change enum

account/migrations/0004_alter_user_admin_type_alter_user_problem_permission.py

@@ -0,0 +1,22 @@
+# Generated by Django 6.0.4 on 2026-05-09 08:18
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("account", "0003_remove_userprofile_class_name_user_class_name"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="user",
+            name="admin_type",
+            field=models.TextField(choices=[("Regular User", "Regular User"), ("Admin", "Admin"), ("Super Admin", "Super Admin")], default="Regular User"),
+        ),
+        migrations.AlterField(
+            model_name="user",
+            name="problem_permission",
+            field=models.TextField(choices=[("None", "None"), ("Own", "Own"), ("All", "All")], default="None"),
+        ),
+    ]

account/models.py

@@ -5,16 +5,16 @@ from django.db import models
 from utils.models import JSONField
 
 
-class AdminType(object):
-    REGULAR_USER = "Regular User"
-    ADMIN = "Admin"
-    SUPER_ADMIN = "Super Admin"
+class AdminType(models.TextChoices):
+    REGULAR_USER = "Regular User", "Regular User"
+    ADMIN = "Admin", "Admin"
+    SUPER_ADMIN = "Super Admin", "Super Admin"
 
 
-class ProblemPermission(object):
-    NONE = "None"
-    OWN = "Own"
-    ALL = "All"
+class ProblemPermission(models.TextChoices):
+    NONE = "None", "None"
+    OWN = "Own", "Own"
+    ALL = "All", "All"
 
 
 class UserManager(models.Manager):
@@ -30,8 +30,8 @@ class User(AbstractBaseUser):
     email = models.TextField(null=True)
     create_time = models.DateTimeField(auto_now_add=True, null=True)
     # One of UserType
-    admin_type = models.TextField(default=AdminType.REGULAR_USER)
-    problem_permission = models.TextField(default=ProblemPermission.NONE)
+    admin_type = models.TextField(default=AdminType.REGULAR_USER, choices=AdminType.choices)
+    problem_permission = models.TextField(default=ProblemPermission.NONE, choices=ProblemPermission.choices)
     reset_password_token = models.TextField(null=True)
     reset_password_token_expire_time = models.DateTimeField(null=True)
     # SSO auth token
@@ -43,9 +43,7 @@ class User(AbstractBaseUser):
     open_api = models.BooleanField(default=False)
     open_api_appkey = models.TextField(null=True)
     is_disabled = models.BooleanField(default=False)
-    raw_password = models.CharField(
-        max_length=20, null=True, blank=True, verbose_name="明文密码"
-    )
+    raw_password = models.CharField(max_length=20, null=True, blank=True, verbose_name="明文密码")
 
     USERNAME_FIELD = "username"
     REQUIRED_FIELDS = []
@@ -68,9 +66,7 @@ class User(AbstractBaseUser):
         return self.problem_permission == ProblemPermission.ALL
 
     def is_contest_admin(self, contest):
-        return self.is_authenticated and (
-            contest.created_by == self or self.admin_type == AdminType.SUPER_ADMIN
-        )
+        return self.is_authenticated and (contest.created_by == self or self.admin_type == AdminType.SUPER_ADMIN)
 
     def set_password(self, raw_password):
         super().set_password(raw_password)

account/serializers.py

@@ -44,9 +44,7 @@ class GenerateUserSerializer(serializers.Serializer):
 
 
 class ImportUserSerializer(serializers.Serializer):
-    users = serializers.ListField(
-        child=serializers.ListField(child=serializers.CharField(max_length=64))
-    )
+    users = serializers.ListField(child=serializers.ListField(child=serializers.CharField(max_length=64)))
 
 
 class UserAdminSerializer(serializers.ModelSerializer):
@@ -118,21 +116,16 @@ class EditUserSerializer(serializers.Serializer):
     id = serializers.IntegerField()
     username = serializers.CharField(max_length=32)
     real_name = serializers.CharField(max_length=32, allow_blank=True, allow_null=True)
-    password = serializers.CharField(
-        min_length=6, allow_blank=True, required=False, default=None
-    )
+    password = serializers.CharField(min_length=6, allow_blank=True, required=False, default=None)
     email = serializers.EmailField(max_length=64)
-    admin_type = serializers.ChoiceField(
-        choices=(AdminType.REGULAR_USER, AdminType.ADMIN, AdminType.SUPER_ADMIN)
-    )
-    problem_permission = serializers.ChoiceField(
-        choices=(ProblemPermission.NONE, ProblemPermission.OWN, ProblemPermission.ALL)
-    )
+    admin_type = serializers.ChoiceField(choices=AdminType.choices)
+    problem_permission = serializers.ChoiceField(choices=ProblemPermission.choices)
     open_api = serializers.BooleanField()
     two_factor_auth = serializers.BooleanField()
     is_disabled = serializers.BooleanField()
     class_name = serializers.CharField(required=False, allow_null=True, allow_blank=True)
 
+
 class EditUserProfileSerializer(serializers.Serializer):
     real_name = serializers.CharField(max_length=32, allow_null=True, required=False)
     avatar = serializers.CharField(max_length=256, allow_blank=True, required=False)
@@ -143,6 +136,7 @@ class EditUserProfileSerializer(serializers.Serializer):
     major = serializers.CharField(max_length=64, allow_blank=True, required=False)
     language = serializers.CharField(max_length=32, allow_blank=True, required=False)
 
+
 class ApplyResetPasswordSerializer(serializers.Serializer):
     email = serializers.EmailField()
     captcha = serializers.CharField()

account/views/oj.py

@@ -78,9 +78,7 @@ class UserProfileAPI(APIView):
                 show_real_name = True
         except User.DoesNotExist:
             return self.error("User does not exist")
-        return self.success(
-            UserProfileSerializer(user.userprofile, show_real_name=show_real_name).data
-        )
+        return self.success(UserProfileSerializer(user.userprofile, show_real_name=show_real_name).data)
 
     @validate_serializer(EditUserProfileSerializer)
     @login_required
@@ -90,9 +88,7 @@ class UserProfileAPI(APIView):
         for k, v in data.items():
             setattr(user_profile, k, v)
         user_profile.save()
-        return self.success(
-            UserProfileSerializer(user_profile, show_real_name=True).data
-        )
+        return self.success(UserProfileSerializer(user_profile, show_real_name=True).data)
 
 
 class Metrics(APIView):
@@ -157,9 +153,7 @@ class TwoFactorAuthAPI(APIView):
         user.save()
 
         label = f"{SysOptions.website_name_shortcut}:{user.username}"
-        image = qrcode.make(
-            _totp_uri(token, label, SysOptions.website_name.replace(" ", ""))
-        )
+        image = qrcode.make(_totp_uri(token, label, SysOptions.website_name.replace(" ", "")))
         return self.success(img2base64(image))
 
     @login_required
@@ -224,9 +218,7 @@ class UserLoginAPI(APIView):
             if not user.two_factor_auth:
                 prev_login = user.last_login
                 auth.login(request, user)
-                request.session["prev_login"] = (
-                    datetime2str(prev_login) if prev_login else ""
-                )
+                request.session["prev_login"] = datetime2str(prev_login) if prev_login else ""
                 return self.success("Succeeded")
 
             # `tfa_code` not in post data
@@ -236,9 +228,7 @@ class UserLoginAPI(APIView):
             if _valid_totp(user.tfa_token, data["tfa_code"]):
                 prev_login = user.last_login
                 auth.login(request, user)
-                request.session["prev_login"] = (
-                    datetime2str(prev_login) if prev_login else ""
-                )
+                request.session["prev_login"] = datetime2str(prev_login) if prev_login else ""
                 return self.success("Succeeded")
             else:
                 return self.error("Invalid two factor verification code")
@@ -262,9 +252,7 @@ class UsernameOrEmailCheck(APIView):
         # True means already exist.
         result = {"username": False, "email": False}
         if data.get("username"):
-            result["username"] = User.objects.filter(
-                username=data["username"].lower()
-            ).exists()
+            result["username"] = User.objects.filter(username=data["username"].lower()).exists()
         if data.get("email"):
             result["email"] = User.objects.filter(email=data["email"].lower()).exists()
         return self.success(result)
@@ -301,9 +289,7 @@ class UserChangeEmailAPI(APIView):
     @login_required
     def post(self, request):
         data = request.data
-        user = auth.authenticate(
-            username=request.user.username, password=data["password"]
-        )
+        user = auth.authenticate(username=request.user.username, password=data["password"])
         if user:
             if user.two_factor_auth:
                 if "tfa_code" not in data:
@@ -356,12 +342,7 @@ class ApplyResetPasswordAPI(APIView):
             user = User.objects.get(email__iexact=data["email"])
         except User.DoesNotExist:
             return self.error("User does not exist")
-        if (
-            user.reset_password_token_expire_time
-            and 0
-            < int((user.reset_password_token_expire_time - now()).total_seconds())
-            < 20 * 60
-        ):
+        if user.reset_password_token_expire_time and 0 < int((user.reset_password_token_expire_time - now()).total_seconds()) < 20 * 60:
             return self.error("You can only reset password once per 20 minutes")
         user.reset_password_token = rand_str()
         user.reset_password_token_expire_time = now() + timedelta(minutes=20)
@@ -453,7 +434,7 @@ class UserRankAPI(APIView):
             n = int(request.GET.get("n", "0"))
         except ValueError:
             n = 0
-        if rule_type not in ContestRuleType.choices():
+        if rule_type not in ContestRuleType.values:
             rule_type = ContestRuleType.ACM
 
         profiles = UserProfile.objects.filter(
@@ -462,9 +443,7 @@ class UserRankAPI(APIView):
             user__username__icontains=username,
         ).select_related("user")
         if rule_type == ContestRuleType.ACM:
-            profiles = profiles.filter(accepted_number__gte=0).order_by(
-                "-accepted_number", "submission_number"
-            )
+            profiles = profiles.filter(accepted_number__gte=0).order_by("-accepted_number", "submission_number")
         else:
             profiles = profiles.filter(total_score__gt=0).order_by("-total_score")
         if n > 0:
@@ -482,19 +461,13 @@ class UserActivityRankAPI(APIView):
         if cached is not None:
             return self.success(cached)
 
