/*
 * Copyright 2012 Hannes Janetzek
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General 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 Lesser General License for more details.
 *
 * You should have received a copy of the GNU Lesser General License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.renderer;

import org.oscim.generator.JobTile;
import org.oscim.renderer.layer.Layers;
import org.oscim.renderer.layer.TextItem;

public final class MapTile extends JobTile {

	/**
	 * VBO layout: - 16 bytes fill coordinates, n bytes polygon vertices, m
	 * bytes lines vertices
	 */
	BufferObject vbo;

	// TextTexture texture;

	/**
	 * Tile data set by TileGenerator:
	 */
	public TextItem labels;
	public Layers layers;

	/**
	 * tile has new data to upload to gl
	 */
	//boolean newData;

	/**
	 * tile is loaded and ready for drawing.
	 */
	//boolean isReady;

	/**
	 * tile is in view region.
	 */
	public boolean isVisible;

	/**
	 * pointer to access relatives in QuadTree
	 */
	public QuadTree rel;

	int lastDraw = 0;

	// keep track which tiles are locked as proxy for this tile
	final static int PROXY_CHILD1 = 1 << 0;
	final static int PROXY_CHILD2 = 1 << 1;
	final static int PROXY_CHILD3 = 1 << 2;
	final static int PROXY_CHILD4 = 1 << 3;
	final static int PROXY_PARENT = 1 << 4;
	final static int PROXY_GRAMPA = 1 << 5;
	final static int PROXY_HOLDER = 1 << 6;

	public byte proxies;

	// counting the tiles that use this tile as proxy
	byte refs;
	byte locked;

	// used when this tile sits in fo another tile.
	// e.g. x:-1,y:0,z:1 for x:1,y:0
	MapTile holder;

	MapTile(int tileX, int tileY, byte zoomLevel) {
		super(tileX, tileY, zoomLevel);
	}

	boolean isActive() {
		return state != 0;
	}

	boolean isLocked() {
		return locked > 0 || refs > 0;
	}

	void lock() {

		locked++;

		if (locked > 1)
			return;

		MapTile p = rel.parent.tile;

		if (p != null && (p.state != 0)) {
			proxies |= PROXY_PARENT;
			p.refs++;
		}

		// FIXME handle root-tile case?
		p = rel.parent.parent.tile;
		if (p != null && (p.state != 0)) {
			proxies |= PROXY_GRAMPA;
			p.refs++;
		}

		for (int j = 0; j < 4; j++) {
			if (rel.child[j] != null) {
				p = rel.child[j].tile;
				if (p != null && (p.state != 0)) {
					proxies |= (1 << j);
					p.refs++;
				}
			}
		}
	}

	void unlock() {

		locked--;

		if (locked > 0 || proxies == 0)
			return;

		if ((proxies & PROXY_PARENT) != 0)
			rel.parent.tile.refs--;

		if ((proxies & PROXY_GRAMPA) != 0)
			rel.parent.parent.tile.refs--;

		for (int i = 0; i < 4; i++) {
			if ((proxies & (1 << i)) != 0)
				rel.child[i].tile.refs--;
		}
		proxies = 0;
	}
}