trait GeofieldBoundaryHandlerTrait in Geofield 8

trait GeofieldBoundaryHandlerTrait {

  /**
   * Gets the query fragment for adding a boundary field to a query.
   *
   * @param string $table_name
   *   The proximity table name.
   * @param string $field_id
   *   The proximity field ID.
   * @param string $filter_lat_north_east
   *   The latitude to filter for.
   * @param string $filter_lon_north_east
   *   The longitude to filter for.
   * @param string $filter_lat_south_west
   *   The latitude to filter for.
   * @param string $filter_lon_south_west
   *   The longitude to filter for.
   *
   * @return string
   *   The fragment to enter to actual query.
   */
  public static function getBoundaryQueryFragment($table_name, $field_id, $filter_lat_north_east, $filter_lon_north_east, $filter_lat_south_west, $filter_lon_south_west) {

    // Define the field name.
    $field_lat = "{$table_name}.{$field_id}_lat";
    $field_lon = "{$table_name}.{$field_id}_lon";

    /*
     * Map shows a map, not a globe. Therefore it will never flip over
     * the poles, but it will move across -180°/+180° longitude.
     * So latitude will always have north larger than south, but east not
     * necessarily larger than west.
     */
    return "({$field_lat} BETWEEN {$filter_lat_south_west} AND {$filter_lat_north_east})\n      AND\n      (\n        ({$filter_lon_south_west} < {$filter_lon_north_east} AND {$field_lon} BETWEEN {$filter_lon_south_west} AND {$filter_lon_north_east})\n        OR\n        (\n          {$filter_lon_south_west} > {$filter_lon_north_east} AND (\n            {$field_lon} BETWEEN {$filter_lon_south_west} AND 180 OR {$field_lon} BETWEEN -180 AND {$filter_lon_north_east}\n          )\n        )\n      )\n    ";
  }

}