package gnu.crypto.sasl;

// ----------------------------------------------------------------------------
// $Id: ClientFactory.java,v 1.4 2005/10/06 04:24:17 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto 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, or (at your option)
// any later version.
//
// GNU Crypto 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; see the file COPYING.  If not, write to the
//
//    Free Software Foundation Inc.,
//    51 Franklin Street, Fifth Floor,
//    Boston, MA 02110-1301
//    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 obligated to do so.  If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------

import gnu.crypto.Registry;
import gnu.crypto.sasl.anonymous.AnonymousClient;
import gnu.crypto.sasl.crammd5.CramMD5Client;
import gnu.crypto.sasl.plain.PlainClient;
import gnu.crypto.sasl.srp.SRPClient;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.HashMap;

import javax.security.auth.callback.CallbackHandler;
import javax.security.sasl.Sasl;
import javax.security.sasl.SaslClient;
import javax.security.sasl.SaslClientFactory;
import javax.security.sasl.SaslException;

/**
 * The implementation of {@link SaslClientFactory}.
 *
 * @version $Revision: 1.4 $
 */
public class ClientFactory implements SaslClientFactory {

   // Constants and variables
   // -------------------------------------------------------------------------

   // Constructor(s)
   // -------------------------------------------------------------------------

   // implicit 0-arguments constructor

   // Class methods
   // -------------------------------------------------------------------------

   public static final Set getNames() {
      return Collections.unmodifiableSet(
            new HashSet(Arrays.asList(getNamesInternal(null))));
   }

   private static final String[] getNamesInternal(Map props) {
      String[] all = new String[] {
         Registry.SASL_SRP_MECHANISM,
         Registry.SASL_CRAM_MD5_MECHANISM,
         Registry.SASL_PLAIN_MECHANISM,
         Registry.SASL_ANONYMOUS_MECHANISM
      };

      if (props == null) {
         return all;
      }
      if (hasPolicy(Sasl.POLICY_PASS_CREDENTIALS, props)) {
         return new String[0];
      }

      List result = new ArrayList(all.length);;
      for (int i = 0; i < all.length; ) {
         result.add(all[i++]);
      }

      if (hasPolicy(Sasl.POLICY_NOPLAINTEXT, props)) {
         result.remove(Registry.SASL_PLAIN_MECHANISM);
      }
      if (hasPolicy(Sasl.POLICY_NOACTIVE, props)) {
         result.remove(Registry.SASL_CRAM_MD5_MECHANISM);
         result.remove(Registry.SASL_PLAIN_MECHANISM);
      }
      if (hasPolicy(Sasl.POLICY_NODICTIONARY, props)) {
         result.remove(Registry.SASL_CRAM_MD5_MECHANISM);
         result.remove(Registry.SASL_PLAIN_MECHANISM);
      }
      if (hasPolicy(Sasl.POLICY_NOANONYMOUS, props)) {
         result.remove(Registry.SASL_ANONYMOUS_MECHANISM);
      }
      if (hasPolicy(Sasl.POLICY_FORWARD_SECRECY, props)) {
         result.remove(Registry.SASL_CRAM_MD5_MECHANISM);
         result.remove(Registry.SASL_ANONYMOUS_MECHANISM);
         result.remove(Registry.SASL_PLAIN_MECHANISM);
      }
      return (String[]) result.toArray(new String[0]);
   }

   public static final ClientMechanism getInstance(String mechanism) {
      if (mechanism == null) {
         return null;
      }
      mechanism = mechanism.trim().toUpperCase();
      if (mechanism.equals(Registry.SASL_SRP_MECHANISM)) {
         return new SRPClient();
      }
      if (mechanism.equals(Registry.SASL_CRAM_MD5_MECHANISM)) {
         return new CramMD5Client();
      }
      if (mechanism.equals(Registry.SASL_PLAIN_MECHANISM)) {
         return new PlainClient();
      }
      if (mechanism.equals(Registry.SASL_ANONYMOUS_MECHANISM)) {
         return new AnonymousClient();
      }
      return null;
   }

   // Instance methods
   // -------------------------------------------------------------------------

   public SaslClient
   createSaslClient(String[] mechanisms, String authorisationID, String protocol,
                    String serverName, Map props, CallbackHandler cbh)
   throws SaslException {
      ClientMechanism result = null;
      String mechanism;
      for (int i = 0; i < mechanisms.length; i++) {
         mechanism = mechanisms[i];
         result = getInstance(mechanism);
         if (result != null) {
            break;
         }
      }

      if (result != null) {
         HashMap attributes = new HashMap();
         if (props != null) {
            attributes.putAll(props);
         }
         attributes.put(Registry.SASL_AUTHORISATION_ID, authorisationID);
         attributes.put(Registry.SASL_PROTOCOL, protocol);
         attributes.put(Registry.SASL_SERVER_NAME, serverName);
         attributes.put(Registry.SASL_CALLBACK_HANDLER, cbh);

         result.init(attributes);
         return result;
      }

      throw new SaslException("No supported mechanism found in given mechanism list");
   }

   public String[] getMechanismNames(Map props) {
      return getNamesInternal(props);
   }

   private static boolean hasPolicy(String propertyName, Map props) {
      return "true".equalsIgnoreCase(String.valueOf(props.get(propertyName)));
   }
}
