/*
 * This program 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. 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If
 * not, see <http://www.gnu.org/licenses/>.
 */
package silentium.commons.crypt;

import silentium.commons.utils.Rnd;

import java.io.IOException;

/**
 * @author KenM
 */
public class LoginCrypt {
	private static final byte[] STATIC_BLOWFISH_KEY = { (byte) 0x6b, (byte) 0x60, (byte) 0xcb, (byte) 0x5b, (byte) 0x82, (byte) 0xce, (byte) 0x90, (byte) 0xb1, (byte) 0xcc, (byte) 0x2b, (byte) 0x6c, (byte) 0x55, (byte) 0x6c, (byte) 0x6c, (byte) 0x6c, (byte) 0x6c };

	private final NewCrypt _staticCrypt = new NewCrypt(STATIC_BLOWFISH_KEY);
	private NewCrypt _crypt;
	private boolean _static = true;

	public void setKey(final byte... key) {
		_crypt = new NewCrypt(key);
	}

	public boolean decrypt(final byte[] raw, final int offset, final int size) throws IOException {
		_crypt.decrypt(raw, offset, size);
		return NewCrypt.verifyChecksum(raw, offset, size);
	}

	public int encrypt(final byte[] raw, final int offset, int size) throws IOException {
		// reserve checksum
		size += 4;

		if (_static) {
			// reserve for XOR "key"
			size += 4;

			// padding
			size += 8 - size % 8;
			NewCrypt.encXORPass(raw, offset, size, Rnd.nextInt());
			_staticCrypt.crypt(raw, offset, size);

			_static = false;
		} else {
			// padding
			size += 8 - size % 8;
			NewCrypt.appendChecksum(raw, offset, size);
			_crypt.crypt(raw, offset, size);
		}
		return size;
	}
}