feat(hadis): add bulk assign topics action to admin viewset

- Add bulk-assign-topics endpoint to AdminHadisViewSet supporting add/replace modes
- Validate leaf topic constraints and handle both M2M categories and primary category_id
- Invalidate hadis cache on bulk updates and return updated count with category details
- Expand AdminHadisBriefSerializer with slug, title_narrator, and status fields

apps/hadis/serializers/serializers_admin.py

@@ -782,7 +782,8 @@ class AdminHadisDetailSerializer(serializers.ModelSerializer):
 class AdminHadisBriefSerializer(serializers.ModelSerializer):
     class Meta:
         model = Hadis
-        fields = ["id", "number", "title"]
+        fields = ["id", "number", "slug", "title", "title_narrator", "status"]
+
 
 
 class AdminHadisCategoryBriefSerializer(serializers.ModelSerializer):

apps/hadis/views_admin.py

@@ -443,6 +443,107 @@ class AdminHadisViewSet(ModelViewSet):
 
         return queryset.order_by("-id")
 
+    @action(detail=False, methods=["post"], url_path="bulk-assign-topics")
+    def bulk_assign_topics(self, request):
+        from django.db import transaction
+        from rest_framework import status as drf_status
+        from .signals import invalidate_hadis_cache
+
+        hadis_ids = request.data.get("hadis_ids") or []
+        category_ids = request.data.get("category_ids") or []
+        mode = request.data.get("mode", "add")
+
+        if not isinstance(hadis_ids, list) or not hadis_ids:
+            return Response(
+                {"detail": "hadis_ids must be a non-empty list."},
+                status=drf_status.HTTP_400_BAD_REQUEST,
+            )
+        if not isinstance(category_ids, list) or not category_ids:
+            return Response(
+                {"detail": "category_ids must be a non-empty list."},
+                status=drf_status.HTTP_400_BAD_REQUEST,
+            )
+
+        try:
+            hadis_ids = [int(hid) for hid in hadis_ids]
+            category_ids = list(dict.fromkeys(int(cid) for cid in category_ids))
+        except (ValueError, TypeError):
+            return Response(
+                {"detail": "Invalid ID format."},
+                status=drf_status.HTTP_400_BAD_REQUEST,
+            )
+
+        categories = list(HadisCategory.objects.filter(id__in=category_ids))
+        if len(categories) != len(category_ids):
+            return Response(
+                {"detail": "One or more selected topics do not exist."},
+                status=drf_status.HTTP_400_BAD_REQUEST,
+            )
+
+        for cat in categories:
+            if cat.children.exists():
+                return Response(
+                    {"detail": "Cannot assign items to a parent category that has subcategories. Please select leaf topics only."},
+                    status=drf_status.HTTP_400_BAD_REQUEST,
+                )
+
+        hadises_qs = Hadis.objects.filter(id__in=hadis_ids)
+        existing_hadis_ids = list(hadises_qs.values_list("id", flat=True))
+        if not existing_hadis_ids:
+            return Response(
+                {"detail": "No matching items found."},
+                status=drf_status.HTTP_404_NOT_FOUND,
+            )
+
+        through_model = Hadis.categories.through
+        first_category_id = category_ids[0]
+
+        with transaction.atomic():
+            if mode == "replace":
+                through_model.objects.filter(hadis_id__in=existing_hadis_ids).delete()
+                relations = [
+                    through_model(hadis_id=hid, hadiscategory_id=cid)
+                    for hid in existing_hadis_ids
+                    for cid in category_ids
+                ]
+                through_model.objects.bulk_create(relations, ignore_conflicts=True)
+                Hadis.objects.filter(id__in=existing_hadis_ids).update(category_id=first_category_id)
+            else:
+                relations = [
+                    through_model(hadis_id=hid, hadiscategory_id=cid)
+                    for hid in existing_hadis_ids
+                    for cid in category_ids
+                ]
+                through_model.objects.bulk_create(relations, ignore_conflicts=True)
+                Hadis.objects.filter(id__in=existing_hadis_ids, category__isnull=True).update(
+                    category_id=first_category_id
+                )
+
+        invalidate_hadis_cache()
+
+        cat_map = {c.id: c for c in categories}
+        ordered_cats = [cat_map[cid] for cid in category_ids if cid in cat_map]
+        categories_detail = [
+            {
+                "id": c.id,
+                "title": c.title,
+                "slug": c.slug,
+                "source_type": c.source_type,
+                "is_topic": True,
+            }
+            for c in ordered_cats
+        ]
+
+        return Response(
+            {
+                "updated_count": len(existing_hadis_ids),
+                "mode": mode,
+                "categories_detail": categories_detail,
+            },
+            status=drf_status.HTTP_200_OK,
+        )
+
+
 
 class AdminHadisCorrectionViewSet(ModelViewSet):
     serializer_class = AdminHadisCorrectionSerializer