/*
 * SaslPlain.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU inetlib, a library.
 * 
 * GNU inetlib 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 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU inetlib 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version.
 */

package gnu.inet.util;

import java.io.UnsupportedEncodingException;
import javax.security.sasl.SaslClient;
import javax.security.sasl.SaslException;

/**
 * SASL mechanism for PLAIN.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public class SaslPlain
  implements SaslClient
{

  private String username;
  private String password;
  private boolean complete;

  public SaslPlain(String username, String password)
  {
    this.username = username;
    this.password = password;
  }

  public String getMechanismName()
  {
    return "PLAIN";
  }

  public boolean hasInitialResponse()
  {
    return true;
  }

  public byte[] evaluateChallenge(byte[] challenge)
    throws SaslException
  {
    try
      {
        byte[] a = username.getBytes("UTF-8");
        byte[] b = password.getBytes("UTF-8");
        byte[] c = new byte[(a.length * 2) + b.length + 2];
        System.arraycopy(a, 0, c, 0, a.length);
        System.arraycopy(a, 0, c, a.length + 1, a.length);
        System.arraycopy(b, 0, c, (a.length * 2) + 2, b.length);
        complete = true;
        return c;
      }
    catch (UnsupportedEncodingException e)
      {
        String msg = "Username or password contains illegal UTF-8";
        throw new SaslException(msg, e);
      }
  }

  public boolean isComplete()
  {
    return complete;
  }

  public byte[] unwrap(byte[] incoming, int off, int len)
    throws SaslException
  {
    byte[] ret = new byte[len - off];
    System.arraycopy(incoming, off, ret, 0, len);
    return ret;
  }

  public byte[] wrap(byte[] outgoing, int off, int len)
    throws SaslException
  {
    byte[] ret = new byte[len - off];
    System.arraycopy(outgoing, off, ret, 0, len);
    return ret;
  }

  public Object getNegotiatedProperty(String name)
  {
    return null;
  }

  public void dispose()
  {
  }
  
}