/*
 * Created on 16-Mar-2006
 * Created by Paul Gardner
 * Copyright (C) 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.core.speedmanager.impl;

import java.io.File;
import java.net.InetSocketAddress;
import java.util.*;

import org.gudy.azureus2.core3.config.COConfigurationManager;
import org.gudy.azureus2.core3.config.ParameterListener;
import org.gudy.azureus2.core3.util.AEDiagnostics;
import org.gudy.azureus2.core3.util.AEDiagnosticsEvidenceGenerator;
import org.gudy.azureus2.core3.util.AEDiagnosticsLogger;
import org.gudy.azureus2.core3.util.AERunnable;
import org.gudy.azureus2.core3.util.AESemaphore;
import org.gudy.azureus2.core3.util.AsyncDispatcher;
import org.gudy.azureus2.core3.util.Constants;
import org.gudy.azureus2.core3.util.Debug;
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.SystemProperties;
import org.gudy.azureus2.core3.util.TimerEvent;
import org.gudy.azureus2.core3.util.TimerEventPerformer;

import com.aelitis.azureus.core.AzureusCore;
import com.aelitis.azureus.core.AzureusCoreLifecycleAdapter;
import com.aelitis.azureus.core.dht.speed.DHTSpeedTester;
import com.aelitis.azureus.core.dht.speed.DHTSpeedTesterContact;
import com.aelitis.azureus.core.dht.speed.DHTSpeedTesterContactListener;
import com.aelitis.azureus.core.dht.speed.DHTSpeedTesterListener;
import com.aelitis.azureus.core.networkmanager.admin.NetworkAdmin;
import com.aelitis.azureus.core.networkmanager.admin.NetworkAdminASN;
import com.aelitis.azureus.core.networkmanager.admin.NetworkAdminPropertyChangeListener;
import com.aelitis.azureus.core.speedmanager.SpeedManager;
import com.aelitis.azureus.core.speedmanager.SpeedManagerAdapter;
import com.aelitis.azureus.core.speedmanager.SpeedManagerLimitEstimate;
import com.aelitis.azureus.core.speedmanager.SpeedManagerListener;
import com.aelitis.azureus.core.speedmanager.SpeedManagerPingMapper;
import com.aelitis.azureus.core.speedmanager.SpeedManagerPingSource;
import com.aelitis.azureus.core.speedmanager.impl.v1.SpeedManagerAlgorithmProviderV1;
import com.aelitis.azureus.core.speedmanager.impl.v2.SpeedManagerAlgorithmProviderV2;
import com.aelitis.azureus.core.util.CopyOnWriteList;


public class 
SpeedManagerImpl 
	implements SpeedManager, SpeedManagerAlgorithmProviderAdapter, AEDiagnosticsEvidenceGenerator
{
	protected static final int UPDATE_PERIOD_MILLIS	= 5000;

	private static final int CONTACT_NUMBER		= 3;
	private static final int CONTACT_PING_SECS	= UPDATE_PERIOD_MILLIS/1000;
	
	
		// keep history for 1 hour
	
	private static final int LONG_PERIOD_SECS	= 60*60;
	
	private static final int LONG_PERIOD_TICKS 	= LONG_PERIOD_SECS / CONTACT_PING_SECS;
	
	private static final int SHORT_ESTIMATE_SECS	= 15;
	private static final int MEDIUM_ESTIMATE_SECS	= 150;
	
	static final int SHORT_ESTIMATE_SAMPLES		= SHORT_ESTIMATE_SECS/CONTACT_PING_SECS;
	static final int MEDIUM_ESTIMATE_SAMPLES	= MEDIUM_ESTIMATE_SECS/CONTACT_PING_SECS;

	private static final int SAVE_PERIOD_SECS	= 15*60;
	private static final int SAVE_PERIOD_TICKS 	= SAVE_PERIOD_SECS / CONTACT_PING_SECS;

	private static final int SPEED_AVERAGE_PERIOD	= 3000;
	
