/*
    *  Licensed to the Apache Software Foundation (ASF) under one
    *  or more contributor license agreements.  See the NOTICE file
    *  distributed with this work for additional information
    *  regarding copyright ownership.  The ASF licenses this file
    *  to you 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 org.apache.directory.server.ntp;
  
  
  import java.io.IOException;
  
  import org.apache.directory.server.ntp.protocol.NtpProtocolCodecFactory;
  import org.apache.directory.server.ntp.protocol.NtpProtocolHandler;
  import org.apache.directory.server.protocol.shared.AbstractProtocolService;
  import org.apache.directory.server.protocol.shared.transport.Transport;
  import org.apache.directory.server.protocol.shared.transport.UdpTransport;
  import org.apache.mina.core.filterchain.DefaultIoFilterChainBuilder;
  import org.apache.mina.core.service.IoAcceptor;
  import org.apache.mina.core.service.IoHandler;
  import org.apache.mina.filter.codec.ProtocolCodecFilter;
  import org.apache.mina.transport.socket.DatagramAcceptor;
  import org.apache.mina.transport.socket.DatagramSessionConfig;
  import org.apache.mina.transport.socket.SocketAcceptor;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Contains the configuration parameters for the NTP protocol provider.
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class NtpServer extends AbstractProtocolService
  {
      /** logger for this class */
      private static final Logger LOG = LoggerFactory.getLogger( NtpServer.class );
  
      /**
       * The default IP port.
       */
      private static final int IP_PORT_DEFAULT = 123;
  
      /** The default service pid. */
      private static final String SERVICE_PID_DEFAULT = "org.apache.directory.server.ntp";
  
      /** The default service name. */
      private static final String SERVICE_NAME_DEFAULT = "ApacheDS NTP Service";
  
  
      /**
       * Creates a new instance of NtpConfiguration.
       */
      public NtpServer()
      {
          super.setServiceId( SERVICE_PID_DEFAULT );
          super.setServiceName( SERVICE_NAME_DEFAULT );
      }
  
  
      /**
       * Start the NTPServer. We initialize the Datagram and Socket, if necessary.
       * 
       * Note that we don't have any filter in the chain, everything is done
       * in the handler.
       * @throws IOException if there are issues binding
       */
      public void start() throws IOException
      {
          IoHandler ntpProtocolHandler = new NtpProtocolHandler();
  
          // Create the chain for the NTP server
          DefaultIoFilterChainBuilder ntpChain = new DefaultIoFilterChainBuilder();
          ntpChain.addLast( "codec", new ProtocolCodecFilter( NtpProtocolCodecFactory.getInstance() ) );
  
          if ( ( transports == null ) || transports.isEmpty() )
          {
              // Default to UDP with port 123
              // We have to create a DatagramAcceptor
              UdpTransportol/shared/transport/UdpTransport.html#UdpTransport">UdpTransport transport = new UdpTransport( IP_PORT_DEFAULT );
              setTransports( transport );
  
              DatagramAcceptor acceptor = transport.getAcceptor();
  
              // Set the handler
              acceptor.setHandler( ntpProtocolHandler );
  
             // Allow the port to be reused even if the socket is in TIME_WAIT state
             acceptor.getSessionConfig().setReuseAddress( true );
 
             // Inject the chain
             acceptor.setFilterChainBuilder( ntpChain );
 
             // Start the listener
             acceptor.bind();
         }
         else
         {
             for ( Transport transport : transports )
             {
                 IoAcceptor acceptor = transport.getAcceptor();
 
                 // Set the handler
                 acceptor.setHandler( ntpProtocolHandler );
 
                 if ( transport instanceof UdpTransport )
                 {
                     // Allow the port to be reused even if the socket is in TIME_WAIT state
                     ( ( DatagramSessionConfig ) acceptor.getSessionConfig() ).setReuseAddress( true );
                 }
                 else
                 {
                     // Disable the disconnection of the clients on unbind
                     acceptor.setCloseOnDeactivation( false );
 
                     // Allow the port to be reused even if the socket is in TIME_WAIT state
                     ( ( SocketAcceptor ) acceptor ).setReuseAddress( true );
 
                     // No Nagle's algorithm
                     ( ( SocketAcceptor ) acceptor ).getSessionConfig().setTcpNoDelay( true );
                 }
 
                 // Inject the chain
                 acceptor.setFilterChainBuilder( ntpChain );
 
                 // Start the listener
                 acceptor.bind();
             }
         }
 
         LOG.info( "NTP server started." );
     }
 
 
     /**
      * {@inheritDoc}
      */
     public void stop()
     {
         for ( Transport transport : getTransports() )
         {
             IoAcceptor acceptor = transport.getAcceptor();
 
             if ( acceptor != null )
             {
                 acceptor.dispose();
             }
         }
 
         LOG.info( "NTP Server stopped." );
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( "NTPServer[" ).append( getServiceName() ).append( "], listening on :" ).append( '\n' );
 
         if ( getTransports() != null )
         {
             for ( Transport transport : getTransports() )
             {
                 sb.append( "    " ).append( transport ).append( '\n' );
             }
         }
 
         return sb.toString();
     }
 }