refactor(reaction): 收敛为单选接口

reaction/serializers.py

@@ -1,18 +1,26 @@
 from reaction.models import ReactionType
 from utils.api import serializers
 
-MAX_REACTIONS = 3
-
 
 class SetReactionSerializer(serializers.Serializer):
     problem_id = serializers.IntegerField()
+    type = serializers.ChoiceField(choices=ReactionType.choices, required=False)
     types = serializers.ListField(
         child=serializers.ChoiceField(choices=ReactionType.choices),
+        required=False,
         allow_empty=False,
     )
 
-    def validate_types(self, value):
-        unique = list(dict.fromkeys(value))
-        if len(unique) > MAX_REACTIONS:
-            raise serializers.ValidationError(f"最多只能选 {MAX_REACTIONS} 个")
-        return unique
+    def validate(self, attrs):
+        reaction_type = attrs.get("type")
+        legacy_types = list(dict.fromkeys(attrs.get("types", [])))
+
+        if len(legacy_types) > 1:
+            raise serializers.ValidationError({"types": "只能选择一个评价"})
+        if reaction_type is None and not legacy_types:
+            raise serializers.ValidationError({"type": "This field is required."})
+        if reaction_type is not None and legacy_types and reaction_type != legacy_types[0]:
+            raise serializers.ValidationError({"types": "新旧评价字段不一致"})
+
+        attrs["type"] = reaction_type or legacy_types[0]
+        return attrs