/*

 *   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());

			}

		}

	}

}