/*

  * Copyright 1999,2004 The Apache Software Foundation.

  * 

  * Licensed 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.

  */

 package org.apache.commons.feedparser.locate.blogservice;

 import org.apache.commons.feedparser.FeedParserException;

 import org.apache.commons.feedparser.locate.*;

 /**

  * Models the Flickr image blog service, encapsulating whether a given weblog

  * is this type of service and where it usually keeps its feeds.

  * 

  * @author Brad Neuberg, bkn3@columbia.edu

  */

 public class Flickr extends BlogService {

     /** Returns whether we can trust the results of this blog service's 

      *  autodiscovery links.  For example, TextAmerica returns invalid 

      *  autodiscovery results.

      */

     public boolean hasValidAutoDiscovery() {

         return true;

     }

     /** Returns whether we should follow HTTP redirects for this blog service.

      *  Some services don't implement HTTP redirects correctly, while others,

      *  like Xanga, require it.

      */

     public boolean followRedirects() {

         return false;

     }

     /** Determines if the weblog at the given resource and with the given

      *  content is this blog service.

      * @param resource A full URI to this resource, such as 

      * "http://www.codinginparadise.org".

      * @param content The full HTML content at the resource's URL.

      * @throws FeedParserException Thrown if an error occurs while 

      * determining the type of this weblog.

      */

     public boolean isThisService(String resource, String content)

                                                 throws FeedParserException {

         return resource.indexOf( "flickr.com" ) != -1;

     }

     /**

      * Returns an array of FeedReferences that contains information on the

      * usual locations this blog service contains its feed.  The feeds should

      * be ordered by quality, so that higher quality feeds come before lower

      * quality ones (i.e. you would want to have an Atom FeedReference

      * object come before an RSS 0.91 FeedReference object in this list).

      * @param resource A URL to the given weblog that might be used to build

      * up where feeds are usually located.

      * @param content The full content of the resource URL, which might

      * be useful to determine where feeds are usually located.  This can be

      * null.

      * @throws FeedParserException Thrown if an error occurs while trying

      * to determine the usual locations of feeds for this service.

      */

     public FeedReference[] getFeedLocations(String resource,

                                             String content)

                                                 throws FeedParserException {

         resource = getBaseFeedPath(resource);

         //  * Input: http://flickr.com/photos/tags/cats/

         //  *

         //  * Output: http://flickr.com/services/feeds/photos_public.gne?tags=cats&format=atom_03

         if ( resource == null )

             return new FeedReference[0];

         int begin = resource.indexOf( "/tags/" );

         //we can't continue here.

         if ( begin == -1 )

             return new FeedReference[0];

         begin += 6;

         int end = resource.lastIndexOf( "/" );

         if ( end == -1 || end < begin )

             end = resource.length();

         String tag = resource.substring( begin, end );

         String location = "http://flickr.com/services/feeds/photos_public.gne?tags=" +

                           tag +

                           "&format=atom_03";

         FeedReference flickrLocations[] =

                 { new FeedReference(location, 

                                     FeedReference.ATOM_MEDIA_TYPE) };

         return flickrLocations;

     }

 }