/*

  *   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 java.util.Date;

 import java.util.List;

 import org.sonews.daemon.AbstractDaemon;

 import org.sonews.config.Config;

 import org.sonews.storage.Article;

 import org.sonews.storage.Headers;

 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.get().warning("Purger interrupted: " + ex);

 		}

 	}

 	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.get().info("Group " + group.getName() + " purged.");

 				}

 				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.get().info("Article " + art.getMessageID() + " purged.");

 				}

 			}

 		}

 	}

 	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.get().info("Purging old messages...");

 			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.get().warning("Could not parse date string: " + dateStr + " " + ex);

 			}

 			// 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.get().info("Lifetime purger is disabled");

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

 		}

 	}

 }