/*
    * ====================================================================
    * 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.nio.charset.Charset;
  import java.util.HashMap;
  import java.util.Locale;
  import java.util.Map;
  
  import org.apache.http.Consts;
  import org.apache.http.HeaderElement;
  import org.apache.http.HttpRequest;
  import org.apache.http.annotation.NotThreadSafe;
  import org.apache.http.auth.ChallengeState;
  import org.apache.http.auth.MalformedChallengeException;
  import org.apache.http.auth.params.AuthPNames;
  import org.apache.http.message.BasicHeaderValueParser;
  import org.apache.http.message.HeaderValueParser;
  import org.apache.http.message.ParserCursor;
  import org.apache.http.util.CharArrayBuffer;
  
  /**
   * Abstract authentication scheme class that lays foundation for all
   * RFC 2617 compliant authentication schemes and provides capabilities common
   * to all authentication schemes defined in RFC 2617.
   *
   * @since 4.0
   */
  @SuppressWarnings("deprecation")
  @NotThreadSafe // AuthSchemeBase, params
  public abstract class RFC2617Scheme extends AuthSchemeBase {
  
      private final Map<String, String> params;
      private final Charset credentialsCharset;
  
      /**
       * Creates an instance of <tt>RFC2617Scheme</tt> with the given challenge
       * state.
       *
       * @since 4.2
       *
       * @deprecated (4.3) do not use.
       */
      @Deprecated
      public RFC2617Scheme(final ChallengeState challengeState) {
          super(challengeState);
          this.params = new HashMap<String, String>();
          this.credentialsCharset = Consts.ASCII;
      }
  
      /**
       * @since 4.3
       */
      public RFC2617Scheme(final Charset credentialsCharset) {
          super();
          this.params = new HashMap<String, String>();
          this.credentialsCharset = credentialsCharset != null ? credentialsCharset : Consts.ASCII;
      }
  
      public RFC2617Scheme() {
          this(Consts.ASCII);
      }
  
  
      /**
       * @since 4.3
       */
      public Charset getCredentialsCharset() {
          return credentialsCharset;
      }
  
      String getCredentialsCharset(final HttpRequest request) {
          String charset = (String) request.getParams().getParameter(AuthPNames.CREDENTIAL_CHARSET);
          if (charset == null) {
              charset = getCredentialsCharset().name();
         }
         return charset;
     }
 
     @Override
     protected void parseChallenge(
             final CharArrayBuffer buffer, final int pos, final int len) throws MalformedChallengeException {
         final HeaderValueParser parser = BasicHeaderValueParser.INSTANCE;
         final ParserCursor cursor = new ParserCursor(pos, buffer.length());
         final HeaderElement[] elements = parser.parseElements(buffer, cursor);
         if (elements.length == 0) {
             throw new MalformedChallengeException("Authentication challenge is empty");
         }
         this.params.clear();
         for (final HeaderElement element : elements) {
             this.params.put(element.getName(), element.getValue());
         }
     }
 
     /**
      * Returns authentication parameters map. Keys in the map are lower-cased.
      *
      * @return the map of authentication parameters
      */
     protected Map<String, String> getParameters() {
         return this.params;
     }
 
     /**
      * Returns authentication parameter with the given name, if available.
      *
      * @param name The name of the parameter to be returned
      *
      * @return the parameter with the given name
      */
     public String getParameter(final String name) {
         if (name == null) {
             return null;
         }
         return this.params.get(name.toLowerCase(Locale.ENGLISH));
     }
 
     /**
      * Returns authentication realm. The realm may not be null.
      *
      * @return the authentication realm
      */
     public String getRealm() {
         return getParameter("realm");
     }
 
 }