App\Ninja\Presenters\InvoicePresenter::paymentStatus PHP Method

    public function paymentStatus()
    {
        if (!$this->entity->balance) {
            return 'PaymentComplete';
        } elseif ($this->entity->isOverdue()) {
            return 'PaymentPastDue';
        } else {
            return 'PaymentDue';
        }
    }