package geniusweb.partiesserver.websocket;

import java.util.concurrent.LinkedBlockingQueue;
import java.util.logging.Level;

import javax.websocket.RemoteEndpoint.Basic;

import tudelft.utilities.logging.Reporter;

/**
 * A send buffer for @ServerEndpoint objects that makes websockets asynchronous.
 * The "asynchronous" mode for websockets can not be used because it throws
 * exceptions the moment you try to send a second datapacket into the socket
 * while the first is not yet finished.
 * 
 * <p>
 * After use, {@link #stop()} must be called to stop the thread managing this
 * queue. Failure to do this may cause memory leaks.
 */
public class SendBuffer {

	private final Basic remote;
	private final LinkedBlockingQueue<String> fifo = new LinkedBlockingQueue<String>();
	private final Thread thread;
	private final Reporter log;

	public SendBuffer(final Basic basicRemote, final Reporter logger) {
		this.remote = basicRemote;
		this.log = logger;
		thread = new Thread(new Runnable() {

			@Override
			public void run() {
				try {
					while (true) {
						remote.sendText(fifo.take());
					}
				} catch (InterruptedException e) {
					// normal termination
					log.log(Level.FINE,
							"sendbuffer is interrupted, assuming the party died.");
				} catch (Exception e) {
					logger.log(Level.SEVERE, "Failed to write to stream", e);
				}
			}
		});
		thread.start();
	}

	public void send(String text) {
		try {
			fifo.put(text);
		} catch (InterruptedException e) {
			log.log(Level.WARNING,
					"sender queue has been interrupted, message may have not been sent",
					e);
		}
	}

	/**
	 * Stop the que, disable, terminate threads
	 */
	public void stop() {
		if (!fifo.isEmpty()) {
			try {
				log.log(Level.FINE, "Allowing short time to send remaining "
						+ fifo.size() + "messages");
				thread.sleep(1000);
			} catch (InterruptedException e) {
				log.log(Level.FINE,
						"Waiting was interrupted, final messages have been deleted");
			}
		}
		thread.interrupt();
		try {
			thread.join(400);
		} catch (InterruptedException e) {
			log.log(Level.WARNING,
					"thread termination was interrupted, unsure about thread state");
		}
	}

}