public class LoginDecoder extends ByteToMessageDecoder {

	private LoginType type;

	int size;

	@Override
	protected void decode(ChannelHandlerContext context, ByteBuf buffer, List<Object> out) throws Exception {
		if (!buffer.isReadable()) {
			throw new IllegalStateException("The data in the buffer could not be read!");
		}

		int loginType = buffer.readUnsignedByte();

		if (loginType != 16 && loginType != 19 && loginType != 18) {
			throw new ProtocolException("Invalid login type received: " + loginType + ".");
		}

		type = loginType == 19 ? LoginType.LOBBY : LoginType.WORLD;

		size = buffer.readUnsignedShort();

		if (buffer.readableBytes() < size) {
			throw new IllegalStateException("Not enough readable bytes from the buffer!");
		}

		int revision = buffer.readInt();
		int subrevision = buffer.readInt();
		if (revision != Constants.REVISION && subrevision != Constants.SUB_REVISION) {
			throw new IllegalStateException("Invalid client version received: " + revision + ", " + subrevision + ".");
		}

		if (type.equals(LoginType.WORLD)) {
			buffer.readByte();
		}

		if (type.equals(LoginType.LOBBY)) {
			decodeLobbyPayload(context, buffer, out);
		} else if (type.equals(LoginType.WORLD)) {
			//decodeWorldPayload(context, buffer, out);
		}
	}

	private void decodeLobbyPayload(ChannelHandlerContext context, ByteBuf buffer, List<Object> out) throws ProtocolException {
		if (buffer.readableBytes() < 2) {
			throw new IllegalStateException("Not enough readable bytes from the buffer!");
		}

		int secureBufferSize = buffer.readUnsignedShort();
		if (buffer.readableBytes() < secureBufferSize) {
			throw new IllegalStateException("Not enough readable bytes from the buffer!");
		}

		byte[] secureBytes = new byte[secureBufferSize];
		buffer.readBytes(secureBytes);
		ByteBuf secureBuffer = Unpooled.wrappedBuffer(new BigInteger(secureBytes).modPow(Protocol.LOGIN_EXPONENT, Protocol.LOGIN_MODULUS).toByteArray());

		int block = secureBuffer.readUnsignedByte();
		if (block != 10) {
			throw new ProtocolException("Invalid block opcode received: " + block + ".");
		}

		int[] xteaKey = new int [4];
		for (int i = 0; i < xteaKey.length; i++) {
			xteaKey[i] = secureBuffer.readInt();
		}

		long loginHash = secureBuffer.readLong();
		if (loginHash != 0) {
			throw new ProtocolException("Invalid login hash received: " + loginHash + ".");
		}

		String password = BufferUtility.readString(secureBuffer);

		long[] loginSeeds = new long[2];
		for (int i = 0; i < loginSeeds.length; i++) {
			loginSeeds[i] = secureBuffer.readLong();
		}

		byte[] xteaBlock = new byte[buffer.readableBytes()];
		buffer.readBytes(xteaBlock);

		XTEACipher xtea = new XTEACipher(xteaKey);
		xtea.decrypt(xteaBlock, 0, xteaBlock.length);

		ByteBuf xteaBuffer = Unpooled.wrappedBuffer(xteaBlock);

		boolean decodeAsString = xteaBuffer.readByte() == 1;
		String username = decodeAsString ? BufferUtility.readString(xteaBuffer) : Base37Utility.decodeBase37(xteaBuffer.readLong());

		xteaBuffer.readUnsignedByte(); // Game identifier.
		xteaBuffer.readUnsignedByte(); // Language identifier.
		xteaBuffer.readUnsignedByte(); // Frame type (Fixed, Resizable, or Full Screen).

		xteaBuffer.readUnsignedShort(); // Canvas width.
		xteaBuffer.readUnsignedShort(); // Canvas height.
		xteaBuffer.readUnsignedByte();

		int[] randomData = new int[24];
		for (int index = 0; index < randomData.length; index++) {
			randomData[index] = xteaBuffer.readUnsignedByte();
		}

		String token = BufferUtility.readString(xteaBuffer);
		if (token != Protocol.LOGIN_TOKEN) {
			throw new ProtocolException("Invalid login token received: " + token + ".");
		}

		int length = xteaBuffer.readUnsignedByte();

		byte[] machineData = new byte[length];
		for (int data = 0; data < machineData.length; data++) {
			machineData[data] = (byte) xteaBuffer.readUnsignedByte();
		}

		xteaBuffer.readInt();
		BufferUtility.readString(xteaBuffer);
		xteaBuffer.readInt();
		xteaBuffer.readInt();
		BufferUtility.readString(xteaBuffer);

		xteaBuffer.readUnsignedByte();

		int[] crc = new int[36];
		for (int index = 0; index < crc.length; index++) {
			crc[index] = xteaBuffer.readInt();
		}

		int[] serverKeys = new int[xteaKey.length];
		for (int i = 0; i < serverKeys.length; i++) {
			serverKeys[i] = xteaKey[i] + 50;
		}

		out.add(new LoginRequestMessage(context.channel(), UsernameUtility.formatForProtocol(username), password, username.contains("@"), new ISAACCipher(serverKeys), new ISAACCipher(xteaKey), type));
	}
}