/*
 * ====================================================================
 * ======== The Apache Software License, Version 1.1
 * ==================
 * ==========================================================
 * Copyright (C) 2002 The Apache Software Foundation. All rights
 * reserved. Redistribution and use in source and binary forms, with
 * or without modifica- tion, are permitted provided that the
 * following conditions are met: 1. Redistributions of source code
 * must retain the above copyright notice, this list of conditions and
 * the following disclaimer. 2. Redistributions in binary form must
 * reproduce the above copyright notice, this list of conditions and
 * the following disclaimer in the documentation and/or other
 * materials provided with the distribution. 3. The end-user
 * documentation included with the redistribution, if any, must
 * include the following acknowledgment: "This product includes
 * software developed by SuperBonBon Industries
 * (http://www.sbbi.net/)." Alternately, this acknowledgment may
 * appear in the software itself, if and wherever such third-party
 * acknowledgments normally appear. 4. The names "UPNPLib" and
 * "SuperBonBon Industries" must not be used to endorse or promote
 * products derived from this software without prior written
 * permission. For written permission, please contact info@sbbi.net.
 * 5. Products derived from this software may not be called
 * "SuperBonBon Industries", nor may "SBBI" appear in their name,
 * without prior written permission of SuperBonBon Industries. THIS
 * SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR ITS
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU- DING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE. This software consists of voluntary contributions made
 * by many individuals on behalf of SuperBonBon Industries. For more
 * information on SuperBonBon Industries, please see
 * <http://www.sbbi.net/>.
 */

package net.tomp2p.upnp;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketTimeoutException;
import java.net.URL;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import net.tomp2p.utils.Timings;

/**
 * This class can be used to listen for UPNP devices responses when a
 * search message is sent by a control point ( using the
 * net.sbbi.upnp.Discovery.sendSearchMessage() method )
 * 
 * @author <a href="mailto:superbonbon@sbbi.net">SuperBonBon</a>
 * @version 1.0
 */
public class DiscoveryListener implements Runnable
{
	private static final int DEFAULT_TIMEOUT = 250;

	private Map<String, Set<DiscoveryResultsHandler>> registeredHandlers =
			new HashMap<String, Set<DiscoveryResultsHandler>>();

	private final Object REGISTRATION_PROCESS = new Object();

	private final static DiscoveryListener singleton = new DiscoveryListener();

	private boolean inService = false;

	private boolean daemon = true;

	private java.net.MulticastSocket skt;

	private DatagramPacket input;

	private DiscoveryListener()
	{
	}

	final static DiscoveryListener getInstance()
	{
		return singleton;
	}

	/**
	 * Sets the listener as a daemon thread
	 * 
	 * @param daemon
	 *           daemon thread
	 */
	public void setDaemon( boolean daemon )
	{
		this.daemon = daemon;
	}

	/**
	 * Registers an SSDP response message handler
	 * 
	 * @param resultsHandler
	 *           the SSDP response message handler
	 * @param searchTarget
	 *           the search target
	 * @throws IOException
	 *            if some errors occurs during SSDP search response
	 *            messages listener thread startup
	 */
	public void registerResultsHandler( DiscoveryResultsHandler resultsHandler,
			String searchTarget ) throws IOException
	{
		synchronized( REGISTRATION_PROCESS )
		{
			if( !inService )
			{
				startDevicesListenerThread();
			}
			Set<DiscoveryResultsHandler> handlers = registeredHandlers.get( searchTarget );
			if( handlers == null )
			{
				handlers = new HashSet<DiscoveryResultsHandler>();
				registeredHandlers.put( searchTarget, handlers );
			}
			handlers.add( resultsHandler );
		}
	}

	/**
	 * Unregisters an SSDP response message handler
	 * 
	 * @param resultsHandler
	 *           the SSDP response message handler
	 * @param searchTarget
	 *           the search target
	 */
	public void unRegisterResultsHandler( DiscoveryResultsHandler resultsHandler,
			String searchTarget )
	{
		synchronized( REGISTRATION_PROCESS )
		{
			Set<DiscoveryResultsHandler> handlers = registeredHandlers.get( searchTarget );
			if( handlers != null )
			{
				handlers.remove( resultsHandler );
				if( handlers.size() == 0 )
				{
					registeredHandlers.remove( searchTarget );
				}
			}
			if( registeredHandlers.size() == 0 )
			{
				stopDevicesListenerThread();
			}
		}
	}

	private void startDevicesListenerThread() throws IOException
	{
		synchronized( singleton )
		{
			if( !inService )
			{

