package zeus.rs2.net.codec;

import java.security.SecureRandom;
import java.util.logging.Logger;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;

import zeus.rs2.model.player.Player;
import zeus.rs2.net.packet.MessageBuilder;
import zeus.rs2.util.BufferUtils;

/**
 *
 * @author Karl
 *
 */
public class RS2LoginDecoder extends FrameDecoder {

	private static final Logger logger = Logger.getLogger(RS2LoginDecoder.class.getName());
	private SecureRandom random = new SecureRandom();

	public enum State {
		STATE_OPCODE, STATE_RESPONSE, STATE_UPDATE, STATE_LOGIN;
	}

	private State state = State.STATE_OPCODE;
	private static final int GAME_OPCODE = 14;
	private static final int UPDATE_OPCODE = 15;
	private static final byte[] INITIAL_RESPONSE = new byte[] {
		0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0
	};

	@Override
	protected Object decode(ChannelHandlerContext chc, Channel channel,
			ChannelBuffer channelBuffer) throws Exception {
		switch(state) {
		case STATE_OPCODE:
			if(channelBuffer.readableBytes() >= 1) {
				int opcode = channelBuffer.readByte();
				switch(opcode) {
				case GAME_OPCODE:
					state = State.STATE_RESPONSE;
					return true;
				case UPDATE_OPCODE:
					state = State.STATE_UPDATE;
					return true;
				default:
					logger.info("Invalid opcode:" + opcode);
					channel.close();
					return false;
				}
			} else {
				return false;
			}
		case STATE_RESPONSE:
			if(channelBuffer.readableBytes() >= 1) {
				long serverKey = random.nextLong();
				channel.write(new MessageBuilder().writeBytes(INITIAL_RESPONSE).writeByte((byte) 0).writeLong(serverKey).toMessage());
				state = State.STATE_LOGIN;
				return true;
			} else {
				return false;
			}
		case STATE_UPDATE:
			if(channelBuffer.readableBytes() >= 4) {
				return true;
			} else {
				return false;
			}
		case STATE_LOGIN:
			if(channelBuffer.readableBytes() >= 1) {
				long clientKey = channelBuffer.readLong();
				long serverKey = channelBuffer.readLong();
				int isaacSeed[] = new int[4];
				isaacSeed[0] = (int) (clientKey >> 32);
				isaacSeed[1] = (int) clientKey;
				isaacSeed[2] = (int) (serverKey >> 32);
				isaacSeed[3] = (int) serverKey;
				int rsaOpcode = channelBuffer.readByte() & 0xFF;
				if(rsaOpcode != 10) {
					logger.info("Invalid rsa opcode:" + rsaOpcode);
					channel.close();
					return false;
				}
				int connectionType = channelBuffer.readByte() & 0xFF;
				if(connectionType != 16 && connectionType != 18) {
					logger.info("Invalid connection type:" + connectionType);
					channel.close();
					return false;
				}
				int loginPacket = channelBuffer.readByte() & 0xFF;
				if(loginPacket != 255) {
					logger.info("Invalid login packet:" + loginPacket);
					channel.close();
					return false;
				}
				int clientVersion = channelBuffer.readShort() & 0xFF;
				if(clientVersion != 319) {
					logger.info("Invalid client version:" + clientVersion);
					channel.close();
					return false;
				}
				for(int i = 0; i < 9; i++) {
					channelBuffer.readInt();
				}
				for(int i = 0; i < 4; i++) {
					isaacSeed[2] += 50;
				}
				String username = BufferUtils.readRS2String(channelBuffer);
				String password = BufferUtils.readRS2String(channelBuffer);
				Player player = new Player(username, password);
				player.addPlayer(player);
				logger.info("Registered player: username: "+username+" password: "+password+".");
				return true;
			} else {
				return false;
			}
		}
		return null;
	}
}