Here is an example of how to get a query Filter from a list of Facet and user query (how to apply a facet on a query) with Elastica.

facets.php

<?php
  /**
   * Return query Filter from a list of query string & allowed Facets
   *
   * @param array   $query            The user query (facet_name => query, facet_name => query...)
   * @param array   $allowed_facets   An array of Elastica\Facet
   *
   * @return \Elastica\Filter\AbstractFilter (if multiple filters, they are combined in BoolAnd filter)
   */
  private function getFacetsFilters($query, $allowed_facets)
  {
    $filters = array();
    if (!is_array($query)) {
      return false;
    }

    if (!$allowed_facets || !is_array($allowed_facets) || empty($allowed_facets)) {
      return false;
    }

    foreach ($query as $facet_name => $term)
    {
      $facet = false;
      foreach ($allowed_facets as $allowed_facet) {
        if ($allowed_facet->getName() === $facet_name) {
          $facet = $allowed_facet; break;
        }
      }

      if ($facet instanceof AbstractFacet) {
        switch (get_class($facet))
        {
          case 'Elastica\Facet\Terms':
            $filters[] = new \Elastica\Filter\Terms($facet->getParam('field'), array($term));
            break;
          case 'Elastica\Facet\Range':
            $ranges = $facet->getParam('ranges');
            if (isset($ranges[(int) $term])) {
              $filters[] = new \Elastica\Filter\NumericRange($facet->getParam('field'), $ranges[(int) $term]);
            }
            break;
          case 'Elastica\Facet\Filter':
            $facet_filters = $facet->toArray();
            if (isset($facet_filters['filter']['exists'])) {
              $filters[] = new \Elastica\Filter\Exists($facet_filters['filter']['exists']['field']);
            } else {
              throw new \Exception(sprintf('The "%s" facet query filter cant be set', $facet_name));
            }
            break;
          default:
            throw new \Exception(sprintf('The "%s" facet query filter is not implemented!!', $facet_name));
        }
      }
    }

    if (count($filters) > 1) {
      $and = new \Elastica\Filter\BoolAnd();

      foreach ($filters as $filter) {
        $and->addFilter($filter);
      }

      return $and;
    } elseif (count($filters) === 1) {
      return $filters[0];
    } else {
      return false;
    }
  }