				startMultiCastSocket();
				Thread deamon = new Thread( this, "DiscoveryListener daemon" );
				deamon.setDaemon( daemon );
				deamon.start();
				while( !inService )
				{
					// wait for the thread to be started let's wait a few
					// ms
					try
					{
						Timings.sleep( 2 );
					}
					catch( InterruptedException ex )
					{
						// don t care
					}
				}
			}
		}
	}

	private void stopDevicesListenerThread()
	{
		synchronized( singleton )
		{
			inService = false;
		}
	}

	private void startMultiCastSocket() throws IOException
	{
		int bindPort = Discovery.DEFAULT_SSDP_SEARCH_PORT;

		skt = new java.net.MulticastSocket( null );
		skt.bind( new InetSocketAddress( InetAddress.getByName( "0.0.0.0" ), bindPort ) );
		skt.setTimeToLive( Discovery.DEFAULT_TTL );
		skt.setSoTimeout( DEFAULT_TIMEOUT );
		skt.joinGroup( InetAddress.getByName( Discovery.SSDP_IP ) );

		byte[] buf = new byte[ 2048 ];
		input = new DatagramPacket( buf, buf.length );

	}

	@Override
	public void run()
	{
		if( !Thread.currentThread().getName().equals( "DiscoveryListener daemon" ) )
		{
			throw new RuntimeException( "No right to call this method" );
		}
		inService = true;
		while( inService )
		{
			try
			{
				listenBroadCast();
			}
			catch( SocketTimeoutException ex )
			{
				// ignoring
			}
			catch( IOException ioEx )
			{
				ioEx.printStackTrace();
			}
			catch( Exception ex )
			{
				ex.printStackTrace();
				inService = false;
			}
		}

		try
		{
			skt.leaveGroup( InetAddress.getByName( Discovery.SSDP_IP ) );
			skt.close();
		}
		catch( Exception ex )
		{
			// ignoring
		}
	}

	private void listenBroadCast() throws IOException
	{
		skt.receive( input );
		InetAddress from = input.getAddress();
		String received =
				new String( input.getData(), input.getOffset(), input.getLength() );
		HttpResponse msg = null;
		try
		{
			msg = new HttpResponse( received );
		}
		catch( IllegalArgumentException ex )
		{
			// crappy http sent

			// log.debug( "Skipping uncompliant HTTP message " + received
			// );

			return;
		}
		String header = msg.getHeader();
		if( header != null && header.startsWith( "HTTP/1.1 200 OK" )
				&& msg.getHTTPHeaderField( "st" ) != null )
		{
			// probably a search repsonse !
			String deviceDescrLoc = msg.getHTTPHeaderField( "location" );
			if( deviceDescrLoc == null || deviceDescrLoc.trim().length() == 0 )
			{
				// log.debug(
				// "Skipping SSDP message, missing HTTP header 'location' field"
				// );

				return;
			}
			URL loc = new URL( deviceDescrLoc );
			//InetAddress locHost = InetAddress.getByName( loc.getHost() );
			
			String st = msg.getHTTPHeaderField( "st" );
			if( st == null || st.trim().length() == 0 )
			{
				// log.debug(
				// "Skipping SSDP message, missing HTTP header 'st' field"
				// );

				return;
			}
			String usn = msg.getHTTPHeaderField( "usn" );
			if( usn == null || usn.trim().length() == 0 )
			{
				// log.debug(
				// "Skipping SSDP message, missing HTTP header 'usn' field"
				// );

				return;
			}
			String maxAge = msg.getHTTPFieldElement( "Cache-Control", "max-age" );
			if( maxAge == null || maxAge.trim().length() == 0 )
			{
				// log.debug(
				// "Skipping SSDP message, missing HTTP header 'max-age' field"
				// );

				return;
			}
			String server = msg.getHTTPHeaderField( "server" );
			if( server == null || server.trim().length() == 0 )
			{
				// log.debug(
				// "Skipping SSDP message, missing HTTP header 'server' field"
				// );

				return;
			}

			String udn = usn;
			int index = udn.indexOf( "::" );
			if( index != -1 )
			{
				udn = udn.substring( 0, index );
			}
			synchronized( REGISTRATION_PROCESS )
			{
				Set<DiscoveryResultsHandler> handlers = registeredHandlers.get( st );
				if( handlers != null )
				{
					for( DiscoveryResultsHandler handler:handlers )
					{
						handler.discoveredDevice( usn, udn, st, maxAge, loc, server, from );
					}
				}
			}
		}
		else
		{
			// log.debug( "Skipping uncompliant HTTP message " + received
			// );
		}
	}
}
