Add merge category functionality for admin users with confirmation prompt

sbas/views.py

@@ -1012,6 +1012,59 @@ def import_llm_questions(request):
     return JsonResponse({"ok": True, "report": report})
 
 
+@login_required
+@user_passes_test(lambda u: u.is_superuser)
+@require_http_methods(["GET", "POST"])
+def merge_category(request):
+    """Admin view: merge one Category into another.
+
+    GET: render form to choose source and target categories.
+    POST: expects 'source' and 'target' (category PKs) and optional 'delete_source' checkbox.
+    The view will reassign all Question.category==source -> target and optionally delete the source Category.
+    """
+    categories = Category.objects.all().order_by('category')
+
+    if request.method == 'GET':
+        return render(request, 'sbas/merge_category.html', {'categories': categories})
+
+    # POST
+    source_id = request.POST.get('source')
+    target_id = request.POST.get('target')
+    delete_source = request.POST.get('delete_source') in ('on', 'true', '1', 'True')
+
+    if not source_id or not target_id:
+        return render(request, 'sbas/merge_category.html', {'categories': categories, 'error': 'Both source and target categories must be selected.'})
+
+    try:
+        source = Category.objects.get(pk=int(source_id))
+        target = Category.objects.get(pk=int(target_id))
+    except Category.DoesNotExist:
+        return render(request, 'sbas/merge_category.html', {'categories': categories, 'error': 'Invalid category selected.'})
+
+    if source.pk == target.pk:
+        return render(request, 'sbas/merge_category.html', {'categories': categories, 'error': 'Source and target must be different.'})
+
+    # perform update inside a transaction
+    from django.db import transaction
+
+    with transaction.atomic():
+        qs = Question.objects.filter(category=source)
+        count = qs.count()
+        qs.update(category=target)
+
+        deleted = False
+        if delete_source:
+            # safe to delete now (no FK references from Question)
+            source.delete()
+            deleted = True
+
+    msg = f"Moved {count} question{'s' if count != 1 else ''} from '{source}' to '{target}'."
+    if deleted:
+        msg += f" Deleted source category '{source}'."
+
+    return render(request, 'sbas/merge_category.html', {'categories': Category.objects.all().order_by('category'), 'success': msg})
+
+
 @login_required
 @user_passes_test(lambda u: u.is_superuser)
 @require_http_methods(["POST"])