"""Stale parse-job recovery helpers (running/queued left behind after worker crash)."""

from __future__ import annotations

import os
from datetime import datetime, timezone

from ..models import ParseJob

# Jobs stuck in running/queued longer than this are considered abandoned.
STALE_JOB_SECONDS = int(os.getenv("STALE_JOB_SECONDS", "900"))


def _aware(dt: datetime | None) -> datetime | None:
    if dt is None:
        return None
    if dt.tzinfo is None:
        return dt.replace(tzinfo=timezone.utc)
    return dt


def job_anchor_time(job: ParseJob) -> datetime | None:
    """Best available timestamp for staleness (prefer last_run_at)."""
    return _aware(job.last_run_at) or _aware(getattr(job, "created_at", None))


def is_stale_job(job: ParseJob, now: datetime | None = None, *, ttl: int | None = None) -> bool:
    if job.status not in ("running", "queued"):
        return False
    now = now or datetime.now(timezone.utc)
    anchor = job_anchor_time(job)
    if anchor is None:
        # No timestamp — treat long-lived running as stale immediately for recovery
        return job.status == "running"
    limit = ttl if ttl is not None else STALE_JOB_SECONDS
    return (now - anchor).total_seconds() >= limit