/*
 * File    : TOTorrentImpl.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.torrent.impl;


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

import org.gudy.azureus2.core3.logging.LogRelation;
import org.gudy.azureus2.core3.torrent.*;
import org.gudy.azureus2.core3.util.*;

import com.aelitis.azureus.core.AzureusCoreFactory;

public class 
TOTorrentImpl
	extends LogRelation
	implements TOTorrent
{
	protected static final String TK_ANNOUNCE			= "announce";
	protected static final String TK_ANNOUNCE_LIST		= "announce-list";
	protected static final String TK_COMMENT			= "comment";
	protected static final String TK_CREATION_DATE		= "creation date";
	protected static final String TK_CREATED_BY			= "created by";
	
	protected static final String TK_INFO				= "info";
	protected static final String TK_NAME				= "name";
	protected static final String TK_LENGTH				= "length";
	protected static final String TK_PATH				= "path";
	protected static final String TK_FILES				= "files";
	protected static final String TK_PIECE_LENGTH		= "piece length";
	protected static final String TK_PIECES				= "pieces";
		
	protected static final String TK_PRIVATE			= "private";

	protected static final String TK_NAME_UTF8			= "name.utf-8";
	protected static final String TK_PATH_UTF8			= "path.utf-8";
	protected static final String TK_COMMENT_UTF8		= "comment.utf-8";
	
	protected static final List	TK_ADDITIONAL_OK_ATTRS = 
		Arrays.asList(new String[]{TK_COMMENT_UTF8, AZUREUS_PROPERTIES });
	
	private byte[]							torrent_name;
	private byte[]							torrent_name_utf8;
	
	private byte[]							comment;
	private URL								announce_url;
	private TOTorrentAnnounceURLGroupImpl	announce_group = new TOTorrentAnnounceURLGroupImpl(this);
	
	private long		piece_length;
	private int			number_of_pieces;
	private byte[][]	pieces;
	
	private byte[]		torrent_hash;
	private HashWrapper	torrent_hash_wrapper;
	
	private boolean				simple_torrent;
	private TOTorrentFileImpl[]	files;

	private long				creation_date;
	private byte[]				created_by;
	
	private Map					additional_properties 		= new HashMap();
	private Map					additional_info_properties	= new HashMap();
	
	protected AEMonitor this_mon 	= new AEMonitor( "TOTorrent" );

	/** 
	 * Constructor for deserialisation
	 */
	
	protected
	TOTorrentImpl()
	{
	}

	/** 
	 * Constructor for creation
	 */
	
	protected
	TOTorrentImpl(
		String		_torrent_name,
		URL			_announce_url,
		boolean		_simple_torrent )
		
		throws TOTorrentException
	{
		try{
		
			torrent_name		= _torrent_name.getBytes( Constants.DEFAULT_ENCODING );
			
			torrent_name_utf8	= torrent_name;
			
			setAnnounceURL( _announce_url );
			
			simple_torrent		= _simple_torrent;
			
		}catch( UnsupportedEncodingException e ){
			
			throw( new TOTorrentException( 	"TOTorrent: unsupported encoding for '" + _torrent_name + "'",
											TOTorrentException.RT_UNSUPPORTED_ENCODING));
		}
	}
	
	public void
	serialiseToBEncodedFile(
		final File		output_file )
	
		throws TOTorrentException
	{		
		byte[]	res = serialiseToByteArray();
						
        BufferedOutputStream bos = null;
						
		try{
			File parent = output_file.getParentFile();
			
			if ( parent == null || ( parent.exists() && !parent.isDirectory())){
				
				throw( new TOTorrentException( "Path '" + output_file + "' is invalid", TOTorrentException.RT_WRITE_FAILS ));
			}
			
			if ( !parent.exists()){
				
				if ( !parent.mkdirs()){
				
					throw( new TOTorrentException( "Failed to create directory '" + parent + "'", TOTorrentException.RT_WRITE_FAILS ));
				}
			}
			
			File temp = new File( parent, output_file.getName() + ".saving");
            
			if ( temp.exists()){
				
				if ( !temp.delete()){
					
					throw( new TOTorrentException( "Insufficient permissions to delete '" + temp + "'", TOTorrentException.RT_WRITE_FAILS ));
				}
			}else{
				
				boolean	ok = false;
				
				try{
					ok = temp.createNewFile();
					
