/* Copyright (c) 2010-2012 Jesper Öqvist <jesper@llbit.se>
 *
 * This file is part of Chunky.
 *
 * Chunky 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.
 *
 * Chunky 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 Chunky.  If not, see <http://www.gnu.org/licenses/>.
 */
package se.llbit.chunky.world;

import java.util.HashMap;
import java.util.Map;

/**
 * A chunk position consists of two integer coordinates x and z.
 * <p>
 * The filename of a chunk is uniquely defined by it's position.
 *
 * @author Jesper Öqvist (jesper@llbit.se)
 */
public class ChunkPosition {
  public int x, z;

  private ChunkPosition(int x, int z) {
    this.x = x;
    this.z = z;
  }

  @Override public String toString() {
    return "[" + x + ", " + z + "]";
  }

  public ChunkPosition regionPosition() {
    return get(x >> 5, z >> 5);
  }

  private final static Map<Integer, Map<Integer, ChunkPosition>> map = new HashMap<>();

  public synchronized static ChunkPosition get(int x, int z) {
    Map<Integer, ChunkPosition> submap = map.get(x);
    if (submap == null) {
      submap = new HashMap<>();
      map.put(x, submap);
    }

    ChunkPosition chunkPosition = submap.get(z);
    if (chunkPosition == null) {
      chunkPosition = new ChunkPosition(x, z);
      submap.put(z, chunkPosition);
    }

    return chunkPosition;
  }

  /**
   * @return The .mca name for the region with this position
   */
  public String getMcaName() {
    return String.format("r.%d.%d.mca", x, z);
  }

  /**
   * @return The long representation of the chunk position
   */
  public long getLong() {
    return (((long) x) << 32) | (0xFFFFFFFFL & z);
  }

  /**
   * @return Decoded chunk position
   */
  public static ChunkPosition get(long longValue) {
    return get((int) (longValue >>> 32), (int) longValue);
  }

  /**
   * @return Integer representation of chunk position
   */
  public int getInt() {
    return (x << 16) | (0xFFFF & z);
  }

  /**
   * @return The region position of a this chunk position
   */
  public ChunkPosition getRegionPosition() {
    return get(x >> 5, z >> 5);
  }
}