		// config items start
	
	private static boolean				DEBUG;

    public  static final String CONFIG_VERSION_STR      = "Auto_Upload_Speed_Version_String"; //Shadow of CONFIG_VERSION for config.
    public  static final String	CONFIG_VERSION			= "Auto Upload Speed Version";
	private static final String	CONFIG_AVAIL			= "AutoSpeed Available";	// informative only

	private static final String	CONFIG_DEBUG			= "Auto Upload Speed Debug Enabled";
	
	
	private static final String[]	CONFIG_PARAMS = {
		CONFIG_DEBUG };
		
	static{
		COConfigurationManager.addAndFireParameterListeners(
				CONFIG_PARAMS,
				new ParameterListener()
				{
					public void 
					parameterChanged(
						String parameterName )
					{						
						DEBUG = COConfigurationManager.getBooleanParameter( CONFIG_DEBUG );
					}
				});
		
	}
	
	private static boolean	emulated_ping_source;
	
		// config end
	
	
	private AzureusCore			core;
	private DHTSpeedTester		speed_tester;
	private SpeedManagerAdapter	adapter;
	
	private SpeedManagerAlgorithmProvider	provider = new nullProvider();
	
	
	private	int							provider_version	= -1;
	private boolean						enabled;

    private Map							contacts	= new HashMap();
	private volatile int				total_contacts;
	private pingContact[]				contacts_array	= new pingContact[0];
	
	private Object	original_limits;
	
	private AsyncDispatcher	dispatcher = new AsyncDispatcher();

	private SpeedManagerPingMapperImpl		ping_mapper;

	private SpeedManagerPingMapperImpl[] 	ping_mappers;
	
	private CopyOnWriteList		transient_mappers = new CopyOnWriteList();

	private AEDiagnosticsLogger	logger;
	
	private String		asn;
	
	private CopyOnWriteList	listeners = new CopyOnWriteList();
	
	public
	SpeedManagerImpl(
		AzureusCore			_core,
		SpeedManagerAdapter	_adapter )
	{
		core			= _core;
		adapter			= _adapter;

		AEDiagnostics.addEvidenceGenerator( this );
		
		logger = AEDiagnostics.getLogger( "SpeedMan" );
		
		ping_mapper	= new SpeedManagerPingMapperImpl( this, "Var", LONG_PERIOD_TICKS, true, false );

		if ( Constants.isCVSVersion()){
			
			SpeedManagerPingMapperImpl		pm2 	= new SpeedManagerPingMapperImpl( this, "Abs", LONG_PERIOD_TICKS, false, false );

			ping_mappers = new SpeedManagerPingMapperImpl[]{ pm2, ping_mapper };
			
		}else{
			
			ping_mappers = new SpeedManagerPingMapperImpl[]{ ping_mapper }; 
		}

		final File	config_dir = new File( SystemProperties.getUserPath(), "net" );
		
		if ( !config_dir.exists()){
			
			config_dir.mkdirs();
		}
		
		NetworkAdmin.getSingleton().addAndFirePropertyChangeListener(
			new NetworkAdminPropertyChangeListener()
			{
				public void
				propertyChanged(
					String		property )
				{
					if ( property == NetworkAdmin.PR_AS ){
						
					    NetworkAdminASN net_asn = NetworkAdmin.getSingleton().getCurrentASN();

						String	as = net_asn.getAS();
						
						if ( as.length() == 0 ){
							
							as = "default";
						}
						
						File history = new File( config_dir, "pm_" + FileUtil.convertOSSpecificChars( as ) + ".dat" );
						
						ping_mapper.loadHistory( history );
						
						asn = net_asn.getASName();
						
						if ( asn.length() == 0 ){
							
							asn = "Unknown";
						}
						
						informListeners( SpeedManagerListener.PR_ASN );
					}
				}
			});
		
		core.addLifecycleListener(
			new AzureusCoreLifecycleAdapter()
			{
				public void
				stopping(
					AzureusCore		core )
				{
					ping_mapper.saveHistory();
				}	
			});

