/*
    * ====================================================================
    * 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.testing.classic;
  
  import java.io.IOException;
  
  import org.apache.hc.client5.http.auth.StandardAuthScheme;
  import org.apache.hc.client5.testing.auth.Authenticator;
  import org.apache.hc.client5.testing.auth.BasicAuthTokenExtractor;
  import org.apache.hc.core5.http.ClassicHttpRequest;
  import org.apache.hc.core5.http.ClassicHttpResponse;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpHeaders;
  import org.apache.hc.core5.http.HttpStatus;
  import org.apache.hc.core5.http.io.HttpServerRequestHandler;
  import org.apache.hc.core5.http.io.entity.EntityUtils;
  import org.apache.hc.core5.http.io.entity.StringEntity;
  import org.apache.hc.core5.http.message.BasicClassicHttpResponse;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.net.URIAuthority;
  import org.apache.hc.core5.util.Args;
  
  public class AuthenticatingDecorator implements HttpServerRequestHandler {
  
      private final HttpServerRequestHandler requestHandler;
      private final Authenticator authenticator;
      private final BasicAuthTokenExtractor authTokenExtractor;
  
      public AuthenticatingDecorator(final HttpServerRequestHandler requestHandler, final Authenticator authenticator) {
          this.requestHandler = Args.notNull(requestHandler, "Request handler");
          this.authenticator = Args.notNull(authenticator, "Authenticator");
          this.authTokenExtractor = new BasicAuthTokenExtractor();
      }
  
      protected void customizeUnauthorizedResponse(final ClassicHttpResponse unauthorized) {
      }
  
      @Override
      public void handle(
              final ClassicHttpRequest request,
              final ResponseTrigger responseTrigger,
              final HttpContext context) throws HttpException, IOException {
          final Header h = request.getFirstHeader(HttpHeaders.AUTHORIZATION);
          final String challengeResponse = h != null ? authTokenExtractor.extract(h.getValue()) : null;
  
          final URIAuthority authority = request.getAuthority();
          final String requestUri = request.getRequestUri();
  
          final boolean authenticated = authenticator.authenticate(authority, requestUri, challengeResponse);
          final Header expect = request.getFirstHeader(HttpHeaders.EXPECT);
          final boolean expectContinue = expect != null && "100-continue".equalsIgnoreCase(expect.getValue());
  
          if (authenticated) {
              if (expectContinue) {
                  responseTrigger.sendInformation(new BasicClassicHttpResponse(HttpStatus.SC_CONTINUE));
              }
              requestHandler.handle(request, responseTrigger, context);
          } else {
              final ClassicHttpResponse unauthorized = new BasicClassicHttpResponse(HttpStatus.SC_UNAUTHORIZED);
              final String realm = authenticator.getRealm(authority, requestUri);
              unauthorized.addHeader(HttpHeaders.WWW_AUTHENTICATE, StandardAuthScheme.BASIC + " realm=\"" + realm + "\"");
              customizeUnauthorizedResponse(unauthorized);
              if (unauthorized.getEntity() == null) {
                  unauthorized.setEntity(new StringEntity("Unauthorized"));
              }
              if (expectContinue || request.getEntity() == null) {
                  // Respond immediately
                  responseTrigger.submitResponse(unauthorized);
                  // Consume request body later
                  EntityUtils.consume(request.getEntity());
              } else {
                  // Consume request body first
                  EntityUtils.consume(request.getEntity());
                 // Respond later
                 responseTrigger.submitResponse(unauthorized);
             }
         }
     }
 
 }