/*
 * Created on 02-Dec-2005
 * 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 com.aelitis.azureus.core.diskmanager.access.impl;

import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.core3.util.DirectByteBuffer;

import com.aelitis.azureus.core.diskmanager.access.DiskAccessRequest;
import com.aelitis.azureus.core.diskmanager.access.DiskAccessRequestListener;
import com.aelitis.azureus.core.diskmanager.cache.CacheFile;
import com.aelitis.azureus.core.diskmanager.cache.CacheFileManagerException;

public class 
DiskAccessRequestImpl

	implements DiskAccessRequest
{
	protected static final short	OP_READ				= 1;
	protected static final short	OP_WRITE			= 2;
	protected static final short	OP_WRITE_AND_FREE	= 3;
	
	
	private CacheFile					file;
	private long						offset;
	private DirectByteBuffer			buffer;
	private DiskAccessRequestListener	listener;
	private short						op;
	private short						cache_policy;
	
	private int							size;
	
	private volatile boolean	cancelled;
	
	protected
	DiskAccessRequestImpl(
		CacheFile					_file,
		long						_offset,
		DirectByteBuffer			_buffer,
		DiskAccessRequestListener	_listener,
		short						_op,
		short						_cache_policy )
	{
		file			= _file;
		offset			= _offset;
		buffer			= _buffer;
		listener		= _listener;
		op				= _op;
		cache_policy	= _cache_policy;
		
		size = buffer.remaining( DirectByteBuffer.SS_FILE );
	}
	
	public int
	getSize()
	{
		return( size );
	}
	
	protected void
	runRequest()
	{
		if ( cancelled ){
			
			listener.requestCancelled( this );
			
			return;
		}
		
		//System.out.println( "DiskReq:" + Thread.currentThread().getName() + ": " + op + " - " + offset );
		
		try{
			if ( op == OP_READ ){
				
				file.read( buffer, offset, cache_policy );
				
			}else if ( op == OP_WRITE ){
				
				file.write( buffer, offset );
				
			}else{
				
				file.writeAndHandoverBuffer( buffer, offset );
			}
			
			listener.requestExecuted( size );
			
			listener.requestComplete( this );
			
		}catch( Throwable e ){
			
			listener.requestFailed( this, e );
		}
	}
	
	protected boolean
	canBeAggregatedWith(
		DiskAccessRequestImpl	other )
	{
		return( op == other.getOperation() && cache_policy == other.getCachePolicy());
	}
	
	protected static void
	runAggregated(
		DiskAccessRequestImpl		base_request,
		DiskAccessRequestImpl[]		requests )
	{
			// assumption - they are all for the same file, sequential offsets and aggregatable, not cancelled
		
		int			op 				= base_request.getOperation();
			
		CacheFile	file 			= base_request.getFile();
		long		offset			= base_request.getOffset();
		short		cache_policy	= base_request.getCachePolicy();
		
		DirectByteBuffer[]	buffers = new DirectByteBuffer[requests.length];
		
		long	current_offset 	= offset;
		long	total_size		= 0;
		
		for (int i=0;i<buffers.length;i++){
		
			DiskAccessRequestImpl	request = requests[i];
			
			if ( current_offset != request.getOffset()){
				
				Debug.out( "assert failed: requests not contiguous" );
			}
			
			int	size = request.getSize();
			
			current_offset += size;
			
			total_size += size;
			
			buffers[i] = request.getBuffer();
		}
		
		try{	
			if ( op == OP_READ ){
				
				file.read( buffers, offset, cache_policy );
				
			}else if ( op == OP_WRITE ){
				
				file.write( buffers, offset );
			
			}else{
				
				file.writeAndHandoverBuffers( buffers, offset );
			}
			
			base_request.getListener().requestExecuted( total_size );

			for (int i=0;i<requests.length;i++){

				DiskAccessRequestImpl	request = requests[i];
				
				request.getListener().requestComplete( request );
				
				if ( request != base_request ){
					
					request.getListener().requestExecuted( 0 );
				}
			}
			
		}catch( CacheFileManagerException e ){
			
			int	fail_index = e.getFailIndex();
			
			for (int i=0;i<fail_index;i++){
				
				DiskAccessRequestImpl	request = requests[i];
				
				request.getListener().requestComplete( request );
			}
			
			for (int i=fail_index;i<requests.length;i++){

				DiskAccessRequestImpl	request = requests[i];
				
				request.getListener().requestFailed( request, e );
			}			
		}catch( Throwable e ){
			
			for (int i=0;i<requests.length;i++){

				DiskAccessRequestImpl	request = requests[i];
				
				request.getListener().requestFailed( request, e );
			}			
		}
	}
	
	public CacheFile
	getFile()
	{
		return( file );
	}
	
	public long
	getOffset()
	{
		return( offset );
	}
	
	public DirectByteBuffer
	getBuffer()
	{
		return( buffer );
	}
	
	public void
	cancel()
	{
		cancelled	= true;
	}
	
	public boolean
	isCancelled()
	{
		return( cancelled );
	}
	
	public short
	getCachePolicy()
	{
		return( cache_policy );
	}
	
	protected int
	getOperation()
	{
		return( op );
	}
	
	public int
	getPriority()
	{
		return( listener.getPriority());
	}
	
	protected DiskAccessRequestListener
	getListener()
	{
		return( listener );
	}
}
