/*
    *  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.
   *
   */
  package org.apache.mina.proxy.handlers.http.basic;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.mina.core.filterchain.IoFilter.NextFilter;
  import org.apache.mina.proxy.ProxyAuthException;
  import org.apache.mina.proxy.handlers.http.AbstractAuthLogicHandler;
  import org.apache.mina.proxy.handlers.http.HttpProxyConstants;
  import org.apache.mina.proxy.handlers.http.HttpProxyRequest;
  import org.apache.mina.proxy.handlers.http.HttpProxyResponse;
  import org.apache.mina.proxy.session.ProxyIoSession;
  import org.apache.mina.proxy.utils.StringUtilities;
  import org.apache.mina.util.Base64;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * HttpBasicAuthLogicHandler.java - HTTP Basic authentication mechanism logic handler.
   * 
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   * @since MINA 2.0.0-M3
   */
  public class HttpBasicAuthLogicHandler extends AbstractAuthLogicHandler {
      private final static Logger logger = LoggerFactory.getLogger(HttpBasicAuthLogicHandler.class);
  
      /**
       * {@inheritDoc}
       */
      public HttpBasicAuthLogicHandler(final ProxyIoSession proxyIoSession) throws ProxyAuthException {
          super(proxyIoSession);
  
          ((HttpProxyRequest) request).checkRequiredProperties(HttpProxyConstants.USER_PROPERTY,
                  HttpProxyConstants.PWD_PROPERTY);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void doHandshake(final NextFilter nextFilter) throws ProxyAuthException {
          logger.debug(" doHandshake()");
  
          if (step > 0) {
              throw new ProxyAuthException("Authentication request already sent");
          }
  
          // Send request
          HttpProxyRequest req = (HttpProxyRequest) request;
          Map<String, List<String>> headers = req.getHeaders() != null ? req.getHeaders()
                  : new HashMap<String, List<String>>();
  
          String username = req.getProperties().get(HttpProxyConstants.USER_PROPERTY);
          String password = req.getProperties().get(HttpProxyConstants.PWD_PROPERTY);
  
          StringUtilities.addValueToHeader(headers, "Proxy-Authorization",
                  "Basic " + createAuthorization(username, password), true);
  
          addKeepAliveHeaders(headers);
          req.setHeaders(headers);
  
          writeRequest(nextFilter, req);
          step++;
      }
  
      /**
       * Computes the authorization header value.
       * 
       * @param username the user name
       * @param password the user password
       * @return the authorization header value as a string
       */
      public static String createAuthorization(final String username, final String password) {
          return new String(Base64.encodeBase64((username + ":" + password).getBytes()));
      }
  
      /**
       * {@inheritDoc}
       */
     @Override
     public void handleResponse(final HttpProxyResponse response) throws ProxyAuthException {
         if (response.getStatusCode() != 407) {
             throw new ProxyAuthException("Received error response code (" + response.getStatusLine() + ").");
         }
     }
 }