"""library_audit_run: resume cursor + progress timestamp for chunked scans

Revision ID: 0039
Revises: 0038
Create Date: 2026-06-07

scan_library_for_rule used to run one 2h pass that timed out on large libraries
and monopolized the concurrency-1 maintenance queue (operator-flagged). It now
runs short time-boxed chunks that re-enqueue: `resume_after_id` persists the
keyset cursor so the next chunk continues where it left off, and
`last_progress_at` lets the recovery sweep tell a progressing multi-chunk audit
from a genuinely stuck one.
"""
from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op

revision: str = "0039"
down_revision: Union[str, None] = "0038"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.add_column(
        "library_audit_run",
        sa.Column(
            "resume_after_id", sa.Integer, nullable=False, server_default="0"
        ),
    )
    op.add_column(
        "library_audit_run",
        sa.Column("last_progress_at", sa.DateTime(timezone=True), nullable=True),
    )


def downgrade() -> None:
    op.drop_column("library_audit_run", "last_progress_at")
    op.drop_column("library_audit_run", "resume_after_id")