public function getInvoiceIdForPaymentGateway()
    {
        return
            implode(str_split(str_pad($this->getSeller()->getId(), 6, 0, STR_PAD_LEFT),3), '-')
            .' / '
            .implode(str_split(str_pad($this->getId(), 6, 0, STR_PAD_LEFT),3), '-')
            .' / '
            .$this->getSeller()->getName();
    }