/*
 * Created on May 6, 2008
 * Created by Paul Gardner
 * 
 * Copyright 2008 Vuze, Inc.  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; version 2 of the License only.
 * 
 * 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.
 */


package com.aelitis.azureus.core.metasearch.impl;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.*;

import org.gudy.azureus2.core3.internat.MessageText;
import org.gudy.azureus2.core3.util.AERunnable;
import org.gudy.azureus2.core3.util.AsyncDispatcher;
import org.gudy.azureus2.core3.util.BDecoder;
import org.gudy.azureus2.core3.util.Base32;
import org.gudy.azureus2.core3.util.Constants;
import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.core3.util.DelayedEvent;
import org.gudy.azureus2.core3.util.FileUtil;
import org.gudy.azureus2.core3.util.IndentWriter;
import org.gudy.azureus2.core3.util.SimpleTimer;
import org.gudy.azureus2.core3.util.SystemTime;
import org.gudy.azureus2.core3.util.TimerEvent;
import org.gudy.azureus2.core3.util.TimerEventPerformer;
import org.gudy.azureus2.core3.util.TimerEventPeriodic;
import org.gudy.azureus2.plugins.utils.StaticUtilities;
import org.gudy.azureus2.plugins.utils.resourcedownloader.ResourceDownloader;
import org.gudy.azureus2.plugins.utils.resourcedownloader.ResourceDownloaderFactory;
import org.gudy.azureus2.plugins.utils.search.SearchProvider;

import com.aelitis.azureus.core.messenger.config.PlatformMetaSearchMessenger;
import com.aelitis.azureus.core.metasearch.*;
import com.aelitis.azureus.core.metasearch.impl.plugin.PluginEngine;
import com.aelitis.azureus.core.metasearch.impl.web.WebEngine;
import com.aelitis.azureus.core.metasearch.impl.web.rss.RSSEngine;
import com.aelitis.azureus.core.util.CopyOnWriteList;
import com.aelitis.azureus.core.vuzefile.VuzeFile;
import com.aelitis.azureus.core.vuzefile.VuzeFileComponent;
import com.aelitis.azureus.core.vuzefile.VuzeFileHandler;

public class 
MetaSearchImpl
	implements MetaSearch
{
	private static final String	CONFIG_FILE = "metasearch.config";
		
	private MetaSearchManagerImpl	manager;
	
	private CopyOnWriteList<EngineImpl> engines 	= new CopyOnWriteList<EngineImpl>();
	private Map<String,Long>			plugin_map	= new HashMap<String,Long>();
	
	private boolean config_dirty;
	
	private CopyOnWriteList<MetaSearchListener> 	listeners 	= new CopyOnWriteList<MetaSearchListener>();
	
	private TimerEventPeriodic	update_check_timer;
	
	private static final int 	UPDATE_CHECK_PERIOD		= 15*60*1000;
	private static final int	MIN_UPDATE_CHECK_SECS	= 10*60;
	
	private Object				MS_UPDATE_CONSEC_FAIL_KEY = new Object();
	
	protected 
	MetaSearchImpl(
		MetaSearchManagerImpl		_manager )
	{
		manager	= _manager;
		
		loadConfig();
	}
	
	protected MetaSearchManagerImpl
	getManager()
	{
		return( manager );
	}
	
	public Engine
	importFromBEncodedMap(
		Map<String,Object>		map )
	
		throws IOException
	{
		return( EngineImpl.importFromBEncodedMap( this, map )); 
	}
	
	public Engine
	importFromJSONString(
		int			type,
		long		id,
		long		last_updated,
		float		rank_bias,
		String		name,
		String		content )
	
		throws IOException
	{
		return( EngineImpl.importFromJSONString( this, type, id, last_updated, rank_bias, name, content ));
	}
	
	public EngineImpl
	importFromPlugin(
		String				_pid,
		SearchProvider		provider )
	
		throws IOException
	{
		synchronized( this ){

				// unfortunately pid can be internationalised and thus musn't be used as a key to
				// a bencoded-map as it can lead of nastyness. Delete any existing entries that have
				// got out of control
			
			Iterator<String>	it = plugin_map.keySet().iterator();
			
			while( it.hasNext()){
				
				if ( it.next().length() > 1024 ){
					
					Debug.out( "plugin_map corrupted, resetting" );
							
					plugin_map.clear();
					
					break;
				}
			}
			
			String pid = Base32.encode( _pid.getBytes( "UTF-8" ));
			
