"""
Minimal background job runner.
"""
import traceback
from concurrent.futures import ThreadPoolExecutor

from . import database as db
from .errors import PipelineError
from .logging_config import get_logger

log = get_logger(__name__)
_executor = ThreadPoolExecutor(max_workers=2)  # transcription is GPU-bound anyway; no benefit to more workers


def submit(job_id: str, fn, *args, **kwargs):
    def _run():
        log.info("Job %s starting", job_id)
        db.update_job(job_id, status="running", progress="Starting...")
        try:
            def progress_cb(msg):
                log.info("Job %s: %s", job_id, msg)
                db.update_job(job_id, progress=msg)
            fn(*args, progress_cb=progress_cb, **kwargs)
            db.update_job(job_id, status="done", progress="Complete")
            log.info("Job %s complete", job_id)
        except PipelineError as e:
            log.error("Job %s failed at stage '%s': %s", job_id, e.stage, e.message)
            db.update_job(
                job_id, status="error",
                error=e.message, error_stage=e.stage,
                error_detail=traceback.format_exc(),
            )
        except Exception as e:
            log.exception("Job %s failed with unexpected error", job_id)
            db.update_job(
                job_id, status="error",
                error=f"Unexpected error: {e}", error_stage="unknown",
                error_detail=traceback.format_exc(),
            )

    _executor.submit(_run)