-        hidden_names = User.objects.filter(
-            Q(admin_type=AdminType.SUPER_ADMIN) | Q(is_disabled=True)
-        ).values_list("username", flat=True)
+        hidden_names = User.objects.filter(Q(admin_type=AdminType.SUPER_ADMIN) | Q(is_disabled=True)).values_list("username", flat=True)
         submissions = Submission.objects.filter(
             contest_id__isnull=True,
             create_time__gte=start,
             result=JudgeStatus.ACCEPTED,
         ).exclude(username__in=hidden_names)
-        data = list(
-            submissions.values("username")
-            .annotate(count=Count("problem_id", distinct=True))
-            .order_by("-count")[:10]
-        )
+        data = list(submissions.values("username").annotate(count=Count("problem_id", distinct=True)).order_by("-count")[:10])
         cache.set(cache_key, data, 600)
         return self.success(data)
 
@@ -506,12 +479,8 @@ class UserProblemRankAPI(APIView):
         if not user.is_authenticated:
             return self.error("User is not authenticated")
 
-        problem = Problem.objects.get(
-            _id=problem_id, contest_id__isnull=True, visible=True
-        )
-        submissions = Submission.objects.filter(
-            problem=problem, result=JudgeStatus.ACCEPTED
-        )
+        problem = Problem.objects.get(_id=problem_id, contest_id__isnull=True, visible=True)
+        submissions = Submission.objects.filter(problem=problem, result=JudgeStatus.ACCEPTED)
 
         all_ac_count = submissions.values("user_id").distinct().count()
 
@@ -519,9 +488,7 @@ class UserProblemRankAPI(APIView):
         class_ac_count = 0
 
         if class_name:
-            users = User.objects.filter(
-                class_name=user.class_name, is_disabled=False
-            ).values_list("id", flat=True)
+            users = User.objects.filter(class_name=user.class_name, is_disabled=False).values_list("id", flat=True)
             user_ids = list(users)
             submissions = submissions.filter(user_id__in=user_ids)
             class_ac_count = submissions.values("user_id").distinct().count()
@@ -539,9 +506,7 @@ class UserProblemRankAPI(APIView):
             )
 
         my_first_submission = my_submissions.order_by("create_time").first()
-        rank = submissions.filter(
-            create_time__lte=my_first_submission.create_time
-        ).count()
+        rank = submissions.filter(create_time__lte=my_first_submission.create_time).count()
         return self.success(
             {
                 "class_name": class_name,
@@ -561,9 +526,7 @@ class ProfileProblemDisplayIDRefreshAPI(APIView):
         ids = list(acm_problems.keys()) + list(oi_problems.keys())
         if not ids:
             return self.success()
-        display_ids = Problem.objects.filter(id__in=ids, visible=True).values_list(
-            "_id", flat=True
-        )
+        display_ids = Problem.objects.filter(id__in=ids, visible=True).values_list("_id", flat=True)
         id_map = dict(zip(ids, display_ids))
         for k, v in acm_problems.items():
             v["_id"] = id_map[k]

contest/migrations/0004_alter_acmcontestrank_unique_together_and_more.py

@@ -0,0 +1,35 @@
+# Generated by Django 6.0.4 on 2026-05-09 08:18
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("contest", "0003_acmcontestrank_acm_rank_contest_user_idx_and_more"),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name="acmcontestrank",
+            unique_together=set(),
+        ),
+        migrations.AlterUniqueTogether(
+            name="oicontestrank",
+            unique_together=set(),
+        ),
+        migrations.AlterField(
+            model_name="contest",
+            name="rule_type",
+            field=models.TextField(choices=[("ACM", "ACM"), ("OI", "OI")]),
+        ),
+        migrations.AddConstraint(
+            model_name="acmcontestrank",
+            constraint=models.UniqueConstraint(fields=("user", "contest"), name="unique_acm_rank_user_contest"),
+        ),
+        migrations.AddConstraint(
+            model_name="oicontestrank",
+            constraint=models.UniqueConstraint(fields=("user", "contest"), name="unique_oi_rank_user_contest"),
+        ),
+    ]

contest/models.py

@@ -15,8 +15,7 @@ class Contest(models.Model):
     # show real time rank or cached rank
     real_time_rank = models.BooleanField()
     password = models.TextField(null=True)
-    # enum of ContestRuleType
-    rule_type = models.TextField()
+    rule_type = models.TextField(choices=ContestRuleType.choices)
     start_time = models.DateTimeField()
     end_time = models.DateTimeField()
     create_time = models.DateTimeField(auto_now_add=True)
@@ -46,13 +45,7 @@ class Contest(models.Model):
 
     # 是否有权查看problem 的一些统计信息 诸如submission_number, accepted_number 等
     def problem_details_permission(self, user):
-        return (
-            self.rule_type == ContestRuleType.ACM
-            or self.status == ContestStatus.CONTEST_ENDED
-            or user.is_authenticated
-            and user.is_contest_admin(self)
-            or self.real_time_rank
-        )
+        return self.rule_type == ContestRuleType.ACM or self.status == ContestStatus.CONTEST_ENDED or user.is_authenticated and user.is_contest_admin(self) or self.real_time_rank
 
     class Meta:
         db_table = "contest"
@@ -78,10 +71,11 @@ class ACMContestRank(AbstractContestRank):
 
     class Meta:
         db_table = "acm_contest_rank"
-        unique_together = (("user", "contest"),)
+        constraints = [
+            models.UniqueConstraint(fields=["user", "contest"], name="unique_acm_rank_user_contest"),
+        ]
         indexes = [
-            models.Index(fields=["contest", "accepted_number", "total_time"],
-                         name="acm_rank_order_idx"),
+            models.Index(fields=["contest", "accepted_number", "total_time"], name="acm_rank_order_idx"),
             models.Index(fields=["contest", "user"], name="acm_rank_contest_user_idx"),
         ]
 
@@ -94,7 +88,9 @@ class OIContestRank(AbstractContestRank):
 
     class Meta:
         db_table = "oi_contest_rank"
-        unique_together = (("user", "contest"),)
+        constraints = [
+            models.UniqueConstraint(fields=["user", "contest"], name="unique_oi_rank_user_contest"),
+        ]
         indexes = [
             models.Index(fields=["contest", "total_score"], name="oi_rank_order_idx"),
             models.Index(fields=["contest", "user"], name="oi_rank_contest_user_idx"),

contest/serializers.py

@@ -9,7 +9,7 @@ class CreateConetestSeriaizer(serializers.Serializer):
     tag = serializers.CharField()
     start_time = serializers.DateTimeField()
     end_time = serializers.DateTimeField()
-    rule_type = serializers.ChoiceField(choices=[ContestRuleType.ACM, ContestRuleType.OI])
+    rule_type = serializers.ChoiceField(choices=ContestRuleType.choices)
     password = serializers.CharField(allow_blank=True, max_length=32)
     visible = serializers.BooleanField()
     real_time_rank = serializers.BooleanField()

flowchart/tasks.py

@@ -3,8 +3,6 @@ import logging
 import time
 
 import dramatiq
-
-logger = logging.getLogger(__name__)
 from django.db import transaction
 from django.utils import timezone
 
@@ -13,6 +11,8 @@ from utils.shortcuts import DRAMATIQ_WORKER_ARGS
 
 from .models import FlowchartSubmission, FlowchartSubmissionStatus
 
+logger = logging.getLogger(__name__)
+
 
 @dramatiq.actor(**DRAMATIQ_WORKER_ARGS(max_retries=3))
 def evaluate_flowchart_task(submission_id):

judge/languages.py

@@ -27,11 +27,7 @@ int main() {
         "max_memory": 256 * 1024 * 1024,
         "compile_command": "/usr/bin/gcc -DONLINE_JUDGE -O2 -w -fmax-errors=3 -std=c17 {src_path} -lm -o {exe_path}",
     },
-    "run": {
-        "command": "{exe_path}",
-        "seccomp_rule": {ProblemIOMode.standard: "c_cpp", ProblemIOMode.file: "c_cpp_file_io"},
-        "env": default_env
-    }
+    "run": {"command": "{exe_path}", "seccomp_rule": {ProblemIOMode.STANDARD: "c_cpp", ProblemIOMode.FILE: "c_cpp_file_io"}, "env": default_env},
 }
 
