"""Archive location, plan, and transfer-journal persistence (US06-01, US06-02).

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.

An ``ArchivePlan`` is one approved preflight turned into durable work, and each
``ArchiveOperation`` is one file's crash-safe journal row (US06-02). The row records
what the transfer *intends* to do before it does it — source, destination, expected
hash — because after a crash that intent plus the files on disk is the only evidence
available for deciding whether an original may be removed.
"""

from __future__ import annotations

from datetime import datetime

from sqlalchemy import (
    Boolean,
    DateTime,
    ForeignKey,
    Integer,
    String,
    UniqueConstraint,
    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()
    )


class ArchivePlan(Base):
    __tablename__ = "archive_plans"

    id: Mapped[str] = mapped_column(String, primary_key=True)
    location_id: Mapped[str] = mapped_column(
        ForeignKey("archive_locations.id"), nullable=False, index=True
    )
    # The preflight token this plan was approved against; re-verified before apply.
    token: Mapped[str] = mapped_column(String, nullable=False)
    albums: Mapped[str | None] = mapped_column(String)  # JSON array
    # archive | restore — the same journal read in the opposite direction (US06-04).
    direction: Mapped[str] = mapped_column(String, nullable=False, default="archive")

    # planned | applying | complete | failed
    state: Mapped[str] = mapped_column(String, nullable=False, default="planned")
    schema_version: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
    asset_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    byte_size: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    # Bumped on every claim and used as the fencing token, so a superseded attempt
    # cannot commit.
    version: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
    worker_id: Mapped[str | None] = mapped_column(String)
    completed_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()
    )


class ArchiveOperation(Base):
    __tablename__ = "archive_operations"
    __table_args__ = (
        UniqueConstraint("plan_id", "sequence", name="uq_archive_operations_plan_sequence"),
    )

    id: Mapped[str] = mapped_column(String, primary_key=True)
    plan_id: Mapped[str] = mapped_column(
        ForeignKey("archive_plans.id", ondelete="CASCADE"), nullable=False, index=True
    )
    sequence: Mapped[int] = mapped_column(Integer, nullable=False)
    album: Mapped[str] = mapped_column(String, nullable=False)
    asset_id: Mapped[str] = mapped_column(ForeignKey("assets.id"), nullable=False, index=True)

    # archive: library → medium. restore: medium → library (US06-04). ``source_path``
    # and ``destination_path`` always mean "from" and "to" for this direction.
    direction: Mapped[str] = mapped_column(String, nullable=False, default="archive")
    source_path: Mapped[str] = mapped_column(String, nullable=False)
    destination_path: Mapped[str] = mapped_column(String, nullable=False)
    # Relative to the location root, because the medium can be mounted elsewhere.
    archive_path: Mapped[str] = mapped_column(String, nullable=False)
    expected_sha256: Mapped[str] = mapped_column(String, nullable=False)
    byte_size: Mapped[int | None] = mapped_column(Integer)
    same_filesystem: Mapped[bool | None] = mapped_column(Boolean)

    # planned | transferring | verified | removing | complete | failed
    journal_state: Mapped[str] = mapped_column(String, nullable=False, default="planned")
    attempt_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    fencing_token: Mapped[int | None] = mapped_column(Integer)
    worker_id: Mapped[str | None] = mapped_column(String)
    verified_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    removed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    error_code: Mapped[str | None] = mapped_column(String)
    error_message: Mapped[str | None] = mapped_column(String)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now(), onupdate=func.now()
    )