				}catch( Throwable e ){
				}
				
				if ( !ok ){
					
					throw( new TOTorrentException( "Insufficient permissions to write '" + temp + "'", TOTorrentException.RT_WRITE_FAILS ));

				}
			}
			
            bos = new BufferedOutputStream( new FileOutputStream( temp, false ), 8192 );
			
            bos.write( res );
			
            bos.flush();
            
            bos.close();
            
            bos = null;
              
              //only use newly saved file if it got this far, i.e. it was written successfully
            
            if ( temp.length() > 1L ) {
            	
                if ( output_file.exists() ) {
                	
                	output_file.delete();
                }
                
                temp.renameTo( output_file );
            }
             	
		}catch( TOTorrentException e ){
			
			throw( e );
			
		}catch( Throwable e){
							
			throw( new TOTorrentException( 	"TOTorrent::serialise: fails '" + e.toString() + "'",
															TOTorrentException.RT_WRITE_FAILS ));
							
		}finally{
							
			if ( bos != null ){
				
				try{
					bos.close();
					
				}catch( IOException e ){
				
					Debug.printStackTrace( e );
				}
			}
		}
	}
	
	protected byte[]
	serialiseToByteArray()
	
		throws TOTorrentException
	{
		Map	root = serialiseToMap();
			
		try{
			return( BEncoder.encode( root ));
			
		}catch( IOException e ){

			throw( 	new TOTorrentException( 	
							"TOTorrent::serialiseToByteArray: fails '" + e.toString() + "'",
							TOTorrentException.RT_WRITE_FAILS ));
			
		}
	}		

	public Map
	serialiseToMap()
	
		throws TOTorrentException
	{		
		Map	root = new HashMap();
		
		writeStringToMetaData( root, TK_ANNOUNCE, announce_url.toString());
		
		TOTorrentAnnounceURLSet[] sets = announce_group.getAnnounceURLSets();
		
		if (sets.length > 0 ){
			
			List	announce_list = new ArrayList();
			
			for (int i=0;i<sets.length;i++){
				
				TOTorrentAnnounceURLSet	set = sets[i];
				
				URL[]	urls = set.getAnnounceURLs();
				
				if ( urls.length == 0 ){
					
					continue;
				}
				
				List sub_list = new ArrayList();
				
				announce_list.add( sub_list );
				
				for (int j=0;j<urls.length;j++){
					
					sub_list.add( writeStringToMetaData( urls[j].toString())); 
				}
			}
			
			if ( announce_list.size() > 0 ){
				
				root.put( TK_ANNOUNCE_LIST, announce_list );
			}
		}
		
		if ( comment != null ){
			
			root.put( TK_COMMENT, comment );			
		}
		
		if ( creation_date != 0 ){
			
			root.put( TK_CREATION_DATE, new Long( creation_date ));
		}
		
		if ( created_by != null ){
			
			root.put( TK_CREATED_BY, created_by );						
		}
		
		Map info = new HashMap();
		
		root.put( TK_INFO, info );
		
		info.put( TK_PIECE_LENGTH, new Long( piece_length ));
		
		if ( pieces == null ){
			
			throw( new TOTorrentException( "Pieces is null", TOTorrentException.RT_WRITE_FAILS ));
		}
		
		byte[]	flat_pieces = new byte[pieces.length*20];
		
		for (int i=0;i<pieces.length;i++){
			
			System.arraycopy( pieces[i], 0, flat_pieces, i*20, 20 );
		}
		
		info.put( TK_PIECES, flat_pieces );
		
		info.put( TK_NAME, torrent_name );
		
		if ( torrent_name_utf8 != null ){
			
			info.put( TK_NAME_UTF8, torrent_name_utf8 );
		}
		
		if ( simple_torrent ){
		
			TOTorrentFile	file = files[0];
			
			info.put( TK_LENGTH, new Long( file.getLength()));
			
		}else{
	
			List	meta_files = new ArrayList();
		
			info.put( TK_FILES, meta_files );
		
			for (int i=0;i<files.length;i++){
				
				TOTorrentFileImpl	file	= files[i];
				
