"""add channels.feed_fallback_at — when a channel's uploads were last read through the API because
its RSS feed would not answer

Revision ID: 0088_channels_feed_fallback_at
Revises: 0087_users_diagnostics_level
Create Date: 2026-09-19

YouTube's RSS feeds go dark for hours at a time, per channel (2026-09-18/19: 393 of 396 answered 404
for four hours; the same channel answers 404 to every retry). The RSS poll then reads the newest
uploads through the Data API instead, at a quota cost, and at most once per `rss_fallback_hours` per
channel: this column is that clock. NULL = never needed it.
"""

import sqlalchemy as sa
from alembic import op

revision: str = "0088_channels_feed_fallback_at"
down_revision: str | None = "0087_users_diagnostics_level"
branch_labels: str | None = None
depends_on: str | None = None


def upgrade() -> None:
    op.add_column(
        "channels", sa.Column("feed_fallback_at", sa.DateTime(timezone=True), nullable=True)
    )


def downgrade() -> None:
    op.drop_column("channels", "feed_fallback_at")