"""Document 文档模型。"""

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

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


class Document(UUIDPrimaryKeyMixin, TimestampMixin, Base):
    """文档模型。

    技术审查 §2.2：documents 表。
    """

    __tablename__ = "documents"

    knowledge_base_id: Mapped[str] = mapped_column(
        String(32),
        ForeignKey("knowledge_bases.id"),
        nullable=False,
        index=True,
        comment="所属知识库 ID",
    )
    user_id: Mapped[str] = mapped_column(
        String(32),
        ForeignKey("users.id"),
        nullable=False,
        index=True,
        comment="所有者用户 ID (冗余，便于隔离校验)",
    )
    category_id: Mapped[str | None] = mapped_column(
        String(32),
        ForeignKey("document_categories.id"),
        nullable=True,
        comment="分类 ID",
    )
    original_filename: Mapped[str] = mapped_column(
        String(512),
        nullable=False,
        comment="原始文件名 (仅展示)",
    )
    storage_path: Mapped[str] = mapped_column(
        String(1024),
        nullable=False,
        comment="相对于 data/ 的物理存储路径",
    )
    markdown_path: Mapped[str | None] = mapped_column(
        String(1024),
        nullable=True,
        comment="相对于 data/ 的 Markdown 文件路径",
    )
    file_size: Mapped[int] = mapped_column(
        Integer,
        nullable=False,
        comment="文件大小 (字节)",
    )
    mime_type: Mapped[str] = mapped_column(
        String(127),
        nullable=False,
        comment="MIME 类型",
    )
    file_ext: Mapped[str] = mapped_column(
        String(16),
        nullable=False,
        comment="文件扩展名 (.docx/.pdf)",
    )
    sha256: Mapped[str] = mapped_column(
        String(64),
        nullable=False,
        comment="文件 SHA-256 哈希",
    )
    doc_token_hash: Mapped[str] = mapped_column(
        String(64),
        unique=True,
        nullable=True,
        index=True,
        comment="SHA-256(document_token) 十六进制",
    )
    doc_token_encrypted: Mapped[str | None] = mapped_column(
        Text,
        nullable=True,
        comment="Fernet 加密的 document_token 原文",
    )
    doc_token_hint: Mapped[str | None] = mapped_column(
        String(16),
        nullable=True,
        comment="document_token 末 8 位明文",
    )
    title: Mapped[str | None] = mapped_column(
        String(512),
        nullable=True,
        comment="文档标题 (用户可改)",
    )
    description: Mapped[str | None] = mapped_column(
        Text,
        nullable=True,
        comment="文档描述 (用户可改)",
    )
    keywords: Mapped[str | None] = mapped_column(
        Text,
        nullable=True,
        comment="关键词 (逗号分隔)",
    )
    content_summary: Mapped[str | None] = mapped_column(
        Text,
        nullable=True,
        comment="抽取式摘要 (~200字)",
    )
    status: Mapped[str] = mapped_column(
        String(16),
        default="PENDING",
        nullable=False,
        comment="状态 (PENDING/PROCESSING/READY/FAILED/DELETED)",
    )
    error_code: Mapped[str | None] = mapped_column(
        String(64),
        nullable=True,
        comment="错误码 (如 SCANNED_PDF_NO_TEXT_LAYER)",
    )

    # 关系
    knowledge_base = relationship("KnowledgeBase", back_populates="documents", lazy="selectin")
    user = relationship("User", back_populates="documents", lazy="selectin")
    category = relationship("DocumentCategory", back_populates="documents", lazy="selectin")
    access_logs = relationship("AccessLog", back_populates="document", lazy="selectin")

    def __repr__(self) -> str:
        return f"<Document {self.original_filename!r} (status={self.status!r})>"