protected function getAjaxUrlAndRouteName(FormInterface $form, array $options)
    {
        $ajaxUrl = $this->requestStack->getMasterRequest()->getRequestUri();
        $routeName = null;

        if ($options['select2']['ajax']) {
            if (null !== $options['select2']['ajax_url']) {
                $ajaxUrl = $options['select2']['ajax_url'];
                $routeName = 'custom_url';
            } else {
                $routeName = $form->getConfig()->getAttribute('select2_ajax_route', $options['select2']['ajax_route']);

                if (null !== $routeName) {
                    $routeParams = $options['select2']['ajax_parameters'];
                    $routeReferenceType = $options['select2']['ajax_reference_type'];
                    $ajaxUrl = $this->router->generate($routeName, $routeParams, $routeReferenceType);
                }
            }
        }

        return [$ajaxUrl, $routeName];
    }