/*
 * Copyright (C) 2004-2015 L2J Server
 * 
 * This file is part of L2J Server.
 * 
 * L2J Server 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.
 * 
 * L2J Server 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 com.l2jserver.gameserver.taskmanager;

import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

import com.l2jserver.Config;
import com.l2jserver.gameserver.model.actor.L2Attackable;
import com.l2jserver.gameserver.model.actor.L2Character;
import com.l2jserver.gameserver.model.actor.templates.L2NpcTemplate;

/**
 * @author NosBit
 */
public final class DecayTaskManager
{
	private final ScheduledExecutorService _decayExecutor = Executors.newSingleThreadScheduledExecutor();
	
	protected final Map<L2Character, ScheduledFuture<?>> _decayTasks = new ConcurrentHashMap<>();
	
	/**
	 * Adds a decay task for the specified character.<br>
	 * <br>
	 * If the decay task already exists it cancels it and re-adds it.
	 * @param character the character
	 */
	public void add(L2Character character)
	{
		if (character == null)
		{
			return;
		}
		
		long delay;
		if (character.getTemplate() instanceof L2NpcTemplate)
		{
			delay = ((L2NpcTemplate) character.getTemplate()).getCorpseTime();
		}
		else
		{
			delay = Config.DEFAULT_CORPSE_TIME;
		}
		
		if ((character instanceof L2Attackable) && (((L2Attackable) character).isSpoiled() || ((L2Attackable) character).isSeeded()))
		{
			delay += Config.SPOILED_CORPSE_EXTEND_TIME;
		}
		
		add(character, delay, TimeUnit.SECONDS);
	}
	
	/**
	 * Adds a decay task for the specified character.<br>
	 * <br>
	 * If the decay task already exists it cancels it and re-adds it.
	 * @param character the character
	 * @param delay the delay
	 * @param timeUnit the time unit of the delay parameter
	 */
	public void add(L2Character character, long delay, TimeUnit timeUnit)
	{
		ScheduledFuture<?> decayTask = _decayExecutor.schedule(new DecayTask(character), delay, TimeUnit.SECONDS);
		
		decayTask = _decayTasks.put(character, decayTask);
		// if decay task already existed cancel it so we use the new time
		if (decayTask != null)
		{
			if (!decayTask.cancel(false))
			{
				// old decay task was completed while canceling it remove and cancel the new one
				decayTask = _decayTasks.remove(character);
				if (decayTask != null)
				{
					decayTask.cancel(false);
				}
			}
		}
	}
	
	/**
	 * Cancels the decay task of the specified character.
	 * @param character the character
	 */
	public void cancel(L2Character character)
	{
		final ScheduledFuture<?> decayTask = _decayTasks.remove(character);
		if (decayTask != null)
		{
			decayTask.cancel(false);
		}
	}
	
	/**
	 * Gets the remaining time of the specified character's decay task.
	 * @param character the character
	 * @return if a decay task exists the remaining time, {@code Long.MAX_VALUE} otherwise
	 */
	public long getRemainingTime(L2Character character)
	{
		final ScheduledFuture<?> decayTask = _decayTasks.get(character);
		if (decayTask != null)
		{
			return decayTask.getDelay(TimeUnit.MILLISECONDS);
		}
		
		return Long.MAX_VALUE;
	}
	
	private class DecayTask implements Runnable
	{
		private final L2Character _character;
		
		protected DecayTask(L2Character character)
		{
			_character = character;
		}
		
		@Override
		public void run()
		{
			_decayTasks.remove(_character);
			_character.onDecay();
		}
	}
	
	@Override
	public String toString()
	{
		StringBuilder ret = new StringBuilder();
		ret.append("============= DecayTask Manager Report ============");
		ret.append(Config.EOL);
		ret.append("Tasks count: ");
		ret.append(_decayTasks.size());
		ret.append(Config.EOL);
		ret.append("Tasks dump:");
		ret.append(Config.EOL);
		
		for (Entry<L2Character, ScheduledFuture<?>> entry : _decayTasks.entrySet())
		{
			ret.append("Class/Name: ");
			ret.append(entry.getKey().getClass().getSimpleName());
			ret.append('/');
			ret.append(entry.getKey().getName());
			ret.append(" decay timer: ");
			ret.append(entry.getValue().getDelay(TimeUnit.MILLISECONDS));
			ret.append(Config.EOL);
		}
		
		return ret.toString();
	}
	
	public static DecayTaskManager getInstance()
	{
		return SingletonHolder._instance;
	}
	
	private static class SingletonHolder
	{
		protected static final DecayTaskManager _instance = new DecayTaskManager();
	}
}