 
@@ -60,11 +56,7 @@ int main() {
         "max_memory": 1024 * 1024 * 1024,
         "compile_command": "/usr/bin/g++ -DONLINE_JUDGE -O2 -w -fmax-errors=3 -std=c++20 {src_path} -lm -o {exe_path}",
     },
-    "run": {
-        "command": "{exe_path}",
-        "seccomp_rule": {ProblemIOMode.standard: "c_cpp", ProblemIOMode.file: "c_cpp_file_io"},
-        "env": default_env
-    }
+    "run": {"command": "{exe_path}", "seccomp_rule": {ProblemIOMode.STANDARD: "c_cpp", ProblemIOMode.FILE: "c_cpp_file_io"}, "env": default_env},
 }
 
 
@@ -91,14 +83,9 @@ class Main {
         "max_cpu_time": 5000,
         "max_real_time": 10000,
         "max_memory": -1,
-        "compile_command": "/usr/bin/javac {src_path} -d {exe_dir}"
+        "compile_command": "/usr/bin/javac {src_path} -d {exe_dir}",
     },
-    "run": {
-        "command": "/usr/bin/java -cp {exe_dir} -XX:MaxRAM={max_memory}k Main",
-        "seccomp_rule": None,
-        "env": default_env,
-        "memory_limit_check_only": 1
-    }
+    "run": {"command": "/usr/bin/java -cp {exe_dir} -XX:MaxRAM={max_memory}k Main", "seccomp_rule": None, "env": default_env, "memory_limit_check_only": 1},
 }
 
 _py3_lang_config = {
@@ -122,11 +109,7 @@ print(add(1, 2))
         "max_memory": 128 * 1024 * 1024,
         "compile_command": "/usr/bin/python3 -m py_compile {src_path}",
     },
-    "run": {
-        "command": "/usr/bin/python3 -BS {exe_path}",
-        "seccomp_rule": "general",
-        "env": default_env
-    }
+    "run": {"command": "/usr/bin/python3 -BS {exe_path}", "seccomp_rule": "general", "env": default_env},
 }
 
 _go_lang_config = {
@@ -154,14 +137,9 @@ func main() {
         "max_real_time": 5000,
         "max_memory": 1024 * 1024 * 1024,
         "compile_command": "/usr/bin/go build -o {exe_path} {src_path}",
-        "env": ["GOCACHE=/tmp", "GOPATH=/tmp", "GOMAXPROCS=1"] + default_env
+        "env": ["GOCACHE=/tmp", "GOPATH=/tmp", "GOMAXPROCS=1"] + default_env,
     },
-    "run": {
-        "command": "{exe_path}",
-        "seccomp_rule": "golang",
-        "env": ["GOMAXPROCS=1"] + default_env,
-        "memory_limit_check_only": 1
-    }
+    "run": {"command": "{exe_path}", "seccomp_rule": "golang", "env": ["GOMAXPROCS=1"] + default_env, "memory_limit_check_only": 1},
 }
 
 _node_lang_config = {
@@ -184,14 +162,9 @@ console.log(add(1, 2))
         "max_real_time": 5000,
         "max_memory": 1024 * 1024 * 1024,
         "compile_command": "/usr/bin/node --check {src_path}",
-        "env": default_env
-    },
-    "run": {
-        "command": "/usr/bin/node {exe_path}",
-        "seccomp_rule": "node",
         "env": default_env,
-        "memory_limit_check_only": 1
-    }
+    },
+    "run": {"command": "/usr/bin/node {exe_path}", "seccomp_rule": "node", "env": default_env, "memory_limit_check_only": 1},
 }
 
 languages = [

problem/migrations/0008_alter_problem_unique_together_and_more.py

@@ -0,0 +1,33 @@
+# Generated by Django 6.0.4 on 2026-05-09 08:18
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("contest", "0004_alter_acmcontestrank_unique_together_and_more"),
+        ("problem", "0007_problem_problem_visible_idx"),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name="problem",
+            unique_together=set(),
+        ),
+        migrations.AlterField(
+            model_name="problem",
+            name="difficulty",
+            field=models.TextField(choices=[("Low", "Low"), ("Mid", "Mid"), ("High", "High")]),
+        ),
+        migrations.AlterField(
+            model_name="problem",
+            name="rule_type",
+            field=models.TextField(choices=[("ACM", "ACM"), ("OI", "OI")]),
+        ),
+        migrations.AddConstraint(
+            model_name="problem",
+            constraint=models.UniqueConstraint(fields=("_id", "contest"), name="unique_problem_id_contest"),
+        ),
+    ]

problem/models.py

@@ -2,7 +2,7 @@ from django.db import models
 
 from account.models import User
 from contest.models import Contest
-from utils.constants import Choices
+from utils.constants import Difficulty
 from utils.models import RichTextField
 
 
@@ -13,25 +13,19 @@ class ProblemTag(models.Model):
         db_table = "problem_tag"
 
 
-class ProblemRuleType(Choices):
-    ACM = "ACM"
-    OI = "OI"
+class ProblemRuleType(models.TextChoices):
+    ACM = "ACM", "ACM"
+    OI = "OI", "OI"
 
 
-class ProblemDifficulty(object):
-    High = "High"
-    Mid = "Mid"
-    Low = "Low"
-
-
-class ProblemIOMode(Choices):
-    standard = "Standard IO"
-    file = "File IO"
+class ProblemIOMode(models.TextChoices):
+    STANDARD = "Standard IO", "Standard IO"
+    FILE = "File IO", "File IO"
 
 
 def _default_io_mode():
     return {
-        "io_mode": ProblemIOMode.standard,
+        "io_mode": ProblemIOMode.STANDARD,
         "input": "input.txt",
         "output": "output.txt",
     }
@@ -66,9 +60,9 @@ class Problem(models.Model):
     memory_limit = models.IntegerField()
     # io mode
     io_mode = models.JSONField(default=_default_io_mode)
-    rule_type = models.TextField()
+    rule_type = models.TextField(choices=ProblemRuleType.choices)
     visible = models.BooleanField(default=True)
-    difficulty = models.TextField()
+    difficulty = models.TextField(choices=Difficulty.choices)
     tags = models.ManyToManyField(ProblemTag)
     source = models.TextField(null=True)
     prompt = models.TextField(null=True)
@@ -91,7 +85,9 @@ class Problem(models.Model):
 
     class Meta:
         db_table = "problem"
-        unique_together = (("_id", "contest"),)
+        constraints = [
+            models.UniqueConstraint(fields=["_id", "contest"], name="unique_problem_id_contest"),
+        ]
         ordering = ("create_time",)
         indexes = [
             models.Index(fields=["contest", "visible"], name="problem_contest_visible_idx"),

problem/serializers.py

@@ -38,7 +38,7 @@ class CreateProblemCodeTemplateSerializer(serializers.Serializer):
 
 
 class ProblemIOModeSerializer(serializers.Serializer):
-    io_mode = serializers.ChoiceField(choices=ProblemIOMode.choices())
+    io_mode = serializers.ChoiceField(choices=ProblemIOMode.choices)
     input = serializers.CharField()
     output = serializers.CharField()
 
@@ -59,22 +59,16 @@ class CreateOrEditProblemSerializer(serializers.Serializer):
     output_description = serializers.CharField()
     samples = serializers.ListField(child=CreateSampleSerializer(), allow_empty=False)
     test_case_id = serializers.CharField(max_length=32)
-    test_case_score = serializers.ListField(
-        child=CreateTestCaseScoreSerializer(), allow_empty=True
-    )
+    test_case_score = serializers.ListField(child=CreateTestCaseScoreSerializer(), allow_empty=True)
     time_limit = serializers.IntegerField(min_value=1, max_value=1000 * 60)
     memory_limit = serializers.IntegerField(min_value=1, max_value=1024)
     languages = LanguageNameMultiChoiceField()
     template = serializers.DictField(child=serializers.CharField(min_length=1))
-    rule_type = serializers.ChoiceField(
-        choices=[ProblemRuleType.ACM, ProblemRuleType.OI]
-    )
+    rule_type = serializers.ChoiceField(choices=ProblemRuleType.choices)
     io_mode = ProblemIOModeSerializer()
     visible = serializers.BooleanField()
-    difficulty = serializers.ChoiceField(choices=Difficulty.choices())
-    tags = serializers.ListField(
-        child=serializers.CharField(max_length=32), allow_empty=False
-    )
+    difficulty = serializers.ChoiceField(choices=Difficulty.choices)
+    tags = serializers.ListField(child=serializers.CharField(max_length=32), allow_empty=False)
     hint = serializers.CharField(allow_blank=True, allow_null=True)
     source = serializers.CharField(max_length=256, allow_blank=True, allow_null=True)
     prompt = serializers.CharField(allow_blank=True, allow_null=True)
@@ -88,13 +82,9 @@ class CreateOrEditProblemSerializer(serializers.Serializer):
     # 流程图相关字段
     allow_flowchart = serializers.BooleanField(required=False, default=False)
     show_flowchart = serializers.BooleanField(required=False, default=False)
-    mermaid_code = serializers.CharField(
-        allow_blank=True, allow_null=True, required=False
-    )
+    mermaid_code = serializers.CharField(allow_blank=True, allow_null=True, required=False)
 
