siftlode/backend/tests/test_hls_reaper.py

"""Idle HLS sessions are reaped on a timer, and a viewer who is merely PAUSED keeps theirs.

plex/stream.py promises "a periodic reaper kills idle ones", but `reap_idle` ran only inside
POST /session: after the last playback, an abandoned session (its ffmpeg still working through the
film, its directory a whole segmented copy of it) lived until somebody pressed play again
(deep-review round 4).

And it must not take a PAUSED viewer's session: a remux finishes long before the film does, and a
paused player with a full buffer fetches nothing, so "finished and unfetched for 30 s" does not mean
"abandoned". Round 4 bought that safety by keeping EVERY finished session for the full ten-minute
idle window — one segmented copy of a film per item, on the volume the download center shares. Round
5 replaced the blanket retention with the signal that already existed: an open player checkpoints its
position every 10 s whether or not it is playing, and that route says "still here".

Both call sites are pinned here, because the bug each time was that only one of them moved: the
periodic pass, and the fact that starting a session no longer sweeps OTHER viewers' sessions at all.
"""

import asyncio
import time
from types import SimpleNamespace

import pytest
from fastapi.testclient import TestClient

import app.main as app_main
import app.state as state
from app.auth import current_user
from app.db import get_db
from app.main import app
from app.models import PlexItem, PlexLibrary, User
from app.plex import paths as plex_paths
from app.plex import stream


class _Configured:
    def __enter__(self):
        return None

    def __exit__(self, *exc):
        return False


def test_the_periodic_pass_is_the_one_that_runs_and_it_uses_the_short_rule(monkeypatch):
    async def _no_sweep():
        return None

    reaped: list[int] = []
    monkeypatch.setattr(app_main, "SessionLocal", _Configured)
    monkeypatch.setattr(app_main.state, "is_configured", lambda db: True)
    monkeypatch.setattr(app_main, "_sweep_hls_orphans", _no_sweep)
    monkeypatch.setattr(app_main, "start_scheduler", lambda: None)
    monkeypatch.setattr(app_main, "shutdown_scheduler", lambda: None)
    monkeypatch.setattr(app_main.plex_subtitles, "shutdown", lambda: None)
    monkeypatch.setattr(app_main, "_HLS_REAP_EVERY_S", 0.01)
    # `reap_idle`, i.e. the SHORT finished rule: a finished session nobody has said they still want
    # is a whole copy of a film sitting on the download volume.
    monkeypatch.setattr(app_main.plex_stream, "reap_idle", lambda: reaped.append(1) or 0)

    async def _cycle():
        async with app_main.lifespan(app):
            await asyncio.sleep(0.2)

    asyncio.run(_cycle())
    assert len(reaped) >= 2, "no periodic reap ran while the app was up"


class _Proc:
    def __init__(self, finished: bool):
        self.finished = finished
        self.killed = False

    def poll(self):
        return 0 if self.finished else None

    def terminate(self):
        self.killed = True

    def wait(self, timeout=None):
        return 0


class _Session:
    def __init__(self, tmp_path, name: str, finished: bool, idle_s: float):
        self.dir = tmp_path / name
        self.dir.mkdir()
        self.proc = _Proc(finished)
        self.last_access = time.time() - idle_s


@pytest.fixture
def sessions(monkeypatch):
    live: dict = {}
    monkeypatch.setattr(stream, "_sessions", live)
    return live


def test_the_periodic_pass_reaps_a_finished_session_nobody_has_claimed(tmp_path, sessions):
    sessions["12345"] = _Session(tmp_path, "done", finished=True, idle_s=45)
    assert stream.reap_idle() == 1
    assert sessions == {}


def test_the_periodic_pass_still_reaps_what_nobody_has_touched_for_the_idle_limit(
    tmp_path, sessions
):
    sessions["1"] = _Session(
        tmp_path, "gone_done", finished=True, idle_s=stream._SESSION_IDLE_S + 5
    )
    sessions["2"] = _Session(
        tmp_path, "gone_live", finished=False, idle_s=stream._SESSION_IDLE_S + 5
    )
    assert stream.reap_idle() == 2
    assert sessions == {}


def test_touching_a_session_keeps_it_through_the_short_rule(tmp_path, sessions):
    s = _Session(tmp_path, "paused", finished=True, idle_s=90)
    sessions["12345"] = s
    stream.touch_session("12345")
    assert stream.reap_idle() == 0
    assert "12345" in sessions and s.dir.exists() and not s.proc.killed


# --- the two call sites, driven through the real routes (DB lane) -------------------------------


def _library_item(db, rating_key: str, *, playable: str = "remux"):
    lib = PlexLibrary(plex_key="1", title="Movies", kind="movie", enabled=True)
    db.add(lib)
    db.flush()
    it = PlexItem(
        rating_key=rating_key,
        library_id=lib.id,
        kind="movie",
        title="A Movie",
        file_path="/media/a.mkv",
        playable=playable,
    )
    db.add(it)
    db.commit()
    return it


def _client(db, user):
    app.dependency_overrides[get_db] = lambda: db
    app.dependency_overrides[current_user] = lambda: user
    return TestClient(app)


def test_a_paused_viewers_checkpoint_keeps_their_session_alive(db, monkeypatch, tmp_path, sessions):
    """The whole reason the short rule is safe again: a paused player fetches nothing, so
    `last_access` never moved on its own — but it does keep checkpointing its position."""
    monkeypatch.setattr(state, "_configured_cache", True)
    it = _library_item(db, "paused1")
    user = User(email="paused@example.com")
    db.add(user)
    db.commit()
    s = _Session(tmp_path, "paused", finished=True, idle_s=90)
    sessions["paused1"] = s
    try:
        resp = _client(db, user).post(
            f"/api/plex/item/{it.rating_key}/progress",
            json={"position_seconds": 600, "duration_seconds": 3000, "final": False},
        )
    finally:
        app.dependency_overrides.clear()
    assert resp.status_code == 200, resp.text
    assert stream.reap_idle() == 0, "the checkpoint did not say the viewer is still there"
    assert "paused1" in sessions and not s.proc.killed


def test_starting_a_session_leaves_another_viewers_paused_one_alone(
    db, monkeypatch, tmp_path, sessions
):
    """The opportunistic sweep this route used to run was not scoped to the key being started: it
    walked the WHOLE registry with the 30 s finished rule, so pressing play on any item killed a
    paused viewer's session — the very case round 4 set out to protect (found in round 5)."""
    monkeypatch.setattr(state, "_configured_cache", True)
    monkeypatch.setattr(plex_paths, "local_media_path", lambda db_, fp: "/local/a.mkv")
    started = _library_item(db, "starting")
    user = User(email="starter@example.com")
    db.add(user)
    db.commit()
    paused = _Session(tmp_path, "paused", finished=True, idle_s=90)
    sessions["someone-else"] = paused

    def fake_start(db_, item, start, audio=None, aoff=0.0, multi=False, transcode=False):
        return SimpleNamespace(
            id="sid",
            media_start_s=start,
            entry="index.m3u8",
            transcode=transcode,
            hw=False,
            tonemap=False,
        )

    monkeypatch.setattr(stream, "start_session", fake_start)
    try:
        resp = _client(db, user).post(f"/api/plex/stream/{started.rating_key}/session")
    finally:
        app.dependency_overrides.clear()
    assert resp.status_code == 200, resp.text
    assert "someone-else" in sessions and not paused.proc.killed