/*******************************************************************************
 * Copyright (c) 2012 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.maps.tile;

/**
 * @author Tuukka Lehtonen
 *
 */
public class TileKey {

    /**
     * Valid values within {0, 1, 2,... , n}. When the value is 0, the only
     * valid (x,y) values are in {(0,0), (1,0)}, meaning half of the whole
     * globe. Every time the value of level increases by one, the map is
     * subdivided by 4 in the x direction and by two in the y direction, i.e.
     * into eight equal size parts.
     */
    private final int level;

    private final int x;

    private final int y;

    private final int hash;

    public TileKey(int level, int x, int y) {
        this.level = level;
        this.x = x;
        this.y = y;
        this.hash = hash();
    }

    private int hash() {
        final int prime = 31;
        int result = 1;
        result = prime * result + level;
        result = prime * result + x;
        result = prime * result + y;
        return result;
    }

    public int getLevel() {
        return level;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    @Override
    public int hashCode() {
        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        final TileKey other = (TileKey) obj;
        if (level != other.level)
            return false;
        if (x != other.x)
            return false;
        if (y != other.y)
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "TileKey [level=" + level + ", x=" + x + ", y=" + y + "]";
    }

}