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;
import java.util.Enumeration;

/**
 * A private Class for the Ivy rendezvous
 *
 * @author	François-Régis Colin
 * @author	Yannick Jestin
 * @author	<a href="http://www.tls.cena.fr/products/ivy/">http://www.tls.cena.fr/products/ivy/</a>
 *
 * right now, the rendez vous is either an UDP socket or a TCP multicast.
 * The watcher will answer to
 * each peer advertising its arrival on the bus. The intrinsics of Unix are so
 * that the broadcast is done using the same socket, which is not a good
 * thing.
 *
 * CHANGELOG:
 * 1.0.10:
 *  - isInDomain() is wrong  in multicast. I've removed it
 *  - there was a remanence effect in the datagrampacket buffer. I clean it up after each message
 *  - cleaned up the getDomain() and getPort() code 
 *  - close message sends an interruption on all threads for a clean exit
 *  - removed the timeout bug eating all the CPU resources
 *  - now handles a Vector of broadcast listeners
 */

class IvyWatcher implements Runnable {
  private static boolean debug = (System.getProperty("IVY_DEBUG")!=null);
  //private Vector domainaddrList;
  private boolean watcherrunning = false;
  private boolean isMulticastAddress = false;
  private Vector broadcastListener ;
  private Ivy  bus;			/* master bus controler */
  private DatagramSocket broadcast;	/* supervision socket */
    // it can also be a MulticastSocket, which inherits from the previous
  /**
   * creates an Ivy watcher.
   * @param bus the bus
   */
  IvyWatcher(Ivy bus) throws IvyException {
    this.bus = bus;
    //domainaddrList = new Vector();
  }
  
  /**
   * the behaviour of the thread watching the UDP socket.
   * this thread will stop either when the bus stops or when the
   * watcherrunning will be set to false
   *
   * TODO: better handling of exceptions, because we juste System.err.println
   * here, run cannot throw IvyException ...
   */
  public void run()  {
    byte buf[] = new byte[256];
    DatagramPacket packet=new DatagramPacket(buf, 256);
    int port;
    traceDebug("IvyWatcher waiting for Broadcast");
    while( watcherrunning && bus.ivyRunning ) try {
	broadcast.receive(packet);
	String msg = new String(packet.getData()) ;
	// clean up the buffer after each message
	for (int i=0;i<buf.length;i++) { buf[i]=0; }
	InetAddress remotehost = packet.getAddress();
	traceDebug("BUSWATCHER Receive Broadcast from "+
	    remotehost.getHostName()+":"+packet.getPort());
	// we used to check if remoteaddr is in our broadcast domain list otherwise we
	// ignore the broadcast
	// if ( !isInDomain( remotehost ) ) continue;
	StringTokenizer st = new StringTokenizer(msg);
	if ( !st.hasMoreTokens()) {
	  System.err.println("Bad format "+msg);
	  continue;
	}
	int version  = Integer.parseInt( st.nextToken() );
	if ( version != bus.PROCOCOLVERSION ) {
	  System.err.println("Ignoring bad protocol version broadcast");
	  continue;
	}
	if  ( ! st.hasMoreTokens()) {
	  System.err.println("Bad format "+msg);
	  continue;
	}
	port = Integer.parseInt( st.nextToken() );
	if ( (bus.applicationPort == port) ) continue;
	traceDebug("BUSWATCHER Broadcast de "
	    +packet.getAddress().getHostName()
	    +":"+packet.getPort()+" port "+port+" version "+version);
	try {
	  Socket socket = new Socket( remotehost, port );
	  bus.addClient(socket,false);
	} catch ( UnknownHostException e ) {
	  System.err.println("Unkonwn host "+remotehost + e.getMessage());
	} catch ( IOException e) {
	  System.err.println("can't connect to "+remotehost+" port "+
	      port+e.getMessage());
	}
    } catch (java.io.InterruptedIOException jii ){
      if (!watcherrunning) break;
      System.out.println("DEBUG IvyClient: I have been interrupted");
    } catch (java.io.IOException ioe ){
     System.err.println("IvyWatcher IOException "+ ioe.getMessage() );
    }
    stop();
  } // while
  
  /**
   * stops the thread waiting on the broadcast socket
   */
  void stop() {
    traceDebug("broadcast listener normal shutdown");
    watcherrunning=false;
    for (Enumeration e = broadcastListener.elements();e.hasMoreElements();) {
      Thread t = (Thread) e.nextElement();
      t.interrupt();
    }
  }

  private static void sendBroadcast(String data, String domain, int port) throws IvyException {
    MulticastSocket send ;
    try {
      InetAddress group = InetAddress.getByName(domain);
      send = new MulticastSocket(port);
      if (group.isMulticastAddress()) { ((MulticastSocket)send).joinGroup(group); } 
      DatagramPacket packet = new DatagramPacket( data.getBytes(), data.length(), group, port );
      send.send(packet);
    } catch ( UnknownHostException e ) {
      throw new IvyException("Broadcast sent on unknown network "+
        e.getMessage());
    } catch ( IOException e ) {
      throw new IvyException("Broadcast error " + e.getMessage() );
    }
  }

  void start(String net) throws IvyException {
    String hello = bus.PROCOCOLVERSION + " " + bus.applicationPort + "\n";
    StringTokenizer st = new StringTokenizer(net,",");
    broadcastListener = new Vector();
    while  ( st.hasMoreTokens()) {
      String s = st.nextToken() ;
      String domainaddr=getDomain(s);
      int port=getPort(s);
      // System.out.println("Domaine: "+domainaddr+" : "+port);
      try {
	InetAddress group = InetAddress.getByName(domainaddr);
	broadcast = new MulticastSocket(port);
	// Handling of multicast address
	if (group.isMulticastAddress()) {
	  isMulticastAddress = true;
	  ((MulticastSocket)broadcast).joinGroup(group);
	} 
      } catch ( IOException e ) {
	throw new IvyException("IvyWatcher I/O error" + e );
      } 
      /*
      try {
	broadcast.setSoTimeout(100);
      } catch ( java.net.SocketException jns ) {
	throw new IvyException("IvyWatcher setSoTimeout error" + jns.getMessage() );
      }
      */
      // starts a Thread listening on the socket
      watcherrunning=true;
      Thread t = new Thread(this);
      broadcastListener.addElement(t);
      t.start();
      // notifies our arrival on each domain: protocol version + port
      sendBroadcast(hello,domainaddr,port);
    }
  }

  /*
   * TODO
   * deprecated since we use Multicast. How to check when we are in UDP
   * broadcast ?
  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;
  }
   */

  private static String getDomain(String net) {
    int sep_index = net.lastIndexOf( ":" );
    if ( sep_index != -1 ) { net = net.substring(0,sep_index); }
    try {
      net += ".255.255.255";
      RE exp = new RE( "^(\\d+\\.\\d+\\.\\d+\\.\\d+).*");
      net = exp.substitute( net , "$1" );
    } catch ( REException e ){
      System.out.println("Bad broascat addr " + net);
      return null;
    }
    //System.out.println("net: "+net);
    return net;
  }

  private static int getPort(String net) {
    int sep_index = net.lastIndexOf( ":" );
    int port= ( sep_index == -1 ) ? Ivy.DEFAULT_PORT :Integer.parseInt( net.substring( sep_index +1 ));
    // System.out.println("net: ["+net+"]\nsep_index: "+sep_index+"\nport: "+port);
    return port;
  }


  private void traceDebug(String s){
    if (debug) System.out.println("-->ivywatcher<-- "+s);
  }
  

} // class IvyWatcher
/* EOF */