/*
 * This file is part of JSTUN. 
 * 
 * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
 * reserved.
 * 
 * This software is licensed under either the GNU Public License (GPL),
 * or the Apache 2.0 license. Copies of both license agreements are
 * included in this distribution.
 */

package de.javawi.jstun.attribute;

import de.javawi.jstun.util.Utility;
import de.javawi.jstun.util.UtilityException;

public class ChangeRequest extends MessageAttribute {
	public static ChangeRequest parse(byte[] data)
			throws MessageAttributeParsingException {
		try {
			if (data.length < 4) {
				throw new MessageAttributeParsingException(
						"Data array too short");
			}
			final ChangeRequest cr = new ChangeRequest();
			final int status = Utility.oneByteToInteger(data[3]);
			switch (status) {
			case 0:
				break;
			case 2:
				cr.setChangePort();
				break;
			case 4:
				cr.setChangeIP();
				break;
			case 6:
				cr.setChangeIP();
				cr.setChangePort();
				break;
			default:
				throw new MessageAttributeParsingException(
						"Status parsing error");
			}
			return cr;
		} catch (final UtilityException ue) {
			throw new MessageAttributeParsingException("Parsing error");
		}
	}

	/*
	 * 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0
	 * 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A B 0|
	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 */
	boolean changeIP = false;

	boolean changePort = false;

	public ChangeRequest() {
		super(MessageAttribute.MessageAttributeType.ChangeRequest);
	}

	@Override
	public byte[] getBytes() throws UtilityException {
		final byte[] result = new byte[8];
		// message attribute header
		// type
		System.arraycopy(Utility.integerToTwoBytes(typeToInteger(type)), 0,
				result, 0, 2);
		// length
		System.arraycopy(Utility.integerToTwoBytes(4), 0, result, 2, 2);

		// change request header
		if (changeIP) {
			result[7] = Utility.integerToOneByte(4);
		}
		if (changePort) {
			result[7] = Utility.integerToOneByte(2);
		}
		if (changeIP && changePort) {
			result[7] = Utility.integerToOneByte(6);
		}
		return result;
	}

	public boolean isChangeIP() {
		return changeIP;
	}

	public boolean isChangePort() {
		return changePort;
	}

	public void setChangeIP() {
		changeIP = true;
	}

	public void setChangePort() {
		changePort = true;
	}
}