPort; /* Application port number */
		internal string applicationUniqueId;  /* identifier Application unique timestamp-ipaddress-port */
		internal int applicationPriority = DEFAULT_PRIORITY;
		internal string ready_message = null;
		
		// for synchronous event 
		private Control syncControl = null;
		/// <summary> Readies the structures for the software bus connexion.
		/// </summary>
		/// <example> This sample shows how to start working with Ivy.
		/// <code>
		/// Ivy bus = new Ivy("Dummy agent","ready");
		/// bus.bindMsg("(.*)",new Ivy.MessageHandler(myMessageListener));
		/// bus.start(null);
		/// </code>
		/// How to send & receive:
		/// the Ivy agent A performs <c>b.bindMsg("^Hello (*)",cb);</c>
		/// the Ivy agent B performs <c>b2.sendMsg("Hello world");</c>
		/// a thread in A will run the callback cb with its second argument set
		/// to a array of string, with one single element, "world"
		/// </example>
		/// <remarks>
		/// the real work begin in the start() method
		/// </remarks>
		/// <seealso cref=" Ivy.start"/>
		/// <param name='name'>The name of your Ivy agent on the software bus
		/// </param>
		/// <param name='message'>The hellow message you will send once ready
		/// </param>
		public Ivy(string name, string message)
		{
			clients = ArrayList.Synchronized( new ArrayList() );
			//callbacks = Hashtable.Synchronized( new Hashtable() );
			//clients_data = Hashtable.Synchronized( new Hashtable() );
			//regexp_out = Hashtable.Synchronized( new Hashtable());
			bindings = Hashtable.Synchronized( new Hashtable());
			appName = name;
			ready_message = message;
			string debug_str = ConfigurationSettings.AppSettings["IVY_DEBUG"];
			if ( debug_str != null ) 
				debug = bool.Parse(debug_str);	
		}
		public Ivy(string name, string message, Control sync) :this( name, message ) 
		{
			syncControl = sync;	
		}
		
		/// <summary> connects the Ivy bus to a domain or list of domains.
		/// </summary>
		/// <remarks>
		/// One thread (IvyWatcher) for each traffic rendezvous (either UDP broadcast or TCP Multicast).
		/// One thread (serverThread/Ivy) to accept incoming connexions on server socket.
		/// a thread for each IvyClient when the connexion has been done.
		/// </remarks>
		/// <param name='domainbus'>a domain of the form 10.0.0:1234, it is similar to the
		/// netmask without the trailing .255. This will determine the meeting point
		/// of the different applications. Right now, this is done with an UDP
		/// broadcast. Beware of routing problems ! You can also use a comma
		/// separated list of domains.
		/// *
		/// 
		/// </param>
		public void  start(string domainbus)
		{
			if (domainbus == null)
				domainbus = Environment.GetEnvironmentVariable("IVYBUS");
			if (domainbus == null)
				domainbus = DEFAULT_DOMAIN;
			try
			{
				IPAddress localaddr = Dns.Resolve(Dns.GetHostName()).AddressList[0];
				app = new MyTcpListener(IPAddress.Any,0);
				app.Start();
				applicationPort =  ((IPEndPoint) app.LocalEndpoint).Port;
				applicationUniqueId = string.Format("{0}-{1}-{2}",
					DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond,
					localaddr.ToString().Replace(".",""),
					applicationPort );
			}
			catch (IOException e)
			{
				throw new IvyException("can't open TCP service socket " + e);
			}
			traceDebug("lib: " + libVersion + " protocol: " + PROCOCOLVERSION + " TCP service open on port " + applicationPort);
			watchers = new ArrayList();
			
			Domain[] d = parseDomains(domainbus);
			// readies the rendezvous : an IvyWatcher (thread) per domain bus
			 for (int index = 0; index < d.Length; index++)
			{
				IvyWatcher watcher = new IvyWatcher(this, d[index].Domainaddr, d[index].Port);
				watchers.Add(watcher);
			}
			serverThread = new Thread(new ThreadStart(this.Run));
			serverThread.Name = "Ivy Tcp Server Thread";
			serverThread.Start();
			// Wait for readyness
			while ( serverThread.ThreadState != ThreadState.Running || !app.IsActive())
			{
				traceDebug( " Ivy Threading start in progress..." );
				Thread.Sleep( 100 );
			}
			// sends the broadcasts and listen to incoming connexions
			 for (int i = 0; i < watchers.Count; i++)
			{
				((IvyWatcher) watchers[i]).start();
			}
		}
		public void SortClients()
		{
			lock ( clients.SyncRoot )
			{
				clients.Sort(new IvyClient.IvyClientPriority());
			}
		}
		/* a small private method for debbugging purposes */
		
