/*
 * Created on 06-Jul-2004
 * Created by Paul Gardner
 * Copyright (C) 2004, 2005, 2006 Aelitis, All Rights Reserved.
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 * 
 * AELITIS, SAS au capital de 46,603.30 euros
 * 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
 *
 */

package com.aelitis.azureus.plugins.removerules;

/**
 * @author parg
 *
 */

import java.net.InetAddress;
import java.util.*;

import org.gudy.azureus2.plugins.torrent.*;
import org.gudy.azureus2.plugins.download.*;
import org.gudy.azureus2.plugins.logging.LoggerChannel;
import org.gudy.azureus2.plugins.ui.config.*;
import org.gudy.azureus2.plugins.ui.model.BasicPluginConfigModel;
import org.gudy.azureus2.plugins.*;

import org.gudy.azureus2.core3.util.*;

public class 
DownloadRemoveRulesPlugin 
	implements Plugin, DownloadManagerListener, HostNameToIPResolverListener
{
	public static final int			INITIAL_DELAY			= 60*1000;
	public static final int			DELAYED_REMOVAL_PERIOD	= 60*1000;
	
	public static final int			AELITIS_BIG_TORRENT_SEED_LIMIT		= 10000;
	public static final int			AELITIS_SMALL_TORRENT_SEED_LIMIT	= 1000;
	
	public static final int			MAX_SEED_TO_PEER_RATIO	= 10;	// 10 to 1
		
	public static final String		AELITIS_HOST_CORE	= "aelitis.com";			// needs to be lowercase
	public static final String		AELITIS_TRACKER		= "tracker.aelitis.com";	// needs to be lowercase
	
	protected String				aelitis_ip;
	
	protected PluginInterface		plugin_interface;
	protected boolean				closing;
	
	protected Map					dm_listener_map		= new HashMap(10);
	protected List					monitored_downloads	= new ArrayList();
	
	protected LoggerChannel 		log;

	protected BooleanParameter 	remove_unauthorised; 
	protected BooleanParameter 	remove_unauthorised_seeding_only; 
	
	protected BooleanParameter 	remove_update_torrents; 

	
	public void
	initialize(
		PluginInterface 	_plugin_interface )
	{
		plugin_interface	= _plugin_interface;
		
		HostNameToIPResolver.addResolverRequest( AELITIS_TRACKER, this );
		
		plugin_interface.getPluginProperties().setProperty( "plugin.version", 	"1.0" );
		plugin_interface.getPluginProperties().setProperty( "plugin.name", "Download Remove Rules" );

		log = plugin_interface.getLogger().getChannel("DLRemRules");

		BasicPluginConfigModel	config = plugin_interface.getUIManager().createBasicPluginConfigModel( "torrents", "download.removerules.name" );
			
		config.addLabelParameter2( "download.removerules.unauthorised.info" );
		
		remove_unauthorised = 
			config.addBooleanParameter2( "download.removerules.unauthorised", "download.removerules.unauthorised", false );
		
		remove_unauthorised_seeding_only = 
			config.addBooleanParameter2( "download.removerules.unauthorised.seedingonly", "download.removerules.unauthorised.seedingonly", true );
		
		remove_unauthorised.addEnabledOnSelection( remove_unauthorised_seeding_only );

		remove_update_torrents = 
			config.addBooleanParameter2( "download.removerules.updatetorrents", "download.removerules.updatetorrents", true );

		new DelayedEvent(
				"DownloadRemovalRules",
				INITIAL_DELAY,
				new AERunnable()
				{
					public void
					runSupport()
					{		
						plugin_interface.getDownloadManager().addListener( DownloadRemoveRulesPlugin.this );
					}
				});
	}
	
	public void
	hostNameResolutionComplete(
		InetAddress	address )
	{
			// resolution will fail if disconnected from net
		
		if ( address != null ){
			
			aelitis_ip	= address.getHostAddress();
		}
	}

	public void
	downloadAdded(
		final Download	download )
	{
			// we don't auto-remove non-persistent downloads as these are managed 
			// elsewhere (e.g. shares)
		
		if ( !download.isPersistent()){
			
			return;
		}
		
		DownloadTrackerListener	listener = 
			new DownloadTrackerListener()
			{
				public void
				scrapeResult(
					DownloadScrapeResult	response )
				{
					if ( closing ){
						
						return;
					}

					handleScrape( download, response );
				}
				
				public void
				announceResult(
					DownloadAnnounceResult			response )
				{
					if ( closing ){
						
						return;
					}
					
					handleAnnounce( download, response );
				}
			};
			
		monitored_downloads.add( download );
		
		dm_listener_map.put( download, listener );
		
		download.addTrackerListener( listener );
	}
		
	protected void
	handleScrape(
		Download				download,
		DownloadScrapeResult	response )
	{
		String	status = response.getStatus();
		
		if ( status == null ){
			
			status = "";
		}
			
		handleAnnounceScrapeStatus( download, status );
	}
	
	protected void
	handleAnnounce(
		Download				download,
		DownloadAnnounceResult	response )
	{
		String	reason = "";
		
		if ( response.getResponseType() == DownloadAnnounceResult.RT_ERROR ){
			
			reason = response.getError();
			
			if ( reason == null ){
				
				reason = "";
			}
		}
				
		handleAnnounceScrapeStatus( download, reason );
	}
	
	protected void
	handleAnnounceScrapeStatus(
		Download		download,
		String			status )
	{
		if ( !monitored_downloads.contains( download )){
			
