from sqlalchemy import Column, Integer, String, ForeignKey
from sqlalchemy.orm import relationship

from app.database import Base


class Section(Base):
    __tablename__ = "sections"

    id = Column(Integer, primary_key=True, index=True)
    document_id = Column(Integer, ForeignKey("pdf_documents.id", ondelete="CASCADE"), nullable=False)
    name = Column(String, nullable=False)
    start_page = Column(Integer, nullable=False)
    end_page = Column(Integer, nullable=False)

    document = relationship("PDFDocument", back_populates="sections")
    # No cascade delete — deleting a section must NOT destroy quizzes/questions
    quizzes = relationship("Quiz", back_populates="section")