/*

  *   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());

       }

     }

   }

 }