-    flowchart_hint = serializers.CharField(
-        allow_blank=True, allow_null=True, required=False
-    )
+    flowchart_hint = serializers.CharField(allow_blank=True, allow_null=True, required=False)
 
 
 class CreateProblemSerializer(CreateOrEditProblemSerializer):
@@ -220,6 +210,7 @@ class ProblemSafeSerializer(BaseProblemSerializer):
             return None
         return obj.flowchart_data
 
+
 class ContestProblemMakePublicSerializer(serializers.Serializer):
     id = serializers.IntegerField()
     display_id = serializers.CharField(max_length=32)

problemset/migrations/0008_alter_problemsetproblem_unique_together_and_more.py

@@ -0,0 +1,54 @@
+# Generated by Django 6.0.4 on 2026-05-09 08:18
+
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("problem", "0008_alter_problem_unique_together_and_more"),
+        ("problemset", "0007_problemset_end_time"),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name="problemsetproblem",
+            unique_together=set(),
+        ),
+        migrations.AlterUniqueTogether(
+            name="problemsetprogress",
+            unique_together=set(),
+        ),
+        migrations.AlterUniqueTogether(
+            name="userbadge",
+            unique_together=set(),
+        ),
+        migrations.AlterField(
+            model_name="problemset",
+            name="status",
+            field=models.TextField(choices=[("draft", "Draft"), ("active", "Active"), ("archived", "Archived")], default="draft", verbose_name="状态"),
+        ),
+        migrations.AlterField(
+            model_name="problemset",
+            name="difficulty",
+            field=models.TextField(choices=[("Easy", "Easy"), ("Medium", "Medium"), ("Hard", "Hard")], default="Easy", verbose_name="难度等级"),
+        ),
+        migrations.AlterField(
+            model_name="problemsetbadge",
+            name="condition_type",
+            field=models.TextField(choices=[("all_problems", "All Problems"), ("problem_count", "Problem Count"), ("score", "Score")], verbose_name="获得条件类型"),
+        ),
+        migrations.AddConstraint(
+            model_name="problemsetproblem",
+            constraint=models.UniqueConstraint(fields=("problemset", "problem"), name="unique_problemset_problem"),
+        ),
+        migrations.AddConstraint(
+            model_name="problemsetprogress",
+            constraint=models.UniqueConstraint(fields=("problemset", "user"), name="unique_problemset_progress_user"),
+        ),
+        migrations.AddConstraint(
+            model_name="userbadge",
+            constraint=models.UniqueConstraint(fields=("user", "badge"), name="unique_user_badge"),
+        ),
+    ]

problemset/models.py

@@ -6,15 +6,31 @@ from problem.models import Problem
 from utils.models import JSONField, RichTextField
 
 
+class ProblemSetStatus(models.TextChoices):
+    DRAFT = "draft", "Draft"
+    ACTIVE = "active", "Active"
+    ARCHIVED = "archived", "Archived"
+
+
+class ProblemSetDifficulty(models.TextChoices):
+    EASY = "Easy", "Easy"
+    MEDIUM = "Medium", "Medium"
+    HARD = "Hard", "Hard"
+
+
+class BadgeConditionType(models.TextChoices):
+    ALL_PROBLEMS = "all_problems", "All Problems"
+    PROBLEM_COUNT = "problem_count", "Problem Count"
+    SCORE = "score", "Score"
+
+
 class ProblemSet(models.Model):
     """题单模型"""
 
     title = models.TextField(verbose_name="题单标题")
     description = RichTextField(verbose_name="题单描述")
     # 创建者
-    created_by = models.ForeignKey(
-        User, on_delete=models.CASCADE, verbose_name="创建者"
-    )
+    created_by = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="创建者")
     # 创建时间
     create_time = models.DateTimeField(auto_now_add=True, verbose_name="创建时间")
     # 更新时间
@@ -22,11 +38,13 @@ class ProblemSet(models.Model):
     # 是否可见
     visible = models.BooleanField(default=True, verbose_name="是否可见")
     # 题单难度等级
-    difficulty = models.TextField(default="Easy", verbose_name="难度等级")
+    difficulty = models.TextField(
+        default=ProblemSetDifficulty.EASY,
+        choices=ProblemSetDifficulty.choices,
+        verbose_name="难度等级",
+    )
     # 题单状态
-    status = models.TextField(
-        default="draft", verbose_name="状态"
-    )  # active, archived, draft
+    status = models.TextField(default=ProblemSetStatus.DRAFT, choices=ProblemSetStatus.choices, verbose_name="状态")
     # 截止时间（到期后自动解除防作弊隐藏）
     end_time = models.DateTimeField(null=True, blank=True, verbose_name="截止时间")
 
@@ -43,9 +61,7 @@ class ProblemSet(models.Model):
 class ProblemSetProblem(models.Model):
     """题单题目关联模型"""
 
-    problemset = models.ForeignKey(
-        ProblemSet, on_delete=models.CASCADE, verbose_name="题单"
-    )
+    problemset = models.ForeignKey(ProblemSet, on_delete=models.CASCADE, verbose_name="题单")
     problem = models.ForeignKey(Problem, on_delete=models.CASCADE, verbose_name="题目")
     # 在题单中的顺序
     order = models.IntegerField(default=0, verbose_name="顺序")
@@ -58,7 +74,9 @@ class ProblemSetProblem(models.Model):
 
     class Meta:
         db_table = "problemset_problem"
-        unique_together = (("problemset", "problem"),)
+        constraints = [
+            models.UniqueConstraint(fields=["problemset", "problem"], name="unique_problemset_problem"),
+        ]
         ordering = ("order",)
         verbose_name = "题单题目"
         verbose_name_plural = "题单题目"
@@ -70,17 +88,13 @@ class ProblemSetProblem(models.Model):
 class ProblemSetBadge(models.Model):
     """题单奖章模型"""
 
-    problemset = models.ForeignKey(
-        ProblemSet, on_delete=models.CASCADE, verbose_name="题单"
-    )
+    problemset = models.ForeignKey(ProblemSet, on_delete=models.CASCADE, verbose_name="题单")
     name = models.TextField(verbose_name="奖章名称")
     description = models.TextField(verbose_name="奖章描述")
     # 奖章图标路径
     icon = models.TextField(verbose_name="奖章图标")
     # 获得条件：完成所有题目、完成指定数量题目、达到指定分数等
-    condition_type = models.TextField(
-        verbose_name="获得条件类型"
-    )  # all_problems, problem_count, score
+    condition_type = models.TextField(choices=BadgeConditionType.choices, verbose_name="获得条件类型")
     condition_value = models.IntegerField(default=0, verbose_name="条件值")
 
     class Meta:
@@ -96,11 +110,7 @@ class ProblemSetBadge(models.Model):
         from django.db import transaction
 
         user_progresses = ProblemSetProgress.objects.filter(problemset=self.problemset)
-        new_badges = [
-            UserBadge(user=progress.user, badge=self)
-            for progress in user_progresses
-            if self._is_eligible(progress)
-        ]
+        new_badges = [UserBadge(user=progress.user, badge=self) for progress in user_progresses if self._is_eligible(progress)]
         with transaction.atomic():
             UserBadge.objects.filter(badge=self).delete()
             if new_badges:
@@ -118,9 +128,7 @@ class ProblemSetBadge(models.Model):
 
     def _check_user_badge_eligibility(self, progress):
         """检查并授予单个用户的徽章（供外部单次调用）"""
-        if self._is_eligible(progress) and not UserBadge.objects.filter(
-            user=progress.user, badge=self
-        ).exists():
+        if self._is_eligible(progress) and not UserBadge.objects.filter(user=progress.user, badge=self).exists():
             UserBadge.objects.create(user=progress.user, badge=self)
             return True
         return False
@@ -129,9 +137,7 @@ class ProblemSetBadge(models.Model):
 class ProblemSetProgress(models.Model):
     """题单进度模型"""
 
-    problemset = models.ForeignKey(
-        ProblemSet, on_delete=models.CASCADE, verbose_name="题单"
-    )
+    problemset = models.ForeignKey(ProblemSet, on_delete=models.CASCADE, verbose_name="题单")
     user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="用户")
     # 加入时间
     join_time = models.DateTimeField(auto_now_add=True, verbose_name="加入时间")
@@ -142,9 +148,7 @@ class ProblemSetProgress(models.Model):
     # 完成进度百分比
     progress_percentage = models.FloatField(default=0.0, verbose_name="完成进度")
     # 已完成的题目数量
-    completed_problems_count = models.IntegerField(
-        default=0, verbose_name="已完成题目数"
-    )
+    completed_problems_count = models.IntegerField(default=0, verbose_name="已完成题目数")
     # 总题目数量
     total_problems_count = models.IntegerField(default=0, verbose_name="总题目数")
     # 获得的总分
@@ -155,7 +159,9 @@ class ProblemSetProgress(models.Model):
 
     class Meta:
         db_table = "problemset_progress"
-        unique_together = (("problemset", "user"),)
+        constraints = [
+            models.UniqueConstraint(fields=["problemset", "user"], name="unique_problemset_progress_user"),
+        ]
         verbose_name = "题单进度"
         verbose_name_plural = "题单进度"
 
