/*
 *
 * MariaDB Client for Java
 *
 * Copyright (c) 2012-2014 Monty Program Ab.
 * Copyright (c) 2015-2020 MariaDB Corporation Ab.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this library; if not, write to Monty Program Ab info@montyprogram.com.
 *
 * This particular MariaDB Client for Java file is work
 * derived from a Drizzle-JDBC. Drizzle-JDBC file which is covered by subject to
 * the following copyright and notice provisions:
 *
 * Copyright (c) 2009-2011, Marcus Eriksson
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this list
 * of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice, this
 * list of conditions and the following disclaimer in the documentation and/or
 * other materials provided with the distribution.
 *
 * Neither the name of the driver nor the names of its contributors may not be
 * used to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS  AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 */

package org.mariadb.jdbc.internal.com.send.authentication;

import java.io.IOException;
import java.util.concurrent.atomic.AtomicInteger;
import org.mariadb.jdbc.authentication.AuthenticationPlugin;
import org.mariadb.jdbc.internal.com.read.Buffer;
import org.mariadb.jdbc.internal.io.input.PacketInputStream;
import org.mariadb.jdbc.internal.io.output.PacketOutputStream;
import org.mariadb.jdbc.internal.util.Utils;
import org.mariadb.jdbc.util.Options;

public class OldPasswordPlugin implements AuthenticationPlugin {
  public static final String TYPE = "mysql_old_password";
  private String authenticationData;
  private byte[] seed;

  @Override
  public String name() {
    return "mysql pre 4.1 password encoding";
  }

  @Override
  public String type() {
    return TYPE;
  }

  public void initialize(String authenticationData, byte[] seed, Options options) {
    this.seed = seed;
    this.authenticationData = authenticationData;
  }

  /**
   * Process old password plugin authentication. see
   * https://mariadb.com/kb/en/library/authentication-plugin-mysql_old_password/
   *
   * @param out out stream
   * @param in in stream
   * @param sequence packet sequence
   * @return response packet
   * @throws IOException if socket error
   */
  public Buffer process(PacketOutputStream out, PacketInputStream in, AtomicInteger sequence)
      throws IOException {

    if (authenticationData == null || authenticationData.isEmpty()) {
      out.writeEmptyPacket(sequence.incrementAndGet());
    } else {
      out.startPacket(sequence.incrementAndGet());
      byte[] seed = Utils.copyWithLength(this.seed, 8);
      out.write(cryptOldFormatPassword(authenticationData, new String(seed)));
      out.write((byte) 0x00);
      out.flush();
    }

    Buffer buffer = in.getPacket(true);
    sequence.set(in.getLastPacketSeq());
    return buffer;
  }

  private byte[] cryptOldFormatPassword(String password, String seed) {
    byte[] result = new byte[seed.length()];

    if ((password == null) || (password.length() == 0)) {
      return new byte[0];
    }

    long[] seedHash = hashPassword(seed);
    long[] passHash = hashPassword(password);

    RandStruct randSeed = new RandStruct(seedHash[0] ^ passHash[0], seedHash[1] ^ passHash[1]);

    for (int i = 0; i < seed.length(); i++) {
      result[i] = (byte) Math.floor((random(randSeed) * 31) + 64);
    }
    byte extra = (byte) Math.floor(random(randSeed) * 31);
    for (int i = 0; i < seed.length(); i++) {
      result[i] ^= extra;
    }
    return result;
  }

  private double random(RandStruct rand) {
    rand.seed1 = (rand.seed1 * 3 + rand.seed2) % rand.maxValue;
    rand.seed2 = (rand.seed1 + rand.seed2 + 33) % rand.maxValue;
    return (double) rand.seed1 / rand.maxValue;
  }

  private long[] hashPassword(String password) {
    long nr = 1345345333L;
    long nr2 = 0x12345671L;
    long add = 7;

    for (int i = 0; i < password.length(); i++) {
      char currChar = password.charAt(i);
      if (currChar == ' ' || currChar == '\t') {
        continue;
      }

      nr ^= (((nr & 63) + add) * (long) currChar) + (nr << 8);
      nr2 += (nr2 << 8) ^ nr;
      add += currChar;
    }
    return new long[] {nr & 0x7FFFFFFF, nr2 & 0x7FFFFFFF};
  }

  private class RandStruct {

    private final long maxValue = 0x3FFFFFFFL;
    private long seed1;
    private long seed2;

    public RandStruct(long seed1, long seed2) {
      this.seed1 = seed1 % maxValue;
      this.seed2 = seed2 % maxValue;
    }
  }
}
