Self-service refund form (#1135)

* Auto-refund

* Add missing template

* Notification for requested refund

* Model-level tests

* Add front-end tests

* Default to notify

src/pretix/control/views/event.py

@@ -41,10 +41,10 @@ from pretix.base.signals import register_ticket_outputs
 from pretix.base.templatetags.money import money_filter
 from pretix.base.templatetags.rich_text import markdown_compile
 from pretix.control.forms.event import (
-    CommentForm, DisplaySettingsForm, EventDeleteForm, EventMetaValueForm,
-    EventSettingsForm, EventUpdateForm, InvoiceSettingsForm, MailSettingsForm,
-    PaymentSettingsForm, ProviderForm, QuickSetupForm,
-    QuickSetupProductFormSet, TaxRuleForm, TaxRuleLineFormSet,
+    CancelSettingsForm, CommentForm, DisplaySettingsForm, EventDeleteForm,
+    EventMetaValueForm, EventSettingsForm, EventUpdateForm,
+    InvoiceSettingsForm, MailSettingsForm, PaymentSettingsForm, ProviderForm,
+    QuickSetupForm, QuickSetupProductFormSet, TaxRuleForm, TaxRuleLineFormSet,
     TicketSettingsForm, WidgetCodeForm,
 )
 from pretix.control.permissions import EventPermissionRequiredMixin
@@ -407,6 +407,43 @@ class InvoiceSettings(EventSettingsViewMixin, EventSettingsFormView):
         })
 
 
+class CancelSettings(EventSettingsViewMixin, EventSettingsFormView):
+    model = Event
+    form_class = CancelSettingsForm
+    template_name = 'pretixcontrol/event/cancel.html'
+    permission = 'can_change_event_settings'
+
+    def get_success_url(self) -> str:
+        return reverse('control:event.settings.cancel', kwargs={
+            'organizer': self.request.event.organizer.slug,
+            'event': self.request.event.slug
+        })
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data()
+        ctx['gets_notification'] = self.request.user.notifications_send and (
+            (
+                self.request.user.notification_settings.filter(
+                    event=self.request.event,
+                    action_type='pretix.event.order.refund.requested',
+                    enabled=True
+                ).exists()
+            ) or (
+                self.request.user.notification_settings.filter(
+                    event__isnull=True,
+                    action_type='pretix.event.order.refund.requested',
+                    enabled=True
+                ).exists() and not
+                self.request.user.notification_settings.filter(
+                    event=self.request.event,
+                    action_type='pretix.event.order.refund.requested',
+                    enabled=False
+                ).exists()
+            )
+        )
+        return ctx
+
+
 class InvoicePreview(EventPermissionRequiredMixin, View):
     permission = 'can_change_event_settings'
 

src/pretix/control/views/orders.py

@@ -583,51 +583,15 @@ class OrderRefundView(OrderView):
         )
 
     def choose_form(self):
-        payments = self.order.payments.filter(
-            state=OrderPayment.PAYMENT_STATE_CONFIRMED
-        )
-        for p in payments:
-            p.full_refund_possible = p.payment_provider.payment_refund_supported(p)
-            p.partial_refund_possible = p.payment_provider.payment_partial_refund_supported(p)
-            p.propose_refund = Decimal('0.00')
-            p.available_amount = p.amount - p.refunded_amount
-
-        unused_payments = set(p for p in payments if p.full_refund_possible or p.partial_refund_possible)
-
-        # Algorithm to choose which payments are to be refunded to create the least hassle
+        payments = list(self.order.payments.filter(state=OrderPayment.PAYMENT_STATE_CONFIRMED))
         if self.start_form.cleaned_data.get('mode') == 'full':
-            to_refund = full_refund = self.order.payment_refund_sum
+            full_refund = self.order.payment_refund_sum
         else:
-            to_refund = full_refund = self.start_form.cleaned_data.get('partial_amount')
-
-        while to_refund and unused_payments:
-            bigger = sorted([p for p in unused_payments if p.available_amount > to_refund],
-                            key=lambda p: p.available_amount)
-            same = [p for p in unused_payments if p.available_amount == to_refund]
-            smaller = sorted([p for p in unused_payments if p.available_amount < to_refund],
-                             key=lambda p: p.available_amount,
-                             reverse=True)
-            if same:
-                for payment in same:
-                    if payment.full_refund_possible or payment.partial_refund_possible:
-                        payment.propose_refund = payment.available_amount
-                        to_refund -= payment.available_amount
-                        unused_payments.remove(payment)
-                        break
-            elif bigger:
-                for payment in bigger:
-                    if payment.partial_refund_possible:
-                        payment.propose_refund = to_refund
-                        to_refund -= to_refund
-                        unused_payments.remove(payment)
-                        break
-            elif smaller:
-                for payment in smaller:
-                    if payment.full_refund_possible or payment.partial_refund_possible:
-                        payment.propose_refund = payment.available_amount
-                        to_refund -= payment.available_amount
-                        unused_payments.remove(payment)
-                        break
+            full_refund = self.start_form.cleaned_data.get('partial_amount')
+        proposals = self.order.propose_auto_refunds(full_refund, payments=payments)
+        to_refund = full_refund - sum(proposals.values())
+        for p in payments:
+            p.propose_refund = proposals.get(p, 0)
 
         if 'perform' in self.request.POST:
             refund_selected = Decimal('0.00')