Add command to reassign feast data and update chants

django/cantusdb_project/main_app/management/commands/reassign_feasts.py

@@ -0,0 +1,58 @@
+from django.core.management.base import BaseCommand
+from main_app.models import Feast, Chant, Sequence
+
+
+FEAST_MAPPING = {
+    2456: 4474,
+    2094: 4475,
+}
+
+
+class Command(BaseCommand):
+    help = "Reassign feasts and update chants accordingly"
+
+    def handle(self, *args, **options):
+
+        for old_feast_id, new_feast_id in FEAST_MAPPING.items():
+            try:
+                old_feast = Feast.objects.get(id=old_feast_id)
+                new_feast = Feast.objects.get(id=new_feast_id)
+            except Feast.DoesNotExist as e:
+                self.stderr.write(self.style.ERROR(f"Feast not found: {e}"))
+                continue
+
+            # Transfer data (if necessary)
+            new_feast.name = new_feast.name or old_feast.name
+            new_feast.description = new_feast.description or old_feast.description
+            new_feast.feast_code = new_feast.feast_code or old_feast.feast_code
+            new_feast.notes = new_feast.notes or old_feast.notes
+            new_feast.month = new_feast.month or old_feast.month
+            new_feast.day = new_feast.day or old_feast.day
+
+            # Calling save method will update 'prefix' field
+            new_feast.save()
+
+            # Reassign chants
+            chants_updated = Chant.objects.filter(feast=old_feast).update(
+                feast=new_feast
+            )
+            self.stdout.write(
+                self.style.SUCCESS(
+                    f"Reassigned {chants_updated} chants from feast {old_feast_id} to {new_feast_id}"
+                )
+            )
+
+            # Reassign sequences
+            sequences_updated = Sequence.objects.filter(feast=old_feast).update(
+                feast=new_feast
+            )
+            self.stdout.write(
+                self.style.SUCCESS(
+                    f"Reassigned {sequences_updated} sequences from feast {old_feast_id} to {new_feast_id}"
+                )
+            )
+
+            old_feast.delete()
+            self.stdout.write(self.style.SUCCESS(f"Deleted old feast {old_feast_id}"))
+
+        self.stdout.write(self.style.SUCCESS("Feast reassignment complete."))

django/cantusdb_project/main_app/models/feast.py

@@ -17,7 +17,6 @@ class Feast(BaseModel):
         blank=True, null=True, validators=[MinValueValidator(1), MaxValueValidator(31)]
     )
 
-    # the `prefix` field can be automatically populated by running `python manage.py add_prefix`
     prefix = models.CharField(max_length=2, blank=True, null=True, editable=False)
 
     class Meta: