add end_time

submission/serializers.py

@@ -1,6 +1,10 @@
+from django.db import models
+from django.utils import timezone
+
 from .models import Submission
 from utils.api import serializers
 from utils.serializers import LanguageNameChoiceField
+from problemset.models import ProblemSetProgress
 
 
 class CreateSubmissionSerializer(serializers.Serializer):
@@ -50,4 +54,36 @@ class SubmissionListSerializer(serializers.ModelSerializer):
         # 没传user或为匿名user
         if self.user is None or not self.user.is_authenticated:
             return False
-        return obj.check_user_permission(self.user)
+        if not obj.check_user_permission(self.user):
+            return False
+        # 题单防作弊：用户加入了包含该题目的 active 题单时，隐藏加入前的提交链接
+        # 如果该题目已在题单中做出来了，则恢复显示
+        if obj.user_id == self.user.id and self.user.is_regular_user():
+            progress = self._get_problemset_progress(obj.problem_id)
+            if (
+                progress
+                and obj.create_time < progress.join_time
+                and str(obj.problem_id) not in progress.progress_detail
+            ):
+                return False
+        return True
+
+    def _get_problemset_progress(self, problem_id):
+        """查询用户是否加入了包含该题目的 active 题单，带缓存避免 N+1"""
+        if not hasattr(self, "_problemset_progress_cache"):
+            self._problemset_progress_cache = {}
+        if problem_id not in self._problemset_progress_cache:
+            self._problemset_progress_cache[problem_id] = (
+                ProblemSetProgress.objects.filter(
+                    user=self.user,
+                    problemset__status="active",
+                    problemset__problemsetproblem__problem_id=problem_id,
+                )
+                .filter(
+                    models.Q(problemset__end_time__isnull=True)
+                    | models.Q(problemset__end_time__gt=timezone.now())
+                )
+                .only("join_time", "progress_detail")
+                .first()
+            )
+        return self._problemset_progress_cache[problem_id]