@@ -165,9 +171,7 @@ class ProblemSetProgress(models.Model):
     def update_progress(self):
         """更新进度信息"""
         # 获取题单中的所有题目
-        problemset_problems = ProblemSetProblem.objects.filter(
-            problemset=self.problemset
-        )
+        problemset_problems = ProblemSetProblem.objects.filter(problemset=self.problemset)
         self.total_problems_count = problemset_problems.count()
 
         # 获取当前题单中所有题目的ID集合（直接用 problem_id FK 字段，无需额外查询）
@@ -199,9 +203,7 @@ class ProblemSetProgress(models.Model):
 
         # 计算完成百分比
         if self.total_problems_count > 0:
-            self.progress_percentage = (
-                completed_count / self.total_problems_count
-            ) * 100
+            self.progress_percentage = (completed_count / self.total_problems_count) * 100
         else:
             self.progress_percentage = 0
 
@@ -224,16 +226,10 @@ class ProblemSetProgress(models.Model):
 class ProblemSetSubmission(models.Model):
     """题单提交记录模型"""
 
-    problemset = models.ForeignKey(
-        ProblemSet, on_delete=models.CASCADE, verbose_name="题单"
-    )
+    problemset = models.ForeignKey(ProblemSet, on_delete=models.CASCADE, verbose_name="题单")
     user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="用户")
-    submission = models.ForeignKey(
-        "submission.Submission", on_delete=models.CASCADE, verbose_name="提交记录"
-    )
-    problem = models.ForeignKey(
-        "problem.Problem", on_delete=models.CASCADE, verbose_name="题目"
-    )
+    submission = models.ForeignKey("submission.Submission", on_delete=models.CASCADE, verbose_name="提交记录")
+    problem = models.ForeignKey("problem.Problem", on_delete=models.CASCADE, verbose_name="题目")
 
     class Meta:
         db_table = "problemset_submission"
@@ -264,23 +260,22 @@ class ProblemSetSubmission(models.Model):
         """编程语言"""
         return self.submission.language
 
+
 class UserBadge(models.Model):
     """用户奖章模型"""
 
     user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="用户")
-    badge = models.ForeignKey(
-        ProblemSetBadge, on_delete=models.CASCADE, verbose_name="奖章"
-    )
+    badge = models.ForeignKey(ProblemSetBadge, on_delete=models.CASCADE, verbose_name="奖章")
     # 获得时间
     earned_time = models.DateTimeField(auto_now_add=True, verbose_name="获得时间")
 
     class Meta:
         db_table = "user_badge"
-        unique_together = (("user", "badge"),)
+        constraints = [
+            models.UniqueConstraint(fields=["user", "badge"], name="unique_user_badge"),
+        ]
         verbose_name = "用户奖章"
         verbose_name_plural = "用户奖章"
 
     def __str__(self):
         return f"{self.user.username} - {self.badge.name}"
-
-

problemset/serializers.py

@@ -1,10 +1,13 @@
 from utils.api import UsernameSerializer, serializers
 
 from .models import (
+    BadgeConditionType,
     ProblemSet,
     ProblemSetBadge,
+    ProblemSetDifficulty,
     ProblemSetProblem,
     ProblemSetProgress,
+    ProblemSetStatus,
     UserBadge,
 )
 
@@ -13,9 +16,7 @@ def get_user_progress_data(problemset, request):
     """获取当前用户在该题单中的进度 - 公共方法"""
     if request and request.user.is_authenticated:
         try:
-            progress = ProblemSetProgress.objects.get(
-                problemset=problemset, user=request.user
-            )
+            progress = ProblemSetProgress.objects.get(problemset=problemset, user=request.user)
             return {
                 "is_joined": True,
                 "progress_percentage": progress.progress_percentage,
@@ -61,9 +62,7 @@ class ProblemSetSerializer(serializers.ModelSerializer):
         request = self.context.get("request")
         if request and request.user.is_authenticated:
             try:
-                progress = ProblemSetProgress.objects.get(
-                    problemset=obj, user=request.user
-                )
+                progress = ProblemSetProgress.objects.get(problemset=obj, user=request.user)
                 return progress.completed_problems_count
             except ProblemSetProgress.DoesNotExist:
                 return 0
@@ -134,11 +133,11 @@ class ProblemSetListSerializer(serializers.ModelSerializer):
             earned_badge_ids = request._user_earned_badge_ids
             # 为每个徽章添加是否已获得的标记
             for badge in badge_data:
-                badge['is_earned'] = badge['id'] in earned_badge_ids
+                badge["is_earned"] = badge["id"] in earned_badge_ids
         else:
             # 未登录用户或未预加载，所有徽章都标记为未获得
             for badge in badge_data:
-                badge['is_earned'] = False
+                badge["is_earned"] = False
 
         return badge_data
 
@@ -148,8 +147,8 @@ class CreateProblemSetSerializer(serializers.Serializer):
 
     title = serializers.CharField(max_length=200)
     description = serializers.CharField()
-    difficulty = serializers.CharField(default="Easy")
-    status = serializers.CharField(default="active")
+    difficulty = serializers.ChoiceField(choices=ProblemSetDifficulty.choices, default=ProblemSetDifficulty.EASY)
+    status = serializers.ChoiceField(choices=ProblemSetStatus.choices, default=ProblemSetStatus.ACTIVE)
     end_time = serializers.DateTimeField(required=False)
 
 
@@ -159,8 +158,8 @@ class EditProblemSetSerializer(serializers.Serializer):
     id = serializers.IntegerField()
     title = serializers.CharField(max_length=200, required=False)
     description = serializers.CharField(required=False)
-    difficulty = serializers.CharField(required=False)
-    status = serializers.CharField(required=False)
+    difficulty = serializers.ChoiceField(choices=ProblemSetDifficulty.choices, required=False)
+    status = serializers.ChoiceField(choices=ProblemSetStatus.choices, required=False)
     visible = serializers.BooleanField(required=False)
     end_time = serializers.DateTimeField(required=False, allow_null=True)
 
@@ -190,9 +189,7 @@ class ProblemSetProblemSerializer(serializers.ModelSerializer):
         progress = self.context.get("user_progress")
         if progress is None:
             try:
-                progress = ProblemSetProgress.objects.get(
-                    problemset=obj.problemset, user=request.user
-                )
+                progress = ProblemSetProgress.objects.get(problemset=obj.problemset, user=request.user)
             except ProblemSetProgress.DoesNotExist:
                 return False
         return str(obj.problem.id) in progress.progress_detail
@@ -227,19 +224,21 @@ class ProblemSetBadgeSerializer(serializers.ModelSerializer):
 
 class CreateProblemSetBadgeSerializer(serializers.Serializer):
     """创建题单奖章序列化器"""
+
     name = serializers.CharField(max_length=100)
     description = serializers.CharField()
     icon = serializers.CharField()
-    condition_type = serializers.CharField()  # all_problems, problem_count, score
+    condition_type = serializers.ChoiceField(choices=BadgeConditionType.choices)
     condition_value = serializers.IntegerField(required=False)
 
 
 class EditProblemSetBadgeSerializer(serializers.Serializer):
     """编辑题单奖章序列化器"""
+
     name = serializers.CharField(max_length=100, required=False)
     description = serializers.CharField(required=False)
     icon = serializers.CharField(required=False)
-    condition_type = serializers.CharField(required=False)  # all_problems, problem_count, score
+    condition_type = serializers.ChoiceField(choices=BadgeConditionType.choices, required=False)
     condition_value = serializers.IntegerField(required=False)
 
 
@@ -259,8 +258,8 @@ class ProblemSetProgressSerializer(serializers.ModelSerializer):
 
         # 尝试从 request 中获取预加载的问题字典（用于批量查询优化）
         problems_dict = {}
-        request = self.context.get('request')
-        if request and hasattr(request, '_problems_dict_cache'):
+        request = self.context.get("request")
+        if request and hasattr(request, "_problems_dict_cache"):
             problems_dict = request._problems_dict_cache
 
         if obj.progress_detail:
@@ -269,22 +268,15 @@ class ProblemSetProgressSerializer(serializers.ModelSerializer):
                 if problems_dict:
                     problem = problems_dict.get(problem_id)
                     if problem:
-                        completed_problems.append({
-                            'id': problem.id,
-                            '_id': problem._id,
-                            'title': problem.title
-                        })
+                        completed_problems.append({"id": problem.id, "_id": problem._id, "title": problem.title})
                     continue
 
