"""Archive location persistence (US06-01).

An archive location is a *medium*, not a path. External disks get mounted at
different mountpoints, and a different disk can be mounted at the same one, so a
recorded root alone can never prove "these bytes went to that volume". Each
location therefore owns a marker file written onto the medium itself; its
``media_id`` is the stable identity, and the root is only where it was last seen.

``capabilities`` and ``state`` are the last probe result, kept so the UI can list
locations without touching a sleeping disk. Preflight always re-probes — a stored
state is a hint, never evidence.
"""

from __future__ import annotations

from datetime import datetime

from sqlalchemy import DateTime, String, func
from sqlalchemy.orm import Mapped, mapped_column

from photo_pipeline.db import Base


class ArchiveLocation(Base):
    __tablename__ = "archive_locations"

    id: Mapped[str] = mapped_column(String, primary_key=True)
    name: Mapped[str] = mapped_column(String, nullable=False, unique=True)
    root: Mapped[str] = mapped_column(String, nullable=False)
    # Written into the marker file on the medium; proves the right volume is mounted.
    media_id: Mapped[str] = mapped_column(String, nullable=False, unique=True)
    capabilities: Mapped[str | None] = mapped_column(String)  # JSON, last probe
    # online | offline | wrong_volume | unwritable — the last probe's verdict.
    state: Mapped[str] = mapped_column(String, nullable=False, default="offline")
    last_seen_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
    )