/**
  * Remove existing payment
  *
  * @param void
  * @return null
  */
 function delete()
 {
     if ($this->active_invoice->isNew()) {
         $this->httpError(HTTP_ERR_NOT_FOUND);
     }
     // if
     if ($this->active_invoice_payment->isNew()) {
         $this->httpError(HTTP_ERR_NOT_FOUND);
     }
     // if
     if (!$this->active_invoice_payment->canDelete($this->logged_user)) {
         $this->httpError(HTTP_ERR_FORBIDDEN);
     }
     // if
     if ($this->request->isSubmitted()) {
         $delete = $this->active_invoice_payment->delete();
         if ($delete && !is_error($delete)) {
             flash_success('Payment has been successfully deleted');
         } else {
             flash_error('Failed to delete selected payment');
         }
         // if
         $this->redirectToUrl($this->active_invoice->getViewUrl());
     } else {
         $this->httpError(HTTP_ERR_BAD_REQUEST);
     }
     // if
 }