/* Copyright (c) 2006-2014. The SimGrid Team.
 * All rights reserved.                                                     */

/* This program is free software; you can redistribute it and/or modify it
 * under the terms of the license (GNU LGPL) which comes with this package. */

package bittorrent;
import java.util.ArrayList;

import org.simgrid.msg.Comm;
import org.simgrid.msg.Host;
import org.simgrid.msg.Msg;
import org.simgrid.msg.MsgException;
import org.simgrid.msg.Process;
import org.simgrid.msg.RngStream;
import org.simgrid.msg.Task;
/**
 * Tracker, handle requests from peers.
 */
public class Tracker extends Process {
	protected RngStream stream;
	/**
	 * Peers list
	 */
	protected ArrayList<Integer> peersList;
	/**
	 * End time for the simulation
	 */
	protected double deadline;
	/**
	 * Current comm received
	 */
	protected Comm commReceived = null;
	
	public Tracker(Host host, String name, String[]args) {
		super(host,name,args);
	}
	
	@Override
	public void main(String[] args) throws MsgException {
		if (args.length != 1) {
			Msg.info("Wrong number of arguments for the tracker.");
			return;
		}
		//Build the RngStream object for randomness
		stream = new RngStream("tracker");
		//Retrieve the end time
		deadline = Double.valueOf(args[0]);
		//Building peers array
		peersList = new ArrayList<Integer>();
		
		Msg.info("Tracker launched.");		
		while (Msg.getClock() < deadline) {
			if (commReceived == null) {
				commReceived = Task.irecv(Common.TRACKER_MAILBOX);
			}
			try {
				if (commReceived.test()) {
					Task task = commReceived.getTask();
					if (task instanceof TrackerTask) {
						TrackerTask tTask = (TrackerTask)task;
						//Sending peers to the peer
						int nbPeers = 0;
						while (nbPeers < Common.MAXIMUM_PEERS && nbPeers < peersList.size()) {
							int nextPeer;
							do {
								nextPeer = stream.randInt(0, peersList.size() - 1);
							} while (tTask.peers.contains(nextPeer));
							tTask.peers.add(peersList.get(nextPeer));
							nbPeers++;
						}
						//Adding the peer to our list
						peersList.add(tTask.peerId);
						tTask.type = TrackerTask.Type.ANSWER;
						//Setting the interval
						tTask.interval = Common.TRACKER_QUERY_INTERVAL;
						//Sending the task back to the peer
						tTask.dsend(tTask.mailbox);
					}
					commReceived = null;
				}
				else {
					waitFor(1);
				}
			}
			catch (MsgException e) {
				commReceived = null;				
			}
		}
		Msg.info("Tracker is leaving");
	}

}