import java.awt.event.*;
import javax.swing.*;
import java.net.*;
import java.io.*;
import java.util.*;

public class TraceRoute extends JFrame {
   private final int SENDER_SLEEP_TIME = 1000;
   private final int INTERFACE_HANDLER_SLEEP_TIME = 5000;

   private String name, comment, host;
   private HashSet set = new HashSet();
   private JTextArea ta = new JTextArea();

   private int port = 2000;
   //private String address = "234.235.236.237";
   private String address = "luna.dsv.su.se";
   private MulticastSocket ms;

   public static void main(String[] args) {
      new TraceRoute(args[0], args[1]);
   }

   public TraceRoute(String name, String comment) {
      this.name = name;
      this.comment = comment;

      try {
         ms = new MulticastSocket(port);
         ms.joinGroup(InetAddress.getByName(address));
         setTitle("GROUP: " + address + " JOINED AT PORT: " + port);
         ms.setTimeToLive(1);
         //ms = (DatagramSocket) ms;
         ms.connect(new InetSocketAddress(address, port));
      } catch(IOException ioe) {
         System.out.println("IOException generated in ms init: " + ioe.getMessage());
      }

      getContentPane().add("Center", new JScrollPane(ta));
      addWindowListener(new L1());
      setSize(640, 400);
      show();

      new Receiver();
      new Sender();
      new InterfaceHandler();
   }

   class L1 extends WindowAdapter {
      public void windowClosing(WindowEvent we) {
         try {
            ms.leaveGroup(InetAddress.getByName(address));
         } catch(Exception e) {}
         dispose();
      }

      public void windowClosed(WindowEvent we) {
         System.exit(1);
      }
   }

   // #################### Sender #################### 
   class Sender extends Thread {
      public Sender() {
         start();
      }

      public void run() {
         while(true) {
            try {
               String message = "From: " + name + " Host: " + InetAddress.getLocalHost().toString() + " Comment: " + comment;
               byte[] data = message.getBytes();
               DatagramPacket packet = new DatagramPacket(data, data.length, InetAddress.getByName(address), port);
               ms.send(packet);
               sleep(SENDER_SLEEP_TIME);
            } catch(Exception e) {}
         }
      }
   }

   // #################### Receiver #################### 
   class Receiver extends Thread {
      public Receiver() {
         start();
      }

      public void run() {
         while(true) {
            String message = null;
            try {
               byte[] data = new byte[1024];
               DatagramPacket packet = new DatagramPacket(data, data.length);
               ms.receive(packet);
               message = new String(data, 0, packet.getLength());
               if(!set.contains(message)) set.add(message);
            } catch(SocketTimeoutException ste) {
               System.out.println("SocketTimeoutException generated");
            } catch(PortUnreachableException pue) {
               System.out.println("PortUnreachableException generated");
            } catch(IOException ioe) {
               System.out.println("IOException generated");
            }
         }
      }
   }

   // #################### InterfaceHandler ####################
   class InterfaceHandler extends Thread {
      public InterfaceHandler() {
         start();
      }

      public void run() {
         while(true) {
            ta.setText("");
            Iterator iter = set.iterator();
            while(iter.hasNext()) {
               String message = (String)iter.next();
               ta.append(getItem("From:", message) + " --- " + getItem("Host:", message) + " --- " + getItem("Comment:", message) + "\n");
            }
            set.clear();

            try {
               sleep(INTERFACE_HANDLER_SLEEP_TIME);
            } catch(Exception e) {}
         }
      }

      private String getItem(String item, String message) {
         StringTokenizer st = new StringTokenizer(message);
         while(!st.nextToken().equals(item)) {}
         return st.nextToken();
      }
   }
}