package net.sf.logdistiller.publishers;
   
   /*
    * 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.
   */
  
  import java.io.*;
  import java.util.*;
  
  import com.sun.syndication.feed.synd.*;
  import com.sun.syndication.io.FeedException;
  import com.sun.syndication.io.SyndFeedInput;
  import com.sun.syndication.io.SyndFeedOutput;
  
  import net.sf.logdistiller.*;
  
  /**
   * Adds LogDistillation reports to a feed file (at the beginning). Any feed format supported by Rome can be used.
   * <p>
   * Parameters (as direct publisher param or global <code>feed.*</code> param):
   * <ul>
   * <li><code>filename</code> (default: <code>feed.xml</code>): the feed file name (relative to output directory)</li>
   * <li><code>maxEntries</code> (default: 100): maximum entries in the feed file: if new entries are added, oldest ones
   * are removed</li>
   * </ul>
   * <p>
   * When the feed file must be created, these parameters are used:
   * <ul>
   * <li><code>type</code> (default: <code>atom_0.3</code>): the feed type (any value supported by Rome)</li>
   * <li><code>title</code>: the feed title (default: "LogDistiller [logdistillation id]"</li>
   * <li><code>link</code>: the feed link (default: LogDistiller's site)</li>
   * <li><code>description</code>: the feed description (default: "LogDistiller reports for [logdistillation id]"</li>
   * </ul>
   *
   * @since 0.7
   */
  public class FeedPublisher
      extends Publisher
  {
      public final static String DEFAULT_FEED_TYPE = "atom_0.3";
  
      public String getId()
      {
          return "feed";
      }
  
      public void publish( LogDistillation logdistillation, LogDistiller.Report report )
          throws IOException, PublishException
      {
          // prepare the data for the entry
          String content = logdistillation.getContent();
          String subject =
              "[logdistiller:" + logdistillation.getDefinition().getId() + "]"
                  + ( ( content == null ) ? "" : ( " " + content ) ) + " global report: "
                  + logdistillation.getEventCount() + " logevents";
          ReportFormat format = ReportFormats.getReportFormat( report.getFormat() );
          StringWriter sw = new StringWriter();
          format.report( logdistillation, sw );
          String body = sw.toString();
          String url = logdistillation.getDefinition().getOutput().getUrl();
  
          // create the new entry
          SyndEntry entry = createEntry( subject, url, format.getContentType(), body );
  
          // add it to the feed (creating it if necessary)
          addEntry( entry, logdistillation, report );
      }
  
      public void publish( LogDistillation.Group group, LogDistiller.Report report )
          throws IOException, PublishException
      {
          // prepare the data for the entry
          LogDistillation logdistillation = group.getLogdistillation();
          String content = logdistillation.getContent();
          String subject =
              "[logdistiller:" + logdistillation.getDefinition().getOutput().getId() + "]"
                  + ( ( content == null ) ? "" : ( " " + content ) ) + " report for group "
                  + group.getDefinition().getId() + ": " + group.getEventCount() + " logevents";
          ReportFormat format = ReportFormats.getReportFormat( report.getFormat() );
          StringWriter sw = new StringWriter();
          format.report( group, sw );
          String body = sw.toString();
          String url = logdistillation.getDefinition().getOutput().getUrl();
  
          // create the new entry
          SyndEntry entry = createEntry( subject, url, format.getContentType(), body );
  
          // add it to the feed (creating it if necessary)
          addEntry( entry, logdistillation, report );
     }
 
     /**
      * Create a new feed for the corresponding report.
      *
      * @param logdistillation
      * @param report
      * @return the new feed
      */
     private SyndFeed createFeed( LogDistillation logdistillation, LogDistiller.Report report )
     {
         String type = report.getParam( "type", DEFAULT_FEED_TYPE );
         String title = report.getParam( "title", "Logdistiller " + logdistillation.getDefinition().getOutput().getId() );
         String url = logdistillation.getDefinition().getOutput().getUrl();
         String link = report.getParam( "link", ( url == null ) ? "http://logdistiller.sf.net/" : url );
         String description =
             report.getParam( "description", "LogDistiller reports for "
                 + logdistillation.getDefinition().getOutput().getId() );
 
         SyndFeed feed = new SyndFeedImpl();
         feed.setFeedType( type );
         feed.setTitle( title );
         feed.setLink( link );
         feed.setDescription( description );
 
         return feed;
     }
 
     /**
      * Create a feed entry.
      *
      * @param title the title of the entry
      * @param link the link of the entry (or <code>null</code>)
      * @param contentType the content-type of the entry
      * @param contentValue the content of the entry
      * @return a new feed entry
      */
     private SyndEntry createEntry( String title, String link, String contentType, String contentValue )
     {
         SyndEntry entry = new SyndEntryImpl();
         entry.setTitle( title );
         if ( link != null )
         {
             entry.setLink( link );
         }
         entry.setPublishedDate( new Date() );
 
         SyndContent content = new SyndContentImpl();
         content.setType( contentType );
         content.setValue( contentValue );
         List<SyndContent> contents = new ArrayList<SyndContent>();
         contents.add( content );
 
         entry.setContents( contents );
         return entry;
     }
 
     /**
      * Add an entry to a feed report, creating the feed if necessary.
      *
      * @param entry the feed entry
      * @param logdistillation the current logdistillation
      * @param report the report configuration
      * @throws IOException
      * @throws PublishException
      */
     private void addEntry( SyndEntry entry, LogDistillation logdistillation, LogDistiller.Report report )
         throws IOException, PublishException
     {
         String filename = report.getParam( "filename", "feed.xml" );
         int maxEntries = Integer.parseInt( report.getParam( "maxEntries", "100" ) );
         File file = logdistillation.newDestinationFile( filename );
 
         // read or create the feed
         SyndFeed feed;
         if ( file.canRead() && ( file.length() > 0 ) )
         {
             SyndFeedInput input = new SyndFeedInput();
             try
             {
                 feed = input.build( file );
             }
             catch ( FeedException fe )
             {
                 throw new PublishException( "error while reading feed " + filename, fe );
             }
         }
         else
         {
             feed = createFeed( logdistillation, report );
         }
 
         // add the new entry
         List<SyndEntry> entries = feed.getEntries();
         entries.add( 0, entry );
         if ( entries.size() > maxEntries )
         {
             entries.remove( entries.size() - 1 );
         }
         feed.setEntries( entries );
 
         // write the feed content to the disk
         SyndFeedOutput output = new SyndFeedOutput();
         // write to a temporary file that will be swapped with the current file only on success
         File tmpFile = logdistillation.newDestinationFile( filename + ".tmp" );
         try
         {
             output.output( feed, tmpFile );
             // ok, we were able to write the whole feed: now we can rotate with the final file
             file.delete();
             tmpFile.renameTo( file );
         }
         catch ( FeedException fe )
         {
             throw new PublishException( "error while writing temporary feed " + filename + ".tmp", fe );
         }
         finally
         {
             tmpFile.delete();
         }
     }
 }