use attendee email in the regular send mail flow

pretix_email_template_plugin/signals.py

@@ -2,28 +2,39 @@
 from django.dispatch import receiver
 from pretix.base.email import BaseMailTextPlaceholder
 from pretix.base.signals import register_text_placeholders
+from pretix.base.services.placeholders import SimpleFunctionalTextPlaceholder
 
 
-class AttendeeEmailPlaceholder(BaseMailTextPlaceholder):
+def get_best_email(position_or_address):
+    from pretix.base.models import InvoiceAddress, OrderPosition
+    if isinstance(position_or_address, InvoiceAddress):
+        return position_or_address.order.email
+    if isinstance(position_or_address, OrderPosition):
+        if position_or_address.attendee_email:
+            return position_or_address.attendee_email
+        else:
+            return position_or_address.order.email
+
+class AttendeeOrOrderEmailPlaceholder(BaseMailTextPlaceholder):
     def __init__(self):
-        self._identifier = "attendee_email"
+        self._identifier = "email"
 
     @property
     def required_context(self):
-        return ["order", "position"]
+        return ["position_or_address"]
 
     @property
     def identifier(self):
         return self._identifier
 
     def render(self, context):
-        position = context["position"]
-        return position.attendee_email
+        position_or_address = context["position_or_address"]
+        return get_best_email(position_or_address)
 
     def render_sample(self, context):
         return "richard@0xparc.org"
 
 
-@receiver(register_text_placeholders, dispatch_uid="placeholder_custom")
+@receiver(register_text_placeholders, dispatch_uid="placeholder_email")
 def register_placeholder_renderers(sender, **kwargs):
-    return AttendeeEmailPlaceholder()
+    return AttendeeOrOrderEmailPlaceholder()