Use payment pledge as variant when cost is zero

aleksis/apps/paweljong/models.py

@@ -397,7 +397,12 @@ class EventRegistration(ExtensibleModel):
 
     def get_invoice(self):
         # FIXME Maybe do not hard-code this
-        client, __ = Client.objects.get_or_create(name=get_site_preferences()["paweljong__event_invoice_client_name"])
+        client, __ = Client.objects.get_or_create(
+            name=get_site_preferences()["paweljong__event_invoice_client_name"],
+            defaults={
+                "pledge_enabled": True,
+            },
+        )
         group, __ = InvoiceGroup.objects.get_or_create(
             name=get_site_preferences()["paweljong__event_invoice_group_name"],
             client=client,

aleksis/apps/paweljong/schema/__init__.py

@@ -52,7 +52,12 @@ class Query(graphene.ObjectType):
 
     @staticmethod
     def resolve_paweljong_payment_choices(root, info):
-        client, __ = Client.objects.get_or_create(name=get_site_preferences()["paweljong__event_invoice_client_name"])
+        client, __ = Client.objects.get_or_create(
+            name=get_site_preferences()["paweljong__event_invoice_client_name"],
+            defaults={
+                "pledge_enabled": True,
+            },
+        )
         group, __ = InvoiceGroup.objects.get_or_create(
             name=get_site_preferences()["paweljong__event_invoice_group_name"],
             client=client,

aleksis/apps/paweljong/schema/event_registration.py

@@ -192,7 +192,12 @@ class SendEventRegistrationMutation(graphene.Mutation):
             # TODO Implement existing voucher handling
 
             invoice = registration.get_invoice()
-            invoice.variant = event_registration["payment"]["payment_method"]
+            if amount == 0:
+                invoice.variant = "pledge"
+            else:
+                invoice.variant = event_registration["payment"]["payment_method"]
+                if invoice.variant == "" or invoice.variant is None:
+                    raise ValidationError(_("The field 'Payment method' is required."))
             invoice.save()
 
         registration.save()