"""E3 S2 characterization net — download job state transitions (B-sub-8).

pause / resume / cancel / delete / redownload currently live inline in the routes, each hand-rolling
the asset bookkeeping (release, error-reset, fresh-asset rebuild). This pins their OBSERVABLE HTTP
behaviour so the logic can move into `service.*` methods (with the routes as thin callers) provably
behaviour-equivalently. DB lane (`db` fixture) — skipped without Postgres.
"""

from sqlalchemy import text

from app.models import DownloadJob, MediaAsset, User


def _seed(db, *, job_status, asset_status="ready", ref_count=1, rel_path=None):
    u = User(email=f"tr-{job_status}-{asset_status}-{ref_count}@example.com")
    db.add(u)
    db.flush()
    asset = MediaAsset(
        source_kind="url",
        source_ref=f"r-{u.id}",
        format_sig="s",
        status=asset_status,
        ref_count=ref_count,
        rel_path=rel_path,
    )
    db.add(asset)
    db.flush()
    job = DownloadJob(
        user_id=u.id,
        asset_id=asset.id,
        source_kind="url",
        source_ref="r",
        status=job_status,
        queue_pos=1,
        profile_snapshot={},
    )
    db.add(job)
    db.commit()
    return u, asset, job


def _ref(db, asset_id):
    return db.execute(
        text("SELECT ref_count FROM media_assets WHERE id = :id"), {"id": asset_id}
    ).scalar()


def test_cancel_releases_the_asset_and_marks_canceled(db, as_user):
    u, asset, job = _seed(db, job_status="running", asset_status="downloading", ref_count=1)
    r = as_user(u).post(f"/api/downloads/{job.id}/cancel")
    assert r.status_code == 200, r.text
    db.expire_all()
    assert db.get(DownloadJob, job.id).status == "canceled"
    assert _ref(db, asset.id) == 0  # the hold was released while the job still counted as holding


def test_pause_then_resume_round_trips_queued(db, as_user):
    u, asset, job = _seed(db, job_status="queued", asset_status="pending")
    c = as_user(u)
    assert c.post(f"/api/downloads/{job.id}/pause").status_code == 200
    db.expire_all()
    assert db.get(DownloadJob, job.id).status == "paused"
    assert c.post(f"/api/downloads/{job.id}/resume").status_code == 200
    db.expire_all()
    assert db.get(DownloadJob, job.id).status == "queued"


def test_resume_resets_a_failed_shared_asset_to_pending(db, as_user):
    u, asset, job = _seed(db, job_status="error", asset_status="error")
    r = as_user(u).post(f"/api/downloads/{job.id}/resume")
    assert r.status_code == 200, r.text
    db.expire_all()
    assert db.get(DownloadJob, job.id).status == "queued"
    # A failed shared asset is reset so the worker actually re-downloads instead of re-inheriting the error.
    assert db.get(MediaAsset, asset.id).status == "pending"


def test_delete_releases_and_removes_the_job(db, as_user):
    u, asset, job = _seed(db, job_status="done", asset_status="ready", ref_count=1, rel_path=None)
    r = as_user(u).request("DELETE", f"/api/downloads/{job.id}")
    assert r.status_code == 200, r.text
    db.expire_all()
    assert db.get(DownloadJob, job.id) is None
    assert db.get(MediaAsset, asset.id) is None  # last holder gone → ready asset freed


def test_redownload_rebuilds_into_a_fresh_asset(db, as_user):
    u, asset, job = _seed(db, job_status="done", asset_status="ready", ref_count=1, rel_path=None)
    old_asset_id = asset.id
    r = as_user(u).post(f"/api/downloads/{job.id}/redownload")
    assert r.status_code == 200, r.text
    db.expire_all()
    j = db.get(DownloadJob, job.id)
    assert j.status == "queued"
    assert j.progress == 0
    assert j.asset_id != old_asset_id  # a fresh private asset, not the old (now-released) one