"""截图主表与处理状态。"""
from __future__ import annotations

from datetime import datetime
from enum import Enum

from sqlalchemy import (
    BigInteger,
    DateTime,
    ForeignKey,
    Index,
    Integer,
    String,
    UniqueConstraint,
    func,
)
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.core.db import Base


class ProcessStatus(str, Enum):
    """处理流水线的状态枚举。"""

    PENDING = "pending"
    RUNNING = "running"
    DONE = "done"
    FAILED = "failed"
    SKIPPED = "skipped"


class Screenshot(Base):
    """截图文件主记录。"""

    __tablename__ = "screenshots"
    __table_args__ = (
        UniqueConstraint("file_hash", name="uq_screenshots_file_hash"),
        Index("ix_screenshots_captured_at", "captured_at"),
        Index("ix_screenshots_ai_status", "ai_status"),
        Index("ix_screenshots_category_id", "category_id"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    path: Mapped[str] = mapped_column(String(1024), nullable=False)
    file_hash: Mapped[str] = mapped_column(String(64), nullable=False)
    width: Mapped[int] = mapped_column(Integer, default=0)
    height: Mapped[int] = mapped_column(Integer, default=0)
    size: Mapped[int] = mapped_column(BigInteger, default=0)

    captured_at: Mapped[datetime] = mapped_column(DateTime, nullable=False)
    imported_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), nullable=False
    )

    thumb_path: Mapped[str | None] = mapped_column(String(1024), nullable=True)

    ocr_status: Mapped[str] = mapped_column(String(16), default=ProcessStatus.PENDING.value)
    ai_status: Mapped[str] = mapped_column(String(16), default=ProcessStatus.PENDING.value)

    # AI 写回的分类：外键 + SET NULL，删除分类时自动把引用置空
    category_id: Mapped[int | None] = mapped_column(
        Integer,
        ForeignKey("categories.id", ondelete="SET NULL"),
        nullable=True,
    )

    is_favorite: Mapped[int] = mapped_column(Integer, default=0)  # 0/1，便于 SQLite 索引
    is_hidden: Mapped[int] = mapped_column(Integer, default=0)

    meta = relationship(
        "ScreenshotMeta",
        back_populates="screenshot",
        uselist=False,
        cascade="all, delete-orphan",
    )
    tags = relationship(
        "Tag",
        secondary="screenshot_tags",
        back_populates="screenshots",
        lazy="selectin",
    )
    todos = relationship(
        "Todo",
        back_populates="screenshot",
        cascade="all, delete-orphan",
    )