# -*- coding: utf-8 -*-
"""错题集：用户在某题答错的聚合记录（用于错题→变式题闭环）"""

from datetime import datetime

from sqlalchemy import Column, DateTime, ForeignKey, Integer, UniqueConstraint

from backend.database import Base


class WrongQuestion(Base):
    __tablename__ = "wrong_questions"
    __table_args__ = (
        UniqueConstraint("user_id", "question_id", name="uk_user_wrong_question"),
    )

    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False, index=True)
    question_id = Column(Integer, ForeignKey("questions.id"), nullable=False, index=True)

    wrong_count = Column(Integer, default=0)
    last_wrong_at = Column(DateTime, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)