		public string domains(string toparse)
		{
			string s = "broadcasting on ";
			Ivy.Domain[] d = parseDomains(toparse);
			for (int index = 0; index < d.Length; index++)
			{
				s += d[index].Domainaddr + ":" + d[index].Port + " ";
			}
			return s;
		}
		
		internal Domain[] parseDomains(string domainbus)
		{
			string[] st = domainbus.Split(',');
			Domain[] d = new Domain[st.Length];
			for (int i = 0; i < st.Length; i++)
			{
				d[i] = new Domain(IvyWatcher.getDomain(st[i]), IvyWatcher.getPort(st[i]));
			}
			return d;
		}
		
		/// <summary> disconnects from the Ivy bus
		/// </summary>
		public void  stop()
		{
			lock(this)
			{
				if (stopped)
					return ;
				stopped = true;
				traceDebug("beginning stopping the bus");
				try
				{
					// stopping the serverThread
					if (serverThread != null)
					{
						app.Stop();
						serverThread.Join();
						serverThread = null;
					}
					// The serverThread might be stopped even before having been created
					if (app != null)
						app.Stop();
					// stopping the IvyWatchers
					if ( watchers != null )
						for (int i = 0; i < watchers.Count; i++)
						{
							((IvyWatcher) watchers[i]).stop();
						}
					// stopping the remaining IvyClients
					// copy the values in temporary variable to eliminate Thread modifying collection
					if ( clients.Count != 0 )
					{
						IvyClient[] copyClient;
						copyClient = new IvyClient[clients.Count];
						lock( clients.SyncRoot )
						{
							clients.CopyTo( copyClient,0 );
						}	
						foreach (IvyClient client in copyClient )
						{
							client.close(true); // will notify the reading thread
							//removeClient(client); already donne in the thread
						}
					}
				}
				catch (IOException e)
				{
					traceDebug("IOexception Stop ");
				}
				traceDebug("the bus should have stopped so far");
			}
		}
		
		
		/// <summary> Send a message to someone on the bus
		/// </summary>
		/// <remarks>
		/// Performs a pattern matching according to everyone's regexps, and sends
		/// the results to the relevant ivy agents.
		/// There is one thread for each client connected, we could also
		/// create another thread each time we send a message.
		/// </remarks>
		/// <param name='message'>A message which will be compared to the regular
		/// expressions of the different clients
		/// </param>
		/// <returns>the number of messages actually sent
		/// 
		/// </returns>
		public int sendMsg(string message)
		{
			int count = 0;
			// an alternate implementation would one sender thread per client
			// instead of one for all the clients. It might be a performance issue
			lock ( clients.SyncRoot )
			{
				foreach (IvyClient client in clients )
				{
					count += client.sendMsg(message);
				}
			}
			return count;
		}
		/// <summary> Send a formated message to someone on the bus
		/// </summary>
		/// <remarks>
		/// Performs a pattern matching according to everyone's regexps, and sends
		/// the results to the relevant ivy agents.
		/// There is one thread for each client connected, we could also
		/// create another thread each time we send a message.
		/// </remarks>
		/// <param name='format'>A string message format to build  the message
		/// <param name='args'>args used in message format
		/// </param>
		/// <returns>the number of messages actually sent
		/// 
		/// </returns>
		public int sendMsg(string format, params object[] args )
		{
			return sendMsg( string.Format( format, args ) );
		}
		/// <summary> Send a formated message to someone on the bus
		/// </summary>
		/// <remarks>
		/// Performs a pattern matching according to everyone's regexps, and sends
		/// the results to the relevant ivy agents.
		/// There is one thread for each client connected, we could also
		/// create another thread each time we send a message.
		/// </remarks>
		/// <param name='format'>A string message format to build  the message
		/// <param name='args'>args used in message format
		/// </param>
		/// <returns>the number of messages actually sent
		/// 
		/// </returns>
		public int sendMsg(CultureInfo culture, string format, params object[] args )
		{
			return sendMsg( string.Format( culture, format, args ) );
		}
		