                 # 如果没有预加载字典，则回退到单独查询（向后兼容）
                 from problem.models import Problem
+
                 try:
                     problem = Problem.objects.get(id=problem_id)
-                    completed_problems.append({
-                        'id': problem.id,
-                        '_id': problem._id,
-                        'title': problem.title
-                    })
+                    completed_problems.append({"id": problem.id, "_id": problem._id, "title": problem.title})
                 except Problem.DoesNotExist:
                     continue
 
@@ -313,5 +305,3 @@ class UpdateProgressSerializer(serializers.Serializer):
     problemset_id = serializers.IntegerField()
     problem_id = serializers.IntegerField()
     submission_id = serializers.CharField(required=False)
-
-

problemset/views/admin.py

@@ -7,6 +7,7 @@ from problemset.models import (
     ProblemSetBadge,
     ProblemSetProblem,
     ProblemSetProgress,
+    ProblemSetStatus,
 )
 from problemset.serializers import (
     AddProblemToSetSerializer,
@@ -35,9 +36,7 @@ class ProblemSetAdminAPI(APIView):
         # 过滤条件
         keyword = request.GET.get("keyword", "").strip()
         if keyword:
-            problem_sets = problem_sets.filter(
-                Q(title__icontains=keyword) | Q(description__icontains=keyword)
-            )
+            problem_sets = problem_sets.filter(Q(title__icontains=keyword) | Q(description__icontains=keyword))
 
         difficulty = request.GET.get("difficulty")
         if difficulty:
@@ -129,12 +128,8 @@ class ProblemSetProblemAdminAPI(APIView):
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
-        problems = ProblemSetProblem.objects.filter(problemset=problem_set).order_by(
-            "order"
-        )
-        serializer = ProblemSetProblemSerializer(
-            problems, many=True, context={"request": request}
-        )
+        problems = ProblemSetProblem.objects.filter(problemset=problem_set).order_by("order")
+        serializer = ProblemSetProblemSerializer(problems, many=True, context={"request": request})
         return self.success(serializer.data)
 
     @super_admin_required
@@ -158,9 +153,7 @@ class ProblemSetProblemAdminAPI(APIView):
             return self.error("题目不存在或不可见")
 
         # 检查题目是否已经在题单中
-        if ProblemSetProblem.objects.filter(
-            problemset=problem_set, problem=problem
-        ).exists():
+        if ProblemSetProblem.objects.filter(problemset=problem_set, problem=problem).exists():
             return self.error("题目已在该题单中")
 
         ProblemSetProblem.objects.create(
@@ -188,9 +181,7 @@ class ProblemSetProblemAdminAPI(APIView):
             return self.error("题单不存在")
 
         try:
-            problem_set_problem = ProblemSetProblem.objects.get(
-                id=problem_set_problem_id, problemset=problem_set
-            )
+            problem_set_problem = ProblemSetProblem.objects.get(id=problem_set_problem_id, problemset=problem_set)
         except ProblemSetProblem.DoesNotExist:
             return self.error("题目不在该题单中")
 
@@ -222,9 +213,7 @@ class ProblemSetProblemAdminAPI(APIView):
             return self.error("题单不存在")
 
         try:
-            problem_set_problem = ProblemSetProblem.objects.get(
-                id=problem_set_problem_id, problemset=problem_set
-            )
+            problem_set_problem = ProblemSetProblem.objects.get(id=problem_set_problem_id, problemset=problem_set)
             problem_set_problem.delete()
 
             # 同步所有用户的进度
@@ -344,9 +333,7 @@ class ProblemSetProgressAdminAPI(APIView):
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
-        progress_list = ProblemSetProgress.objects.filter(
-            problemset=problem_set
-        ).order_by("-join_time")
+        progress_list = ProblemSetProgress.objects.filter(problemset=problem_set).order_by("-join_time")
         serializer = ProblemSetProgressSerializer(progress_list, many=True)
         return self.success(serializer.data)
 
@@ -360,9 +347,7 @@ class ProblemSetProgressAdminAPI(APIView):
             return self.error("题单不存在")
 
         try:
-            progress = ProblemSetProgress.objects.get(
-                problemset=problem_set, user_id=user_id
-            )
+            progress = ProblemSetProgress.objects.get(problemset=problem_set, user_id=user_id)
             progress.delete()
             return self.success("用户已从题单中移除")
         except ProblemSetProgress.DoesNotExist:
@@ -419,7 +404,7 @@ class ProblemSetStatusAPI(APIView):
             return self.error("题单不存在")
 
         status = data.get("status")
-        if status not in ["active", "archived", "draft"]:
+        if status not in ProblemSetStatus.values:
             return self.error("无效的状态")
 
         problem_set.status = status

problemset/views/oj.py

@@ -34,16 +34,12 @@ class ProblemSetAPI(APIView):
         problem_sets = ProblemSet.objects.filter(visible=True).exclude(status="draft").select_related("created_by")
 
         # 使用annotate在查询时计算题目数量，避免N+1查询
-        problem_sets = problem_sets.annotate(
-            problems_count=Count("problemsetproblem", distinct=True)
-        )
+        problem_sets = problem_sets.annotate(problems_count=Count("problemsetproblem", distinct=True))
 
         # 过滤条件
         keyword = request.GET.get("keyword", "").strip()
         if keyword:
-            problem_sets = problem_sets.filter(
-                Q(title__icontains=keyword) | Q(description__icontains=keyword)
-            )
+            problem_sets = problem_sets.filter(Q(title__icontains=keyword) | Q(description__icontains=keyword))
 
         difficulty = request.GET.get("difficulty")
         if difficulty:
@@ -70,29 +66,15 @@ class ProblemSetAPI(APIView):
 
             if problem_set_ids:
                 # 批量查询用户在这些题单中的进度
-                user_progresses = ProblemSetProgress.objects.filter(
-                    problemset_id__in=problem_set_ids,
-                    user=request.user
-                ).select_related("problemset")
+                user_progresses = ProblemSetProgress.objects.filter(problemset_id__in=problem_set_ids, user=request.user).select_related("problemset")
                 # 构建映射：题单ID -> 进度对象
                 user_progress_map = {progress.problemset_id: progress for progress in user_progresses}
 
                 # 批量查询用户已获得的奖章ID（这些题单相关的）
-                user_earned_badge_ids = set(
-                    UserBadge.objects.filter(
-                        user=request.user,
-                        badge__problemset_id__in=problem_set_ids
-                    ).values_list('badge_id', flat=True)
-                )
+                user_earned_badge_ids = set(UserBadge.objects.filter(user=request.user, badge__problemset_id__in=problem_set_ids).values_list("badge_id", flat=True))
 
         # 预加载奖章信息（在获取ID之后应用，避免在获取ID时也预加载）
-        problem_sets = problem_sets.prefetch_related(
-            Prefetch(
-                "problemsetbadge_set",
-                queryset=ProblemSetBadge.objects.all(),
-                to_attr="badges"
-            )
-        )
+        problem_sets = problem_sets.prefetch_related(Prefetch("problemsetbadge_set", queryset=ProblemSetBadge.objects.all(), to_attr="badges"))
 
         # 将用户进度映射和已获得的奖章ID集合存储到request中，供序列化器使用
         request._user_progress_map = user_progress_map
@@ -108,11 +90,7 @@ class ProblemSetDetailAPI(APIView):
     def get(self, request, problem_set_id):
         """获取题单详情"""
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=problem_set_id, visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=problem_set_id, visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
@@ -126,32 +104,19 @@ class ProblemSetProblemAPI(APIView):
     def get(self, request, problem_set_id):
         """获取题单中的题目列表"""
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=problem_set_id, visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=problem_set_id, visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
-        problems = (
-            ProblemSetProblem.objects.filter(problemset=problem_set)
-            .select_related("problem__created_by")
-            .prefetch_related("problem__tags")
-            .order_by("order")
-        )
+        problems = ProblemSetProblem.objects.filter(problemset=problem_set).select_related("problem__created_by").prefetch_related("problem__tags").order_by("order")
         # 预取当前用户的题单进度，供 get_is_completed 使用，避免 N+1
         user_progress = None
         if request.user.is_authenticated:
             try:
-                user_progress = ProblemSetProgress.objects.get(
-                    problemset=problem_set, user=request.user
-                )
+                user_progress = ProblemSetProgress.objects.get(problemset=problem_set, user=request.user)
             except ProblemSetProgress.DoesNotExist:
                 pass
-        serializer = ProblemSetProblemSerializer(
-            problems, many=True, context={"request": request, "user_progress": user_progress}
-        )
+        serializer = ProblemSetProblemSerializer(problems, many=True, context={"request": request, "user_progress": user_progress})
         return self.success(serializer.data)
 
 
@@ -163,23 +128,15 @@ class ProblemSetProgressAPI(APIView):
         """加入题单"""
         data = request.data
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=data["problemset_id"], visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=data["problemset_id"], visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
-        if ProblemSetProgress.objects.filter(
-            problemset=problem_set, user=request.user
-        ).exists():
+        if ProblemSetProgress.objects.filter(problemset=problem_set, user=request.user).exists():
             return self.error("已经加入该题单")
 
