/*
 * 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 silentium.gameserver.taskmanager;

import java.util.Collection;

import javolution.util.FastSet;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import silentium.gameserver.ThreadPoolManager;
import silentium.gameserver.configs.NPCConfig;
import silentium.gameserver.model.L2Object;
import silentium.gameserver.model.L2World;
import silentium.gameserver.model.L2WorldRegion;
import silentium.gameserver.model.actor.L2Attackable;
import silentium.gameserver.model.actor.L2Character;
import silentium.gameserver.model.actor.L2Playable;
import silentium.gameserver.model.actor.instance.L2GuardInstance;

public class KnownListUpdateTaskManager
{
	protected static final Logger _log = LoggerFactory.getLogger(KnownListUpdateTaskManager.class.getName());

	private final static int FULL_UPDATE_TIMER = 100;
	public static boolean updatePass = true;

	// Do full update every FULL_UPDATE_TIMER * KNOWNLIST_UPDATE_INTERVAL
	public static int _fullUpdateTimer = FULL_UPDATE_TIMER;

	protected static final FastSet<L2WorldRegion> _failedRegions = new FastSet<>(1);

	protected KnownListUpdateTaskManager()
	{
		ThreadPoolManager.getInstance().scheduleAiAtFixedRate(new KnownListUpdate(), 1000, NPCConfig.KNOWNLIST_UPDATE_INTERVAL);
	}

	public static KnownListUpdateTaskManager getInstance()
	{
		return SingletonHolder._instance;
	}

	private class KnownListUpdate implements Runnable
	{
		public KnownListUpdate()
		{
		}

		@Override
		public void run()
		{
			try
			{
				boolean failed;
				for (L2WorldRegion regions[] : L2World.getInstance().getAllWorldRegions())
				{
					for (L2WorldRegion r : regions) // go through all world regions
					{
						// avoid stopping update if something went wrong in updateRegion()
						try
						{
							failed = _failedRegions.contains(r); // failed on last pass

							if (r.isActive()) // and check only if the region is active
								updateRegion(r, (_fullUpdateTimer == FULL_UPDATE_TIMER || failed), updatePass);

							if (failed)
								_failedRegions.remove(r); // if all ok, remove
						}
						catch (Exception e)
						{
							_log.warn("KnownListUpdateTaskManager: updateRegion(" + _fullUpdateTimer + "," + updatePass + ") failed for region " + r.getName() + ". Full update scheduled. " + e.getMessage(), e);
							_failedRegions.add(r);
						}
					}
				}
				updatePass = !updatePass;

				if (_fullUpdateTimer > 0)
					_fullUpdateTimer--;
				else
					_fullUpdateTimer = FULL_UPDATE_TIMER;
			}
			catch (Exception e)
			{
				_log.warn("", e);
			}
		}
	}

	public void updateRegion(L2WorldRegion region, boolean fullUpdate, boolean forgetObjects)
	{
		Collection<L2Object> vObj = region.getVisibleObjects().values();
		for (L2Object object : vObj) // and for all members in region
		{
			if (object == null || !object.isVisible())
				continue; // skip dying objects

			// Some mobs need faster knownlist update
			final boolean aggro = (NPCConfig.GUARD_ATTACK_AGGRO_MOB && object instanceof L2GuardInstance) || (object instanceof L2Attackable);

			if (forgetObjects)
			{
				object.getKnownList().forgetObjects(aggro || fullUpdate);
				continue;
			}

			for (L2WorldRegion regi : region.getSurroundingRegions())
			{
				if (object instanceof L2Playable || (aggro && regi.isActive()) || fullUpdate)
				{
					Collection<L2Object> inrObj = regi.getVisibleObjects().values();
					for (L2Object _object : inrObj)
						if (_object != object)
							object.getKnownList().addKnownObject(_object);
				}
				else if (object instanceof L2Character)
				{
					if (regi.isActive())
					{
						Collection<L2Playable> inrPls = regi.getVisiblePlayable().values();
						for (L2Object _object : inrPls)
							if (_object != object)
								object.getKnownList().addKnownObject(_object);
					}
				}
			}
		}
	}

	private static class SingletonHolder
	{
		protected static final KnownListUpdateTaskManager _instance = new KnownListUpdateTaskManager();
	}
}