/*

  *   SONEWS News Server

  *   see AUTHORS for the list of contributors

  *

  *   This program is free software: you can redistribute it and/or modify

  *   it under the terms of the GNU General Public License as published by

  *   the Free Software Foundation, either version 3 of the License, or

  *   (at your option) any later version.

  *

  *   This program is distributed in the hope that it will be useful,

  *   but WITHOUT ANY WARRANTY; without even the implied warranty of

  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  *   GNU General Public License for more details.

  *

  *   You should have received a copy of the GNU General Public License

  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

  */

 package org.sonews.util;

 import org.sonews.daemon.AbstractDaemon;

 import org.sonews.config.Config;

 import org.sonews.storage.Article;

 import org.sonews.storage.Headers;

 import java.util.Date;

 import java.util.List;

 import org.sonews.storage.Channel;

 import org.sonews.storage.Group;

 import org.sonews.storage.StorageBackendException;

 import org.sonews.storage.StorageManager;

 /**

  * The purger is started in configurable intervals to search

  * for messages that can be purged. A message must be deleted if its lifetime

  * has exceeded, if it was marked as deleted or if the maximum number of

  * articles in the database is reached.

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public class Purger extends AbstractDaemon

 {

   /**

    * Loops through all messages and deletes them if their time

    * has come.

    */

   @Override

   public void run()

   {

     try

     {

       while(isRunning())

       {

         purgeDeleted();

         purgeOutdated();

         Thread.sleep(120000); // Sleep for two minutes

       }

     }

     catch(StorageBackendException ex)

     {

       ex.printStackTrace();

     }

     catch(InterruptedException ex)

     {

       Log.msg("Purger interrupted: " + ex, true);

     }

   }

   private void purgeDeleted()

     throws StorageBackendException

   {

     List<Channel> groups = StorageManager.current().getGroups();

     for(Channel channel : groups)

     {

       if(!(channel instanceof Group))

         continue;

       Group group = (Group)channel;

       // Look for groups that are marked as deleted

       if(group.isDeleted())

       {

         List<Long> ids = StorageManager.current().getArticleNumbers(group.getInternalID());

         if(ids.size() == 0)

         {

           StorageManager.current().purgeGroup(group);

           Log.msg("Group " + group.getName() + " purged.", true);

         }

         for(int n = 0; n < ids.size() && n < 10; n++)

         {

           Article art = StorageManager.current().getArticle(ids.get(n), group.getInternalID());

           StorageManager.current().delete(art.getMessageID());

           Log.msg("Article " + art.getMessageID() + " purged.", true);

         }

       }

     }

   }

   private void purgeOutdated()

     throws InterruptedException, StorageBackendException

   {

     long articleMaximum =

       Config.inst().get("sonews.article.maxnum", Long.MAX_VALUE);

     long lifetime =

       Config.inst().get("sonews.article.lifetime", -1);

     if(lifetime > 0 || articleMaximum < Stats.getInstance().getNumberOfNews())

     {

       Log.msg("Purging old messages...", true);

       String mid = StorageManager.current().getOldestArticle();

       if (mid == null) // No articles in the database

       {

         return;

       }

       Article art = StorageManager.current().getArticle(mid);

       long artDate = 0;

       String dateStr = art.getHeader(Headers.DATE)[0];

       try

       {

         artDate = Date.parse(dateStr) / 1000 / 60 / 60 / 24;

       }

       catch (IllegalArgumentException ex)

       {

         Log.msg("Could not parse date string: " + dateStr + " " + ex, true);

       }

       // Should we delete the message because of its age or because the

       // article maximum was reached?

       if (lifetime < 0 || artDate < (new Date().getTime() + lifetime))

       {

         StorageManager.current().delete(mid);

         System.out.println("Deleted: " + mid);

       }

       else

       {

         Thread.sleep(1000 * 60); // Wait 60 seconds

         return;

       }

     }

     else

     {

       Log.msg("Lifetime purger is disabled", true);

       Thread.sleep(1000 * 60 * 30); // Wait 30 minutes

     }

   }

 }