/*
 * Created on Apr 30, 2004
 * Created by Alon Rohter
 * Copyright (C) 2004, 2005, 2006 Aelitis, 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.
 * 
 * AELITIS, SAS au capital de 46,603.30 euros
 * 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
 *
 */

package com.aelitis.azureus.core.peermanager.messaging.bittorrent;

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

import com.aelitis.azureus.core.peermanager.messaging.Message;
import com.aelitis.azureus.core.peermanager.messaging.MessageException;



/**
 * BitTorrent request message.
 * NOTE: Overrides equals()
 */
public class BTRequest implements BTMessage {
  private byte version;
  private DirectByteBuffer buffer = null;
  private String description = null;
  
  private final int piece_number;
  private final int piece_offset;
  private final int length;
  private final int hashcode;
  
  
  public BTRequest( int piece_number, int piece_offset, int length, byte version ) {
    this.piece_number = piece_number;
    this.piece_offset = piece_offset;
    this.length = length;
    this.version = version;
    this.hashcode = piece_number + piece_offset + length;
  }

  
  public int getPieceNumber() {  return piece_number;  }
  
  public int getPieceOffset() {  return piece_offset;  }
  
  public int getLength() {  return length;  }
  
  
    
  public String getID() {  return BTMessage.ID_BT_REQUEST;  }
  public byte[] getIDBytes() {  return BTMessage.ID_BT_REQUEST_BYTES;  }
  
  public String getFeatureID() {  return BTMessage.BT_FEATURE_ID;  } 
  
  public int getFeatureSubID() {  return BTMessage.SUBID_BT_REQUEST;  }
  
  public int getType() {  return Message.TYPE_PROTOCOL_PAYLOAD;  }
    
  public byte getVersion() { return version; };

  public String getDescription() {
    if( description == null ) {
      description = BTMessage.ID_BT_REQUEST + " piece #" + piece_number + ":" + piece_offset + "->" + (piece_offset + length -1);
    }
    
    return description;
  }
  
  
  public DirectByteBuffer[] getData() {
    if( buffer == null ) {
      buffer = DirectByteBufferPool.getBuffer( DirectByteBuffer.AL_MSG_BT_REQUEST, 12 );
      buffer.putInt( DirectByteBuffer.SS_MSG, piece_number );
      buffer.putInt( DirectByteBuffer.SS_MSG, piece_offset );
      buffer.putInt( DirectByteBuffer.SS_MSG, length );
      buffer.flip( DirectByteBuffer.SS_MSG );
    }
    
    return new DirectByteBuffer[]{ buffer };
  }
  
  
  public Message deserialize( DirectByteBuffer data, byte version ) throws MessageException {   
    if( data == null ) {
      throw new MessageException( "[" +getID() + "] decode error: data == null" );
    }
    
    if( data.remaining( DirectByteBuffer.SS_MSG ) != 12 ) {
      throw new MessageException( "[" +getID() + "] decode error: payload.remaining[" +data.remaining( DirectByteBuffer.SS_MSG )+ "] != 12" );
    }
    
    int num = data.getInt( DirectByteBuffer.SS_MSG );
    if( num < 0 ) {
      throw new MessageException( "[" +getID() + "] decode error: num < 0" );
    }
    
    int offset = data.getInt( DirectByteBuffer.SS_MSG );
    if( offset < 0 ) {
      throw new MessageException( "[" +getID() + "] decode error: offset < 0" );
    }
    
    int length = data.getInt( DirectByteBuffer.SS_MSG );
    if( length < 0 ) {
      throw new MessageException( "[" +getID() + "] decode error: length < 0" );
    }
    
    data.returnToPool();
    
    return new BTRequest( num, offset, length, version );
  }
  
  
  public void destroy() {
    if( buffer != null )  buffer.returnToPool();
  } 
  
  
  //used for removing individual requests from the message queue
  public boolean equals( Object obj ) {
    if( this == obj )  return true;
    if( obj != null && obj instanceof BTRequest ) {
      BTRequest other = (BTRequest)obj;
      if( other.piece_number == this.piece_number &&
          other.piece_offset == this.piece_offset &&
          other.length == this.length )  return true;
    }
    return false;
  }

  public int hashCode() {  return hashcode;  }
}