		COConfigurationManager.addAndFireParameterListener( 
			CONFIG_VERSION,
			new ParameterListener()
			{
				public void
				parameterChanged(
					final String name )
				{
					dispatcher.dispatch(
						new AERunnable()
						{
							public void
							runSupport()
							{
								boolean	do_reset = provider_version == -1;
								
								int version = COConfigurationManager.getIntParameter( name );
								
								if ( version != provider_version ){
									
									provider_version = version;
									
									if ( isEnabled()){
										
										setEnabledSupport( false );
										
										setEnabledSupport( true );
									}
								}
								
								if ( do_reset ){
									
									enableOrAlgChanged();
								}
							}
						});
				}
			});
		
		COConfigurationManager.setParameter( CONFIG_AVAIL, false );
		
		SimpleTimer.addPeriodicEvent(
			"SpeedManager:timer",
			UPDATE_PERIOD_MILLIS,
			new TimerEventPerformer()
			{
				private int	tick_count;
				
				public void 
				perform(
					TimerEvent event ) 
				{
						// if enabled the ping stream drives the stats update for the ping mappers
						// When not enabled we do it here instead
					
					if ( !enabled || contacts_array.length == 0 ){
											
						int	x	= (adapter.getCurrentDataUploadSpeed(SPEED_AVERAGE_PERIOD) + adapter.getCurrentProtocolUploadSpeed(SPEED_AVERAGE_PERIOD));
						int	y 	= (adapter.getCurrentDataDownloadSpeed(SPEED_AVERAGE_PERIOD) + adapter.getCurrentProtocolDownloadSpeed(SPEED_AVERAGE_PERIOD));
						
						for (int i=0;i<ping_mappers.length;i++){
							
							ping_mappers[i].addSpeed( x, y );
						}
					}
					
					tick_count++;
					
					if ( tick_count % SAVE_PERIOD_TICKS == 0 ){
						
						ping_mapper.saveHistory();
					}
				}
			});
		
		emulated_ping_source	= false;
		
		if ( emulated_ping_source ){
			
			Debug.out( "Emulated ping source!!!!" );
		
			setSpeedTester( new TestPingSourceRandom( this ));
		}
	}
	
	public SpeedManager
	getSpeedManager()
	{
		return( this );
	}
	
	public String
	getASN()
	{
		return( asn );
	}
	
	public SpeedManagerLimitEstimate
	getEstimatedUploadCapacityBytesPerSec()
	{
		return( ping_mapper.getEstimatedUploadCapacityBytesPerSec());	
	}
	
	public void
	setEstimatedUploadCapacityBytesPerSec(
		int		bytes_per_sec,
		float	metric )
	{
		ping_mapper.setEstimatedUploadCapacityBytesPerSec( bytes_per_sec, metric );	
	}

	public SpeedManagerLimitEstimate
	getEstimatedDownloadCapacityBytesPerSec()
	{
		return( ping_mapper.getEstimatedDownloadCapacityBytesPerSec());	
	}
	
	public void
	setEstimatedDownloadCapacityBytesPerSec(
		int		bytes_per_sec,
		float	metric )
	{
		ping_mapper.setEstimatedDownloadCapacityBytesPerSec( bytes_per_sec, metric );	
	}
	
	public void
	reset()
	{
		ping_mapper.reset();
	}
	
	protected void
	enableOrAlgChanged()
	{
		total_contacts		= 0;
		
