"""PatreonSeenMedia — per-source ledger of Patreon media already
downloaded+processed.

Replaces gallery-dl's archive.sqlite3 with our own queryable table so
routine walks can skip media we've already ingested (and a future
"recovery" mode can deliberately bypass the ledger to re-walk).

`filehash` is normally a Patreon CDN MD5 (32 hex chars), but videos —
which have no stable content hash at discovery time — use a sentinel of
the form ``video:<post_id>:<media_id>``, hence String(128) rather than 32.
"""

from datetime import datetime

from sqlalchemy import ForeignKey, Integer, String, UniqueConstraint, func
from sqlalchemy.orm import Mapped, mapped_column
from sqlalchemy.types import DateTime

from .base import Base


class PatreonSeenMedia(Base):
    __tablename__ = "patreon_seen_media"
    __table_args__ = (
        # Dedup key the downloader upserts against: one ledger row per
        # (source, media). A second sighting of the same media is a no-op.
        UniqueConstraint("source_id", "filehash", name="uq_patreon_seen_media_source_id"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    source_id: Mapped[int] = mapped_column(
        ForeignKey("source.id", ondelete="CASCADE"), nullable=False, index=True
    )
    filehash: Mapped[str] = mapped_column(String(128), nullable=False)
    post_id: Mapped[str | None] = mapped_column(String(64), nullable=True)
    seen_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )