content: /*
   This file is part of Airsonic.
  
   Airsonic 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.
  
   Airsonic 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 Airsonic.  If not, see <http://www.gnu.org/licenses/>.
  
   Copyright 2016 (C) Airsonic Authors
   Based upon Subsonic, Copyright 2009 (C) Sindre Mehus
   */
  package org.airsonic.player.service.metadata;
  
  import org.airsonic.player.domain.MediaFile;
  import org.airsonic.player.domain.MusicFolder;
  import org.airsonic.player.service.SettingsService;
  import org.apache.commons.io.FilenameUtils;
  import org.apache.commons.lang.StringUtils;
  
  import java.io.File;
  import java.util.List;
  
  
  /**
   * Parses meta data from media files.
   *
   * @author Sindre Mehus
   */
  public abstract class MetaDataParser {
  
      /**
       * Parses meta data for the given file.
       *
       * @param file The file to parse.
       * @return Meta data for the file, never null.
       */
      public MetaData getMetaData(File file) {
  
          MetaData metaData = getRawMetaData(file);
          String artist = metaData.getArtist();
          String albumArtist = metaData.getAlbumArtist();
          String album = metaData.getAlbumName();
          String title = metaData.getTitle();
  
          if (artist == null) {
              artist = guessArtist(file);
          }
          if (albumArtist == null) {
              albumArtist = guessArtist(file);
          }
          if (album == null) {
              album = guessAlbum(file, artist);
          }
          if (title == null) {
              title = guessTitle(file);
          }
  
          title = removeTrackNumberFromTitle(title, metaData.getTrackNumber());
          metaData.setArtist(artist);
          metaData.setAlbumArtist(albumArtist);
          metaData.setAlbumName(album);
          metaData.setTitle(title);
  
          return metaData;
      }
  
      /**
       * Parses meta data for the given file. No guessing or reformatting is done.
       *
       *
       * @param file The file to parse.
       * @return Meta data for the file.
       */
      public abstract MetaData getRawMetaData(File file);
  
      /**
       * Updates the given file with the given meta data.
       *
       * @param file     The file to update.
       * @param metaData The new meta data.
       */
      public abstract void setMetaData(MediaFile file, MetaData metaData);
  
      /**
       * Returns whether this parser is applicable to the given file.
       *
       * @param file The file in question.
       * @return Whether this parser is applicable to the given file.
       */
      public abstract boolean isApplicable(File file);
  
      /**
       * Returns whether this parser supports tag editing (using the {@link #setMetaData} method).
       *
       * @return Whether tag editing is supported.
       */
      public abstract boolean isEditingSupported();
  
      /**
       * Guesses the artist for the given file.
       */
      String guessArtist(File file) {
          File parent = file.getParentFile();
          if (isRoot(parent)) {
              return null;
          }
          File grandParent = parent.getParentFile();
          return isRoot(grandParent) ? null : grandParent.getName();
      }
  
      /**
       * Guesses the album for the given file.
       */
      String guessAlbum(File file, String artist) {
          File parent = file.getParentFile();
          String album = isRoot(parent) ? null : parent.getName();
          if (artist != null && album != null) {
              album = album.replace(artist + " - ", "");
          }
          return album;
      }
  
      /**
       * Guesses the title for the given file.
       */
      public String guessTitle(File file) {
          return StringUtils.trim(FilenameUtils.getBaseName(file.getPath()));
      }
  
      private boolean isRoot(File file) {
          SettingsService settings = getSettingsService();
          List<MusicFolder> folders = settings.getAllMusicFolders(false, true);
          for (MusicFolder folder : folders) {
              if (file.equals(folder.getPath())) {
                  return true;
              }
          }
          return false;
      }
  
      abstract SettingsService getSettingsService();
  
      /**
       * Removes any prefixed track number from the given title string.
       *
       * @param title       The title with or without a prefixed track number, e.g., "02 - Back In Black".
       * @param trackNumber If specified, this is the "true" track number.
       * @return The title with the track number removed, e.g., "Back In Black".
       */
      protected String removeTrackNumberFromTitle(String title, Integer trackNumber) {
          title = title.trim();
  
          // Don't remove numbers if true track number is missing, or if title does not start with it.
          if (trackNumber == null || !title.matches("0?" + trackNumber + "[. -].*")) {
              return title;
          }
  
          String result = title.replaceFirst("^\\d{2}[. -]+", "");
          return result.isEmpty() ? title : result;
      }
  }