		SpeedManagerAlgorithmProvider	old_provider = provider;
		
		if ( provider_version == 1 ){
			
			if ( !( provider instanceof SpeedManagerAlgorithmProviderV1 )){
				
				provider = new SpeedManagerAlgorithmProviderV1( this );
			}
		}else if ( provider_version == 2 ){
			
			if ( !( provider instanceof SpeedManagerAlgorithmProviderV2 )){
				
				provider = new SpeedManagerAlgorithmProviderV2( this );
			}
            
        }else if ( provider_version == 3 ){

            provider = new SpeedManagerAlgorithmProviderV2( this );

        }else{
						
			Debug.out( "Unknown provider version " + provider_version );
			
			if ( !( provider instanceof nullProvider )){
				
				provider = new nullProvider();
			}
		}
		
		if ( old_provider != provider ){
		
			log( "Algorithm set to " + provider.getClass().getName());
		}
		
		if ( old_provider != null ){
			
			old_provider.destroy();
		}
		
		provider.reset();
	}
	
	public SpeedManagerPingMapper
	createTransientPingMapper()
	{
		SpeedManagerPingMapper res = new SpeedManagerPingMapperImpl( this, "Transient", LONG_PERIOD_TICKS, true, true );
		
		transient_mappers.add( res );
		
		if ( transient_mappers.size() > 32 ){
			
			Debug.out( "Transient mappers are growing too large" );
		}
		
		return( res );
	}
	
	protected void
	destroy(
		SpeedManagerPingMapper	mapper )
	{
		transient_mappers.remove( mapper );
	}
	
	public void
	setSpeedTester(
		DHTSpeedTester	_tester )
	{
		if ( speed_tester != null ){
			
			if ( !emulated_ping_source ){
			
				Debug.out( "speed tester already set!" );
			}
			
			return;
		}
		
		COConfigurationManager.setParameter( CONFIG_AVAIL, true );

		speed_tester	= _tester; 
				
		speed_tester.addListener(
				new DHTSpeedTesterListener()
				{
					private DHTSpeedTesterContact[]	last_contact_group = new DHTSpeedTesterContact[0];
										
					public void 
					contactAdded(
						DHTSpeedTesterContact contact )
					{
						if ( core.getInstanceManager().isLANAddress(contact.getAddress().getAddress())){
							
							contact.destroy();
							
						}else{
							log( "activePing: " + contact.getString());
							
							contact.setPingPeriod( CONTACT_PING_SECS );
							
							synchronized( contacts ){
								
								pingContact	source = new pingContact( contact );
								
								contacts.put( contact, source );
								
								contacts_array = new pingContact[ contacts.size() ];
								
								contacts.values().toArray( contacts_array );
							
								total_contacts++;
							
								provider.pingSourceFound( source, total_contacts > CONTACT_NUMBER );
							}
							
							contact.addListener(
								new DHTSpeedTesterContactListener()
								{
									public void
									ping(
										DHTSpeedTesterContact	contact,
										int						round_trip_time )
									{
									}
									
									public void
									pingFailed(
										DHTSpeedTesterContact	contact )
									{
									}
									
									public void
									contactDied(
										DHTSpeedTesterContact	contact )
									{
										log( "deadPing: " + contact.getString());
										
										synchronized( contacts ){
											
											pingContact source = (pingContact)contacts.remove( contact );
											
											if ( source != null ){
												
												contacts_array = new pingContact[ contacts.size() ];
												
												contacts.values().toArray( contacts_array );
												
												provider.pingSourceFailed( source );
											}
										}
									}
								});
						}
					}
					
					public void
					resultGroup(
						DHTSpeedTesterContact[]	st_contacts,
						int[]					round_trip_times )
					{
						if ( !enabled ){
							
							for (int i=0;i<st_contacts.length;i++){
								
								st_contacts[i].destroy();
							}
							
							return;
						}
						
						boolean	sources_changed = false;
						
						for (int i=0;i<st_contacts.length;i++){
							
							boolean	found = false;
							
							for (int j=0;j<last_contact_group.length;j++){
							
								if ( st_contacts[i] == last_contact_group[j] ){
									
									found = true;
									
