/*
    * ====================================================================
    *
    *  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 org.apache.http.annotation.NotThreadSafe;
  
  import org.apache.commons.codec.binary.Base64;
  import org.apache.http.Header;
  import org.apache.http.HttpRequest;
  import org.apache.http.auth.AuthenticationException;
  import org.apache.http.auth.ChallengeState;
  import org.apache.http.auth.ContextAwareAuthScheme;
  import org.apache.http.auth.Credentials;
  import org.apache.http.auth.AUTH;
  import org.apache.http.auth.InvalidCredentialsException;
  import org.apache.http.auth.MalformedChallengeException;
  import org.apache.http.auth.params.AuthParams;
  import org.apache.http.message.BufferedHeader;
  import org.apache.http.protocol.BasicHttpContext;
  import org.apache.http.protocol.HttpContext;
  import org.apache.http.util.CharArrayBuffer;
  import org.apache.http.util.EncodingUtils;
  
  /**
   * Basic authentication scheme as defined in RFC 2617.
   * <p>
   * The following parameters can be used to customize the behavior of this
   * class:
   * <ul>
   *  <li>{@link org.apache.http.auth.params.AuthPNames#CREDENTIAL_CHARSET}</li>
   * </ul>
   *
   * @since 4.0
   */
  @NotThreadSafe
  public class BasicScheme extends RFC2617Scheme {
  
      /** Whether the basic authentication process is complete */
      private boolean complete;
  
      /**
       * Creates an instance of <tt>BasicScheme</tt> with the given challenge
       * state.
       *
       * @since 4.2
       */
      public BasicScheme(final ChallengeState challengeState) {
          super(challengeState);
          this.complete = false;
      }
  
      public BasicScheme() {
          this(null);
      }
  
      /**
       * Returns textual designation of the basic authentication scheme.
       *
       * @return <code>basic</code>
       */
      public String getSchemeName() {
          return "basic";
      }
  
      /**
       * Processes the Basic challenge.
       *
       * @param header the challenge header
       *
       * @throws MalformedChallengeException is thrown if the authentication challenge
       * is malformed
       */
      @Override
      public void processChallenge(
              final Header header) throws MalformedChallengeException {
         super.processChallenge(header);
         this.complete = true;
     }
 
     /**
      * Tests if the Basic authentication process has been completed.
      *
      * @return <tt>true</tt> if Basic authorization has been processed,
      *   <tt>false</tt> otherwise.
      */
     public boolean isComplete() {
         return this.complete;
     }
 
     /**
      * Returns <tt>false</tt>. Basic authentication scheme is request based.
      *
      * @return <tt>false</tt>.
      */
     public boolean isConnectionBased() {
         return false;
     }
 
     /**
      * @deprecated (4.2) Use {@link ContextAwareAuthScheme#authenticate(Credentials, HttpRequest, org.apache.http.protocol.HttpContext)}
      */
     @Deprecated
     public Header authenticate(
             final Credentials credentials, final HttpRequest request) throws AuthenticationException {
         return authenticate(credentials, request, new BasicHttpContext());
     }
 
     /**
      * Produces basic authorization header for the given set of {@link Credentials}.
      *
      * @param credentials The set of credentials to be used for authentication
      * @param request The request being authenticated
      * @throws InvalidCredentialsException if authentication credentials are not
      *   valid or not applicable for this authentication scheme
      * @throws AuthenticationException if authorization string cannot
      *   be generated due to an authentication failure
      *
      * @return a basic authorization string
      */
     @Override
     public Header authenticate(
             final Credentials credentials,
             final HttpRequest request,
             final HttpContext context) throws AuthenticationException {
 
         if (credentials == null) {
             throw new IllegalArgumentException("Credentials may not be null");
         }
         if (request == null) {
             throw new IllegalArgumentException("HTTP request may not be null");
         }
 
         String charset = AuthParams.getCredentialCharset(request.getParams());
         return authenticate(credentials, charset, isProxy());
     }
 
     /**
      * Returns a basic <tt>Authorization</tt> header value for the given
      * {@link Credentials} and charset.
      *
      * @param credentials The credentials to encode.
      * @param charset The charset to use for encoding the credentials
      *
      * @return a basic authorization header
      */
     public static Header authenticate(
             final Credentials credentials,
             final String charset,
             boolean proxy) {
         if (credentials == null) {
             throw new IllegalArgumentException("Credentials may not be null");
         }
         if (charset == null) {
             throw new IllegalArgumentException("charset may not be null");
         }
 
         StringBuilder tmp = new StringBuilder();
         tmp.append(credentials.getUserPrincipal().getName());
         tmp.append(":");
         tmp.append((credentials.getPassword() == null) ? "null" : credentials.getPassword());
 
         byte[] base64password = Base64.encodeBase64(
                 EncodingUtils.getBytes(tmp.toString(), charset), false);
 
         CharArrayBuffer buffer = new CharArrayBuffer(32);
         if (proxy) {
             buffer.append(AUTH.PROXY_AUTH_RESP);
         } else {
             buffer.append(AUTH.WWW_AUTH_RESP);
         }
         buffer.append(": Basic ");
         buffer.append(base64password, 0, base64password.length);
 
         return new BufferedHeader(buffer);
     }
 
 }