/**
 * Implementation of the pathauto_node hook
 *
 * @arg $op
 *    the operation to perform -- currently 'placeholders' or 'values'
 * @arg $node
 *    if called with $op='value', generate the placeholder values for $node
 * @return
 *    returns the placeholder names or values for the given node
 */
function audio_pathauto_node($op, $node=null) {
  switch ($op) {
  case 'placeholders':
    return array(t('[audioalbum]') => t('The album name of the audio file.'),
                 t('[audioartist]') => t('The artist name of the audio file.'),
                 t('[audiogenre]') => t('The genre of the audio file.'),
                 t('[audiotitle]') => t('The title of the audio file.'),
                 t('[audiotrack]') => t('The track number of the audio file.'),
                 t('[audioyear]') => t('The year of the audio file.'));
  case 'values':
    {
      $empty = array(t('[audioalbum]') => '',
                     t('[audioartist]') => '',
                     t('[audiogenre]') => '',
                     t('[audiotitle]') => '',
                     t('[audiotrack]') => '',
                     t('[audioyear]') => '');
      if ($node->type != 'audio')
        return $empty;
      if (!$node->audio)
        $node = node_load(array('nid' => $node->nid));
      if (empty($node->audio))
        return $empty;
      return array(t('[audioalbum]') => pathauto_cleanstring($node->audio['album']),
                   t('[audioartist]') => pathauto_cleanstring($node->audio['artist']),
                   t('[audiogenre]') => pathauto_cleanstring($node->audio['genre']),
                   t('[audiotitle]') => pathauto_cleanstring($node->audio['title']),
                   t('[audiotrack]') => pathauto_cleanstring($node->audio['track']),
                   t('[audioyear]') => pathauto_cleanstring($node->audio['year']));
    }
  }
}