# -*- coding: utf-8 -*-
"""学生-知识点掌握度与薄弱权重"""
from datetime import datetime
from sqlalchemy import Column, Integer, DateTime, ForeignKey, UniqueConstraint

from backend.database import Base


class StudentKnowledgeMastery(Base):
    __tablename__ = "student_knowledge_mastery"
    __table_args__ = (
        UniqueConstraint("user_id", "knowledge_point_id", name="uk_user_kp"),
    )

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

    # 掌握度 0-100
    mastery_score = Column(Integer, nullable=False, default=0)

    # 原始统计
    correct_count = Column(Integer, default=0)
    wrong_count = Column(Integer, default=0)

    # 薄弱权重：越大表示越薄弱，用于推荐排序
    weakness_weight = Column(Integer, default=0)

    last_practiced_at = Column(DateTime, nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)