import java.net.*;
import java.io.*;
import java.applet.*;

public abstract class PS10Applet extends DoubleBufferApplet {
  int clientID = -1;
  Socket s;
  DataInputStream in;
  PrintStream out;
  PS10Listener listener;
  String serverHost;
  public static final int PORT = 6800;

  // override this to provide specific applet behaviour.
  // You get messages for your own ID as well.
  public abstract void receiveMessage(int otherID, int x, int y);

  // use this method to send out (ID labelled) messages
  public void sendMessage(int x, int y) {
    if (out != null)
      out.println(clientID + " " + x + " " + y);
    else
      System.out.println("Tried to send a message, but wasn't connected.");
  }
  
  public void init() {
    System.out.println("Init called");
    serverHost = this.getCodeBase().getHost();
    super.init();
  }

  // start - open a socket to the same host as we're on at the given port
  // create some streams and a listener object to handle input stream
  public void start() {
    System.out.println("Start called");
    try {
      s = new Socket(serverHost, PORT);
      in = new DataInputStream(s.getInputStream());
      out = new PrintStream(s.getOutputStream());
            
      listener = new PS10Listener(this, in);
      System.out.println("Connected to " + s.getInetAddress().getHostName() + ":" + s.getPort());
    }
    catch (IOException e) { System.out.println(e.toString()); }
    super.start();
  }

  // Stop: notify the server, tell our listener thread to stop, and destroy
  // all the thread objects (to catch possible errors)
  public void stop() {
    System.out.println("stop called - disconnecting from server.");
    sendMessage(-99, -99);
    out.println("BYE");
    listener.stop();

    listener = null;
    in = null;
    out = null;
    s = null;

    super.stop();
  }
  
  public void setID(int id) {
    if (clientID == -1) {
      clientID = id;
      System.out.println("ID set to " + id);
    } else {
      System.out.println("Refused to set our ID to " + id);
    }
  }
}

// Object to handle socket input. Parses messages and routes them back
// through the applet call interface
class PS10Listener extends Thread {
  DataInputStream in;
  PS10Applet applet;

  public PS10Listener(PS10Applet ac, DataInputStream in) {
    this.in = in;
    this.applet = ac;
    this.start();
  }

  public void run() {
    String line;
    try {
      while (true) {
	line = in.readLine();
	if (line == null)
	  break;
	else if (line.startsWith("0 WELCOME"))	  // our welcome message - get ID
	  applet.setID(Integer.parseInt(line.substring(10))); // skip 0 WELCOME
	else {					  // must be a foreign mouseclick
	  int p1, p2, p3, id, x, y;
	  try {
	    p1 = line.indexOf(' ', 0);		  // first space
	    p2 = line.indexOf(' ', p1+1);		  // second space
	    p3 = line.length();			  // end of string
	    id = Integer.parseInt(line.substring(0, p1));
	    x = Integer.parseInt(line.substring(p1+1, p2));
	    y = Integer.parseInt(line.substring(p2+1, p3));
	    applet.receiveMessage(id, x, y);
	  } catch (StringIndexOutOfBoundsException e) {
	    System.out.println("Error parsing input " + line);
	  } catch (NumberFormatException n) {
	    System.out.println("Error parsing input " + line);
	  }
	}
      }
    }
    catch (IOException e) { System.out.println(e.toString()); }
    finally { System.out.println("PS10 Listener thread died - were we stopped?"); }
  }
}