				Map	file_map = new HashMap();
		
				meta_files.add( file_map );
				
				file_map.put( TK_LENGTH, new Long( file.getLength()));
				
				List path = new ArrayList();
				
				file_map.put( TK_PATH, path );
				
				byte[][]	path_comps = file.getPathComponents();
				
				for (int j=0;j<path_comps.length;j++){
					
					path.add( path_comps[j]);
				}
				
				if ( file.isUTF8()){
					
					List utf8_path = new ArrayList();
					
					file_map.put( TK_PATH_UTF8, utf8_path );
										
					for (int j=0;j<path_comps.length;j++){
						
						utf8_path.add( path_comps[j]);
					}
				}
				
				Map file_additional_properties = file.getAdditionalProperties();
				
				Iterator prop_it = file_additional_properties.keySet().iterator();
				
				while( prop_it.hasNext()){
					
					String	key = (String)prop_it.next();
					
					file_map.put( key, file_additional_properties.get( key ));
				}
			}
		}
		
		Iterator info_it = additional_info_properties.keySet().iterator();
		
		while( info_it.hasNext()){
		
			String	key = (String)info_it.next();
			
			info.put( key, additional_info_properties.get( key ));	
		}
		
		Iterator it = additional_properties.keySet().iterator();
		
		while( it.hasNext()){
			
			String	key = (String)it.next();
			
			Object	value = additional_properties.get( key );
			
			if ( value != null ){
				
				root.put( key, value );
			}
		}
		
		return( root );
	}
	
	public void
	serialiseToXMLFile(
	  File		file )
		  
	  throws TOTorrentException
	{
		TOTorrentXMLSerialiser	serialiser = new TOTorrentXMLSerialiser( this );
		
		serialiser.serialiseToFile( file );
	}
	
	public byte[]
	getName()
	{
		return( torrent_name );
	}
	
	protected void
	setName(
		byte[]	_name )
	{
		torrent_name	= _name;
	}
	
	public boolean
	isSimpleTorrent()
	{
		return( simple_torrent );
	}
	
	public byte[]
	getComment()
	{
		return( comment );
	}
	
	protected void
	setComment(
		byte[]		_comment )
	
	{
		comment = _comment;
	}
	
	public void
	setComment(
		String	_comment )
	{
		try{
		
			byte[]	utf8_comment = _comment.getBytes( Constants.DEFAULT_ENCODING );
			
			setComment( utf8_comment );
			
			setAdditionalByteArrayProperty( TK_COMMENT_UTF8, utf8_comment );
			
		}catch( UnsupportedEncodingException e ){
			
			Debug.printStackTrace( e );
			
			comment = null;
		}
	}
		
	public URL
	getAnnounceURL()
	{
		return( announce_url );
	}
	
	public boolean
	setAnnounceURL(
		URL		url )
	{
		URL newURL = anonymityTransform( url );
		String s0 = (newURL == null) ? "" : newURL.toString();
		String s1 = (announce_url == null) ? "" : announce_url.toString();
		if (s0.equals(s1))
			return false;
		
		announce_url	= newURL;
		return true;
	}

	public long
	getCreationDate()
	{
		return( creation_date );
	}
	
	public void
	setCreationDate(
		long		_creation_date )
	{
		creation_date 	= _creation_date;
	}
	
	protected void
	setCreatedBy(
		byte[]		_created_by )
	{
		created_by	= _created_by;
	}
	
	protected void
	setCreatedBy(
		String		_created_by )
	{
		try{
		
			setCreatedBy( _created_by.getBytes( Constants.DEFAULT_ENCODING ));
			
		}catch( UnsupportedEncodingException e ){
			
			Debug.printStackTrace( e );
			
			created_by = null;
		}	
	}
	
	public byte[]
	getCreatedBy()
	{
		return( created_by );
	}
	
	public byte[]
	getHash()
	
		throws TOTorrentException
	{
		if ( torrent_hash == null ){
			
			Map	root = serialiseToMap();
				
