"""DocumentCategory 文档分类模型。"""

from sqlalchemy import ForeignKey, Integer, String
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.models.base import Base, TimestampMixin, UUIDPrimaryKeyMixin


class DocumentCategory(UUIDPrimaryKeyMixin, TimestampMixin, Base):
    """文档分类模型。

    技术审查 §2.2：document_categories 表。
    """

    __tablename__ = "document_categories"

    knowledge_base_id: Mapped[str] = mapped_column(
        String(32),
        ForeignKey("knowledge_bases.id"),
        nullable=False,
        index=True,
        comment="所属知识库 ID",
    )
    name: Mapped[str] = mapped_column(
        String(255),
        nullable=False,
        comment="分类名称",
    )
    sort_order: Mapped[int] = mapped_column(
        Integer,
        default=0,
        nullable=False,
        comment="排序序号",
    )

    # 关系
    knowledge_base = relationship("KnowledgeBase", back_populates="categories", lazy="selectin")
    documents = relationship("Document", back_populates="category", lazy="selectin")

    def __repr__(self) -> str:
        return f"<DocumentCategory {self.name!r} (kb={self.knowledge_base_id!r})>"