add more status updates

apps/submissions/models.py

@@ -294,11 +294,12 @@ class Submission(models.Model):
         currently owns the row, so the per-email cap and trust list don't
         depend on the caller remembering to set it.
 
-        Additionally: when an UPDATE flips `status` to `rejected` from any
-        other state, this method queues `send_rejection_email()` via
-        `transaction.on_commit`. Centralising the email here means **every**
-        save path -- admin, the validation worker, ad-hoc shell, any future
-        view -- fires the email through a single hook. Plan.md §7.3.
+        Additionally: when an UPDATE flips `status` to a state with a
+        dedicated email (`rejected`, `printing`, `completed`), this method
+        queues the matching `send_*_email()` via `transaction.on_commit`.
+        Centralising the dispatch here means **every** save path -- admin,
+        the validation worker, ad-hoc shell, any future view -- fires the
+        email through a single hook. Plan.md §7.3.
         """
         if not self.slug:
             self.slug = self._generate_unique_slug()
@@ -319,27 +320,37 @@ class Submission(models.Model):
 
         super().save(*args, **kwargs)
 
-        # Fire on TRANSITIONS only: an UPDATE that flips status to rejected.
-        # Don't fire on inserts that start out as rejected -- those should
-        # be impossible by design (plan.md §7.3 doesn't define a (none) ->
-        # rejected edge), and even if some weird path creates one we'd
-        # rather stay silent than spam a fresh victim.
-        if (
-            not is_new
-            and old_status != new_status
-            and new_status == self.Status.REJECTED
-        ):
+        # Fire on TRANSITIONS only: an UPDATE that flips status into one of
+        # the email-bearing target states. Don't fire on inserts that start
+        # out in those states -- by plan.md §7.3 no submit-time edge lands
+        # in rejected/printing/completed, and even if some weird path did,
+        # we'd rather stay silent than send "your print is ready" to a fresh
+        # victim of a fixture/data-migration import.
+        if not is_new and old_status != new_status:
             # Local imports keep this module out of the apps/submissions
             # import-cycle (emails.py imports from here).
             from django.db import transaction
-            from .emails import send_rejection_email
-
-            transaction.on_commit(
-                lambda sub=self, prev=old_status: send_rejection_email(
-                    sub, previous_status=prev
-                )
+            from .emails import (
+                send_completed_email,
+                send_printing_email,
+                send_rejection_email,
             )
 
+            if new_status == self.Status.REJECTED:
+                transaction.on_commit(
+                    lambda sub=self, prev=old_status: send_rejection_email(
+                        sub, previous_status=prev
+                    )
+                )
+            elif new_status == self.Status.PRINTING:
+                transaction.on_commit(
+                    lambda sub=self: send_printing_email(sub)
+                )
+            elif new_status == self.Status.COMPLETED:
+                transaction.on_commit(
+                    lambda sub=self: send_completed_email(sub)
+                )
+
         # Refresh the snapshot so a follow-up save on the same instance
         # compares against the just-persisted state, not the original load.
         self._original_status = new_status