			Long	l_id = plugin_map.get( pid );
			
			long	id;
			
			if ( l_id == null ){
				
				id = manager.getLocalTemplateID();
						
				plugin_map.put( pid, new Long( id ));
						
				configDirty();

			}else{
				
				id = l_id.longValue();
			}
			
			EngineImpl engine = (EngineImpl)getEngine( id );
			
			if ( engine == null ){
				
				engine = new PluginEngine( this, id, provider );
				
				engine.setSource( Engine.ENGINE_SOURCE_LOCAL );
				
				engine.setSelectionState( Engine.SEL_STATE_MANUAL_SELECTED );
				
				addEngine( engine );
				
			}else{
				
				if ( engine instanceof PluginEngine ){
					
					((PluginEngine)engine).setProvider( provider );
					
				}else{
					
					Debug.out( "Inconsistent: plugin must be a PluginEngine!" );
					
					plugin_map.remove( pid );
					
					removeEngine( engine );
					
					throw( new IOException( "Inconsistent" ));
				}
			}
			
			return( engine );
		}	
	}
	
	public SearchProvider
	resolveProvider(
		PluginEngine	for_engine )
	{
		List<EngineImpl> l = engines.getList();

		for ( EngineImpl e: l ){
			
			if ( e instanceof PluginEngine ){
				
				PluginEngine pe = (PluginEngine)e;
				
				SearchProvider provider = pe.getProvider();
				
				if ( provider != null ){
					
					if ( pe.getName().equals( for_engine.getName())){
						
						return( provider );
					}
				}
			}
		}
		
		return( null );
	}
	
	public Engine 
	createRSSEngine(
		String		name,
		URL 		url )
	
		throws MetaSearchException 
	{
		EngineImpl engine = 
			new RSSEngine( 
					this, 
					manager.getLocalTemplateID(), 
					SystemTime.getCurrentTime(), 
					1.0f,
					name, 
					url.toExternalForm(), 
					false,
					WebEngine.AM_TRANSPARENT,
					null,
					new String[0] );
		
		engine.setSource( Engine.ENGINE_SOURCE_RSS );
		
		addEngine( engine, false );
				
		log( "Created RSS engine '" + url + "'" );
		
		return( engine );
	}
	
	protected void
	enableUpdateChecks()
	{
		synchronized( this ){
			
			if ( update_check_timer == null ){
				
				update_check_timer = SimpleTimer.addPeriodicEvent(
						"MS:updater",
						UPDATE_CHECK_PERIOD,
						new TimerEventPerformer()
						{
							public void 
							perform(
								TimerEvent event) 
							{
								checkUpdates();
							}
						});
			}
		}
	}
	
	protected void
	checkUpdates()
	{
		Iterator<EngineImpl> it = engines.iterator();
		
		while( it.hasNext()){
				
			EngineImpl	engine = (EngineImpl)it.next();
				
			String	update_url = engine.getUpdateURL();
			
			if ( update_url != null ){
				
				long	now				= SystemTime.getCurrentTime();
				
				long	last_check 		= engine.getLastUpdateCheck();
				
				if ( last_check > now ){
					
					last_check = now;
					
					engine.setLastUpdateCheck( now );
				}
				
				long	check_secs	= engine.getUpdateCheckSecs();
				
				if ( check_secs < MIN_UPDATE_CHECK_SECS ){
					
					log( "Engine '" + engine.getName() + "': Update check period too small (" + check_secs + " secs) adjusting to " + MIN_UPDATE_CHECK_SECS + ": " + engine.getName());
					
					check_secs = MIN_UPDATE_CHECK_SECS;
				}
				
				long	check_millis	= check_secs*1000;
				
				long	next_check		= last_check + check_millis;
				
				Object	consec_fails_o = engine.getUserData( MS_UPDATE_CONSEC_FAIL_KEY );
				
				int	consec_fails = consec_fails_o==null?0:((Integer)consec_fails_o).intValue();
				
				if ( consec_fails > 0 ){
					
					next_check += ( UPDATE_CHECK_PERIOD << consec_fails );
				}
				
				if ( next_check < now ){
				
					if ( updateEngine( engine )){
						
						consec_fails	= 0;
						
						engine.setLastUpdateCheck( now );
						
