/**
  * Validate coupon code input data
  * @author Anyun
  * @param  int $code
  * @return  
  */
 public static function isCouponAvailable($code)
 {
     $app = \Slim\Slim::getInstance();
     $validata = $app->validata;
     if (!trim($code)) {
         $app->halt(400);
     }
     $coupon = Coupon::valid()->where('code', 'like', trim($code))->get();
     if (!$coupon) {
         $app->halt(400, 'Cart Info is invalid.');
     }
 }