/*
 * Created on 25-May-2004
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, 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; 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.
 *
 */

package org.gudy.azureus2.update;

/**
 * @author parg
 *
 */

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

import org.gudy.azureus2.plugins.logging.LoggerChannel;

public class 
UpdateJarPatcher 
{
	private static String MANIFEST_NAME = "META-INF/MANIFEST.MF";
	
	protected Map		patch_entries	= new HashMap();

	protected
	UpdateJarPatcher(
		InputStream		input_file,
		InputStream		patch_file,
		OutputStream	output_file,
		LoggerChannel	log )
	
		throws IOException
	{
		readPatchEntries( patch_file );
		
		JarInputStream	jis = new JarInputStream(input_file);
		
		JarOutputStream	jos = new JarOutputStream(output_file);

		boolean 	manifest_found	= false;
		
		while( true ){
			
			JarEntry is_entry = jis.getNextJarEntry();
			
			if ( is_entry == null ){
				
				break;
			}
			
			if ( is_entry.isDirectory()){
				
				continue;
			}
			
			String	name = is_entry.getName();
			
			if ( name.equalsIgnoreCase( MANIFEST_NAME )){
				
				manifest_found	= true;
			}
			
			InputStream	eis = getPatch( name);
			
			if ( eis != null ){
				
				log.log( "patch - replace: " + name );
				
			}else{
				
				eis = jis;
			}
			
			JarEntry os_entry = new JarEntry(name);
			
			writeEntry( jos, os_entry, eis );
		}
		
			// write any new entries
		
		Iterator	it = patch_entries.keySet().iterator();
		
		while( it.hasNext()){
			
			String	name = (String)it.next();
			
			if ( name.equalsIgnoreCase( MANIFEST_NAME )){
				
				manifest_found = true;
			}
		
			log.log( "patch - add: " + name);
		
			InputStream	eis = (InputStream)patch_entries.get(name);
			
			JarEntry os_entry = new JarEntry(name);
			
			writeEntry( jos, os_entry, eis );			
		}
		
		if ( !manifest_found ){
			
			JarEntry entry = new JarEntry( MANIFEST_NAME );
		
			ByteArrayInputStream bais = new ByteArrayInputStream("Manifest-Version: 1.0\r\n\r\n".getBytes());
		
			writeEntry( jos, entry, bais );
		}
		
		jos.finish();	// FLUSH is not sufficient!!!!
	}
	
	private static void 
	writeEntry(
		JarOutputStream 	jos, 
		JarEntry 			entry,
		InputStream 		data ) 
	
		throws IOException 
	{
		jos.putNextEntry(entry);

		byte[]	newBytes = new byte[4096];
		
		int size = data.read(newBytes);

		while (size != -1){
			
			jos.write(newBytes, 0, size);
			
			size = data.read(newBytes);
		}
	}
	
	protected void
	readPatchEntries(
		InputStream		is )
	
		throws IOException
	{
		JarInputStream	jis = new JarInputStream(is );
			
		while( true ){
			
			JarEntry ent = jis.getNextJarEntry();
			
			if ( ent == null ){
				
				break;
			}
			
			if ( ent.isDirectory()){
				
				continue;
			}
			
			ByteArrayOutputStream	baos = new ByteArrayOutputStream();
				
			byte[]	buffer = new byte[8192];
				
			while( true ){
					
				int	l = jis.read( buffer );
					
				if ( l <= 0 ){
						
					break;
				}
					
				baos.write( buffer, 0, l );
			}
				
			patch_entries.put( ent.getName(), new ByteArrayInputStream( baos.toByteArray()));
		}
	}
	
		
	public InputStream
	getPatch(
		String	name )
	{
		return((InputStream)patch_entries.remove(name));
	}
}