		/// <summary> Subscribes to a regular expression.
		/// </summary>
		/// <remarks>
		/// The callback will be executed with
		/// the saved parameters of the regexp as arguments when a message will sent
		/// by another agent. A program doesn't receive its own messages.
		/// </remarks>
		/// 
		/// <param name='regexp'>a regular expression, groups are done with parenthesis
		/// </param>
		/// <param name='callback'>any objects implementing the Ivy.MessageListener
		/// </param>
		/// <returns>the id of the regular expression
		/// 
		/// </returns>
		//
		// for compatibility raison with old IVY
		public int bindMsg(String regexp, MessageHandler callback)
		{
			return bindMsg( regexp, callback, null);
		}
		public int bindMsg(string regexp, MessageHandler callback, params object[] args )
		{
			// creates a new binding (regexp,callback)
			ApplicationBinding newbind;
			newbind.type = BindingType.BindRegexp;
			newbind.key = serial++;
			newbind.regexp = regexp;
			newbind.callback = callback;
			newbind.args = args;
			lock (bindings.SyncRoot) bindings.Add( newbind.key, newbind);
			// notifies the other clients this new regexp
			lock ( clients.SyncRoot )
			{
				foreach (IvyClient c in clients )
				{
					c.sendBinding(newbind);
				}
			}
			return newbind.key;
		}
		
		/// <summary> unsubscribes a regular expression
		/// </summary>
		/// <param name='id'>the id of the regular expression, returned when it was bound
		/// 
		/// </param>
		public void  unBindMsg(int id)
		{
			if ( ! bindings.ContainsKey( id )  )
			{
				throw new IvyException("client wants to remove an unexistant regexp " + id);
			}
			ApplicationBinding bind = (ApplicationBinding) bindings[id];
			lock( clients.SyncRoot )
			{
				foreach (IvyClient c in clients )
				{
					c.delBinding(bind);
				}
			}
			lock( bindings.SyncRoot ) bindings.Remove( id );
		}
		
		/// <summary> unsubscribes a regular expression
		/// </summary>
		/// <returns>a boolean, true if the regexp existed, false otherwise or
		/// whenever an exception occured during unbinding
		/// </returns>
		/// <param name='re'>the string for the regular expression
		/// 
		/// </param>
		public bool unBindMsg(string re)
		{
			foreach (ApplicationBinding bind in bindings.Values )
			{
				if ( bind.regexp == re )
				{
					try
					{
						unBindMsg(bind.key);
					}
					catch (IvyException ie)
					{
						return false;
					}
					return true;
				}
			}
			return false;
		}


		/// <summary> Subscribes to a simple expression ( msg ar1 arg2 arg3 etc).
		/// </summary>
		/// <remarks>
		/// The callback will be executed with
		/// the saved parameters of the regexp as arguments when a message will sent
		/// by another agent. A program doesn't receive its own messages.
		/// </remarks>
		/// 
		/// <param name='regexp'>a regular expression, groups are done with parenthesis
		/// </param>
		/// <param name='callback'>any objects implementing the Ivy.MessageListener
		/// </param>
		/// <returns>the id of the regular expression
		/// 
		/// </returns>
		
		public int bindSimpleMsg(string expression, MessageHandler callback, params object[] args )
		{
			// creates a new binding (regexp,callback)
			ApplicationBinding newbind;
			newbind.type = BindingType.BindSimple;
			newbind.key = serial++;
			newbind.regexp = expression;
			newbind.callback = callback;
			newbind.args = args;
			lock (bindings.SyncRoot) bindings.Add( newbind.key, newbind);
			// notifies the other clients this new regexp
			lock ( clients.SyncRoot )
			{
				foreach (IvyClient c in clients )
				{
					c.sendBinding(newbind);
				}
			}
			return newbind.key;
		}

		internal void FireDirectMessage (IvyClient app, int id, string arg )
		{
			if ( directMessageReceived != null )
			{
				if ( syncControl != null )
					syncControl.Invoke( directMessageReceived, new object[]{app,id,arg});
				else directMessageReceived( app, id, arg);
			}
		}
		internal void FireClientConnected (IvyClient app)
		{
			if ( clientConnected != null )
			{
				if ( syncControl != null )
					syncControl.Invoke( clientConnected, new object[]{app});
				else clientConnected( app);
			}
		}
		internal void FireClientDisconnected (IvyClient app)
		{
			if ( clientDisconnected != null )
			{
				if ( syncControl != null )
					syncControl.Invoke( clientDisconnected, new object[]{app});
				else clientDisconnected( app);
			}
		}
		internal void FireClientAddBinding (IvyClient app, string regexp)
		{
			if ( addBinding != null )
			{
				if ( syncControl != null )
					syncControl.Invoke( addBinding, new object[]{app,regexp});
				else addBinding( app,regexp);
			}
		}
		internal void FireClientRemoveBinding (IvyClient app,  string regexp)
		{
			if ( removeBinding != null )
			{
				if ( syncControl != null )
					syncControl.Invoke( removeBinding, new object[]{app,regexp});
				else removeBinding( app,regexp);
			}
		}
		internal bool FireDie (IvyClient app, int id )
		{
			if ( dieReceived != null )
			{
				if ( syncControl != null )
				 syncControl.Invoke( dieReceived, new object[]{app,id});
			 else return dieReceived( app, id);
			}
			return false;
		}