			return;
		}
		
		status = status.toLowerCase();
		
		boolean	download_completed = download.isComplete();
				
		if ( 	status.indexOf( "not authori" ) != -1 ||
				status.toLowerCase().indexOf( "unauthori" ) != -1 ){
	
			if ( remove_unauthorised.getValue() &&
				 (	(!remove_unauthorised_seeding_only.getValue()) ||
				 	download_completed )){
			
				log.log(download.getTorrent(), LoggerChannel.LT_INFORMATION, "Download '"
						+ download.getName() + "' is unauthorised and removal triggered");
			
				removeDownload( download );
				
				return;
			}
		}
						
		Torrent	torrent = download.getTorrent();
		
		if ( torrent != null && torrent.getAnnounceURL() != null ){
		
			String	url_string = torrent.getAnnounceURL().toString().toLowerCase();
			
			if ( 	url_string.indexOf( AELITIS_HOST_CORE ) != -1 ||
					( aelitis_ip != null && url_string.indexOf( aelitis_ip ) != -1 )){
	
					// emergency instruction from tracker
				
				if ( 	( download_completed && status.indexOf( "too many seeds" ) != -1 ) ||
						status.indexOf( "too many peers" ) != -1 ){
		
					log.log(download.getTorrent(), LoggerChannel.LT_INFORMATION,
							"Download '" + download.getName()
									+ "' being removed on instruction from the tracker");

					removeDownloadDelayed( download );
					
				}else if ( download_completed && remove_update_torrents.getValue()){
					
					long	seeds	= download.getLastScrapeResult().getSeedCount();
					long	peers	= download.getLastScrapeResult().getNonSeedCount();
						
						// try to maintain an upper bound on seeds that isn't going to
						// kill the tracker

					if ( seeds / ( peers==0?1:peers ) > MAX_SEED_TO_PEER_RATIO ){
						
						log.log(download.getTorrent(), LoggerChannel.LT_INFORMATION,
								"Download '" + download.getName()
										+ "' being removed to reduce swarm size");
						
						removeDownloadDelayed( download );		

					}else{
					
						long	creation_time	= download.getCreationTime();
						
						long	running_mins = ( SystemTime.getCurrentTime() - creation_time )/(60*1000);
						
						if ( running_mins > 15 ){
						
								// big is a relative term here and generally distinguishes between core updates
								// and plugin updates
							
							boolean	big_torrent = torrent.getSize() > 1024*1024;
							
							if ( 	( seeds > AELITIS_BIG_TORRENT_SEED_LIMIT && big_torrent ) ||
									( seeds > AELITIS_SMALL_TORRENT_SEED_LIMIT && !big_torrent )){
						
	
								log.log( "Download '" + download.getName() + "' being removed to reduce swarm size" );
						
								removeDownloadDelayed( download );		
							}
						}
					}
				}
			}
		}
	}
	
	protected void
	removeDownloadDelayed(
		final Download		download )
	{
		monitored_downloads.remove( download );
		
			// we need to delay this because other actions may be being performed
			// on the download (e.g. completion may trigger update install)
		
		plugin_interface.getUtilities().createThread( 
			"delayedRemoval",
			new AERunnable()
			{
				public void
				runSupport()
				{
					try{
						Thread.sleep(DELAYED_REMOVAL_PERIOD);
						
						removeDownload( download );
						
					}catch( Throwable e ){
						
						Debug.printStackTrace( e );
					}
				}
			});
	}
	
	protected void
	removeDownload(
		final Download		download )
	{
		monitored_downloads.remove( download );
		
		if ( download.getState() == Download.ST_STOPPED ){
			
			try{
				download.remove();
				
			}catch( Throwable e ){
				
				log.logAlert( "Automatic removal of download '" + download.getName() + "' failed", e );
			}
		}else{
			
			download.addListener( 
				new DownloadListener()
				{
					public void
					stateChanged(
						Download		download,
						int				old_state,
						int				new_state )
					{
						log.log(download.getTorrent(), LoggerChannel.LT_INFORMATION,
							"download state changed to '" + new_state + "'");
						
						if ( new_state == Download.ST_STOPPED ){
							
							try{
								download.remove();
								
								String msg = 
									plugin_interface.getUtilities().getLocaleUtilities().getLocalisedMessageText(
										"download.removerules.removed.ok",
										new String[]{ download.getName() });
									
								log.logAlert( 
									LoggerChannel.LT_INFORMATION,
									msg );
							
							}catch( Throwable e ){
								
								log.logAlert( "Automatic removal of download '" + download.getName() + "' failed", e );
							}
						}
					}
	
					public void
					positionChanged(
						Download	download, 
						int oldPosition,
						int newPosition )
					{
					}
				});
			
			try{
				download.stop();
				
			}catch( DownloadException e ){
				
				log.logAlert( "Automatic removal of download '" + download.getName() + "' failed", e );
			}
		}
	}
	
	public void
	downloadRemoved(
		Download	download )
	{
		monitored_downloads.remove( download );
		
		DownloadTrackerListener	listener = (DownloadTrackerListener)dm_listener_map.remove(download);
		
		if ( listener != null ){
			
			download.removeTrackerListener( listener );
		}
	}
		
	public void
	destroyInitiated()
	{
		closing	= true;
	}
		
	public void
	destroyed()
	{
	}
}
