refactor(reaction): 后台统计去掉排序，增加最近评价时间

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

reaction/views/admin.py

@@ -1,13 +1,9 @@
-from django.db.models import Count, F, FloatField, Q
+from django.db.models import Count, F, Max, Q
-from django.db.models.functions import Cast
 
 from account.decorators import super_admin_required
 from reaction.models import Reaction, ReactionType
 from utils.api import APIView
 
-MIN_USERS_FOR_RATIO = 3
-DEFAULT_ORDERING = "-users"
-
 
 class ReactionStatsAPI(APIView):
     @super_admin_required
@@ -15,27 +11,15 @@ class ReactionStatsAPI(APIView):
         queryset = (
             Reaction.objects.values(pid=F("problem___id"), title=F("problem__title"))
             .annotate(users=Count("user", distinct=True))
+            .annotate(last_time=Max("create_time"))
             .annotate(**{t.value: Count("id", filter=Q(type=t.value)) for t in ReactionType})
-            .annotate(**{f"{t.value}_ratio": Cast(t.value, FloatField()) / Cast("users", FloatField()) for t in ReactionType})
+            .order_by("-users")
         )
 
         problem_id = request.GET.get("problem")
         if problem_id:
             queryset = queryset.filter(problem___id__iexact=problem_id, problem__contest_id__isnull=True)
 
-        ordering = request.GET.get("ordering") or DEFAULT_ORDERING
-        prefix = "-" if ordering.startswith("-") else ""
-        field = ordering.lstrip("-")
-        if field == "users":
-            order_by = f"{prefix}users"
-        elif field in ReactionType.values:
-            # 按占比排序时过滤低样本，避免 1 人点 1 个就冲到 100%
-            queryset = queryset.filter(users__gte=MIN_USERS_FOR_RATIO)
-            order_by = f"{prefix}{field}_ratio"
-        else:
-            order_by = DEFAULT_ORDERING
-
-        queryset = queryset.order_by(order_by)
         data = self.paginate_data(request, queryset)
         data["results"] = list(data["results"])
         return self.success(data)