membershipworks: More thoroughly check if events are ready for an invoice

membershipworks/forms.py

@@ -25,7 +25,7 @@ class EventInvoiceForm(forms.Form):
         if hasattr(self.event, "invoice") is not None:
             raise forms.ValidationError("An invoice was already created!")
 
-        if self.event.total_due_to_instructor is None:
+        if not self.event.ready_for_invoice:
             raise forms.ValidationError(
                 "Event missing required information to generate invoice"
             )

membershipworks/models.py

@@ -563,6 +563,18 @@ class EventExt(Event):
             return self.instructor.member == member
         return False
 
+    def ready_for_invoice(self) -> bool:
+        return (
+            self.instructor is not None
+            and self.instructor.member is not None
+            and self.materials_fee is not None
+            and (
+                self.materials_fee_included_in_price is not None
+                or self.materials_fee == 0
+            )
+            and self.total_due_to_instructor is not None
+        )
+
     class Meta:
         verbose_name = "event"
         ordering = ["-start"]

membershipworks/templates/membershipworks/event_detail.dj.html

@@ -27,7 +27,7 @@
             <a class="btn btn-primary"
                href="{% url 'membershipworks:event-invoice-pdf' event.invoice.pk %}">View PDF</a>
           </div>
-        {% elif event.total_due_to_instructor is None %}
+        {% elif not event.ready_for_invoice %}
           <p class="card-text text-center">
             This event is missing required information to generate an invoice. Please contact us at <a href="mailto:info@claremontmakerspace.org">info@claremontmakerspace.org</a>.
           </p>