/*******************************************************************************
 * Copyright 2013-2014 alladin-IT GmbH
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package at.alladin.rmbt.controlServer.server;

import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 
 * @author lb
 *
 */
public class ProxyEchoService extends Thread {
	
	//eager initialization -> makes synchronization of getInstance() unnecessary
	private static ProxyEchoService instance = new ProxyEchoService();
	
	private final static int MAX_THREADS = 20;

	private final ExecutorService serverSocketPool;
	
	private final Queue<ProxyEchoRequest> requests;
	
	private volatile boolean run = true;

	/**
	 * 
	 * @return
	 */
	public static ProxyEchoService getInstance() {
		return instance;
	}
	
	/**
	 * 
	 * @param maxThreads
	 */
	private ProxyEchoService() {
		super();
		serverSocketPool = Executors.newFixedThreadPool(MAX_THREADS);
		requests = new ConcurrentLinkedQueue<>();
		start();
	}
	
	/*
	 * (non-Javadoc)
	 * @see java.lang.Thread#run()
	 */
	@Override
	public void run() {
		System.out.println("PROXY ECHO SERVER: starting");
		while (run) {
			if (!requests.isEmpty()) {
				serverSocketPool.submit(new ProxyEchoServerSocket(requests.poll()));
			}								
		}
		serverSocketPool.shutdownNow();
		System.out.println("PROXY ECHO SERVER: stopping");
	}
	
	/**
	 * 
	 */
	public void terminate() {
		run = false;
	}
	
	/**
	 * 
	 * @param port
	 * @return
	 */
	public synchronized void listen(final ProxyEchoRequest request) {
		System.out.println("PROXY ECHO SERVER: adding new request to queue on port: " + request.getPort());
		requests.add(request);
	}	
	
	
}