/* 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.io.File;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import se.llbit.log.Log;

/**
 * Utility methods to scan world directories for region files.
 *
 * @author Jesper Öqvist (jesper@llbit.se)
 */
public class WorldScanner {

  // TODO: use region discovery listener instead


  /**
   * Interface for world scan listeners
   */
  public interface Operator {
    /**
     * Called when a new region has been discovered.
     */
    void foundRegion(File worldDirectory, int x, int z);
  }


  private static final Pattern anvilPattern = Pattern.compile("r\\.([^\\.]+)\\.([^\\.]+)\\.mca");

  /**
   * Search for existing chunks in the given region directory.
   */
  public static void findExistingChunks(File regionDirectory, Operator operator) {
    if (!regionDirectory.exists())
      return;

    if (!regionDirectory.isDirectory()) {
      Log.warn(String
          .format("Failed to read region directory for world %s!", regionDirectory.getPath()));
      return;
    }

    for (File anvilFile : regionDirectory.listFiles()) {

      Matcher matcher = anvilPattern.matcher(anvilFile.getName());

      if (!anvilFile.isDirectory() && matcher.matches()) {

        String x = matcher.group(1);
        String z = matcher.group(2);
        if (x != null && z != null) {
          operator.foundRegion(regionDirectory, Integer.parseInt(x), Integer.parseInt(z));
        }
      }
    }
  }
}