from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey
from sqlalchemy.orm import relationship
from .base_model import BaseModel, CreateModel, UpdateModel, DeleteModel


class QuestionModel(BaseModel, CreateModel, UpdateModel, DeleteModel):
    """
    题目模型
    对应数据库表: questions
    """
    __tablename__ = 'questions'

    subject = Column(String(50), nullable=False, comment='学科')
    type = Column(String(50), nullable=False, comment='题型')
    difficulty = Column(Integer, nullable=False, comment='难度等级')
    content = Column(Text, nullable=False, comment='题目内容')
    answer = Column(Text, comment='答案')
    explanation = Column(Text, comment='解析')
    version = Column(String(20), comment='题目版本')
    tags = Column(String(255), comment='题目标签')

    # 与选项的一对多关系
    options = relationship('QuestionOptionModel', back_populates='question')

    # 与知识点的多对多关系
    knowledge_points = relationship('KnowledgePointModel',
                                    secondary='question_knowledge_points',
                                    back_populates='questions')

    def __repr__(self):
        return f"<Question(id={self.id}, content={self.content[:20]}...)>"