/*
 * File    : TRTrackerServerImpl.java
 * Created : 5 Oct. 2003
 * By      : Parg 
 * 
 * Azureus - a Java Bittorrent client
 *
 * 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.
 *
 * 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 ( see the LICENSE file ).
 *
 * 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 org.gudy.azureus2.core3.tracker.server.impl.tcp;


import java.net.*;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.*;


import org.gudy.azureus2.core3.util.*;
import org.gudy.azureus2.core3.config.*;
import org.gudy.azureus2.core3.tracker.server.*;
import org.gudy.azureus2.core3.tracker.server.impl.*;


public abstract class 
TRTrackerServerTCP 
	extends 	TRTrackerServerImpl
{
	private static int 	THREAD_POOL_SIZE		= COConfigurationManager.getIntParameter( "Tracker Max Threads" );
	
	public static long PROCESSING_GET_LIMIT			= COConfigurationManager.getIntParameter( "Tracker Max GET Time" )*1000;
	public static int  PROCESSING_POST_MULTIPLIER	= COConfigurationManager.getIntParameter( "Tracker Max POST Time Multiplier" );
	
	static{
			// sanity checks
		
		if ( THREAD_POOL_SIZE <= 0 ){
			THREAD_POOL_SIZE	= 1;
		}
		if ( PROCESSING_GET_LIMIT < 0 ){
			PROCESSING_GET_LIMIT = 0;
		}
		if ( PROCESSING_POST_MULTIPLIER < 0 ){
			PROCESSING_POST_MULTIPLIER	= 0;
		}
	}
	
	private boolean	ssl;
	private int		port;
	private boolean	apply_ip_filter;
	
	private ThreadPool	thread_pool;
	
	private AEMonitor this_mon 	= new AEMonitor( "TRTrackerServerTCP" );

	public
	TRTrackerServerTCP(
		String		_name,
		int			_port,
		boolean		_ssl,
		boolean		_apply_ip_filter )
		
		throws TRTrackerServerException
	{
		super( _name );
		
		port					= _port;
		ssl						= _ssl;
		apply_ip_filter			= _apply_ip_filter;

		thread_pool = new ThreadPool( "TrackerServer:TCP:"+port, THREAD_POOL_SIZE );
			
		if ( PROCESSING_GET_LIMIT > 0 ){
			
			thread_pool.setExecutionLimit( PROCESSING_GET_LIMIT );
		}
	}
	
	public void
	runProcessor(
		TRTrackerServerProcessorTCP	processor )
	{
		thread_pool.run( processor );
	}
	
	protected boolean
	isIPFilterEnabled()
	{
		return( apply_ip_filter );
	}
	
	static boolean	LOG_DOS_TO_FILE	= false;
	
	static{
		
		LOG_DOS_TO_FILE = System.getProperty("azureus.log.dos") != null;
	}
	
	protected static File		dos_log_file;
	
	protected static AEMonitor class_mon 	= new AEMonitor( "TRTrackerServerTCP:class" );

	Map	DOS_map = 
		new LinkedHashMap( 1000, (float)0.75, true )
		{
			protected boolean 
			removeEldestEntry(
				Map.Entry eldest) 
			{
				return( checkDOSRemove( eldest ));
			}
		};
	
	List	dos_list	= new ArrayList(128);
	
	long	last_dos_check				= 0;
	long	MAX_DOS_ENTRIES				= 10000;
	long	MAX_DOS_RETENTION			= 10000;
	int		DOS_CHECK_DEAD_WOOD_COUNT	= 512;
	int		DOS_MIN_INTERVAL			= 1000;
	int		dos_check_count				= 0;
	
	protected boolean
	checkDOS(
		String		ip )
	
		throws UnknownHostException
	{
		InetAddress	inet_address = InetAddress.getByName(ip);
		
		if ( inet_address.isLoopbackAddress() || InetAddress.getLocalHost().equals( inet_address )){
			
			return( false);
		}
		
		boolean	res;
		
		last_dos_check = SystemTime.getCurrentTime();
		
		DOSEntry	entry = (DOSEntry)DOS_map.get(ip);
		
		if ( entry == null ){
						
			entry = new DOSEntry(ip);
			
			DOS_map.put( ip, entry );
			
			res	= false;
			
		}else{
	
			res = last_dos_check - entry.last_time < DOS_MIN_INTERVAL;
			
			if ( res && LOG_DOS_TO_FILE ){
				
				dos_list.add( entry );
			}
			
			entry.last_time = last_dos_check;
		}
		
			// remove dead wood
		
		dos_check_count++;
		
		if ( dos_check_count == DOS_CHECK_DEAD_WOOD_COUNT ){
			
			dos_check_count = 0;
			
			Iterator	it = DOS_map.values().iterator();
			
			while( it.hasNext()){
				
				DOSEntry	this_entry = (DOSEntry)it.next();
				
				if ( last_dos_check - this_entry.last_time > MAX_DOS_RETENTION ){
					
					it.remove();
										
				}else{
					
					break;
				}
			}
			
			if ( dos_list.size() > 0 ){
				
				try{
					class_mon.enter();
					
					if ( dos_log_file == null ){
											
						dos_log_file = new File( System.getProperty("user.dir" ) + File.separator + "dos.log" );
					}
					
					PrintWriter pw = null;
					
					try{
						
						pw = new PrintWriter( new FileWriter( dos_log_file, true ));
						
						for (int i=0;i<dos_list.size();i++){
							
							DOSEntry	this_entry = (DOSEntry)dos_list.get(i);
							
							String ts = new SimpleDateFormat("hh:mm:ss - ").format( new Date(this_entry.last_time ));
						
							pw.println( ts + this_entry.ip );
						}
						
					}catch( Throwable e ){
						
					}finally{
						
						dos_list.clear();
						
						if ( pw != null ){
							
							try{
								
								pw.close();
								
							}catch( Throwable e ){
							}
						}
					}
				}finally{
					
					class_mon.exit();
				}
			}
		}
		
		return( res );
	}
	
	protected boolean
	checkDOSRemove(
		Map.Entry		eldest )
	{
		boolean res = 	DOS_map.size() > MAX_DOS_ENTRIES || 
						last_dos_check - ((DOSEntry)eldest.getValue()).last_time > 	MAX_DOS_RETENTION;
				
		return( res );
	}
	
	protected class
	DOSEntry
	{
		String		ip;
		long		last_time;
		
		protected
		DOSEntry(
			String		_ip )
		{
			ip			= _ip;
			last_time	= last_dos_check;
		}
	}
	
	public int
	getPort()
	{
		return( port );
	}
	
	public String
	getHost()
	{
		return( COConfigurationManager.getStringParameter( "Tracker IP", "" ));
	}
	
	public boolean
	isSSL()
	{
		return( ssl );
	}
	
	
	protected boolean
	handleExternalRequest(
		String			client_address,
		String			url,
		URL				absolute_url,
		String			header,
		InputStream		is,
		OutputStream	os )
		
		throws IOException
	{
		for (int i=0;i<listeners.size();i++){
			
			TRTrackerServerListener	listener;
			
			try{
				this_mon.enter();
				
				if ( i >= listeners.size()){
					
					break;
				}
				
				listener = (TRTrackerServerListener)listeners.elementAt(i);
				
			}finally{
				
				this_mon.exit();
			}
			
			if (listener.handleExternalRequest( client_address, url, absolute_url, header, is, os )){
				
				return( true );
			}
		}
		
		return( false );
	}
	

}
