Fix duplicate human_readable_id values in Order model

This migration resolves duplicate human_readable_id values by assigning unique IDs where necessary. A data migration script is introduced to identify and fix duplicates before altering the field.

core/migrations/0018_alter_order_human_readable_id.py

@@ -1,9 +1,31 @@
-# Generated by Django 5.1.8 on 2025-05-06 13:58
+from django.db.models import Count
 
 import core.utils
 from django.db import migrations, models
 
 
+def fix_duplicates(apps, schema_editor):
+    Order = apps.get_model("core", "Order")
+    duplicates = (
+        Order.objects.values("human_readable_id")
+        .annotate(count=Count("id"))
+        .filter(count__gt=1)
+    )
+    for duplicate in duplicates:
+        h_id = duplicate["human_readable_id"]
+        orders = Order.objects.filter(human_readable_id=h_id).order_by("id")
+        for order in orders[1:]:
+            new_id = order.human_readable_id
+            while Order.objects.filter(human_readable_id=new_id).exists():
+                from core.utils import generate_human_readable_id
+                new_id = generate_human_readable_id()
+            order.human_readable_id = new_id
+            order.save()
+
+
+def reverse_func(apps, schema_editor):
+    pass
+
 class Migration(migrations.Migration):
 
     dependencies = [
@@ -11,6 +33,7 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
+        migrations.RunPython(fix_duplicates, reverse_func),
         migrations.AlterField(
             model_name='order',
             name='human_readable_id',