/**
 * This file is part of aion-emu <aion-emu.com>.
 *
 *  aion-emu 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  aion-emu 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 aion-emu.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.aionemu.gameserver.network.aion;

import java.nio.ByteBuffer;

import com.aionemu.commons.network.packet.BaseServerPacket;
import com.aionemu.gameserver.network.Crypt;

/**
 * Base class for every GS -> Aion Server Packet.
 * 
 * @author -Nemesiss-
 */
public abstract class AionServerPacket extends BaseServerPacket
{
	/**
	 * Constructs new server packet
	 */
	protected AionServerPacket()
	{
		super();
		setOpcode(ServerPacketsOpcodes.getOpcode(getClass()));
	}

	/**
	 * Write packet opcodec and two additional bytes
	 * 
	 * @param buf
	 * @param value
	 */
	private final void writeOP(ByteBuffer buf, int value)
	{
		/** obfuscate packet id */
		byte op = Crypt.encodeOpcodec(value);
		buf.put(op);

		/** put static server packet code */
		buf.put(Crypt.staticServerPacketCode);

		/** for checksum? */
		buf.put((byte) ~op);
	}

	/**
	 * Write and encrypt this packet data for given connection, to given buffer.
	 * 
	 * @param con
	 * @param buf
	 */
	public final void write(AionConnection con, ByteBuffer buf)
	{
		buf.putShort((short) 0);
		writeOP(buf, getOpcode());
		writeImpl(con, buf);
		buf.flip();
		buf.putShort((short) buf.limit());
		ByteBuffer b = buf.slice();
		buf.position(0);
		con.encrypt(b);
	}

	/**
	 * Write data that this packet represents to given byte buffer.
	 * 
	 * @param con
	 * @param buf
	 */
	protected void writeImpl(AionConnection con, ByteBuffer buf)
	{
		
	}
}