									break;
								}
							}
							
							if ( !found ){
									
								sources_changed = true;
								
								break;
							}
						}
						
						last_contact_group = st_contacts;
						
						pingContact[]	sources = new pingContact[st_contacts.length];
					
						boolean	miss = false;
						
						int	worst_value	= -1;
						
						int	num_values	= 0;
						int	total		= 0;
						
						synchronized( contacts ){

							for (int i=0;i<st_contacts.length;i++){
								
								pingContact source = sources[i] = (pingContact)contacts.get( st_contacts[i] );
								
								if ( source != null ){
									
									int	rtt = round_trip_times[i];
									
									if ( rtt > 0 ){
										
										if ( rtt > worst_value ){
											
											worst_value = rtt;
										}
										
										num_values++;
										
										total += rtt;
									}
									
									source.setPingTime( rtt );
									
								}else{
									
									miss = true;
								}
							}
						}
						
						if ( miss ){
							
							Debug.out( "Auto-speed: source missing" );
							
						}else{
						
							provider.calculate( sources );
							
								// remove worst value if we have > 1
							
							if ( num_values > 1 ){
								
								total -= worst_value;
								num_values--;
							}

							if ( num_values> 0 ){
								
								addPingHistory( total/num_values, sources_changed );
							}
						}
					}
				});
		
		SimpleTimer.addPeriodicEvent(
			"SpeedManager:stats",
			SpeedManagerAlgorithmProvider.UPDATE_PERIOD_MILLIS,
			new TimerEventPerformer()
			{
				public void
				perform(
					TimerEvent	event )
				{
					if ( enabled ){
					
						provider.updateStats();
					}
				}
			});
	}
	


	protected void
	addPingHistory(
		int			rtt,
		boolean		re_base )
	{
		int	x	= (adapter.getCurrentDataUploadSpeed(SPEED_AVERAGE_PERIOD) + adapter.getCurrentProtocolUploadSpeed(SPEED_AVERAGE_PERIOD));
		int	y 	= (adapter.getCurrentDataDownloadSpeed(SPEED_AVERAGE_PERIOD) + adapter.getCurrentProtocolDownloadSpeed(SPEED_AVERAGE_PERIOD));
		
		for (int i=0;i<ping_mappers.length;i++){
			
			ping_mappers[i].addPing( x, y, rtt, re_base );
		}
		
		Iterator it = transient_mappers.iterator();
		
		while( it.hasNext()){
			
			((SpeedManagerPingMapperImpl)it.next()).addPing( x, y, rtt, re_base );
		}
	}
	
	public boolean
	isAvailable()
	{
		return( speed_tester != null );
	}
		
	public void
	setEnabled(
		final boolean		_enabled )
	{
			// unfortunately we need this to run synchronously as the caller may be disabling it
			// and then setting speed limits in which case we can't go async and restore the
			// original values below and overwrite the new limit...
		
		final AESemaphore	sem = new AESemaphore( "SpeedManagerImpl.setEnabled" );
		
			// single thread enable/disable (and derivative reset) ops
		
		dispatcher.dispatch(
			new AERunnable()
			{
				public void
				runSupport()
				{
					try{
						setEnabledSupport( _enabled );
						
					}finally{
						
						sem.release();
					}
				}
			});
		
		if ( !sem.reserve( 10000 )){
			
			Debug.out( "operation didn't complete in time" );
		}
	}
	
	protected void
	setEnabledSupport(
		boolean	_enabled )
	{
		if ( enabled != _enabled ){
			
			log( "Enabled set to " + _enabled );
			
			if ( _enabled ){
				
				original_limits	= adapter.getLimits();
				
