// ========================================================================
   // Copyright (c) 2008-2009 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.io.IOException;
  
  import org.eclipse.jetty.http.HttpHeaders;
  import org.eclipse.jetty.http.HttpSchemes;
  import org.eclipse.jetty.http.HttpStatus;
  import org.eclipse.jetty.io.Buffer;
  
  /**
   * RedirectListener
   *
   * Detect and handle the redirect responses
   */
  public class RedirectListener extends HttpEventListenerWrapper
  {
      private final HttpExchange _exchange;
      private HttpDestination _destination;
      private String _location;
      private int _attempts;
      private boolean _requestComplete;
      private boolean _responseComplete;
      private boolean _redirected;
  
      public RedirectListener(HttpDestination destination, HttpExchange ex)
      {
          // Start of sending events through to the wrapped listener
          // Next decision point is the onResponseStatus
          super(ex.getEventListener(),true);
  
          _destination = destination;
          _exchange = ex;
      }
  
      @Override
      public void onResponseStatus( Buffer version, int status, Buffer reason )
          throws IOException
      {
          _redirected = ((status == HttpStatus.MOVED_PERMANENTLY_301 ||
                          status == HttpStatus.MOVED_TEMPORARILY_302) &&
                         _attempts < _destination.getHttpClient().maxRedirects());
  
          if (_redirected)
          {
              setDelegatingRequests(false);
              setDelegatingResponses(false);
          }
  
          super.onResponseStatus(version,status,reason);
      }
  
  
      @Override
      public void onResponseHeader( Buffer name, Buffer value )
          throws IOException
      {
          if (_redirected)
          {
              int header = HttpHeaders.CACHE.getOrdinal(name);
              switch (header)
              {
                  case HttpHeaders.LOCATION_ORDINAL:
                      _location = value.toString();
                      break;
              }
          }
          super.onResponseHeader(name,value);
      }
  
      @Override
      public void onRequestComplete() throws IOException
      {
          _requestComplete = true;
  
          if (checkExchangeComplete())
          {
              super.onRequestComplete();
          }
      }
  
      @Override
      public void onResponseComplete() throws IOException
      {
          _responseComplete = true;
  
          if (checkExchangeComplete())
         {
             super.onResponseComplete();
         }
     }
 
     public boolean checkExchangeComplete()
         throws IOException
     {
         if (_redirected && _requestComplete && _responseComplete)
         {
             if (_location != null)
             {
                 if (_location.indexOf("://")>0)
                 {
                     _exchange.setURL(_location);
                 }
                 else
                 {
                     _exchange.setRequestURI(_location);
                 }
 
                 // destination may have changed
                 boolean isHttps = HttpSchemes.HTTPS.equals(String.valueOf(_exchange.getScheme()));
                 HttpDestination destination=_destination.getHttpClient().getDestination(_exchange.getAddress(),isHttps);
 
                 if (_destination==destination)
                 {
                     _destination.resend(_exchange);
                 }
                 else
                 {
                     // unwrap to find ultimate listener.
                     HttpEventListener listener=this;
                     while(listener instanceof HttpEventListenerWrapper)
                     {
                         listener=((HttpEventListenerWrapper)listener).getEventListener();
                     }
                     
                     //reset the listener
                     _exchange.getEventListener().onRetry();
                     _exchange.reset();
                     _exchange.setEventListener(listener);
 
                     // Set the new Host header
                     Address address = _exchange.getAddress();
                     int port = address.getPort();
                     StringBuilder hostHeader = new StringBuilder( 64 );
                     hostHeader.append( address.getHost() );
                     if( !( ( port == 80 && !isHttps ) || ( port == 443 && isHttps ) ) ) 
                     {
                         hostHeader.append( ':' );
                         hostHeader.append( port );
                     }
                     
                     _exchange.setRequestHeader( HttpHeaders.HOST, hostHeader.toString() );
 
                     destination.send(_exchange);
                 }
 
                 return false;
             }
             else
             {
                 setDelegationResult(false);
             }
         }
 
         return true;
     }
 
     public void onRetry()
     {
         _redirected=false;
         _attempts++;
 
         setDelegatingRequests(true);
         setDelegatingResponses(true);
 
         _requestComplete=false;
         _responseComplete=false;
 
         super.onRetry();
     }
 
     /**
      * Delegate failed connection
      */
     @Override
     public void onConnectionFailed( Throwable ex )
     {
         setDelegatingRequests(true);
         setDelegatingResponses(true);
 
         super.onConnectionFailed( ex );
     }
 
     /**
      * Delegate onException
      */
     @Override
     public void onException( Throwable ex )
     {
         setDelegatingRequests(true);
         setDelegatingResponses(true);
 
         super.onException( ex );
     }
 }