	
		/*
		* removes a client from the list
		*/
		internal void  removeClient(IvyClient c)
		{
			lock( clients.SyncRoot )
			{
				clients.Remove(c);
			}
		}
		
		
		/// <summary> gives a list of IvyClient(s) with the name given in parameter
		/// </summary>
		/// <param name='name'>The name of the Ivy agent you're looking for
		/// </param>
		public ArrayList getIvyClientsByName(string name)
		{
			ArrayList v = new ArrayList();
			foreach (IvyClient ic in  clients )
			{
				if (((ic.ApplicationName).CompareTo(name)) == 0)
					v.Add(ic);
			}
			return v;
		}
		
		/////////////////////////////////////////////////////////////////:
		//
		// Protected methods
		//
		/////////////////////////////////////////////////////////////////:
		
		internal void  addClient(Socket socket)
		{
			if (stopped)
					return ;
			IvyClient client = new IvyClient(this,socket);
			lock ( clients.SyncRoot )
			{
				clients.Add(client);
			}
			traceDebug(ClientNames);
		}
		
		internal void  callCallback(IvyClient client, Int32 key, string[] tab)
		{
			ApplicationBinding bind = ( ApplicationBinding ) bindings[key];
			if (bind.callback == null)
			{
				throw new IvyException("(callCallback) Not regexp matching id " + key);
			}
			if ( syncControl != null )
				syncControl.Invoke( bind.callback, new object[]{client,tab});
			else bind.callback(client, tab);
		}
		
		
		public static string getDomain(string domainbus)
		{
			if (domainbus == null)
			{
				domainbus = ConfigurationSettings.AppSettings["IVYBUS"];
			}
			if (domainbus == null)
			{
				domainbus = Environment.GetEnvironmentVariable("IVYBUS");
			}
			if (domainbus == null)
				domainbus = DEFAULT_DOMAIN;
			return domainbus;
		}
		
		
		/// checks the "validity" of a regular expression.
		internal bool CheckRegexp(string exp)
		{
			bool regexp_ok = true;
			// TODO Bug 
			// ClockStop ClockStart & ^Clock(Start|Pause)
			// should Stop to the first parent
			if ((sent_messageClasses != null) && exp.StartsWith("^")  )
			{
				regexp_ok = false;
				// extract first word from regexp...
				string token = Regex.Replace(exp, @"^\^(?<token>[a-zA-Z_0-9-]+).*" , @"${token}");

				foreach (string exp_class in  sent_messageClasses)
				{
					if ( exp_class.StartsWith(token) )
						return true;
				}
			}
			return regexp_ok;
		}
		
		/*
		* prevents two clients from connecting to each other at the same time
		* there might still be a lingering bug here, that we could avoid with the
		* SchizoToken.
		*/
		internal bool checkConnected(IvyClient clnt)
		{
			if (clnt.AppPort == 0)
				return false;
			lock( clients.SyncRoot )
			{
				foreach (IvyClient client in clients )
				{
					if (clnt != client && client.sameClient(clnt))
						return true;
				}
			}
			return false;
		}
		
		/*
		* the service socket thread reader main loop
		*/
		private void  Run()
		{
			traceDebug("Ivy service Thread started"); 
			bool running = true;
			while (running)
			{
				try
				{
					Socket socket = app.AcceptSocket();
					if (stopped)
						break;
					// early disconnexion
					addClient(socket); // the peer called me
				}
				catch (IOException e)
				{
				
					traceDebug("Error IvyServer exception:  " + e.Message);
					Console.Out.WriteLine("Ivy server socket reader caught an exception " + e.Message);
					// e.printStackTrace();
				}
				catch (SocketException e)
				{
					traceDebug("my server socket has been closed");
					running = false;
				}
			}
			traceDebug("Ivy service Thread stopped");
		}
		
		
		private void  traceDebug(string s)
		{
			if (debug)
				Console.Out.WriteLine("-->ivy<-- " + s);
		}
		
		internal class Domain
		{
			public virtual string Domainaddr
			{
				get
				{
					return domainaddr;
				}
				
			}
			public virtual int Port
			{
				get
				{
					return port;
				}
				
			}
			private string domainaddr;
			private int port;
			public Domain( string domainaddr, int port)
			{
				this.domainaddr = domainaddr; this.port = port;
			}
			public override string ToString()
			{
				return domainaddr + ":" + port;
			}
		}
		
	}
}