"""PatreonFailedMedia — per-source dead-letter ledger of Patreon media that
keeps failing to download/validate.

Plan #705 (#7). A media that fails every walk (404'd CDN URL, deleted post,
geo-blocked Mux stream, persistently-corrupt bytes) would otherwise re-error
forever and re-burn backfill chunks. After ``attempts`` reaches the dead-letter
threshold the ingester skips it on routine tick/backfill walks (recovery still
re-attempts it — the operator's "try everything again"). A later clean download
clears the row (the media recovered).

`filehash` is the same per-media key the seen-ledger uses (32-hex CDN MD5, or a
``video:`` / ``post:filename`` synthesized key) — hence String(128). UNIQUE
(source_id, filehash) is the upsert key.
"""

from datetime import datetime

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

from .base import Base


class PatreonFailedMedia(Base):
    __tablename__ = "patreon_failed_media"
    __table_args__ = (
        UniqueConstraint(
            "source_id", "filehash", name="uq_patreon_failed_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)
    attempts: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
    last_error: Mapped[str | None] = mapped_column(Text, nullable=True)
    first_failed_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )
    last_failed_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )
