/*
  * TeleStax, Open Source Cloud Communications
  * Copyright 2011-2016, TeleStax Inc. and individual contributors
  * by the @authors tag.
  *
  * This program is free software: you can redistribute it and/or modify
  * under the terms of the GNU Affero 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 Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>
  *
  * This file incorporates work covered by the following copyright and
  * permission notice:
  *
  *   JBoss, Home of Professional Open Source
  *   Copyright 2007-2011, Red Hat, Inc. and individual contributors
  *   by the @authors tag. See the copyright.txt in the distribution for a
  *   full listing of individual contributors.
  *
  *   This 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 software 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 software; if not, write to the Free
  *   Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  *   02110-1301 USA, or see the FSF site: http://www.fsf.org.
  */

package org.jdiameter.client.impl.helpers;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.StringTokenizer;

/**
 * This class allows to convert string to IPv4/IPv6 object instance
 *
 * @author erick.svenson@yahoo.com
 * @author <a href="mailto:brainslog@gmail.com"> Alexandre Mendonca </a>
 * @author <a href="mailto:baranowb@gmail.com"> Bartosz Baranowski </a>
 */
public class IPConverter {

  /**
   * Convert defined string to IPv4 object instance
   * @param address string representation of ip address
   * @return IPv4 object instance
   */
  public static InetAddress InetAddressByIPv4(String address) {
    StringTokenizer addressTokens = new StringTokenizer(address, ".");
    byte[] bytes;
    if (addressTokens.countTokens() == 4) {
      bytes = new byte[]{
          getByBytes(addressTokens),
          getByBytes(addressTokens),
          getByBytes(addressTokens),
          getByBytes(addressTokens)
      };
    }
    else {
      return null;
    }

    try {
      return InetAddress.getByAddress(bytes);
    } catch (UnknownHostException e) {
      return null;
    }
  }

  private static byte getByBytes(StringTokenizer addressTokens) {
    int word = Integer.parseInt(addressTokens.nextToken());
    return (byte) (word & 0xff);
  }

  /**
   * Convert defined string to IPv6 object instance
   * @param address string representation of ip address
   * @return IPv6 object instance
   */
  public static InetAddress InetAddressByIPv6(String address) {
    StringTokenizer addressTokens = new StringTokenizer(address, ":");
    byte[] bytes = new byte[16];
    if (addressTokens.countTokens() == 8) {
      int count = 0;
      while (addressTokens.hasMoreTokens()) {
        int word = Integer.parseInt(addressTokens.nextToken(), 16);
        bytes[count * 2]     = (byte) ((word >> 8) & 0xff);
        bytes[count * 2 + 1] = (byte) (word & 0xff);
        count++;
      }
    }
    else {
      return null;
    }
    try {
      return InetAddress.getByAddress(bytes);
    } catch (UnknownHostException e) {
      return null;
    }
  }
}