/* 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 2, 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * http://www.gnu.org/copyleft/gpl.html
 */
package com.l2dot.gameserver.pathfinding.utils;

import com.l2dot.gameserver.pathfinding.Node;

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

	public BinaryNodeHeap(int size)
	{
		_list = new Node[size+1];
		_size = 0;
	}
	public void add(Node n) {
		_size++;
		int pos  = _size;
		_list[pos] = n;
		while (pos != 1)
		{
			int p2 = pos/2;
			if (_list[pos].getCost() <= _list[p2].getCost())
			{
				Node temp = _list[p2];
				_list[p2] = _list[pos];
				_list[pos] = temp;
		        pos = p2;
			}
			else
				break;
		}
	}
	public Node removeFirst()
	{
		Node first = _list[1];
		_list[1] = _list[_size];
		_list[_size] = null;
		_size--;
		int pos = 1;
		int cpos;
		int dblcpos;
		Node 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(Node 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;
	}
}