         # 创建进度记录
-        progress = ProblemSetProgress.objects.create(
-            problemset=problem_set, user=request.user
-        )
+        progress = ProblemSetProgress.objects.create(problemset=problem_set, user=request.user)
         progress.update_progress()
 
         return self.success("成功加入题单")
@@ -187,18 +144,12 @@ class ProblemSetProgressAPI(APIView):
     def get(self, request, problem_set_id):
         """获取题单进度"""
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=problem_set_id, visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=problem_set_id, visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
         try:
-            progress = ProblemSetProgress.objects.get(
-                problemset=problem_set, user=request.user
-            )
+            progress = ProblemSetProgress.objects.get(problemset=problem_set, user=request.user)
         except ProblemSetProgress.DoesNotExist:
             return self.error("未加入该题单")
 
@@ -210,18 +161,12 @@ class ProblemSetProgressAPI(APIView):
         """更新进度"""
         data = request.data
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=data["problemset_id"], visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=data["problemset_id"], visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
         try:
-            progress = ProblemSetProgress.objects.get(
-                problemset=problem_set, user=request.user
-            )
+            progress = ProblemSetProgress.objects.get(problemset=problem_set, user=request.user)
         except ProblemSetProgress.DoesNotExist:
             return self.error("未加入该题单")
 
@@ -230,9 +175,7 @@ class ProblemSetProgressAPI(APIView):
 
         # 获取该题目在题单中的分值
         try:
-            problemset_problem = ProblemSetProblem.objects.get(
-                problemset=problem_set, problem_id=problem_id
-            )
+            problemset_problem = ProblemSetProblem.objects.get(problemset=problem_set, problem_id=problem_id)
             problem_score = problemset_problem.score
         except ProblemSetProblem.DoesNotExist:
             problem_score = 0
@@ -296,9 +239,7 @@ class UserProgressAPI(APIView):
 
     def get(self, request):
         """获取用户的题单进度列表"""
-        progress_list = ProblemSetProgress.objects.filter(user=request.user).order_by(
-            "-join_time"
-        )
+        progress_list = ProblemSetProgress.objects.filter(user=request.user).order_by("-join_time")
         serializer = ProblemSetProgressSerializer(progress_list, many=True)
         return self.success(serializer.data)
 
@@ -315,16 +256,12 @@ class UserBadgeAPI(APIView):
             # 获取指定用户的徽章
             try:
                 target_user = User.objects.get(username=username, is_disabled=False)
-                badges = UserBadge.objects.filter(user=target_user).order_by(
-                    "-earned_time"
-                )
+                badges = UserBadge.objects.filter(user=target_user).order_by("-earned_time")
             except User.DoesNotExist:
                 return self.error("用户不存在")
         else:
             # 获取当前用户的徽章
-            badges = UserBadge.objects.filter(user=request.user).order_by(
-                "-earned_time"
-            )
+            badges = UserBadge.objects.filter(user=request.user).order_by("-earned_time")
 
         serializer = UserBadgeSerializer(badges, many=True)
         return self.success(serializer.data)
@@ -336,11 +273,7 @@ class ProblemSetBadgeAPI(APIView):
     def get(self, request, problem_set_id):
         """获取题单的奖章列表"""
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=problem_set_id, visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=problem_set_id, visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
@@ -355,18 +288,12 @@ class ProblemSetUserProgressAPI(APIView):
     def get(self, request, problem_set_id: int):
         """获取题单的用户进度列表"""
         try:
-            problem_set = (
-                ProblemSet.objects.filter(id=problem_set_id, visible=True)
-                .exclude(status="draft")
-                .get()
-            )
+            problem_set = ProblemSet.objects.filter(id=problem_set_id, visible=True).exclude(status="draft").get()
         except ProblemSet.DoesNotExist:
             return self.error("题单不存在")
 
         # 获取所有参与该题单的用户进度，使用 select_related 预加载用户信息
-        progresses = ProblemSetProgress.objects.filter(
-            problemset=problem_set
-        ).select_related("user")
+        progresses = ProblemSetProgress.objects.filter(problemset=problem_set).select_related("user")
 
         # 班级过滤
         class_name = request.GET.get("class_name", "").strip()
@@ -386,9 +313,7 @@ class ProblemSetUserProgressAPI(APIView):
             progresses = progresses.filter(completed_problems_count=0)
 
         # 排序
-        progresses = progresses.order_by(
-            "-is_completed", "-progress_percentage", "join_time"
-        )
+        progresses = progresses.order_by("-is_completed", "-progress_percentage", "join_time")
 
         # 计算统计数据（基于所有数据，而非分页数据）
         # 使用一次查询获取所有统计数据
@@ -416,10 +341,7 @@ class ProblemSetUserProgressAPI(APIView):
         # 提前获取题单的所有题目（用于前端显示未完成题目和序列化器）
         # 使用 select_related 和 only 优化查询，只选择需要的字段
         all_problemset_problems = (
-            ProblemSetProblem.objects.filter(problemset=problem_set)
-            .select_related("problem")
-            .only("problem__id", "problem___id", "problem__title", "order")
-            .order_by("order")
+            ProblemSetProblem.objects.filter(problemset=problem_set).select_related("problem").only("problem__id", "problem___id", "problem__title", "order").order_by("order")
         )
 
         # 构建题单所有题目的数据结构和映射
@@ -444,11 +366,7 @@ class ProblemSetUserProgressAPI(APIView):
                 completed_problem_ids.update(progress.progress_detail.keys())
 
         # 从已加载的题单题目中构建 problems_dict，避免重复查询
-        problems_dict = {
-            pid: all_problems_map[pid]
-            for pid in completed_problem_ids
-            if pid in all_problems_map
-        }
+        problems_dict = {pid: all_problems_map[pid] for pid in completed_problem_ids if pid in all_problems_map}
 
         # 将预加载的问题字典存储到 request 中，供序列化器使用
         request._problems_dict_cache = problems_dict

submission/migrations/0005_alter_submission_result.py

@@ -0,0 +1,33 @@
+# Generated by Django 6.0.4 on 2026-05-09 08:18
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("submission", "0004_submission_problem_user_idx"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="submission",
+            name="result",
+            field=models.IntegerField(
+                choices=[
+                    (-2, "Compile Error"),
+                    (-1, "Wrong Answer"),
+                    (0, "Accepted"),
+                    (1, "CPU Time Limit Exceeded"),
+                    (2, "Real Time Limit Exceeded"),
+                    (3, "Memory Limit Exceeded"),
+                    (4, "Runtime Error"),
+                    (5, "System Error"),
+                    (6, "Pending"),
+                    (7, "Judging"),
+                    (8, "Partially Accepted"),
+                ],
+                db_index=True,
+                default=6,
+            ),
+        ),
+    ]

submission/models.py

@@ -7,18 +7,18 @@ from utils.models import JSONField
 from utils.shortcuts import rand_str
 
 
-class JudgeStatus:
-    COMPILE_ERROR = -2
-    WRONG_ANSWER = -1
-    ACCEPTED = 0
-    CPU_TIME_LIMIT_EXCEEDED = 1
-    REAL_TIME_LIMIT_EXCEEDED = 2
-    MEMORY_LIMIT_EXCEEDED = 3
-    RUNTIME_ERROR = 4
-    SYSTEM_ERROR = 5
-    PENDING = 6
-    JUDGING = 7
-    PARTIALLY_ACCEPTED = 8
+class JudgeStatus(models.IntegerChoices):
+    COMPILE_ERROR = -2, "Compile Error"
+    WRONG_ANSWER = -1, "Wrong Answer"
+    ACCEPTED = 0, "Accepted"
+    CPU_TIME_LIMIT_EXCEEDED = 1, "CPU Time Limit Exceeded"
+    REAL_TIME_LIMIT_EXCEEDED = 2, "Real Time Limit Exceeded"
+    MEMORY_LIMIT_EXCEEDED = 3, "Memory Limit Exceeded"
+    RUNTIME_ERROR = 4, "Runtime Error"
+    SYSTEM_ERROR = 5, "System Error"
+    PENDING = 6, "Pending"
+    JUDGING = 7, "Judging"
+    PARTIALLY_ACCEPTED = 8, "Partially Accepted"
 
 
 class Submission(models.Model):
@@ -29,7 +29,7 @@ class Submission(models.Model):
     user_id = models.IntegerField(db_index=True)
     username = models.TextField()
     code = models.TextField()
-    result = models.IntegerField(db_index=True, default=JudgeStatus.PENDING)
+    result = models.IntegerField(choices=JudgeStatus.choices, db_index=True, default=JudgeStatus.PENDING)
     # 从JudgeServer返回的判题详情
     info = JSONField(default=dict)
     language = models.TextField()
@@ -40,11 +40,7 @@ class Submission(models.Model):
     ip = models.TextField(null=True)
 
     def check_user_permission(self, user, check_share=True):
-        if (
-            self.user_id == user.id
-            or not user.is_regular_user()
-            or self.problem.created_by_id == user.id
-        ):
+        if self.user_id == user.id or not user.is_regular_user() or self.problem.created_by_id == user.id:
             return True
 
         if check_share:
@@ -58,15 +54,9 @@ class Submission(models.Model):
         db_table = "submission"
         ordering = ("-create_time",)
         indexes = [
-            models.Index(
-                fields=["user_id", "create_time"], name="user_create_time_idx"
-            ),
-            models.Index(
-                fields=["contest_id", "-create_time"], name="contest_create_time_idx"
-            ),
-            models.Index(
-                fields=["problem_id", "user_id"], name="problem_user_idx"
-            ),
+            models.Index(fields=["user_id", "create_time"], name="user_create_time_idx"),
+            models.Index(fields=["contest_id", "-create_time"], name="contest_create_time_idx"),
+            models.Index(fields=["problem_id", "user_id"], name="problem_user_idx"),
         ]
 
     def __str__(self):

tutorial/models.py

@@ -3,16 +3,22 @@ from django.db import models
 from account.models import User
 
 
-class Tutorial(models.Model):
-    TYPE_CHOICES = [
-        ('python', 'Python'),
-        ('c', 'C'),
-    ]
+class TutorialType(models.TextChoices):
+    PYTHON = "python", "Python"
+    C = "c", "C"
 