			}else{
				
				ping_mapper.saveHistory();
			}
			
			enableOrAlgChanged();
			
			enabled	= _enabled;
			
			if ( speed_tester != null ){
				
				speed_tester.setContactNumber( enabled?CONTACT_NUMBER:0);
			}
			
			if ( !enabled ){
									
				adapter.setLimits( original_limits, true, provider.getAdjustsDownloadLimits());
			}
		}
	}
	
	public boolean
	isEnabled()
	{
		return( enabled );
	}
	
	public DHTSpeedTester
	getSpeedTester()
	{
		return( speed_tester );
	}
	
	public SpeedManagerPingSource[]
	getPingSources()
	{
		return( contacts_array );
	}
	
	public SpeedManagerPingMapper
	getActiveMapper()
	{
		return( ping_mapper );
	}
	
	public SpeedManagerPingMapper
	getPingMapper()
	{
		return( getActiveMapper());
	}
	
	public SpeedManagerPingMapper[]
	getMappers()
	{
		return( ping_mappers );
	}
	
	public int
	getIdlePingMillis()
	{
		return( provider.getIdlePingMillis());
	}
	
	public int
	getCurrentPingMillis()
	{
		return( provider.getCurrentPingMillis());
	}
	
	public int
	getMaxPingMillis()
	{
		return( provider.getMaxPingMillis());
	}
	
		/**
		 * Returns the current view of when choking occurs
		 * @return speed in bytes/sec
		 */
	
	public int
	getCurrentChokeSpeed()
	{
		return( provider.getCurrentChokeSpeed());
	}
	
	public int
	getMaxUploadSpeed()
	{
		return( provider.getMaxUploadSpeed());
	}

	public int
	getCurrentUploadLimit()
	{
		return( adapter.getCurrentUploadLimit());
	}
	
	public void
	setCurrentUploadLimit(
		int		bytes_per_second )
	{
		if ( enabled ){
			
			adapter.setCurrentUploadLimit( bytes_per_second );
		}
	}
	
	public int
	getCurrentDownloadLimit()
	{
		return( adapter.getCurrentDownloadLimit());
	}

	public void 
	setCurrentDownloadLimit(
		int bytes_per_second) 
	{
		if ( enabled ){

			adapter.setCurrentDownloadLimit( bytes_per_second );
		}
	}
		
	public int
	getCurrentProtocolUploadSpeed()
	{
		return( adapter.getCurrentProtocolUploadSpeed(-1));
	}
	
	public int
	getCurrentDataUploadSpeed()
	{
		return( adapter.getCurrentDataUploadSpeed(-1));
	}
	
    public int
    getCurrentDataDownloadSpeed()
    {
        return( adapter.getCurrentDataDownloadSpeed(-1) );
    }

    public int
    getCurrentProtocolDownloadSpeed()
    {
        return( adapter.getCurrentProtocolDownloadSpeed(-1) );
    }

	public void
	setLoggingEnabled(
		boolean	enabled )
	{
		COConfigurationManager.setParameter( CONFIG_DEBUG, enabled );
	}
	
	public void
	log(
		String		str )
	{
		logger.log( str );
	}
	
	protected void
	informDownCapChanged()
	{
		informListeners( SpeedManagerListener.PR_DOWN_CAPACITY );
	}
	
	protected void
	informUpCapChanged()
	{
		informListeners( SpeedManagerListener.PR_UP_CAPACITY );
	}
	
	protected void
	informListeners(
		int		type )
	{
		Iterator	it = listeners.iterator();
		
		while( it.hasNext()){
			
			try{
				((SpeedManagerListener)it.next()).propertyChanged( type );
				
			}catch( Throwable e ){
				
				Debug.printStackTrace(e);
			}
		}
	}
	
	public void
	addListener(
		SpeedManagerListener		l )
	{
		listeners.add( l );
	}
	
	public void
	removeListener(
		SpeedManagerListener		l )
	{
		listeners.remove( l );
	}
	
	public void 
	generate(
		IndentWriter writer) 
	{
		writer.println( "SpeedManager: enabled=" + enabled + ",provider=" + provider );
		
		try{
			writer.indent();
			
			ping_mapper.generateEvidence( writer );
			
