/*

 *   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.util.Log;

import java.nio.ByteBuffer;

import java.nio.channels.SocketChannel;

import java.util.concurrent.ArrayBlockingQueue;

/**

 * Does most of the work: parsing input, talking to client and Database.

 * @author Christian Lins

 * @since sonews/0.5.0

 */

class ConnectionWorker extends AbstractDaemon

{

  // 256 pending events should be enough

  private static ArrayBlockingQueue<SocketChannel> pendingChannels

    = new ArrayBlockingQueue<SocketChannel>(256, true);

  /**

   * Registers the given channel for further event processing.

   * @param channel

   */

  public static void addChannel(SocketChannel channel)

    throws InterruptedException

  {

    pendingChannels.put(channel);

  }

  /**

   * Processing loop.

   */

  @Override

  public void run()

  {

    while(isRunning())

    {

      try

      {

        // Retrieve and remove if available, otherwise wait.

        SocketChannel channel = pendingChannels.take();

        if(channel != null)

        {

          // Connections.getInstance().get() MAY return null

          NNTPConnection conn = Connections.getInstance().get(channel);

          // Try to lock the connection object

          if(conn != null && conn.tryReadLock())

          {

            ByteBuffer buf = conn.getBuffers().nextInputLine();

            while(buf != null) // Complete line was received

            {

              final byte[] line = new byte[buf.limit()];

              buf.get(line);

              ChannelLineBuffers.recycleBuffer(buf);

              // Here is the actual work done

              conn.lineReceived(line);

              // Read next line as we could have already received the next line

              buf = conn.getBuffers().nextInputLine();

            }

            conn.unlockReadLock();

          }

          else

          {

            addChannel(channel);

          }

        }

      }

      catch(InterruptedException ex)

      {

        Log.msg("ConnectionWorker interrupted: " + ex, true);

      }

      catch(Exception ex)

      {

        Log.msg("Exception in ConnectionWorker: " + ex, false);

        ex.printStackTrace();

      }

    } // end while(isRunning())

  }

}