/**
* Filter by city.
*
* @param string $city_id
* @return Builder
*/
public function city($city_id = null)
{
if (!$city_id) {
return;
}
$exploded = explode('region', $city_id);
if (count($exploded) > 1) {
$cities = Region::whereId($exploded[1])->first()->cities()->select('id')->get();
return $this->builder->whereIn('city_id', $cities);
}
return $this->builder->where('city_id', $city_id);
}