					}else{
						
						consec_fails++;
						
						if ( consec_fails > 3 ){
							
							consec_fails	= 0;
							
								// skip to next scheduled update time
							
							engine.setLastUpdateCheck( now );
						}
					}
					
					engine.setUserData( MS_UPDATE_CONSEC_FAIL_KEY, consec_fails==0?null:new Integer( consec_fails ));
				}
			}
		}
	}
	
	protected boolean
	updateEngine(
		EngineImpl		engine )
	{
		String	update_url = engine.getUpdateURL();

		int	pos = update_url.indexOf('?');
		
		if ( pos == -1 ){
			
			update_url += "?";
			
		}else{
			
			update_url += "&";
		}
		
		update_url += 	"az_template_uid=" + engine.getUID() + 
						"&az_template_version=" + engine.getVersion() +
						"&az_version=" + Constants.AZUREUS_VERSION +
					    "&az_locale=" + MessageText.getCurrentLocale().toString() +
					    "&az_rand=" + Math.abs( new Random().nextLong());
		
		log( "Engine " + engine.getName() + ": auto-update check via " + update_url );
		
		try{
			ResourceDownloaderFactory rdf = StaticUtilities.getResourceDownloaderFactory();
			
			ResourceDownloader url_rd = rdf.create( new URL( update_url ));
			
			ResourceDownloader rd = rdf.getMetaRefreshDownloader( url_rd );
			
			InputStream is = rd.download();
			
			try{
				Map<String,Object> map = BDecoder.decode( new BufferedInputStream( is ));
				
				log( "    update check reply: " + map );
				
					// reply is either "response" meaning "no update" and giving possibly changed update secs
					// or Vuze file with updated template
				
				Map<String,Object> response = (Map<String,Object>)map.get( "response" );
				
				if ( response != null ){
					
					Long	update_secs = (Long)response.get( "update_url_check_secs" );
					
					if ( update_secs == null ){
						
						engine.setLocalUpdateCheckSecs( 0 );
						
					}else{
						
						int	check_secs = update_secs.intValue();
						
						if ( check_secs < MIN_UPDATE_CHECK_SECS ){
							
							log( "    update check secs for to small, min is " + MIN_UPDATE_CHECK_SECS);
							
							check_secs = MIN_UPDATE_CHECK_SECS;
						}
							
						engine.setLocalUpdateCheckSecs( check_secs );
					}
					
					return( true );
					
				}else{
					
					VuzeFile vf = VuzeFileHandler.getSingleton().loadVuzeFile( map );
					
					if ( vf == null ){
						
						log( "    failed to decode vuze file" );
						
						return( false );
					}
										
					Engine[] updated_engines = manager.loadFromVuzeFile( vf );
					
					if ( updated_engines.length > 0 ){
						
						String	existing_uid = engine.getUID();
						
						boolean	found = false;
						
						String	engine_str = "";
						
						for (int i=0;i<updated_engines.length;i++){
							
							Engine updated_engine = updated_engines[i];
							
							engine_str += (i==0?"":",") + updated_engine.getName() + ": uid=" + updated_engine.getUID() + ",version=" + updated_engine.getVersion();
							
							if ( updated_engine.getUID().equals( existing_uid )){
								
								found	= true;
							}
						}
						
						if ( !found ){
							
							log( "    existing engine not found in updated set, deleting" );
							
							engine.delete();
							
						}
							
						log( "    update complete: new engines=" + engine_str );
						
					}else{
						
						log( "    no engines found in vuze file" );
					}
					
					return( true );
				}
			}finally{
				
				is.close();
			}
		}catch( Throwable e ){
			
			log( "    update check failed", e );
			
			return( false );
		}
	}
	
	public void 
	addEngine(
		Engine 	engine )
	{
		addEngine( (EngineImpl)engine, false );
	}
	
	public Engine 
	addEngine(
		long 		id )
	
		throws MetaSearchException 
	{
		try{

			PlatformMetaSearchMessenger.templateDetails details = PlatformMetaSearchMessenger.getTemplate( manager.getExtensionKey(), id );
		
			log( "Downloading definition of template " + id );
			log( details.getValue());
		
			if ( details.isVisible()){
			
				Engine engine = 
					importFromJSONString( 
						details.getType()==PlatformMetaSearchMessenger.templateDetails.ENGINE_TYPE_JSON?Engine.ENGINE_TYPE_JSON:Engine.ENGINE_TYPE_REGEX,
						details.getId(),
						details.getModifiedDate(),
						details.getRankBias(),
						details.getName(),
						details.getValue());
				
				engine.setSource( Engine.ENGINE_SOURCE_VUZE );
				engine.setSelectionState( Engine.SEL_STATE_DESELECTED );
				
				addEngine( engine );
				
				return( engine );
				
