/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.http.impl.auth;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.http.Header;
  import org.apache.http.HttpRequest;
  import org.apache.http.auth.AuthenticationException;
  import org.apache.http.auth.Credentials;
  import org.apache.http.protocol.HttpContext;
  import org.apache.http.util.Args;
  import org.ietf.jgss.GSSException;
  import org.ietf.jgss.Oid;
  
  /**
   * SPNEGO (Simple and Protected GSSAPI Negotiation Mechanism) authentication
   * scheme.
   *
   * @since 4.1
   *
   * @deprecated (4.2)  use {@link SPNegoScheme} or {@link KerberosScheme}.
   */
  @Deprecated
  public class NegotiateScheme extends GGSSchemeBase {
  
      private final Log log = LogFactory.getLog(getClass());
  
      private static final String SPNEGO_OID       = "1.3.6.1.5.5.2";
      private static final String KERBEROS_OID     = "1.2.840.113554.1.2.2";
  
      private final SpnegoTokenGenerator spengoGenerator;
  
      /**
       * Default constructor for the Negotiate authentication scheme.
       *
       */
      public NegotiateScheme(final SpnegoTokenGenerator spengoGenerator, final boolean stripPort) {
          super(stripPort);
          this.spengoGenerator = spengoGenerator;
      }
  
      public NegotiateScheme(final SpnegoTokenGenerator spengoGenerator) {
          this(spengoGenerator, false);
      }
  
      public NegotiateScheme() {
          this(null, false);
      }
  
      /**
       * Returns textual designation of the Negotiate authentication scheme.
       *
       * @return {@code Negotiate}
       */
      @Override
      public String getSchemeName() {
          return "Negotiate";
      }
  
      @Override
      public Header authenticate(
              final Credentials credentials,
              final HttpRequest request) throws AuthenticationException {
          return authenticate(credentials, request, null);
      }
  
      /**
       * Produces Negotiate authorization Header based on token created by
       * processChallenge.
       *
       * @param credentials Never used be the Negotiate scheme but must be provided to
       * satisfy common-httpclient API. Credentials from JAAS will be used instead.
      * @param request The request being authenticated
      *
      * @throws AuthenticationException if authorisation string cannot
      *   be generated due to an authentication failure
      *
      * @return an Negotiate authorisation Header
      */
     @Override
     public Header authenticate(
             final Credentials credentials,
             final HttpRequest request,
             final HttpContext context) throws AuthenticationException {
         return super.authenticate(credentials, request, context);
     }
 
     @Override
     protected byte[] generateToken(final byte[] input, final String authServer) throws GSSException {
         return super.generateToken(input, authServer);
     }
 
     @Override
     protected byte[] generateToken(final byte[] input, final String authServer, final Credentials credentials) throws GSSException {
         /* Using the SPNEGO OID is the correct method.
          * Kerberos v5 works for IIS but not JBoss. Unwrapping
          * the initial token when using SPNEGO OID looks like what is
          * described here...
          *
          * http://msdn.microsoft.com/en-us/library/ms995330.aspx
          *
          * Another helpful URL...
          *
          * http://publib.boulder.ibm.com/infocenter/wasinfo/v7r0/index.jsp?topic=/com.ibm.websphere.express.doc/info/exp/ae/tsec_SPNEGO_token.html
          *
          * Unfortunately SPNEGO is JRE >=1.6.
          */
 
         /** Try SPNEGO by default, fall back to Kerberos later if error */
         Oid negotiationOid  = new Oid(SPNEGO_OID);
 
         byte[] token = input;
         boolean tryKerberos = false;
         try {
             token = generateGSSToken(token, negotiationOid, authServer, credentials);
         } catch (final GSSException ex){
             // BAD MECH means we are likely to be using 1.5, fall back to Kerberos MECH.
             // Rethrow any other exception.
             if (ex.getMajor() == GSSException.BAD_MECH ){
                 log.debug("GSSException BAD_MECH, retry with Kerberos MECH");
                 tryKerberos = true;
             } else {
                 throw ex;
             }
 
         }
         if (tryKerberos){
             /* Kerberos v5 GSS-API mechanism defined in RFC 1964.*/
             log.debug("Using Kerberos MECH " + KERBEROS_OID);
             negotiationOid  = new Oid(KERBEROS_OID);
             token = generateGSSToken(token, negotiationOid, authServer, credentials);
 
             /*
              * IIS accepts Kerberos and SPNEGO tokens. Some other servers Jboss, Glassfish?
              * seem to only accept SPNEGO. Below wraps Kerberos into SPNEGO token.
              */
             if (token != null && spengoGenerator != null) {
                 try {
                     token = spengoGenerator.generateSpnegoDERObject(token);
                 } catch (final IOException ex) {
                     log.error(ex.getMessage(), ex);
                 }
             }
         }
         return token;
     }
 
     /**
      * Returns the authentication parameter with the given name, if available.
      *
      * <p>There are no valid parameters for Negotiate authentication so this
      * method always returns {@code null}.</p>
      *
      * @param name The name of the parameter to be returned
      *
      * @return the parameter with the given name
      */
     @Override
     public String getParameter(final String name) {
         Args.notNull(name, "Parameter name");
         return null;
     }
 
     /**
      * The concept of an authentication realm is not supported by the Negotiate
      * authentication scheme. Always returns {@code null}.
      *
      * @return {@code null}
      */
     @Override
     public String getRealm() {
         return null;
     }
 
     /**
      * Returns {@code true}.
      * Negotiate authentication scheme is connection based.
      *
      * @return {@code true}.
      */
     @Override
     public boolean isConnectionBased() {
         return true;
     }
 
 }