package geniusweb.partiesserver.websocket;

import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;

import tudelft.utilities.logging.Reporter;

/**
 * Keeps track of threads active for a PartySocket. Needed so that we can kill
 * all relevant threads when it comes to forced termination.
 */
public class ActiveThreads {
	private final List<Thread> threads = new LinkedList<>();
	private final Reporter log;

	public ActiveThreads(Reporter log) {
		this.log = log;
	}

	/**
	 * Add the current thread as active thread
	 */
	public synchronized void add() {
		threads.add(Thread.currentThread());
	}

	/**
	 * Remove the current thread as active thread. To be called when thread
	 * finished nicely.
	 */
	public synchronized void remove() {
		threads.remove(Thread.currentThread());

	}

	/**
	 * 
	 * @return true if no threads currently running.
	 */
	public synchronized boolean isEmpty() {
		return threads.isEmpty();
	}

	@SuppressWarnings("deprecation")
	public synchronized void killall() {

		/*
		 * The method stop(Throwable) does not work anymore. we need to call
		 * stop() which will result in nonsense stacktrace pointing to US
		 * instead of the real problem. Only solution is to print stacktrace
		 * ourselves.
		 */
		for (Thread thread : threads) {
			String stacktrace = "";
			for (StackTraceElement element : thread.getStackTrace()) {
				stacktrace += "\t" + element.toString() + "\n";
			}

			/* the most powerful kill, deprecated but required here. */
			try {
				thread.stop();
				log.log(Level.INFO,
						"Killed thread with stack trace\n" + stacktrace);
			} catch (ThreadDeath e) {
				log.log(Level.INFO, "Noticed thread already was stopped.");
			}
		}
		threads.clear();
	}
}