"""Steward's own backups as a scheduled job: make the file, send it, record
how it went (milestone 507)."""
from __future__ import annotations

from sqlalchemy import text
from sqlalchemy.ext.asyncio import create_async_engine


async def migration_heads(database_url: str) -> list[str]:
    """The migration revisions the database is at, for the manifest."""
    engine = create_async_engine(database_url)
    try:
        async with engine.connect() as conn:
            return list((await conn.execute(text("SELECT version_num FROM alembic_version"))).scalars())
    finally:
        await engine.dispose()