initial commit

apps/events/migrations/0010_backfill_registration_discounts.py

@@ -0,0 +1,55 @@
+from django.db import migrations
+
+
+def copy_payment_discounts(apps, schema_editor):
+    Registration = apps.get_model("events", "Registration")
+    Payment = apps.get_model("payments", "Payment")
+
+    payments = (
+        Payment.objects.exclude(discount_code__isnull=True)
+        .select_related("discount_code")
+        .order_by("id")
+    )
+    for payment in payments:
+        registration = (
+            Registration.objects.filter(event_id=payment.event_id, user_id=payment.user_id)
+            .order_by("-registered_at")
+            .first()
+        )
+        if not registration:
+            continue
+
+        updated_fields = []
+        if payment.discount_code_id and not registration.discount_code_id:
+            registration.discount_code_id = payment.discount_code_id
+            updated_fields.append("discount_code")
+        if payment.discount_amount and not registration.discount_amount:
+            registration.discount_amount = payment.discount_amount
+            updated_fields.append("discount_amount")
+        if payment.amount is not None and registration.final_price is None:
+            registration.final_price = payment.amount
+            updated_fields.append("final_price")
+
+        if updated_fields:
+            registration.save(update_fields=updated_fields)
+
+        if payment.registration_id is None:
+            payment.registration_id = registration.id
+            payment.save(update_fields=["registration"])
+
+
+def reverse_copy_payment_discounts(apps, schema_editor):
+    # No-op for reverse; data retention preferred.
+    pass
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("payments", "0003_payment_registration"),
+        ("events", "0009_registration_discount_amount_and_more"),
+    ]
+
+    operations = [
+        migrations.RunPython(copy_payment_discounts, reverse_copy_payment_discounts),
+    ]