/*
 * 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.geo.pathfinding.utils;

import silentium.gameserver.geo.pathfinding.geonodes.GeoNode;

/**
 * @author -Nemesiss-
 */
public class BinaryNodeHeap
{
	private final GeoNode[] _list;
	private int _size;

	public BinaryNodeHeap(int size)
	{
		_list = new GeoNode[size + 1];
		_size = 0;
	}

	public void add(GeoNode n)
	{
		_size++;
		int pos = _size;
		_list[pos] = n;

		while (pos != 1)
		{
			int p2 = pos / 2;
			if (_list[pos].getCost() <= _list[p2].getCost())
			{
				GeoNode temp = _list[p2];
				_list[p2] = _list[pos];
				_list[pos] = temp;
				pos = p2;
			}
			else
				break;
		}
	}

	public GeoNode removeFirst()
	{
		GeoNode first = _list[1];
		_list[1] = _list[_size];
		_list[_size] = null;
		_size--;

		int pos = 1;
		int cpos, dblcpos;
		GeoNode temp;

		while (true)
		{
			cpos = pos;
			dblcpos = cpos * 2;
			if ((dblcpos + 1) <= _size)
			{
				if (_list[cpos].getCost() >= _list[dblcpos].getCost())
					pos = dblcpos;

				if (_list[pos].getCost() >= _list[dblcpos + 1].getCost())
					pos = dblcpos + 1;
			}
			else if (dblcpos <= _size)
			{
				if (_list[cpos].getCost() >= _list[dblcpos].getCost())
					pos = dblcpos;
			}

			if (cpos != pos)
			{
				temp = _list[cpos];
				_list[cpos] = _list[pos];
				_list[pos] = temp;
			}
			else
				break;
		}
		return first;
	}

	public boolean contains(GeoNode n)
	{
		if (_size == 0)
			return false;

		for (int i = 1; i <= _size; i++)
		{
			if (_list[i].equals(n))
				return true;
		}
		return false;
	}

	public boolean isEmpty()
	{
		return _size == 0;
	}
}