Views selective filters show terms hierarchy

Question

I'm using Views Selective Filters, trying to expose taxonomy terms filters with its depth/hierarchy.

Whenever I configure a filter with criterion Content, for instance Country (field_country) where field_country is a term, I have this extra setting window to choose the widget :

Instead, with the same field, but selective filter option, that extra settings window doesn't appear.

The Exposed form style is provided by Better Exposed Filters, but I let the default style for that filter.

Is there a configuration step I'm missing ? A necessary module combination to achieve that ? Meanwhile, I updated to Views selective filters dev version, plus a patch providing taxonomy weight ordering for the filters. This is the relevant part, from views_handler_filter_selective.inc :

/**
 * Get list of options for current view, only at runtime.
 */
protected function get_oids() {
//...
// Sort values.
  $sort_option = $this->options['selective_display_sort'];
  switch($sort_option) {
    case 'WEIGHT':
      $terms = taxonomy_term_load_multiple(array_keys($oids));
      usort($terms, function($a, $b) {
        return $a->weight - $b->weight;
      });
      $oids_ordered_by_weight = array();
      foreach ($terms as $term) {
        $oids_ordered_by_weight["$term->tid"] = $oids[$term->tid];
      }
      $oids = $oids_ordered_by_weight;
      break;
  }

And I'm trying now to figure out how to overwrite that to show hierarchy instead.

Answer 1

I realised the BEF desired option "Nested checkboxes" was missing for all selective filters. Since into better_exposed_filters_exposed_form_plugin.inc, the missing option depends on :

if ($bef_nested) {
  $display_options['bef_ul'] = t('Nested Checkboxes/Radio Buttons');
}

So I added the following :

/* line 314 */
if ($filter instanceof views_handler_filter_selective) {
  $bef_nested = TRUE;
}
/* line 493 */
if ($bef_nested) {
  //...
  $bef_options[$label]['more_options']['bef_select_all_none_nested'] = array(
    '#disabled' => !$filter instanceof views_handler_filter_selective &&(!$filter->options['expose']['multiple'] || !$filter->options['hierarchy']),

I know this is a very quick hack and should be improved for general use. Alternate proposals are warmly welcome.

Last, I had to patch also Views selective filters handler, resulting in :

case 'HCHY':
  $options = array();
  //get remaining terms tids
  $remaining_terms = taxonomy_term_load_multiple(array_keys($oids));
  $tids = array();
  foreach ($remaining_terms as $term) {
    $tids[$term->tid] = $term->tid; 
  }
  //get vocabulary tree
  $anyterm = array_shift($remaining_terms); 
  $tree = taxonomy_get_tree($anyterm->vid);
  if ($tree) {
    //we flag the terms to avoid displaying them more than once
    $flagged = array();
    //we keep tree items if they match with current selection
    foreach ($tree as $trm) {
      if(in_array($trm->tid, $tids ) && !in_array($trm->tid, $flagged) ){
        //so we always keep its parents displayed
        $parents_all = taxonomy_get_parents_all($trm->tid);

        if($anyterm->vid == '3'){//country vocab, Three levels taxonomy
          switch (count($parents_all)) {
            case 3: 
              $parent = $parents_all[1];
              $gd_parent = $parents_all[2];
              break;
            case 2: 
              $gd_parent = $parents_all[1];
              break;
            default:
              break;
          }
          //Add the gd_parent to options
          if(!in_array($gd_parent->tid, $flagged) && !is_null($gd_parent->tid)){

            $gd_parent_depth = get_term_depth($gd_parent->tid)-1;
            $choice = new stdClass();
            $choice->option = array($gd_parent->tid => str_repeat('-', $gd_parent_depth) . $gd_parent->name);
            $options[] = $choice;
            $flagged[] = $gd_parent->tid;
          }   
          //Add the parent to options
          if(!in_array($parent->tid, $flagged) && !is_null($parent->tid)){

            $parent_depth = get_term_depth($parent->tid)-1;
            $choice2 = new stdClass();
            $choice2->option = array($parent->tid => str_repeat('-', $parent_depth) . $parent->name);
            $options[] = $choice2;
            $flagged[] = $parent->tid;
          }
        }

        //last, add the term itself to options
        $choice3 = new stdClass();
        $choice3->option = array($trm->tid => str_repeat('-', $trm->depth) . $trm->name);
        $options[] = $choice3;   
        $flagged[] = $trm->tid;
      }
    }
  }
  $oids = $options;

/*
 * Returns a term depth (https://www.drupal.org/node/886526#comment-7708315)
 */
function get_term_depth($tid) {
  $limit = 5;
  $depth = 0;
  while ($parent = db_select('taxonomy_term_hierarchy', 't') ->condition('tid', $tid, '=') ->fields('t') ->execute() ->fetchAssoc()) {
    $depth ++;
    $tid = $parent['parent'];
    if ($depth > $limit) {
      break;
    }
  }
  return $depth;
}

Both are necessary, usual nested checkboxes from BEF do not work as is. This might be useful for some of you.