"""Conformance harness fixtures.

Provides an `emu` fixture (an EmuControl client). Two modes:

- Attach: point RRDC_PORT at an already-running emulator's control port.

- Launch: set RRDC_EMU_CMD to a shell command that starts one (the literal

  {port} is substituted). The suite spawns it, waits for /status, and tears it

  down afterward.

If nothing is listening and no RRDC_EMU_CMD is set, the tests SKIP (so a bare

`pytest` in CI without an emulator is a skip, not a failure).

"""

import os

import signal

import subprocess

import sys

import pytest

HERE = os.path.dirname(os.path.abspath(__file__))

sys.path.insert(0, os.path.join(HERE, "..", "client"))

from emu_control import EmuControl  # noqa: E402

def _kill(proc):

    for sig in (signal.SIGTERM, signal.SIGKILL):

        try:

            os.killpg(os.getpgid(proc.pid), sig)

            proc.wait(timeout=5)

            return

        except Exception:

            continue

@pytest.fixture(scope="session")

def emu():

    port = int(os.environ.get("RRDC_PORT", "8080"))

    cmd = os.environ.get("RRDC_EMU_CMD")

    proc = None

    if cmd:

        proc = subprocess.Popen(

            cmd.replace("{port}", str(port)), shell=True, start_new_session=True,

            stdout=subprocess.DEVNULL, stderr=subprocess.STDOUT)

    client = EmuControl(port)

    try:

        timeout = float(os.environ.get("RRDC_BOOT_TIMEOUT", "20"))

        client.wait_ready(tries=max(1, int(timeout / 0.1)), delay=0.1)

    except Exception as ex:

        if proc is not None:

            _kill(proc)

        pytest.skip(f"no emulator on control port {port}: {ex} "

                    f"(set RRDC_EMU_CMD to launch one, or RRDC_PORT to attach)")

    yield client

    if proc is not None:

        _kill(proc)