/*
 * 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 com.edelvez.gameserver.pathfinding.utils;

import com.edelvez.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;
	}
}
