/*

  *   SONEWS News Server

  *   see AUTHORS for the list of contributors

  *

  *   This program is free software: you can redistribute it and/or modify

  *   it under the terms of the GNU General Public License as published by

  *   the Free Software Foundation, either version 3 of the License, or

  *   (at your option) any later version.

  *

  *   This program is distributed in the hope that it will be useful,

  *   but WITHOUT ANY WARRANTY; without even the implied warranty of

  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  *   GNU General Public License for more details.

  *

  *   You should have received a copy of the GNU General Public License

  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

  */

 package org.sonews.daemon;

 import org.sonews.config.Config;

 import org.sonews.util.Log;

 import org.sonews.util.Stats;

 import java.io.IOException;

 import java.net.InetSocketAddress;

 import java.net.Socket;

 import java.nio.channels.SocketChannel;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.List;

 import java.util.ListIterator;

 import java.util.Map;

 /**

  * Daemon thread collecting all NNTPConnection instances. The thread

  * checks periodically if there are stale/timed out connections and

  * removes and purges them properly.

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public final class Connections extends AbstractDaemon

 {

 	private static final Connections instance = new Connections();

 	/**

 	 * @return Active Connections instance.

 	 */

 	public static Connections getInstance()

 	{

 		return Connections.instance;

 	}

 	private final List<NNTPConnection> connections = new ArrayList<NNTPConnection>();

 	private final Map<SocketChannel, NNTPConnection> connByChannel = new HashMap<SocketChannel, NNTPConnection>();

 	private Connections()

 	{

 		setName("Connections");

 	}

 	/**

 	 * Adds the given NNTPConnection to the Connections management.

 	 * @param conn

 	 * @see org.sonews.daemon.NNTPConnection

 	 */

 	public void add(final NNTPConnection conn)

 	{

 		synchronized (this.connections) {

 			this.connections.add(conn);

 			this.connByChannel.put(conn.getSocketChannel(), conn);

 		}

 	}

 	/**

 	 * @param channel

 	 * @return NNTPConnection instance that is associated with the given

 	 * SocketChannel.

 	 */

 	public NNTPConnection get(final SocketChannel channel)

 	{

 		synchronized (this.connections) {

 			return this.connByChannel.get(channel);

 		}

 	}

 	int getConnectionCount(String remote)

 	{

 		int cnt = 0;

 		synchronized (this.connections) {

 			for (NNTPConnection conn : this.connections) {

 				assert conn != null;

 				assert conn.getSocketChannel() != null;

 				Socket socket = conn.getSocketChannel().socket();

 				if (socket != null) {

 					InetSocketAddress sockAddr = (InetSocketAddress) socket.getRemoteSocketAddress();

 					if (sockAddr != null) {

 						if (sockAddr.getHostName().equals(remote)) {

 							cnt++;

 						}

 					}

 				} // if(socket != null)

 			}

 		}

 		return cnt;

 	}

 	/**

 	 * Run loops. Checks periodically for timed out connections and purged them

 	 * from the lists.

 	 */

 	@Override

 	public void run()

 	{

 		while (isRunning()) {

 			int timeoutMillis = 1000 * Config.inst().get(Config.TIMEOUT, 180);

 			synchronized (this.connections) {

 				final ListIterator<NNTPConnection> iter = this.connections.listIterator();

 				NNTPConnection conn;

 				while (iter.hasNext()) {

 					conn = iter.next();

 					if ((System.currentTimeMillis() - conn.getLastActivity()) > timeoutMillis

 						&& conn.getBuffers().isOutputBufferEmpty()) {

 						// A connection timeout has occurred so purge the connection

 						iter.remove();

 						// Close and remove the channel

 						SocketChannel channel = conn.getSocketChannel();

 						connByChannel.remove(channel);

 						try {

 							assert channel != null;

 							assert channel.socket() != null;

 							// Close the channel; implicitely cancels all selectionkeys

 							channel.close();

 							Log.get().info("Disconnected: " + channel.socket().getRemoteSocketAddress()

 								+ " (timeout)");

 						} catch (IOException ex) {

 							Log.get().warning("Connections.run(): " + ex);

 						}

 						// Recycle the used buffers

 						conn.getBuffers().recycleBuffers();

 						Stats.getInstance().clientDisconnect();

 					}

 				}

 			}

 			try {

 				Thread.sleep(10000); // Sleep ten seconds

 			} catch (InterruptedException ex) {

 				Log.get().warning("Connections Thread was interrupted: " + ex.getMessage());

 			}

 		}

 	}

 }