/*
*
* IvyWatcher : gestion des messages UDP pour annoncer les arrivées 
*
*/
package fr.dgac.ivy ;

import java.lang.Thread;
import java.net.*;
import java.io.*;
import java.util.StringTokenizer;
import gnu.regexp.*;
import java.util.Vector;
public class IvyWatcher extends Thread {
  Ivy  bus; /* master bus controler */
  DatagramSocket broadcast; /* supervision socket */
  private Vector domainaddrList;
  private static boolean debug = (System.getProperty("IVY_DEBUG")!=null);
  
  public void close() {
    broadcast.close();
  }
  private void sendBroadcast( String data, String net ) throws IvyException
  {
	DatagramPacket packet;
	// transformation en forme de broadcast w.x.y.z en w.x.y.255
	try {
		// simple trick to expend to 255 thank's Alex
	net += ".255.255.255";
	RE exp = new RE( "^(\\d+\\.\\d+\\.\\d+\\.\\d+).*");
	net = exp.substitute( net , "$1" );
	} catch ( REException e ){
		throw new IvyException("Bad broascat addr");
	}
	// broadcast sur l'adresse iadr
    try {
	  InetAddress iaddr = InetAddress.getByName(net);
	  domainaddrList.addElement( iaddr );
	  packet = new DatagramPacket(
		      data.getBytes(),
		      data.length(),
		      iaddr,
		      broadcast.getLocalPort() );
      broadcast.send( packet );
    } catch ( UnknownHostException e ) {
      throw new IvyException("Broadcast sur réseau inconnu " + e );
    } catch ( IOException e ) {
      throw new IvyException("broadcast send erreur " + e );
    }
  }
  public void sendStart(String domain) throws IvyException {
	String domainaddr;
	// parse Domain to get port number
	int port;
	  int sep_index = domain.lastIndexOf( ":" );
	  if ( sep_index == -1 )
		{
		  port = bus.DEFAULT_PORT;
		  domainaddr = domain;
		}
	  else 
	  { 
		  port = Integer.parseInt( domain.substring( sep_index +1 ));
		  domainaddr = domain.substring(0,sep_index);
	  }
	// create the UDP socket
	try {
      broadcast = new MulticastSocket(port );
    } catch ( IOException e ) {
      throw new IvyException("IvyWatcher erreur I/O" + e );
    }
	// start UDP receiver
    start();
	// send hello world on UDP sockets
	String hello = "3 "+bus.getApplicationPort()+"\n";
	StringTokenizer st = new StringTokenizer(domainaddr," \t:,");
    while  ( st.hasMoreTokens()) {
    sendBroadcast( hello, st.nextToken() );
	}
  }
  
  IvyWatcher(Ivy bus) throws IvyException {
    this.bus = bus;
    domainaddrList = new Vector();
  }
  
  public void run() {
    DatagramPacket packet;
    byte buf[] = new byte[256];
    int port;
    int version;
    /**/
    traceDebug("IvyWatcher waiting for Broadcast");
    while( bus.ivyRunning() )
	{
    try {
	    /* receive antoher application port */
        packet = new DatagramPacket(buf, 256);
        broadcast.receive( packet );
        String msg = new String(packet.getData()) ;
		InetAddress remotehost = packet.getAddress();
        traceDebug("BUSWATCHER Receive Broadcast from:"+
				   remotehost.getHostName()+
				   ":"+packet.getPort()
				   +"'"+msg+"'");
		//  check if remoteaddr is in our broadcast domain list
		if ( !isInDomain( remotehost ) )
			continue;
        StringTokenizer st = new StringTokenizer(msg);
        if  ( ! st.hasMoreTokens()) {
          System.err.println("Bad format "+msg);
          continue;
        }
        version  = Integer.parseInt( st.nextToken() );
        if  ( ! st.hasMoreTokens()) {
          System.err.println("Bad format "+msg);
          continue;
        }
        port = Integer.parseInt( st.nextToken() );
		// TODO: More checking  here host port domain etc....
        if ( (bus.getApplicationPort() == port) )
		{
			continue;
		}
        traceDebug("BUSWATCHER Broadcast de "
	    +packet.getAddress().getHostName()+":"+packet.getPort()+" port "+port);
          /* connect to the application */
          try {
            Socket socket = new Socket( remotehost, port );
            bus.addClient( socket );
          } catch ( UnknownHostException e ) {
            System.err.println("Unkonwn host "+remotehost);
          } catch ( IOException e) {
            System.err.println("can't connect to "+remotehost+" port "+port);
          }
	
    } catch (  IOException e ) {
		// TODO: comment distinger la fin normale de 'erreur
      /* fermeture de la socket arret normal */
      traceDebug("Error IvyWatcher exception:  "  +  e.getMessage());
    }
	}// end while
  }
  
  private void traceDebug(String s){
    if (debug) System.out.println("-->ivywatcher<-- "+s);
  }
  private boolean isInDomain( InetAddress host ){
	  byte rem_addr[] = host.getAddress();
	  for ( int i = 0 ; i < domainaddrList.size(); i++ )
	  {
		  byte addr[] = ((InetAddress)domainaddrList.elementAt(i)).getAddress();
		  int j ;
		  for (  j = 0 ; j < 4 ; j++  )
			  if ( (addr[j] != -1) && (addr[j] != rem_addr[j]) ) break;
		  if ( j == 4 ) 
			{
			  traceDebug( "host " + host + " is in domain\n" );
			  return true;
		    }
	  }
	  traceDebug( "host " + host + " Not in domain\n" );
	  return false;
  }
}