			}else{
				
				throw( new MetaSearchException( "Search template is not visible" ));
			}
		}catch( MetaSearchException e ){
			
			throw( e );
			
		}catch( Throwable e ){
		
			throw( new MetaSearchException( "Template load failed", e ));
		}	
	}
		
	public void 
	addEngine(
		EngineImpl 	new_engine,
		boolean		loading )
	{		
		boolean	add_op = true;
		
		synchronized( this ){
			
			Iterator<EngineImpl>	it = engines.iterator();
			
			while( it.hasNext()){
				
				Engine existing_engine = it.next();
				
				if ( existing_engine.getId() == new_engine.getId()){
					
					log( "Updating engine with same ID " + existing_engine.getId() + ": " + existing_engine.getName() + "/" + existing_engine.getUID());
					
					it.remove();
					
					new_engine.setUID( existing_engine.getUID());
					
					if ( existing_engine.sameLogicAs( new_engine )){
						
						new_engine.setVersion( existing_engine.getVersion());

					}else{
						
						new_engine.setVersion( existing_engine.getVersion() + 1 );
						
						log( "    new version=" + new_engine.getVersion());
					}
					 
					add_op = false;
					
				}else if ( existing_engine.getUID().equals( new_engine.getUID())){
					
					log( "Removing engine with same UID " + existing_engine.getUID() + "(" + existing_engine.getName() + ")" );
					
					it.remove();
				}
			}
			
			engines.add( new_engine );
		}
		
		if ( new_engine.getUpdateURL() != null ){
			
			enableUpdateChecks();
		}
		
		if ( !loading ){
			
			log( "Engine '" + new_engine.getName() + "' added" );
			
			saveConfig();
		
			Iterator<MetaSearchListener> it = listeners.iterator();
			
			while( it.hasNext()){
				
				MetaSearchListener listener = it.next();
				
				try{
					if ( add_op ){
						
						listener.engineAdded( new_engine );
						
					}else{
						
						listener.engineUpdated( new_engine );
					}
				}catch( Throwable e ){
					
					Debug.printStackTrace(e);
				}
			}
		}
	}
	
	public void 
	removeEngine(
		Engine 	engine )
	{
		if ( engines.remove((EngineImpl)engine )){
		
			log( "Engine '" + engine.getName() + "' removed" );
			
			saveConfig();
			
			Iterator<MetaSearchListener> it = listeners.iterator();
			
			while( it.hasNext()){
				
				try{
	
					it.next().engineRemoved( engine );
	
				}catch( Throwable e ){
					
					Debug.printStackTrace(e);
				}
			}
		}
	}
	
	public String
	getFUD()
	{
		List<EngineImpl> l = engines.getList();
		
		List<Long>	ids = new ArrayList<Long>();
		
		for ( EngineImpl engine: l ){
			
			if ( engine.getSource() == Engine.ENGINE_SOURCE_VUZE ){
				
				ids.add( engine.getId());
			}
		}
		
		Collections.sort( ids );
		
		String	fud = "";

		for ( Long id: ids ){
		
			fud += (fud.length()==0?"":",") +id; 
		}
		
		return( fud );
	}
	
	protected void
	addPotentialAssociation(
		EngineImpl		engine,
		String			key )
	{
		manager.addPotentialAssociation(engine, key);	
	}
	
	public Engine[] 
	getEngines(
		boolean		active_only,
		boolean		ensure_up_to_date )
	{
		if ( ensure_up_to_date ){
			
			manager.ensureEnginesUpToDate();
		}
		
		List<EngineImpl> l = engines.getList();
				
