"""Windows gateway service invariants and launcher identity after PM cutover."""

from __future__ import annotations

import sys
import types
from types import SimpleNamespace

import pytest

from hermes_cli import main as cli_main

def test_restore_windows_gateway_service_waits_out_stop_pending(monkeypatch):
    import hermes_cli.update_cmd as update_cmd
    import hermes_cli.update_cmd_windows as update_cmd_windows

    statuses = iter(["stop_pending", "stopped"])
    service = SimpleNamespace(status=lambda: next(statuses))
    fake_psutil = SimpleNamespace(win_service_get=lambda _name: service)
    restarted = []
    monkeypatch.setitem(sys.modules, "psutil", fake_psutil)
    monkeypatch.setattr(update_cmd._time, "sleep", lambda _seconds: None)
    monkeypatch.setattr(
        update_cmd,
        "_start_windows_gateway_service",
        lambda name: restarted.append(name),
    )
    monkeypatch.setattr(
        update_cmd_windows,
        "_start_windows_gateway_service",
        lambda name: restarted.append(name),
    )

    update_cmd._restore_windows_gateway_service("HermesGateway")

    assert restarted == ["HermesGateway"]


def test_stop_windows_gateway_service_waits_for_original_descendants(
    monkeypatch,
):
    """SCM STOPPED is insufficient while the original process identity lives."""
    import hermes_cli.update_cmd as update_cmd

    service = SimpleNamespace(status=lambda: "stopped")
    fake_psutil = SimpleNamespace(
        win_service_get=lambda _name: service,
        Process=lambda pid: SimpleNamespace(create_time=lambda: 12.5),
    )
    monkeypatch.setitem(sys.modules, "psutil", fake_psutil)
    monkeypatch.setattr(
        update_cmd.subprocess,
        "run",
        lambda *_a, **_k: SimpleNamespace(returncode=0, stdout="", stderr=""),
    )
    with pytest.raises(RuntimeError, match="process tree"):
        update_cmd._stop_windows_gateway_service(
            "HermesGateway",
            expected_processes=((123, 12.5),),
            timeout=0,
        )


def _fake_psutil_tree(tree, venv_exe, worker_exe, dead=None):
    """Build a psutil stand-in where ``tree`` maps worker pid -> parent pid.

    Parents whose pid is even are venv-side (``venv_exe``); odd parents are
    unrelated ancestors (``worker_exe``) that must NOT be returned. Pids in
    ``dead`` (a live reference — later additions count) are uninspectable:
    construction raises, exactly like psutil.NoSuchProcess for an exited
    process.
    """

    dead_set = dead if dead is not None else set()

    class FakeProc:
        def __init__(self, pid):
            self.pid = pid
            if pid in dead_set:
                raise ValueError(f"process {pid} has exited")
            if pid not in tree and pid not in tree.values():
                raise ValueError(f"no such pid {pid}")

        def parent(self):
            ppid = tree.get(self.pid)
            return FakeProc(ppid) if ppid else None

        def parents(self):
            return []

        def exe(self):
            # Parents of workers are the launchers under test.
            return venv_exe if self.pid % 2 == 0 else worker_exe

    mod = types.SimpleNamespace(Process=FakeProc)
    return mod


@pytest.mark.platforms("windows")
def test_pause_stops_launcher_after_worker_drain(
    monkeypatch,
    tmp_path,
):
    """Capture the launcher identity while its worker is still inspectable."""
    import hermes_cli.gateway as gateway_mod
    import gateway.status as status_mod

    # The install venv is whatever hermes_constants.project_venv_dir resolves for the checkout (a
    # CI checkout has no venv/ and the test interpreter lives elsewhere); pin it to the fixture layout.
    monkeypatch.setattr("hermes_constants.project_venv_dir", lambda root: cli_main.PROJECT_ROOT / "venv")
    venv_exe = str(cli_main.PROJECT_ROOT / "venv" / "Scripts" / "python.exe")
    worker_exe = r"C:\Users\x\AppData\Roaming\uv\python\cpython-3.11\python.exe"

    profile_home = tmp_path / "profiles" / "default"
    profile_home.mkdir(parents=True)
    # The PID file records the WORKER (even-numbered parent 400 is its launcher).
    worker_pid, launcher_pid = 500, 400
    profile_proc = SimpleNamespace(
        profile="default", path=profile_home, pid=worker_pid
    )

    monkeypatch.setattr(gateway_mod, "find_gateway_pids", lambda **_k: [worker_pid])
    monkeypatch.setattr(
        gateway_mod, "find_windows_gateway_services", lambda **_k: []
    )
    monkeypatch.setattr(
        gateway_mod, "find_profile_gateway_processes", lambda **_k: [profile_proc]
    )
    monkeypatch.setattr(gateway_mod, "_get_restart_drain_timeout", lambda: 0.1)
    # Graceful drain succeeds: the worker exits, leaving zero survivors — and
    # an exited worker is UNINSPECTABLE afterwards, exactly like the real
    # process table. Resolving the launcher after this point is impossible,
    # so the pause must snapshot launcher ancestors before draining. This is
    # precisely the case that used to leave the launcher alive and abort.
    drained_dead: set[int] = set()

    def _drain_marks_workers_dead(pids, *, timeout):
        drained_dead.update(int(p) for p in pids)
        return set()

    monkeypatch.setattr(
        cli_main,
        "_wait_for_windows_update_gateway_exit",
        _drain_marks_workers_dead,
    )

    fake = _fake_psutil_tree(
        {worker_pid: launcher_pid}, venv_exe, worker_exe, dead=drained_dead
    )
    monkeypatch.setitem(sys.modules, "psutil", fake)

    terminated = []
    monkeypatch.setattr(
        status_mod,
        "terminate_pid",
        lambda pid, force=False, **kwargs: terminated.append(int(pid)),
    )

    cli_main._pause_windows_gateways_for_update()

    assert terminated == [launcher_pid]


def test_stop_service_refuses_pid_reuse_before_sc_stop(monkeypatch):
    import hermes_cli.update_cmd as update_cmd

    fake_psutil = SimpleNamespace(
        win_service_get=lambda _name: SimpleNamespace(
            status=lambda: "running", pid=lambda: 11
        ),
        Process=lambda _pid: SimpleNamespace(create_time=lambda: 99.0),
    )
    calls = []
    monkeypatch.setitem(sys.modules, "psutil", fake_psutil)
    monkeypatch.setattr(update_cmd.subprocess, "run", lambda *_a, **_k: calls.append(True))

    with pytest.raises(RuntimeError, match="identity changed"):
        update_cmd._stop_windows_gateway_service(
            "HermesGateway", expected_service_identity=(11, 11.0)
        )

    assert calls == []