Drupal Apache Solr: prevent facet's filtering influence on facet item count

gistfile1.php

<?php

  // Add tags to fq and facet.field fields to exclude each facet's filtering
  // from influencing its own facet item count
  // @see http://drupal.org/node/1446824#comment-5634040
  $params = $query->getParams();
  $fq = $params['fq'];

  if (!empty($fq)) {
    $facet_field = $params['facet.field'];

    foreach ($facet_field as $idx => $facet) {
      $tag = "PREFIX_$facet";

      $facet_field[$idx] = "{!ex=$tag}". $facet;

      foreach ($fq as &$option) {
        $label_end_pos = strpos($option, ':');
        $label = substr($option, 0, $label_end_pos);

        if ($label == $facet) {
          $option = "{!tag=$tag}". $option;
        }
      }

    }
    $query->replaceParam('fq', $fq);
    $query->replaceParam('facet.field', $facet_field);
  }