"""Short-lived-session DB helpers + staging paths shared by the worker parent and the child pipeline."""

from pathlib import Path

from sqlalchemy import text

from app.config import settings
from app.db import SessionLocal
from app.models import DownloadJob, MediaAsset


# --- small DB helpers (short-lived sessions; the download itself holds no transaction) -------


def _set_job(job_id: int, **fields) -> None:
    with SessionLocal() as db:
        job = db.get(DownloadJob, job_id)
        if job is None:
            return
        for k, v in fields.items():
            setattr(job, k, v)
        db.commit()


def _job_status(job_id: int) -> str | None:
    with SessionLocal() as db:
        return db.execute(
            text("SELECT status FROM download_jobs WHERE id = :id"), {"id": job_id}
        ).scalar()


def _touch_job(job_id: int) -> None:
    """Bump a running job's `updated_at` without changing any value — a stall-watchdog heartbeat for
    phases that legitimately write no progress. Extraction writes nothing, and a multi-client-set
    fallback re-writes identical values (progress 0 / phase 'downloading'), so ORM `onupdate` would
    NOT fire and two slow extraction attempts could otherwise cross the stall timeout and be killed
    mid-extraction though they'd have succeeded."""
    with SessionLocal() as db:
        db.execute(
            text("UPDATE download_jobs SET updated_at=now() WHERE id=:id AND status='running'"),
            {"id": job_id},
        )
        db.commit()


def _requeue_if_running(job_id: int, phase: str) -> None:
    """Put the job back to 'queued' for a later retry, but ONLY while it is still 'running'. The
    route flips status to paused/cancelled to stop a job; a blind `status='queued'` here would
    clobber that and silently revive a job the user just cancelled. The conditional WHERE makes the
    requeue a no-op unless we still own a running job."""
    with SessionLocal() as db:
        db.execute(
            text(
                "UPDATE download_jobs SET status='queued', phase=:phase, updated_at=now() "
                "WHERE id=:id AND status='running'"
            ),
            {"id": job_id, "phase": phase},
        )
        db.commit()


def _reset_asset_pending(asset_id: int) -> None:
    with SessionLocal() as db:
        asset = db.get(MediaAsset, asset_id)
        if asset and asset.status == "downloading":
            asset.status = "pending"
            db.commit()


def _staging_dir(asset_id: int) -> Path:
    return Path(settings.download_root) / ".staging" / f"asset-{asset_id}"


def _edit_staging_dir(asset_id: int) -> Path:
    return Path(settings.download_root) / ".staging" / f"edit-{asset_id}"