"""KnowledgeBase 知识库模型。"""

from sqlalchemy import Boolean, ForeignKey, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship

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


class KnowledgeBase(UUIDPrimaryKeyMixin, TimestampMixin, Base):
    """知识库模型。

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

    __tablename__ = "knowledge_bases"

    user_id: Mapped[str] = mapped_column(
        String(32),
        ForeignKey("users.id"),
        nullable=False,
        index=True,
        comment="所有者用户 ID",
    )
    name: Mapped[str] = mapped_column(
        String(255),
        nullable=False,
        comment="知识库名称",
    )
    description: Mapped[str | None] = mapped_column(
        Text,
        nullable=True,
        comment="知识库描述",
    )
    enabled: Mapped[bool] = mapped_column(
        Boolean,
        default=True,
        nullable=False,
        comment="是否启用",
    )
    status: Mapped[str] = mapped_column(
        String(16),
        default="active",
        nullable=False,
        comment="状态 (active/deleted)",
    )
    token_hash: Mapped[str] = mapped_column(
        String(64),
        unique=True,
        nullable=False,
        index=True,
        comment="SHA-256(secret_token) 十六进制",
    )
    token_encrypted: Mapped[str | None] = mapped_column(
        Text,
        nullable=True,
        comment="Fernet 加密的 token 原文",
    )
    token_hint: Mapped[str | None] = mapped_column(
        String(16),
        nullable=True,
        comment="token 末 8 位明文，供后台识别",
    )
    token_expires_at: Mapped[str | None] = mapped_column(
        String(32),
        nullable=True,
        comment="链接过期时间，NULL=长期有效",
    )
    deleted_at: Mapped[str | None] = mapped_column(
        String(32),
        nullable=True,
        index=True,
        comment="进入回收站时间（NULL=未删除），3 天后自动清理",
    )

    # 关系
    user = relationship("User", back_populates="knowledge_bases", lazy="selectin")
    documents = relationship("Document", back_populates="knowledge_base", lazy="selectin")
    categories = relationship("DocumentCategory", back_populates="knowledge_base", lazy="selectin")
    access_logs = relationship("AccessLog", back_populates="knowledge_base", lazy="selectin")

    def __repr__(self) -> str:
        return f"<KnowledgeBase {self.name!r} (user={self.user_id!r})>"