package org.esigate.impl;
   
   import java.net.URI;
   
   import org.apache.commons.lang3.StringUtils;
   import org.apache.http.HttpRequest;
   import org.apache.http.HttpResponse;
   import org.apache.http.HttpStatus;
   import org.apache.http.ProtocolException;
  import org.apache.http.client.methods.HttpGet;
  import org.apache.http.client.methods.HttpHead;
  import org.apache.http.client.methods.HttpUriRequest;
  import org.apache.http.client.methods.RequestBuilder;
  import org.apache.http.impl.client.DefaultRedirectStrategy;
  import org.apache.http.protocol.HttpContext;
  import org.esigate.api.RedirectStrategy2;
  import org.esigate.http.OutgoingRequest;
  import org.esigate.http.ResourceUtils;
  import org.esigate.util.UriUtils;
  
  /**
   * The redirect strategy for fetching fragments.
   * 
   * <p>
   * This strategy is based on {@link DefaultRedirectStrategy} but differs for local redirections:
   * 
   * <p>
   * If a local (same provider) redirection is detected, the URI is returned as relative. This ensure that a public
   * (visible) url is not used instead of the provider url for the next requests.
   * 
   * @author Nicolas Richeton
   * 
   */
  public class FragmentRedirectStrategy implements RedirectStrategy2 {
      private final DefaultRedirectStrategy redirectStrategy = new DefaultRedirectStrategy();
  
      /**
       * @see DefaultRedirectStrategy#isRedirected(HttpRequest, HttpResponse, HttpContext)
       */
      @Override
      public boolean isRedirected(HttpRequest request, HttpResponse response, HttpContext context)
              throws ProtocolException {
          return this.redirectStrategy.isRedirected(request, response, context);
      }
  
      /**
       * @see DefaultRedirectStrategy#getRedirect(HttpRequest, HttpResponse, HttpContext)
       */
      @Override
      public HttpUriRequest getRedirect(HttpRequest request, HttpResponse response, HttpContext context)
              throws ProtocolException {
  
          // Code from DefaultRedirectStrategy
          // To ensure usage of the local getLocationURI implementation.
  
          final URI uri = getLocationURI(request, response, context);
          final String method = request.getRequestLine().getMethod();
          if (method.equalsIgnoreCase(HttpHead.METHOD_NAME)) {
              return new HttpHead(uri);
          } else if (method.equalsIgnoreCase(HttpGet.METHOD_NAME)) {
              return new HttpGet(uri);
          } else {
              final int status = response.getStatusLine().getStatusCode();
              if (status == HttpStatus.SC_TEMPORARY_REDIRECT) {
                  return RequestBuilder.copy(request).setUri(uri).build();
              } else {
                  return new HttpGet(uri);
              }
          }
      }
  
      /**
       * For local redirects, converts to relative urls.
       * 
       * @param request
       *            must be an {@link OutgoingRequest}.
       */
      @Override
      public URI getLocationURI(HttpRequest request, HttpResponse response, HttpContext context) throws ProtocolException {
          URI uri = this.redirectStrategy.getLocationURI(request, response, context);
  
          String resultingPageUrl = uri.toString();
  
          DriverRequest driverRequest = ((OutgoingRequest) request).getOriginalRequest();
  
          // Remove context if present
          if (StringUtils.startsWith(resultingPageUrl, driverRequest.getVisibleBaseUrl())) {
              resultingPageUrl =
                      "/"
                              + StringUtils.stripStart(
                                      StringUtils.replace(resultingPageUrl, driverRequest.getVisibleBaseUrl(), ""), "/");
          }
          resultingPageUrl = ResourceUtils.getHttpUrlWithQueryString(resultingPageUrl, driverRequest, false);
  
          return UriUtils.createURI(ResourceUtils.getHttpUrlWithQueryString(resultingPageUrl, driverRequest, false));
      }
  
  }