			Map info = (Map)root.get( TK_INFO );
				
			setHashFromInfo( info );		
		}
		
		return( torrent_hash );
	}
	
	public HashWrapper
	getHashWrapper()

		throws TOTorrentException
	{
		if ( torrent_hash_wrapper == null ){
			getHash();
		}
		
		return( torrent_hash_wrapper );
	}
	
	public boolean
	hasSameHashAs(
		TOTorrent		other )
	{
		try{
			byte[]	other_hash = other.getHash();
				
			return( Arrays.equals( getHash(), other_hash ));
				
		}catch( TOTorrentException e ){
			
			Debug.printStackTrace( e );
			
			return( false );
		}
	}
	
	protected void
	setHashFromInfo(
		Map		info )
		
		throws TOTorrentException
	{	
		try{
			SHA1Hasher s = new SHA1Hasher();
				
			torrent_hash = s.calculateHash(BEncoder.encode(info));
	
			torrent_hash_wrapper = new HashWrapper( torrent_hash );
			
		}catch( Throwable e ){
				
			throw( new TOTorrentException( 	"TOTorrent::setHashFromInfo: fails '" + e.toString() + "'",
											TOTorrentException.RT_HASH_FAILS ));
		}
	}
	
	public void
	setPrivate(
		boolean	_private_torrent )
	
		throws TOTorrentException
	{
		additional_info_properties.put( TK_PRIVATE, new Long(_private_torrent?1:0));
		
			// update torrent hash
		
		torrent_hash	= null;
		
		getHash();
	}
	
	public boolean
	getPrivate()
	{
		Object o = additional_info_properties.get( TK_PRIVATE );
		
		if ( o instanceof Long ){
			
			return(((Long)o).intValue() != 0 );
		}
		
		return( false );
	}
	
	public TOTorrentAnnounceURLGroup
	getAnnounceURLGroup()
	{
		return( announce_group );
	}

	protected void
	addTorrentAnnounceURLSet(
		URL[]		urls )
	{
		announce_group.addSet( new TOTorrentAnnounceURLSetImpl( this, urls ));
	}
	
	public long
	getSize()
	{
		long	res = 0;
		
		for (int i=0;i<files.length;i++){
			
			res += files[i].getLength();
		}
		
		return( res );
	}

	public long
	getPieceLength()
	{
		return( piece_length );
	}
	
	protected void
	setPieceLength(
		long	_length )
	{
		piece_length	= _length;
	}
	
	public int
	getNumberOfPieces()
	{
		return( number_of_pieces );
	}
	
	public byte[][]
	getPieces()
	{
		return( pieces );
	}
	
	public void
	setPieces(
		byte[][]	_pieces )
	{
		pieces = _pieces;
		
		if ( pieces != null ){
			
			number_of_pieces = pieces.length;
		}
	}
	
	public TOTorrentFile[]
	getFiles()
	{
		return( files );
	}
	
	protected void
	setFiles(
		TOTorrentFileImpl[]		_files )
	{
		files	= _files;
	}
	
	protected boolean
	getSimpleTorrent()
	{
		return( simple_torrent );
	}
	
	protected void
	setSimpleTorrent(
		boolean	_simple_torrent )
	{
		simple_torrent	= _simple_torrent;
	}
	
	protected Map
	getAdditionalProperties()
	{
		return( additional_properties );
	}
	
	public void
	setAdditionalStringProperty(
		String		name,
		String		value )
	{
		try{
		
			setAdditionalByteArrayProperty( name, writeStringToMetaData( value ));
			
		}catch( TOTorrentException e ){
			
				// hide encoding exceptions as default encoding must be available
			
			Debug.printStackTrace( e );
		}
	}
		
	public String
	getAdditionalStringProperty(
		String		name )
	{	
		try{			
		
			return( readStringFromMetaData( getAdditionalByteArrayProperty(name)));
			
		}catch( TOTorrentException e ){
			
				// hide encoding exceptions as default encoding must be available
			
			Debug.printStackTrace( e );
			
			return( null );
		}
	}
	
	public void
	setAdditionalByteArrayProperty(
		String		name,
		byte[]		value )
	{
		additional_properties.put( name, value );
	}
		
	public void
	setAdditionalProperty(
		String		name,
		Object		value )
	{
		if ( name instanceof String ){
			
			setAdditionalStringProperty(name,(String)value);
			