		}finally{
			
			writer.exdent();
		}
	}
	
	protected class
	pingContact
		implements SpeedManagerPingSource
	{
		private DHTSpeedTesterContact	contact;
		
		private int	ping_time;
		
		protected
		pingContact(
			DHTSpeedTesterContact	_contact )
		{
			contact	= _contact;
		}
		
		protected void
		setPingTime(
			int		time )
		{
			ping_time = time;
		}
		
		public InetSocketAddress
		getAddress()
		{
			return( contact.getAddress());	
		}
		
		public int
		getPingTime()
		{
			return( ping_time );
		}
		
		public void
		destroy()
		{
			contact.destroy();
		}
	}
	
	protected class
	SMUnlimited
		implements SpeedManagerAlgorithmProvider
	{
		private int	good_signals;
		
		public void 
		destroy() 
		{
		}
		
		public void
		reset()
		{
			adapter.setCurrentDownloadLimit( 0 );
			adapter.setCurrentUploadLimit( 0 );
		}
		
		public void
		updateStats()
		{
		}
		
		public void
		pingSourceFound(
			SpeedManagerPingSource		source,
			boolean						is_replacement )
		{
		}
		
		public void
		pingSourceFailed(
			SpeedManagerPingSource		source )
		{
		}
				
		public void
		calculate(
			SpeedManagerPingSource[]	sources )
		{
				// trivial test implementation
			
			SpeedManagerLimitEstimate est = ping_mapper.getEstimatedUploadLimit( true );
			
			if ( est != null ){
				
				double	metric_rating = ping_mapper.getCurrentMetricRating();
				
				if ( metric_rating == 1 ){
				
					good_signals++;
					
				}else{
					
					good_signals = 0;
				}
				
				if ( metric_rating == -1 ){
					
					adapter.setCurrentUploadLimit( est.getBytesPerSec() + (good_signals < 3?-1024:1024 ));
					
				}else if ( metric_rating <= 0 ){
						
					adapter.setCurrentUploadLimit( est.getBytesPerSec() + 1024 );
						
				}else{
					
					adapter.setCurrentUploadLimit( est.getBytesPerSec() + 5*1024);

				}
			}
		}
				
		public int
		getIdlePingMillis()
		{
			return( 0 );
		}
		
		public int
		getCurrentPingMillis()
		{
			return( 0 );
		}
		
		public int
		getMaxPingMillis()
		{
			return( 0 );
		}
				
		public int
		getCurrentChokeSpeed()
		{
			return( 0 );
		}
		
		public int
		getMaxUploadSpeed()
		{
			return( 0 );
		}
			
		public boolean
		getAdjustsDownloadLimits()
		{
			return( true );
		}
	}
	
	protected class
	nullProvider
		implements SpeedManagerAlgorithmProvider
	{		
		public void
		reset()
		{
		}
		
		public void 
		destroy() 
		{
		}
		
		public void
		updateStats()
		{
		}
		
		public void
		pingSourceFound(
			SpeedManagerPingSource		source,
			boolean						is_replacement )
		{
		}
		
		public void
		pingSourceFailed(
			SpeedManagerPingSource		source )
		{
		}
				
		public void
		calculate(
			SpeedManagerPingSource[]	sources )
		{
		}
				
		public int
		getIdlePingMillis()
		{
			return( 0 );
		}
		
		public int
		getCurrentPingMillis()
		{
			return( 0 );
		}
		
		public int
		getMaxPingMillis()
		{
			return( 0 );
		}
				
		public int
		getCurrentChokeSpeed()
		{
			return( 0 );
		}
		
		public int
		getMaxUploadSpeed()
		{
			return( 0 );
		}
			
		public boolean
		getAdjustsDownloadLimits()
		{
			return( false );
		}
	}
}