+
+class ExerciseType(models.TextChoices):
+    MCQ = "mcq", "选择题"
+    SORT = "sort", "代码排序"
+    FILL = "fill", "代码填空"
+
+
+class Tutorial(models.Model):
     title = models.CharField(max_length=128)
     content = models.TextField()
     code = models.TextField(null=True, blank=True)
-    type = models.CharField(max_length=10, choices=TYPE_CHOICES, default='python')
+    type = models.CharField(max_length=10, choices=TutorialType.choices, default=TutorialType.PYTHON)
     created_by = models.ForeignKey(User, on_delete=models.CASCADE)
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
@@ -21,21 +27,15 @@ class Tutorial(models.Model):
 
     class Meta:
         db_table = "tutorial"
-        ordering = ['order', '-created_at']
+        ordering = ["order", "-created_at"]
 
     def __str__(self):
         return self.title
 
 
 class Exercise(models.Model):
-    TYPE_CHOICES = [
-        ("mcq", "选择题"),
-        ("sort", "代码排序"),
-        ("fill", "代码填空"),
-    ]
-
     tutorial = models.ForeignKey(Tutorial, on_delete=models.CASCADE, related_name="exercises")
-    type = models.CharField(max_length=16, choices=TYPE_CHOICES)
+    type = models.CharField(max_length=16, choices=ExerciseType.choices)
     data = models.JSONField()
     order = models.IntegerField(default=0)
     created_at = models.DateTimeField(auto_now_add=True)

tutorial/serializers.py

@@ -2,7 +2,7 @@ from rest_framework import serializers
 
 from account.serializers import UserSerializer
 
-from .models import Exercise, Tutorial
+from .models import Exercise, ExerciseType, Tutorial
 
 
 class TutorialListSerializer(serializers.ModelSerializer):
@@ -65,13 +65,13 @@ class ExerciseSerializer(serializers.ModelSerializer):
 
 class CreateExerciseSerializer(serializers.Serializer):
     tutorial_id = serializers.IntegerField()
-    type = serializers.ChoiceField(choices=["mcq", "sort", "fill"])
+    type = serializers.ChoiceField(choices=ExerciseType.choices)
     data = serializers.JSONField()
     order = serializers.IntegerField(default=0)
 
 
 class EditExerciseSerializer(serializers.Serializer):
     id = serializers.IntegerField()
-    type = serializers.ChoiceField(choices=["mcq", "sort", "fill"])
+    type = serializers.ChoiceField(choices=ExerciseType.choices)
     data = serializers.JSONField()
     order = serializers.IntegerField(default=0)

utils/constants.py

@@ -1,24 +1,20 @@
-class Choices:
-    @classmethod
-    def choices(cls):
-        d = cls.__dict__
-        return [d[item] for item in d.keys() if not item.startswith("__")]
+from django.db import models
 
 
-class ContestType:
-    PUBLIC_CONTEST = "Public"
-    PASSWORD_PROTECTED_CONTEST = "Password Protected"
+class ContestType(models.TextChoices):
+    PUBLIC_CONTEST = "Public", "Public"
+    PASSWORD_PROTECTED_CONTEST = "Password Protected", "Password Protected"
 
 
-class ContestStatus:
-    CONTEST_NOT_START = "1"
-    CONTEST_ENDED = "-1"
-    CONTEST_UNDERWAY = "0"
+class ContestStatus(models.TextChoices):
+    CONTEST_NOT_START = "1", "Not Started"
+    CONTEST_ENDED = "-1", "Ended"
+    CONTEST_UNDERWAY = "0", "Underway"
 
 
-class ContestRuleType(Choices):
-    ACM = "ACM"
-    OI = "OI"
+class ContestRuleType(models.TextChoices):
+    ACM = "ACM", "ACM"
+    OI = "OI", "OI"
 
 
 class CacheKey:
@@ -31,10 +27,10 @@ class CacheKey:
     user_activity_rank = "user_activity_rank"
 
 
-class Difficulty(Choices):
-    LOW = "Low"
-    MID = "Mid"
-    HIGH = "High"
+class Difficulty(models.TextChoices):
+    LOW = "Low", "Low"
+    MID = "Mid", "Mid"
+    HIGH = "High", "High"
 
 
 CONTEST_PASSWORD_SESSION_KEY = "contest_password"

utils/migrate_data.py

@@ -12,18 +12,11 @@ os.environ.setdefault("DJANGO_SETTINGS_MODULE", "oj.settings")
 django.setup()
 from django.conf import settings
 from account.models import User, UserProfile, AdminType, ProblemPermission
-from problem.models import Problem, ProblemTag, ProblemDifficulty, ProblemRuleType
+from problem.models import Problem, ProblemTag, ProblemRuleType
+from utils.constants import Difficulty
 
-admin_type_map = {
-    0: AdminType.REGULAR_USER,
-    1: AdminType.ADMIN,
-    2: AdminType.SUPER_ADMIN
-}
-languages_map = {
-    1: "C",
-    2: "C++",
-    3: "Java"
-}
+admin_type_map = {0: AdminType.REGULAR_USER, 1: AdminType.ADMIN, 2: AdminType.SUPER_ADMIN}
+languages_map = {1: "C", 2: "C++", 3: "Java"}
 email_regex = re.compile(r"(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$)")
 
 # pk -> name
@@ -46,9 +39,7 @@ def get_input_result():
 def set_problem_display_id_prefix():
     while True:
         print("Please input a prefix which will be used in all the imported problem's displayID")
-        print(
-            "For example, if your input is 'old'(no quote), the problems' display id will be old1, old2, old3..\ninput:",
-            end="")
+        print("For example, if your input is 'old'(no quote), the problems' display id will be old1, old2, old3..\ninput:", end="")
         resp = input()
         if resp.strip():
             return resp.strip()
@@ -60,8 +51,8 @@ def set_problem_display_id_prefix():
 
 def get_stripped_output_md5(test_case_id, output_name):
     output_path = os.path.join(settings.TEST_CASE_DIR, test_case_id, output_name)
-    with open(output_path, 'r') as f:
-        return hashlib.md5(f.read().rstrip().encode('utf-8')).hexdigest()
+    with open(output_path, "r") as f:
+        return hashlib.md5(f.read().rstrip().encode("utf-8")).hexdigest()
 
 
 def get_test_case_score(test_case_id):
@@ -79,9 +70,7 @@ def get_test_case_score(test_case_id):
             test_case["stripped_output_md5"] = test_case.pop("striped_output_md5")
         else:
             test_case["stripped_output_md5"] = get_stripped_output_md5(test_case_id, test_case["output_name"])
-        test_case_score.append({"input_name": test_case["input_name"],
-                                "output_name": test_case.get("output_name", "-"),
-                                "score": 0})
+        test_case_score.append({"input_name": test_case["input_name"], "output_name": test_case.get("output_name", "-"), "score": 0})
     if need_rewrite:
         with open(info_path, "w") as f:
             f.write(json.dumps(info))
@@ -120,7 +109,7 @@ def import_users():
 def import_tags():
     i = 0
     print("\nFind these tags in old data:")
-    print(", ".join(tags.values()), '\n')
+    print(", ".join(tags.values()), "\n")
     print("import tags now? (yes/no)")
     if get_input_result():
         for tagname in tags.values():
@@ -149,14 +138,13 @@ def import_problems():
                 print("%s has the same display_id with the db problem" % data["title"])
                 continue
             try:
-                creator_id = \
-                    User.objects.filter(username=users[data["created_by"]]["username"]).values_list("id", flat=True)[0]
+                creator_id = User.objects.filter(username=users[data["created_by"]]["username"]).values_list("id", flat=True)[0]
             except (User.DoesNotExist, IndexError):
                 print("The origin creator does not exist, set it to default_creator")
                 creator_id = default_creator.id
             data["created_by_id"] = creator_id
             data.pop("created_by")
-            data["difficulty"] = ProblemDifficulty.Mid
+            data["difficulty"] = Difficulty.MID
             if data["spj_language"]:
                 data["spj_language"] = languages_map[data["spj_language"]]
             data["samples"] = json.loads(data["samples"])