		}else{
		
			additional_properties.put( name, value );
		}
	}
	
	public byte[]
	getAdditionalByteArrayProperty(
		String		name )
	{
		Object	obj = additional_properties.get( name );
		
		if ( obj instanceof byte[] ){
			
			return((byte[])obj);
		}
		
		return( null );
	}
	
	public void
	setAdditionalLongProperty(
		String		name,
		Long		value )
	{
		additional_properties.put( name, value );
	}
		
	public Long
	getAdditionalLongProperty(
		String		name )
	{
		Object	obj = additional_properties.get( name );
		
		if ( obj instanceof Long ){
			
			return((Long)obj);
		}
		
		return( null );
	}
	
	public void
	setAdditionalListProperty(
		String		name,
		List		value )
	{
		additional_properties.put( name, value );
	}
		
	public List
	getAdditionalListProperty(
		String		name )
	{
		Object	obj = additional_properties.get( name );
		
		if ( obj instanceof List ){
			
			return((List)obj);
		}
		
		return( null );	
	}
	
	public void
	setAdditionalMapProperty(
		String		name,
		Map 		value )
	{
		additional_properties.put( name, value );
	}
		
	public Map
	getAdditionalMapProperty(
		String		name )
	{
		Object	obj = additional_properties.get( name );
		
		if ( obj instanceof Map ){
			
			return((Map)obj);
		}
		
		return( null );	
	}
	
	public Object
	getAdditionalProperty(
		String		name )
	{
		return(additional_properties.get( name ));
	}
	
	public void
	removeAdditionalProperty(
		String name )
	{
		additional_properties.remove( name );
	}

	public void
	removeAdditionalProperties()
	{
		Map	new_props = new HashMap();
		
		Iterator it = additional_properties.keySet().iterator();
		
		while( it.hasNext()){
			
			String	key = (String)it.next();
			
			if ( TK_ADDITIONAL_OK_ATTRS.contains(key)){
			
				new_props.put( key, additional_properties.get( key ));
			}
		}
		
		additional_properties = new_props;
	}

	protected void
	addAdditionalProperty(
		String			name,
		Object			value )
	{
		additional_properties.put( name, value );
	}
		
	protected void
	addAdditionalInfoProperty(
		String			name,
		Object			value )
	{
		additional_info_properties.put( name, value );
	}	
	
	protected Map
	getAdditionalInfoProperties()
	{
		return( additional_info_properties );	
	}
	
	protected String
	readStringFromMetaData(
		Map		meta_data,
		String	name )
		
		throws TOTorrentException
	{
		Object	obj = meta_data.get(name);
		
		if ( obj instanceof byte[]){
			
			return(readStringFromMetaData((byte[])obj));
		}
		
		return( null );
	}
	
	protected String
	readStringFromMetaData(
		byte[]		value )
		
		throws TOTorrentException
	{
		try{
			if ( value == null ){
				
				return( null );
			}
			
			return(	new String(value, Constants.DEFAULT_ENCODING ));
			
		}catch( UnsupportedEncodingException e ){
			
			throw( new TOTorrentException( 	"TOTorrentDeserialise: unsupported encoding for '" + value + "'",
											TOTorrentException.RT_UNSUPPORTED_ENCODING));
		}
	}
	
	protected void
	writeStringToMetaData(
		Map		meta_data,
		String	name,
		String	value )
		
		throws TOTorrentException
	{
		meta_data.put( name, writeStringToMetaData( value ));	
	}
	
	protected byte[]
	writeStringToMetaData(
		String		value )
		
		throws TOTorrentException
	{
		try{
			
			return(	value.getBytes( Constants.DEFAULT_ENCODING ));
			
		}catch( UnsupportedEncodingException e ){
			
			throw( new TOTorrentException( 	"TOTorrent::writeStringToMetaData: unsupported encoding for '" + value + "'",
											TOTorrentException.RT_UNSUPPORTED_ENCODING));
		}
	}
	
	protected URL
	anonymityTransform(
		URL		url )
	{
		/*
		 * 	hmm, doing this is harder than it looks as we have issues hosting
		 *  (both starting tracker instances and also short-cut loopback for seeding
		 *  leave as is for the moment
		if ( HostNameToIPResolver.isNonDNSName( url.getHost())){
			
