Banktransfer: Show reference when switching payment method to bank transfer

src/pretix/base/payment.py

@@ -513,7 +513,7 @@ class BasePaymentProvider:
 
         return timing and pricing
 
-    def payment_form_render(self, request: HttpRequest, total: Decimal) -> str:
+    def payment_form_render(self, request: HttpRequest, total: Decimal, order: Order=None) -> str:
         """
         When the user selects this provider as their preferred payment method,
         they will be shown the HTML you return from this method.
@@ -522,13 +522,15 @@ class BasePaymentProvider:
         and render the returned form. If your payment method doesn't require
         the user to fill out form fields, you should just return a paragraph
         of explanatory text.
+
+        :param order: Only set when this is a change to a new payment method for an existing order.
         """
         form = self.payment_form(request)
         template = get_template('pretixpresale/event/checkout_payment_form_default.html')
         ctx = {'request': request, 'form': form}
         return template.render(ctx)
 
-    def checkout_confirm_render(self, request) -> str:
+    def checkout_confirm_render(self, request, order: Order=None) -> str:
         """
         If the user has successfully filled in their payment data, they will be redirected
         to a confirmation page which lists all details of their order for a final review.
@@ -537,6 +539,8 @@ class BasePaymentProvider:
 
         In most cases, this should include a short summary of the user's input and
         a short explanation on how the payment process will continue.
+
+        :param order: Only set when this is a change to a new payment method for an existing order.
         """
         raise NotImplementedError()  # NOQA
 

src/pretix/plugins/banktransfer/payment.py

@@ -155,12 +155,13 @@ class BankTransfer(BasePaymentProvider):
                     {'payment_banktransfer_bank_details': _('Please enter your bank account details.')})
         return cleaned_data
 
-    def payment_form_render(self, request) -> str:
+    def payment_form_render(self, request, total=None, order=None) -> str:
         template = get_template('pretixplugins/banktransfer/checkout_payment_form.html')
         ctx = {
             'request': request,
             'event': self.event,
             'settings': self.settings,
+            'code': self._code(order) if order else None,
             'details': self.settings.get('bank_details', as_type=LazyI18nString),
         }
         return template.render(ctx)
@@ -174,8 +175,8 @@ class BankTransfer(BasePaymentProvider):
     def payment_is_valid_session(self, request):
         return True
 
-    def checkout_confirm_render(self, request):
-        return self.payment_form_render(request)
+    def checkout_confirm_render(self, request, order=None):
+        return self.payment_form_render(request, order=order)
 
     def order_pending_mail_render(self, order, payment) -> str:
         template = get_template('pretixplugins/banktransfer/email/order_pending.txt')

src/pretix/plugins/banktransfer/templates/pretixplugins/banktransfer/checkout_payment_form.html

@@ -16,7 +16,11 @@
     {% if details %}
         {{ details|linebreaksbr }}<br>
     {% endif %}
-    <strong>
-        {% trans "We will assign you a personal reference code to use after you completed the order." %}
-    </strong>
+    {% if code %}
+        <strong>{% trans "Reference code (important):" %} {{ code }}</strong>
+    {% else %}
+        <strong>
+            {% trans "We will assign you a personal reference code to use after you completed the order." %}
+        </strong>
+    {% endif %}
 </address>

src/pretix/presale/views/order.py

@@ -416,7 +416,10 @@ class OrderPaymentConfirm(EventViewMixin, OrderDetailMixin, TemplateView):
         ctx = super().get_context_data(**kwargs)
         ctx['order'] = self.order
         ctx['payment'] = self.payment
-        ctx['payment_info'] = self.payment.payment_provider.checkout_confirm_render(self.request)
+        if 'order' in inspect.signature(self.payment.payment_provider.checkout_confirm_render).parameters:
+            ctx['payment_info'] = self.payment.payment_provider.checkout_confirm_render(self.request, order=self.order)
+        else:
+            ctx['payment_info'] = self.payment.payment_provider.checkout_confirm_render(self.request)
         ctx['payment_provider'] = self.payment.payment_provider
         return ctx
 
@@ -568,7 +571,9 @@ class OrderPayChangeMethod(EventViewMixin, OrderDetailMixin, TemplateView):
                 continue
             current_fee = sum(f.value for f in self.open_fees) or Decimal('0.00')
             fee = provider.calculate_fee(pending_sum - current_fee)
-            if 'total' in inspect.signature(provider.payment_form_render).parameters:
+            if 'order' in inspect.signature(provider.payment_form_render).parameters:
+                form = provider.payment_form_render(self.request, abs(pending_sum + fee - current_fee), order=self.order)
+            elif 'total' in inspect.signature(provider.payment_form_render).parameters:
                 form = provider.payment_form_render(self.request, abs(pending_sum + fee - current_fee))
             else:
                 form = provider.payment_form_render(self.request)