Invoice address: Make Peppol required in Belgium if available (Z#23220397) (#5808)

* Invoice address: Make Peppol required in Belgium if available (Z#23220397)

* Fix failing test, remove template bit that's now impossible

src/pretix/base/invoicing/national.py

@@ -36,9 +36,11 @@ class ItalianSdITransmissionType(TransmissionType):
     identifier = "it_sdi"
     verbose_name = pgettext_lazy("italian_invoice", "Italian Exchange System (SdI)")
     public_name = pgettext_lazy("italian_invoice", "Exchange System (SdI)")
-    exclusive = True
     enforce_transmission = True
 
+    def is_exclusive(self, event, country: Country, is_business: bool) -> bool:
+        return str(country) == "IT"
+
     def is_available(self, event, country: Country, is_business: bool):
         return str(country) == "IT" and super().is_available(event, country, is_business)
 

src/pretix/base/invoicing/peppol.py

@@ -179,6 +179,12 @@ class PeppolTransmissionType(TransmissionType):
     def is_available(self, event, country: Country, is_business: bool):
         return is_business and super().is_available(event, country, is_business)
 
+    def is_exclusive(self, event, country: Country, is_business: bool) -> bool:
+        if is_business and str(country) == "BE" and event and event.settings.invoice_address_from_country == "BE":
+            # Peppol is required to be used for intra-Belgian B2B invoices
+            return True
+        return False
+
     @property
     def invoice_address_form_fields(self) -> dict:
         return {

src/pretix/base/invoicing/transmission.py

@@ -58,15 +58,6 @@ class TransmissionType:
         """
         return 100
 
-    @property
-    def exclusive(self) -> bool:
-        """
-        If a transmission type is exclusive, no other type can be chosen if this type is
-        available. Use e.g. if a certain transmission type is legally required in a certain
-        jurisdiction.
-        """
-        return False
-
     @property
     def enforce_transmission(self) -> bool:
         """
@@ -82,6 +73,15 @@ class TransmissionType:
             for provider, _ in providers
         )
 
+    def is_exclusive(self, event, country: Country, is_business: bool) -> bool:
+        """
+        If a transmission type is exclusive, no other type can be chosen if this type is
+        available. Use e.g. if a certain transmission type is legally required in a certain
+        jurisdiction. Event can be None in organizer-level contexts. Exclusiveness has no effect if
+        the type is not available.
+        """
+        return False
+
     def invoice_address_form_fields_required(self, country: Country, is_business: bool):
         return set()