/*
 * This file is part of the OdinMS Maple Story Server Copyright (C) 2008 ~ 2010
 * Patrick Huy <patrick.huy@frz.cc> Matthias Butz <matze@odinms.de> Jan
 * Christian Meyer <vimes@odinms.de>
 * 
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License version 3 as published by
 * the Free Software Foundation. You may not use, modify or distribute this
 * program under any other version of the GNU Affero General Public License.
 * 
 * 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 Affero General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package javastory.server.handling;

import javastory.channel.ChannelClient;
import javastory.client.GameClient;
import javastory.cryptography.AesTransform;
import javastory.cryptography.CustomEncryption;
import javastory.io.GamePacket;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolEncoder;
import org.apache.mina.filter.codec.ProtocolEncoderOutput;

public class PacketEncoder implements ProtocolEncoder {

	@Override
	public void encode(final IoSession session, final Object message, final ProtocolEncoderOutput out) throws Exception {
		final ChannelClient client = (ChannelClient) session.getAttribute(GameClient.CLIENT_KEY);

		if (client != null) {
			final byte[] packet = ((GamePacket) message).getBytes();
			final byte[] packetCopy = new byte[packet.length];
			System.arraycopy(packet, 0, packetCopy, 0, packet.length);

			final byte[] raw = new byte[packetCopy.length + 4];
			final AesTransform serverCrypto = client.getServerCrypto();
			synchronized (serverCrypto) {
				final byte[] header = serverCrypto.constructHeader(packetCopy.length);
				System.arraycopy(header, 0, raw, 0, 4);

				CustomEncryption.encrypt(packetCopy);
				serverCrypto.transform(packetCopy);
			}
			System.arraycopy(packetCopy, 0, raw, 4, packetCopy.length);
			out.write(IoBuffer.wrap(raw));
		} else {
			out.write(IoBuffer.wrap(((GamePacket) message).getBytes()));
		}
	}

	@Override
	public void dispose(final IoSession session) throws Exception {
		// nothing to do
	}
}