		List<EngineImpl> result;
		
		if ( active_only ){
			
			result = new ArrayList<EngineImpl>();
			
			for (int i=0;i<l.size();i++){
				
				EngineImpl	e = l.get(i);
				
				if ( e.isActive()){
					
					result.add( e );
				}
			}
		}else{
			
			result = l;
		}
		
		return( (Engine[])result.toArray( new Engine[ result.size() ]));
	}
	
	public Engine
	getEngine(
		long		id )
	{
		List<EngineImpl> l = engines.getList();
		
		for( int i=0;i<l.size();i++){
			
			Engine e = l.get(i);
			
			if ( e.getId() == id ){
				
				return( e );
			}
		}

		return( null );
	}
	
	public Engine
	getEngineByUID(
		String	uid )
	{
		List<EngineImpl> l = engines.getList();
		
		for( int i=0;i<l.size();i++){
			
			Engine e = l.get(i);
			
			if ( e.getUID().equals( uid )){
				
				return( e );
			}
		}

		return( null );
	}
	
	public int
	getEngineCount()
	{
		return( engines.size());
	}
	
	public Engine[] 
	search(
		final ResultListener 	original_listener,
		SearchParameter[] 		searchParameters,
		String					headers,
		int						max_results_per_engine )
	{
		return( search( original_listener, searchParameters, headers, new HashMap<String,String>(), max_results_per_engine ));
	}
	
	public Engine[] 
  	search(
  		final ResultListener 	original_listener,
  		SearchParameter[] 		searchParameters,
  		String					headers,
  		Map<String,String>		context,
  		int						max_results_per_engine )
  	{
  		return( search( null, original_listener, searchParameters, headers, context, max_results_per_engine ));
  	}
	
	public Engine[] 
	search(
		Engine[]				engines,
		final ResultListener 	listener,
		SearchParameter[] 		search_parameters,
		String					headers,
		final int				max_results_per_engine )
	{
		return( search( engines, listener, search_parameters, headers, new HashMap<String,String>(), max_results_per_engine ));
	}
	
	public void
	enginePreferred(
		Engine		engine )
	{
		Engine[] engines = getEngines( true, false );
		
		int	num_other_preferred = 0;
		
		for ( Engine e: engines ){
			
			if ( e.getId() == engine.getId()){
				
				e.setPreferredDelta( +1 );
				
			}else{
				
				if ( e.getPreferredWeighting() > 0 ){
					
					num_other_preferred++;
				}
			}
		}
				
		if ( num_other_preferred > 0 ){
			
			float negative_weighting = -1 / num_other_preferred;
		
			for ( Engine e: engines ){
			
				if ( e.getId() != engine.getId() && e.getPreferredWeighting() > 0 ){
				
					e.setPreferredDelta( negative_weighting );
				}
			}
		}
	}
	
	public Engine[] 
  	search(
  		Engine[]				engines,
  		final ResultListener 	original_listener,
  		SearchParameter[] 		searchParameters,
  		String					headers,
  		Map<String,String>		context,
  		final int				max_results_per_engine )
	{
		String batch_millis_str = context.get( Engine.SC_BATCH_PERIOD );
		
		final long batch_millis = batch_millis_str==null?0:Long.parseLong( batch_millis_str );
		
		String rem_dups_str = context.get( Engine.SC_REMOVE_DUP_HASH );
		
		final boolean rem_dups = rem_dups_str==null?false:rem_dups_str.equalsIgnoreCase( "true" );

		ResultListener	listener = 
			new ResultListener()
			{
					// 	single thread listener calls
			
				private AsyncDispatcher dispatcher = new AsyncDispatcher( 5000 );

				final private Map<Engine,List<Result[]>>	pending_results = new HashMap<Engine,List<Result[]>>();
				
				final private Map<Engine,Set<String>>	result_hashes = new HashMap<Engine, Set<String>>();
				
				public void
				contentReceived(
					final Engine engine, 
					final String content ) 
				{
					dispatcher.dispatch(
							new AERunnable()
							{
								public void
								runSupport()
								{
									original_listener.contentReceived( engine, content );
								}
							});
				}
				
				public void 
				matchFound(
					final Engine 	engine, 
					final String[] 	fields )
				{
					dispatcher.dispatch(
							new AERunnable()
							{
								public void
								runSupport()
								{
									original_listener.matchFound( engine, fields );
								}
							});	
				}
				
				public void 
				resultsReceived(
					final Engine 	engine,
					final Result[] 	results )
				{
					dispatcher.dispatch(
						new AERunnable()
						{
							public void
							runSupport()
							{
								Result[] results_to_return = null;
								
								if ( batch_millis > 0 ){
									
									List<Result[]> list = pending_results.get( engine );
																		
