/*
 * Created on Oct 5, 2003
 * Created by Paul Gardner
 * Modified Apr 13, 2004 by Alon Rohter
 * Copyright (C) 2004 Aelitis, All Rights Reserved.
 * 
 */

package org.gudy.azureus2.core3.torrent.impl;


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

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

public class 
TOTorrentFileHasher 
{
	protected boolean	do_other_per_file_hash;
	protected int		piece_length;
	
	protected Vector	pieces = new Vector();
	
	protected byte[]	buffer;
	protected int		buffer_pos;
	 
	protected SHA1Hasher					overall_sha1_hash;
	protected ED2KHasher					overall_ed2k_hash;
	
	protected byte[]						sha1_digest;
	protected byte[]						ed2k_digest;
	
	protected byte[]						per_file_sha1_digest;
	protected byte[]						per_file_ed2k_digest;
	
	protected TOTorrentFileHasherListener	listener;
		
	protected boolean						cancelled;
	
	protected
	TOTorrentFileHasher(
		boolean							_do_other_overall_hashes,
		boolean							_do_other_per_file_hash,				
		int								_piece_length,
		TOTorrentFileHasherListener		_listener )
	{
		if ( _do_other_overall_hashes ){
		  overall_sha1_hash 	= new SHA1Hasher();
						
		  overall_ed2k_hash 	= new ED2KHasher();
		}
		
		do_other_per_file_hash	= _do_other_per_file_hash;
		piece_length			= _piece_length;
		listener				= _listener;
		
		buffer = new byte[piece_length];
	}
		
	long
	add(
		File		_file )
		
		throws TOTorrentException
	{
		long		file_length = 0;
		
		InputStream is = null;
		
		SHA1Hasher	sha1_hash		= null;
		ED2KHasher	ed2k_hash		= null;
		
		try{
			if ( do_other_per_file_hash ){
				
				sha1_hash		= new SHA1Hasher();
				ed2k_hash		= new ED2KHasher();
			}
			
			is = new BufferedInputStream(new FileInputStream( _file ), 65536);

			while(true){
	
				if ( cancelled ){
						
					throw( new TOTorrentException( 	"TOTorrentCreate: operation cancelled",
													TOTorrentException.RT_CANCELLED ));
				}
				
				int	len = is.read( buffer, buffer_pos, piece_length - buffer_pos );
				
				if ( len > 0 ){
					
					if ( do_other_per_file_hash ){
						
						sha1_hash.update( buffer, buffer_pos, len );
						ed2k_hash.update( buffer, buffer_pos, len );
					}
					
					
					file_length += len;
					
					buffer_pos += len;
					
					if ( buffer_pos == piece_length ){
						
						// hash this piece
						
						byte[] hash = new SHA1Hasher().calculateHash(buffer);

						if ( overall_sha1_hash != null ){
							
							overall_sha1_hash.update( buffer );
							overall_ed2k_hash.update( buffer );
						}
						
						pieces.add( hash );
						
						if ( listener != null ){
							
							listener.pieceHashed( pieces.size() );
						}
						
						buffer_pos = 0;					
					}
				}else{
					
					break;
				}		
			}
			
			if ( do_other_per_file_hash ){
				
				per_file_sha1_digest = sha1_hash.getDigest();
				per_file_ed2k_digest = ed2k_hash.getDigest();
			}
			
		}catch( TOTorrentException e ){
			
			throw( e );
			
		}catch( Throwable e ){
			
			throw( new TOTorrentException( 	"TOTorrentFileHasher: file read fails '" + e.toString() + "'",
											TOTorrentException.RT_READ_FAILS ));
		}finally {
			if (is != null) {
				try {
					is.close();
				}
				catch (Exception e) {
				}
			}
		}
		
		return( file_length );
	}
	
	protected byte[]
	getPerFileSHA1Digest()
	{
		return( per_file_sha1_digest );
	}
	
	protected byte[]
	getPerFileED2KDigest()
	{
		return( per_file_ed2k_digest );
	}
	
	protected byte[][]
	getPieces()
		
		throws TOTorrentException
	{
		try{
			if ( buffer_pos > 0 ){
								
				byte[] rem = new byte[buffer_pos];
				
				System.arraycopy( buffer, 0, rem, 0, buffer_pos );
				
				pieces.addElement(new SHA1Hasher().calculateHash(rem));
				
				if ( overall_sha1_hash != null ){
					
					overall_sha1_hash.update( rem );
					overall_ed2k_hash.update( rem );
				}
				
				if ( listener != null ){
							
					listener.pieceHashed( pieces.size() );
				}
				
				buffer_pos = 0;
			}
		
			if ( overall_sha1_hash != null && sha1_digest == null ){
				
				sha1_digest	= overall_sha1_hash.getDigest();
				ed2k_digest	= overall_ed2k_hash.getDigest();
			}
			
			byte[][] res = new byte[pieces.size()][];
		
			pieces.copyInto( res );
		
			return( res );
			
		}catch( Throwable e ){
			
			throw( new TOTorrentException( 	"TOTorrentFileHasher: file read fails '" + e.toString() + "'",
											TOTorrentException.RT_READ_FAILS ));
		}
	}
	
	protected byte[]
	getED2KDigest()
	
		throws TOTorrentException
	{
		if ( ed2k_digest == null ){
			
			getPieces();
		}
		
		return( ed2k_digest );
	}
	
	protected byte[]
	getSHA1Digest()
	
		throws TOTorrentException
	{
		if ( sha1_digest == null ){
			
			getPieces();
		}
		
		return( sha1_digest );
	}
	
	protected void
	cancel()
	{
		cancelled	= true;
	}
}
