package geniusweb.partiesserver;

import java.util.logging.Level;

import geniusweb.partiesserver.repository.RunningPartiesRepo;
import geniusweb.partiesserver.repository.RunningParty;
import geniusweb.party.Party;
import tudelft.utilities.logging.ReportToLogger;
import tudelft.utilities.logging.Reporter;

/**
 * 
 * This object keeps the {@link RunningPartiesRepo} up to date. Main job is to
 * remove parties that have been timed out. When a party times out, it calls
 * {@link Party#terminate()} but that might fail to stop a party. In the end,
 * the protocol should close the connection after the deadline. Start and run
 * only once.
 */
public class RunningPartiesUpdater implements Runnable {
	private final long period;
	private final Reporter log = new ReportToLogger("partiesserver");
	private final RunningPartiesRepo running;
	/**
	 * when a negotiation runs out of time, the protocol may want to inform all
	 * parties about the failed session. If the parties are all killed at that
	 * moment, this is impossible. Therefore we wait KILL_DELAY extra time
	 * before really killing the parties.
	 */
	private static final long KILL_DELAY = 2000;

	/**
	 * @param repo   the {@link RunningPartiesRepo} that must be updated
	 *               automatically
	 * @param period the period with which to check time-out (ms). Recommended
	 *               1000. After constructing you can run this in separate
	 *               thread or just call {@link #run()}
	 * 
	 */
	public RunningPartiesUpdater(RunningPartiesRepo repo, final long period) {
		this.running = repo;
		this.period = period;
	}

	/**
	 * 
	 * run the updater. Please run only one of this to avoid neeedless CPU load.
	 */
	@Override
	public void run() {
		try {
			while (true) {
				Thread.sleep(period);
				update();
			}
		} catch (InterruptedException e) {
			System.err
					.println("ERROR:  RunningPartiesUpdater was interrupted!");
		}
	}

	/**
	 * Removes parties when they ran out of time. Called when some file that may
	 * be relevant has changed, and periodically every {@link #period}.
	 * Synchronized to avoid weird states if filesystem changes rapidly. We
	 * ignore everything but jar files.
	 */
	void update() {
		for (RunningParty party : running.list()) {
			long now = System.currentTimeMillis();
			if (now >= party.getEndDate().getTime() + KILL_DELAY) {
				log.log(Level.WARNING,
						"party " + party.getID() + " still running "
								+ KILL_DELAY / 1000
								+ "s after deadline. Removed now.");
				running.remove(party.getID());
				try {
					Thread.sleep(20);
				} catch (InterruptedException e) {
				}
			}
		}
	}

}