									if ( list == null ){
																			
										results_to_return = results;
										
										pending_results.put( engine, new ArrayList<Result[]>());
										
										new DelayedEvent(
											"SearchBatcher",
											batch_millis,
											new AERunnable()
											{
												public void 
												runSupport() 
												{
													dispatcher.dispatch(
														new AERunnable()
														{
															public void 
															runSupport() 
															{
																batchResultsComplete( engine );
															}
														});
												}
											});
									}else{
																															
										list.add( results );
									}
								}else{
								
									results_to_return = results;
								}
								
								if ( results_to_return != null ){
									
									results_to_return = truncateResults( engine, results_to_return, max_results_per_engine );
									
									original_listener.resultsReceived( engine, results_to_return );
								}
							}
						});
				}
			
				public void 
				resultsComplete(
					final Engine engine )
				{
					dispatcher.dispatch(
							new AERunnable()
							{
								public void
								runSupport()
								{
									if ( batch_millis > 0 ){

										batchResultsComplete( engine );
									}
									
									original_listener.resultsComplete( engine );
								}
							});
				}
			
				protected void
				batchResultsComplete(
					Engine engine )
				{
					List<Result[]> list = pending_results.remove( engine );
					
					if ( list != null ){
						
						List<Result> x = new ArrayList<Result>();
						
						for ( Result[] y: list ){
							
							x.addAll( Arrays.asList( y ));
						}
						
						Result[] results = x.toArray( new Result[ x.size()]);
					
						results = truncateResults( engine, results, max_results_per_engine );
					
						original_listener.resultsReceived( engine, results );
					}
				}
				
				protected Result[]
             	truncateResults(
             		Engine		engine,
             		Result[] 	a_results,
             		int			max )
             	{
					Set<String>	hash_set = result_hashes.get( engine );
					
					if ( hash_set == null ){
						
						hash_set = new HashSet<String>();
						
						result_hashes.put( engine, hash_set );
					}
						
					List<Result>	results = new ArrayList<Result>( a_results.length );
					
					for ( Result r: a_results ){
							
						String name = r.getName();
							
						if ( name == null || name.trim().length() == 0 ){
								
							continue;
						}
					
						if ( rem_dups ){

							String hash = r.getHash();
							
							if ( 	hash == null ||
									hash.length() == 0 ){
								
								results.add( r );
								
							}else{
								
								if ( !hash_set.contains( hash )){
									
									results.add( r );
									
									hash_set.add( hash );
								}
							}
						}else{
							
							results.add( r );
						}
					}
					
             		if ( max < results.size() ){
             		
             			log( "Truncating search results for " + engine.getName() + " from " + results.size() + " to " + max );
             			
             			Collections.sort(
             				results,
             				new Comparator<Result>()
             				{
             					Map<Result,Float>	ranks = new HashMap<Result, Float>();
             					
             					public int 
             					compare(
             						Result r1, 
             						Result r2) 
             					{						
             						Float	rank1 = (Float)ranks.get(r1);
             						
             						if ( rank1 == null ){	
             							rank1 = new Float(r1.getRank());
             							ranks.put( r1, rank1 );
             						}
             						
             						Float	rank2 = (Float)ranks.get(r2);
             						
             						if ( rank2 == null ){	
             							rank2 = new Float(r2.getRank());
             							ranks.put( r2, rank2 );
             						}
             						
             						return( -rank1.compareTo( rank2 ));
             					}
             				});
             		
             			Result[] x = new Result[max];
             			
             			int	pos = 0;
             			
             			while( pos < max ){
             			
             				x[pos] = results.get( pos );
             				
             				pos++;
             			}
             			
             			return( x );
             			
             		}else{
             			
             			return( results.toArray( new Result[ results.size()] ));
             		}
             	}
				
				public void 
				engineFailed(
					final Engine 	engine,
					final Throwable	e )
				{
					dispatcher.dispatch(
							new AERunnable()
							{
								public void
								runSupport()
								{
									original_listener.engineFailed( engine, e );
								}
							});
				}
				
				public void 
				engineRequiresLogin(
					final Engine 	engine,
					final Throwable	e )
				{
					dispatcher.dispatch(
							new AERunnable()
							{
								public void
								runSupport()
								{
									original_listener.engineRequiresLogin( engine, e );
								}
							});
				}
			};
			
