/*
    * ====================================================================
    * 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.hc.client5.http.protocol;
  
  import java.io.IOException;
  
  import org.apache.hc.client5.http.RouteInfo;
  import org.apache.hc.client5.http.auth.AuthCache;
  import org.apache.hc.client5.http.auth.AuthExchange;
  import org.apache.hc.client5.http.auth.AuthScheme;
  import org.apache.hc.client5.http.auth.CredentialsProvider;
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.http.EntityDetails;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpHost;
  import org.apache.hc.core5.http.HttpRequest;
  import org.apache.hc.core5.http.HttpRequestInterceptor;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.net.URIAuthority;
  import org.apache.hc.core5.util.Args;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Request interceptor that can preemptively authenticate against known hosts,
   * if there is a cached {@link AuthScheme} instance in the local
   * {@link AuthCache} associated with the given target or proxy host.
   *
   * @since 4.1
   */
  @Contract(threading = ThreadingBehavior.STATELESS)
  public class RequestAuthCache implements HttpRequestInterceptor {
  
      private static final Logger LOG = LoggerFactory.getLogger(RequestAuthCache.class);
  
      public RequestAuthCache() {
          super();
      }
  
      @Override
      public void process(final HttpRequest request, final EntityDetails entity, final HttpContext context)
              throws HttpException, IOException {
          Args.notNull(request, "HTTP request");
          Args.notNull(context, "HTTP context");
  
          final HttpClientContext clientContext = HttpClientContext.adapt(context);
          final String exchangeId = clientContext.getExchangeId();
  
          final AuthCache authCache = clientContext.getAuthCache();
          if (authCache == null) {
              if (LOG.isDebugEnabled()) {
                  LOG.debug("{} Auth cache not set in the context", exchangeId);
              }
              return;
          }
  
          final CredentialsProvider credsProvider = clientContext.getCredentialsProvider();
          if (credsProvider == null) {
              if (LOG.isDebugEnabled()) {
                  LOG.debug("{} Credentials provider not set in the context", exchangeId);
              }
              return;
          }
  
          final RouteInfo route = clientContext.getHttpRoute();
          if (route == null) {
              if (LOG.isDebugEnabled()) {
                  LOG.debug("{} Route info not set in the context", exchangeId);
              }
              return;
          }
  
          final URIAuthority authority = request.getAuthority();
         final HttpHost target;
         if (authority != null) {
             target = new HttpHost(
                     request.getScheme(),
                     authority.getHostName(),
                     authority.getPort() >= 0 ? authority.getPort() : route.getTargetHost().getPort());
         } else {
             target = route.getTargetHost();
         }
         final AuthExchange targetAuthExchange = clientContext.getAuthExchange(target);
         if (targetAuthExchange.getState() == AuthExchange.State.UNCHALLENGED) {
             final AuthScheme authScheme = authCache.get(target);
             if (authScheme != null) {
                 if (LOG.isDebugEnabled()) {
                     LOG.debug("{} Re-using cached '{}' auth scheme for {}", exchangeId, authScheme.getName(), target);
                 }
                 targetAuthExchange.select(authScheme);
             }
         }
 
         final HttpHost proxy = route.getProxyHost();
         if (proxy != null) {
             final AuthExchange proxyAuthExchange = clientContext.getAuthExchange(proxy);
             if (proxyAuthExchange.getState() == AuthExchange.State.UNCHALLENGED) {
                 final AuthScheme authScheme = authCache.get(proxy);
                 if (authScheme != null) {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug("{} Re-using cached '{}' auth scheme for {}", exchangeId, authScheme.getName(), proxy);
                     }
                     proxyAuthExchange.select(authScheme);
                 }
             }
         }
     }
 
 }