			// remove the port as it is uninteresting and could leak information about the
			// tracker
			
			String	url_string = url.toString();
			
			String	port_string = ":" + (url.getPort()==-1?url.getDefaultPort():url.getPort());
			
			int	port_pos = url_string.indexOf( ":" + url.getPort());
			
			if ( port_pos != -1 ){
				
				try{
					
					return( new URL( url_string.substring(0,port_pos) + url_string.substring(port_pos+port_string.length())));
					
				}catch( MalformedURLException e){
					
					Debug.printStackTrace(e);
				}
			}
		}
		*/
		
		return( url );
	}
	
	public void
	print()
	{
		try{
			byte[]	hash = getHash();
			
			System.out.println( "name = " + torrent_name );
			System.out.println( "announce url = " + announce_url );
			System.out.println( "announce group = " + announce_group.getAnnounceURLSets().length );
			System.out.println( "creation date = " + creation_date );
			System.out.println( "creation by = " + created_by );
			System.out.println( "comment = " + comment );
			System.out.println( "hash = " + ByteFormatter.nicePrint( hash ));
			System.out.println( "piece length = " + getPieceLength() );
			System.out.println( "pieces = " + getNumberOfPieces() );
			
			Iterator info_it = additional_info_properties.keySet().iterator();
			
			while( info_it.hasNext()){
			
				String	key = (String)info_it.next();
				Object	value = additional_info_properties.get( key );
				
				try{
				
					System.out.println( "info prop '" + key + "' = '" + 
										( value instanceof byte[]?new String((byte[])value, Constants.DEFAULT_ENCODING):value.toString()) + "'" );
				}catch( UnsupportedEncodingException e){
				
					System.out.println( "info prop '" + key + "' = unsupported encoding!!!!");	
				}
			}	
					
			Iterator it = additional_properties.keySet().iterator();
			
			while( it.hasNext()){
			
				String	key = (String)it.next();
				Object	value = additional_properties.get( key );
				
				try{
				
					System.out.println( "prop '" + key + "' = '" + 
										( value instanceof byte[]?new String((byte[])value, Constants.DEFAULT_ENCODING):value.toString()) + "'" );
				}catch( UnsupportedEncodingException e){
				
					System.out.println( "prop '" + key + "' = unsupported encoding!!!!");	
				}
			}
			
			if ( pieces == null ){
			
				System.out.println( "\tpieces = null" );
				
			}else{
				for (int i=0;i<pieces.length;i++){
				
					System.out.println( "\t" + ByteFormatter.nicePrint(pieces[i]));
				}
			}
											 
			for (int i=0;i<files.length;i++){
				
				byte[][]path_comps = files[i].getPathComponents();
				
				String	path_str = "";
				
				for (int j=0;j<path_comps.length;j++){
					
					try{
					
						path_str += (j==0?"":File.separator) + new String( path_comps[j], Constants.DEFAULT_ENCODING );

					}catch( UnsupportedEncodingException e ){
	
						System.out.println( "file - unsupported encoding!!!!");	
					}
				}
				
				System.out.println( "\t" + path_str + " (" + files[i].getLength() + ")" );
			}
		}catch( TOTorrentException e ){
			
			Debug.printStackTrace( e );
		}
	}
	
	public AEMonitor
	getMonitor()
	{
		return( this_mon );
	}

	/* (non-Javadoc)
	 * @see org.gudy.azureus2.core3.logging.LogRelation#getLogRelationText()
	 */
	public String getRelationText() {
		return "Torrent: '" + new String(torrent_name) + "'";  
	}

	/* (non-Javadoc)
	 * @see org.gudy.azureus2.core3.logging.LogRelation#queryForClass(java.lang.Class)
	 */
	public Object[] getQueryableInterfaces() {
		// yuck
		try {
			return new Object[] { AzureusCoreFactory.getSingleton()
					.getGlobalManager().getDownloadManager(this) };
		} catch (Exception e) {
		}

		return null;
	}
}