		SearchExecuter se = new SearchExecuter( context, listener );
		
		if ( engines == null ){
			
			engines = getEngines( true, true );
		}
		
		String	engines_str = "";
		
		for (int i=0;i<engines.length;i++){
			
			engines_str += (i==0?"":",") + engines[i].getId();
		}
		
		log( "Search: engines=" + engines_str );
		
		for (int i=0;i<engines.length;i++){
			
			se.search( engines[i], searchParameters, headers, max_results_per_engine );
		}
		
		return( engines );
	}
	
	public void
	exportEngines(
		File	target )
	
		throws MetaSearchException
	{
		Engine[] engines = getEngines( true, false );
		
		VuzeFile	vf = VuzeFileHandler.getSingleton().create();
		
		for ( Engine engine: engines ){
		
			try{
				vf.addComponent(
					VuzeFileComponent.COMP_TYPE_METASEARCH_TEMPLATE,
					engine.exportToBencodedMap());
				
			}catch( IOException e ){
				
				Debug.out( e );
			}
			
		}
		
		try{
			vf.write( target );
			
		}catch( IOException e ){
			
			throw( new MetaSearchException( "Failed to write file", e ));
		}
	}
	
	public void
	addListener(
		MetaSearchListener		listener )
	{
		listeners.add( listener );
	}
	
	public void
	removeListener(
		MetaSearchListener		listener )
	{
		listeners.remove( listener );
	}
	
	protected void
	loadConfig()
	{
		log( "Loading configuration" );
		
		synchronized( this ){
			
			Map<String,Object> map = FileUtil.readResilientConfigFile( CONFIG_FILE );
			
			List<Map<String,Object>>	l_engines = (List<Map<String,Object>>)map.get( "engines" );
			
			if( l_engines != null ){
				
				for (int i=0;i<l_engines.size();i++){
					
					Map<String,Object>	m = (Map<String,Object>)l_engines.get(i);
					
					try{
						Engine e = importFromBEncodedMap( m );
						
						addEngine( (EngineImpl)e, true );
						
						log( "    loaded " + e.getString());
						
					}catch( Throwable e ){
						
						log( "Failed to import engine from " + m, e );
					}
				}
			}
			
			Map<String,Long>	p_map = (Map<String,Long>)map.get( "plugin_map" );
			
			if ( p_map != null ){
				
				plugin_map = p_map;
			}
		}
		
		if ( update_check_timer != null ){
			
			new AsyncDispatcher().dispatch(
					new AERunnable()
					{
						public void 
						runSupport() 
						{
							checkUpdates();
						}
					});
		}
	}
	
	protected void
	configDirty()
	{
		synchronized( this ){
			
			if ( config_dirty ){
				
				return;
			}
			
			config_dirty = true;
		
			new DelayedEvent( 
				"MetaSearch:save", 5000,
				new AERunnable()
				{
					public void 
					runSupport() 
					{
						synchronized( this ){
							
							if ( !config_dirty ){

								return;
							}
							
							saveConfig();
						}	
					}
				});
		}
	}
	
	protected void
	saveConfig()
	{
		log( "Saving configuration" );
		
		synchronized( this ){
			
			config_dirty = false;
			
			Map<String,Object> map = new HashMap<String, Object>();
			
			List<Map<String,Object>>	l_engines = new ArrayList<Map<String,Object>>();
			
			map.put( "engines", l_engines );
			
			Iterator<EngineImpl>	it = engines.iterator();
			
			while( it.hasNext()){
				
				Engine e = it.next();
			
				try{
					
					l_engines.add( e.exportToBencodedMap());
					
				}catch( Throwable f ){
					
					log( "Failed to export engine " + e.getName(), f );
				}
			}
			
			if ( plugin_map != null ){
				
				map.put( "plugin_map", plugin_map );
			}
			
			FileUtil.writeResilientConfigFile( CONFIG_FILE, map );
		}
	}
	
	protected void
	log(
		String	str )
	{
		manager.log( "search :"  + str );
	}
	
	protected void
	log(
		String		str,
		Throwable 	e )
	{
		manager.log( "search :"  +  str, e );
	}
	
	protected void
	generate(
		IndentWriter		writer )
	{
		Iterator<EngineImpl> it = engines.iterator();
		
		while( it.hasNext()){
				
			EngineImpl	e = it.next();
			
			writer.println( e.getString( true ));
		}	
	}
}
