"""Download/edit child process — runs ONE job's heavy work (yt-dlp download or ffmpeg edit) in its
own process, launched and supervised by the worker (`app.worker._run_supervised`).

Why a separate process: a worker THREAD can't be killed, a C-level spin (a catastrophic regex, a
tight yt-dlp retry loop) can't even be cooperatively cancelled, and one such thread starves the
others via the GIL. Running the work in a child means the supervisor can SIGTERM/SIGKILL it (and its
process group, so ffmpeg grandchildren die too) on a stall / pause / wall-clock breach.

Contract: the asset is already claimed ('downloading') by the parent. This process does the work and
writes the terminal job/asset state itself (done / error, or a cooperative pause via the in-flight
progress hook), then exits 0. An unexpected crash exits non-zero and the parent fails the job.
"""
import logging
import sys

from app.db import SessionLocal
from app.models import DownloadJob

log = logging.getLogger("siftlode.worker.runner")


def main() -> None:
    logging.basicConfig(level=logging.INFO)
    if len(sys.argv) != 2:
        print("usage: python -m app.downloads.runner <job_id>", file=sys.stderr)
        raise SystemExit(2)
    job_id = int(sys.argv[1])

    with SessionLocal() as db:
        job = db.get(DownloadJob, job_id)
        if job is None:
            return
        asset_id = job.asset_id
        job_kind = job.job_kind
        spec = dict(job.profile_snapshot or {})
        source_kind, source_ref = job.source_kind, job.source_ref
    if asset_id is None:
        return

    # Imported here (not at module top) so the child pays the yt-dlp import cost only when it has
    # real work, and to keep the import graph obvious: runner is a thin entry over worker's helpers.
    from app.worker import _download, _process_edit

    if job_kind == "edit":
        _process_edit(job_id, asset_id)
    else:
        _download(job_id, asset_id, source_kind, source_ref, spec)


if __name__ == "__main__":
    main()