Add merge category functionality for admin users with confirmation prompt

sbas/templates/sbas/merge_category.html

@@ -0,0 +1,48 @@
+{% extends 'sbas/base.html' %}
+
+{% block content %}
+  <h2>Merge Category</h2>
+
+  {% if error %}
+    <div class="alert alert-danger">{{ error }}</div>
+  {% endif %}
+
+  {% if success %}
+    <div class="alert alert-success">{{ success }}</div>
+  {% endif %}
+
+  <p>This admin tool will move all questions assigned to the <strong>Source</strong> category into the <strong>Target</strong> category. Optionally you may delete the Source category after the move.</p>
+
+  <form method="post">
+    {% csrf_token %}
+    <div class="mb-3">
+      <label for="id_source" class="form-label">Source category (to be merged)</label>
+      <select name="source" id="id_source" class="form-select">
+        <option value="">-- select source --</option>
+        {% for c in categories %}
+          <option value="{{ c.pk }}">{{ c }}</option>
+        {% endfor %}
+      </select>
+    </div>
+
+    <div class="mb-3">
+      <label for="id_target" class="form-label">Target category (destination)</label>
+      <select name="target" id="id_target" class="form-select">
+        <option value="">-- select target --</option>
+        {% for c in categories %}
+          <option value="{{ c.pk }}">{{ c }}</option>
+        {% endfor %}
+      </select>
+    </div>
+
+    <div class="form-check mb-3">
+      <input class="form-check-input" type="checkbox" value="on" id="id_delete_source" name="delete_source">
+      <label class="form-check-label" for="id_delete_source">
+        Delete source category after merge
+      </label>
+    </div>
+
+    <button type="submit" class="btn btn-danger" onclick="return confirm('Are you sure you want to move all questions from the source to the target category? This action cannot be undone.');">Merge categories</button>
+  </form>
+
+{% endblock %}

sbas/urls.py

@@ -110,6 +110,7 @@ urlpatterns = [
         views.generate_exam,
         name="generate_exam",
     ),
+    path("category/merge/", views.merge_category, name="merge_category"),
     #path(
     #    "exam/<int:pk>/scores/<int:cid>/<str:passcode>/",
     #    views.exam_scores_cid_user,

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"])