{
  lib,
  pkgs,
  ...
}:
let
  jfLib = import ./jellyfin-test-lib.nix { inherit pkgs lib; };
in
pkgs.testers.runNixOSTest {
  name = "jellyfin-set-defaults";

  nodes.machine =
    { ... }:
    {
      imports = [ jfLib.jellyfinTestConfig ];
    };

  testScript = ''
    import json

    import importlib.util
    _spec = importlib.util.spec_from_file_location("jf_helpers", "${jfLib.helpers}")
    assert _spec and _spec.loader
    _jf = importlib.util.module_from_spec(_spec)
    _spec.loader.exec_module(_jf)
    setup_jellyfin = _jf.setup_jellyfin
    jellyfin_api = _jf.jellyfin_api

    auth_header = 'MediaBrowser Client="NixOS Test", DeviceId="test-1337", Device="TestDevice", Version="1.0"'
    script = "${../services/jellyfin/jellyfin-set-defaults.py}"

    start_all()

    token, user_id, movie_id, media_source_id = setup_jellyfin(
        machine, retry, auth_header,
        "${jfLib.payloads.auth}", "${jfLib.payloads.empty}",
    )

    with subtest("Preference is not set initially"):
        raw = jellyfin_api(
            machine, "GET",
            f"/DisplayPreferences/usersettings?userId={user_id}&client=emby",
            auth_header, token=token,
        )
        prefs = json.loads(raw)
        custom = prefs.get("CustomPrefs", {})
        assert custom.get("preferFmp4HlsContainer") != "true", \
            f"Expected preference to be unset, got: {custom}"

    with subtest("Script sets preference for all users"):
        CREDS_DIR = "/run/jf-defaults-creds"
        machine.succeed(f"mkdir -p {CREDS_DIR}")
        machine.succeed(f"echo 'dummy-api-key' > {CREDS_DIR}/jellyfin-api-key")

        # The script uses api_key query param which requires a real Jellyfin API key.
        # In the test, we use the auth token via a patched approach: call the script
        # by providing the token as the API key. Jellyfin accepts api_key= with either
        # an API key or an access token.
        machine.succeed(f"echo '{token}' > {CREDS_DIR}/jellyfin-api-key")

        machine.succeed(
            f"CREDENTIALS_DIRECTORY={CREDS_DIR} "
            f"JELLYFIN_URL=http://127.0.0.1:8096 "
            f"${pkgs.python3}/bin/python {script}"
        )

    with subtest("Preference is now enabled"):
        raw = jellyfin_api(
            machine, "GET",
            f"/DisplayPreferences/usersettings?userId={user_id}&client=emby",
            auth_header, token=token,
        )
        prefs = json.loads(raw)
        custom = prefs.get("CustomPrefs", {})
        assert custom.get("preferFmp4HlsContainer") == "true", \
            f"Expected preferFmp4HlsContainer=true, got: {custom}"

    with subtest("Script is idempotent"):
        machine.succeed(
            f"CREDENTIALS_DIRECTORY={CREDS_DIR} "
            f"JELLYFIN_URL=http://127.0.0.1:8096 "
            f"${pkgs.python3}/bin/python {script}"
        )

        raw = jellyfin_api(
            machine, "GET",
            f"/DisplayPreferences/usersettings?userId={user_id}&client=emby",
            auth_header, token=token,
        )
        prefs = json.loads(raw)
        custom = prefs.get("CustomPrefs", {})
        assert custom.get("preferFmp4HlsContainer") == "true", \
            f"Expected preference to remain true after re-run, got: {custom}"
  '';
}