//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.client;
  
  import java.util.List;
  
  import org.eclipse.jetty.client.api.Request;
  import org.eclipse.jetty.client.api.Response;
  import org.eclipse.jetty.client.api.Result;
  import org.eclipse.jetty.client.util.BufferingResponseListener;
  import org.eclipse.jetty.http.HttpHeader;
  import org.eclipse.jetty.http.HttpHeaderValue;
  
  /**
   * <p>A protocol handler that handles the 100 response code.</p>
   */
  public class ContinueProtocolHandler implements ProtocolHandler
  {
      public static final String NAME = "continue";
      private static final String ATTRIBUTE = ContinueProtocolHandler.class.getName() + ".100continue";
  
      private final ResponseNotifier notifier;
  
      public ContinueProtocolHandler()
      {
          this.notifier = new ResponseNotifier();
      }
  
      @Override
      public String getName()
      {
          return NAME;
      }
  
      @Override
      public boolean accept(Request request, Response response)
      {
          boolean expect100 = request.getHeaders().contains(HttpHeader.EXPECT, HttpHeaderValue.CONTINUE.asString());
          HttpConversation conversation = ((HttpRequest)request).getConversation();
          boolean handled100 = conversation.getAttribute(ATTRIBUTE) != null;
          return expect100 && !handled100;
      }
  
      @Override
      public Response.Listener getResponseListener()
      {
          // Return new instances every time to keep track of the response content
          return new ContinueListener();
      }
  
      protected void onContinue(Request request)
      {
      }
  
      protected class ContinueListener extends BufferingResponseListener
      {
          @Override
          public void onSuccess(Response response)
          {
              // Handling of success must be done here and not from onComplete(),
              // since the onComplete() is not invoked because the request is not completed yet.
  
              Request request = response.getRequest();
              HttpConversation conversation = ((HttpRequest)request).getConversation();
              // Mark the 100 Continue response as handled
              conversation.setAttribute(ATTRIBUTE, Boolean.TRUE);
  
              // Reset the conversation listeners, since we are going to receive another response code
              conversation.updateResponseListeners(null);
  
              HttpExchange exchange = conversation.getExchanges().peekLast();
              assert exchange.getResponse() == response;
              switch (response.getStatus())
              {
                  case 100:
                  {
                      // All good, continue
                      exchange.resetResponse();
                      exchange.proceed(null);
                      onContinue(request);
                      break;
                  }
                  default:
                 {
                     // Server either does not support 100 Continue,
                     // or it does and wants to refuse the request content,
                     // or we got some other HTTP status code like a redirect.
                     List<Response.ResponseListener> listeners = exchange.getResponseListeners();
                     HttpContentResponse contentResponse = new HttpContentResponse(response, getContent(), getMediaType(), getEncoding());
                     notifier.forwardSuccess(listeners, contentResponse);
                     exchange.proceed(new HttpRequestException("Expectation failed", request));
                     break;
                 }
             }
         }
 
         @Override
         public void onFailure(Response response, Throwable failure)
         {
             HttpConversation conversation = ((HttpRequest)response.getRequest()).getConversation();
             // Mark the 100 Continue response as handled
             conversation.setAttribute(ATTRIBUTE, Boolean.TRUE);
             // Reset the conversation listeners to allow the conversation to be completed
             conversation.updateResponseListeners(null);
 
             HttpExchange exchange = conversation.getExchanges().peekLast();
             assert exchange.getResponse() == response;
             List<Response.ResponseListener> listeners = exchange.getResponseListeners();
             HttpContentResponse contentResponse = new HttpContentResponse(response, getContent(), getMediaType(), getEncoding());
             notifier.forwardFailureComplete(listeners, exchange.getRequest(), exchange.getRequestFailure(), contentResponse, failure);
         }
 
         @Override
         public void onComplete(Result result)
         {
         }
     }
 }