File

from pathlib import Path

import ctypes

import hashlib

import os

import subprocess

import sys

import time

ROOT = Path(__file__).resolve().parents[1]

PROJECTS = ROOT / 'projects'

WRAPPER = PROJECTS / 'low_latency_relay_v2.py'

OLD_PID = 6996

EXPECTED_SHA = '7e65993f482ef7b6c5cae323800ab445bc8cfba59196a2fc6ad2d10ffa32793f'

LOCK = ROOT / 'bridge-data' / 'sheet-relay' / 'll2-switch-20260830-0816.lock'

LOCK.parent.mkdir(parents=True, exist_ok=True)

try:

    fd = os.open(str(LOCK), os.O_CREAT | os.O_EXCL | os.O_WRONLY)

except FileExistsError:

    print('SWITCH_ALREADY_CLAIMED')

    raise SystemExit(0)

with os.fdopen(fd, 'w', encoding='utf-8') as f:

    f.write(f'pid={os.getpid()} started={time.time()}\n')

if not WRAPPER.is_file():

    raise SystemExit('WRAPPER_MISSING')

actual_sha = hashlib.sha256(WRAPPER.read_bytes()).hexdigest()

print('WRAPPER_SHA256=' + actual_sha)

if actual_sha != EXPECTED_SHA:

    raise SystemExit('WRAPPER_SHA_MISMATCH')

compile(WRAPPER.read_text(encoding='utf-8'), str(WRAPPER), 'exec')

probe = subprocess.run(

    [

        'powershell', '-NoProfile', '-Command',

        f"$p=Get-CimInstance Win32_Process -Filter 'ProcessId={OLD_PID}' -ErrorAction SilentlyContinue; if($p){{$p.CommandLine}}"

    ],

    capture_output=True, text=True, check=False,

)

old_cmd = probe.stdout.strip()

print('OLD_CMD=' + old_cmd)

if 'low_latency_relay.py' not in old_cmd:

    raise SystemExit('OLD_PID_GUARD_FAILED')

killed = subprocess.run(['taskkill', '/PID', str(OLD_PID), '/F'], capture_output=True, text=True, check=False)

print('TASKKILL_RC=' + str(killed.returncode))

if killed.returncode != 0:

    raise SystemExit('OLD_WORKER_KILL_FAILED: ' + killed.stderr.strip())

flags = getattr(subprocess, 'CREATE_NO_WINDOW', 0)

new = subprocess.Popen(

    [sys.executable, str(WRAPPER)],

    cwd=str(ROOT),

    stdin=subprocess.DEVNULL,

    stdout=subprocess.DEVNULL,

    stderr=subprocess.DEVNULL,

    creationflags=flags,

)

time.sleep(2.0)

if new.poll() is not None:

    rollback = PROJECTS / 'low_latency_relay.py'

    if rollback.is_file():

        rb = subprocess.Popen(

            [sys.executable, str(rollback)],

            cwd=str(ROOT), stdin=subprocess.DEVNULL,

            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,

            creationflags=flags,

        )

        print('ROLLBACK_PID=' + str(rb.pid))

    raise SystemExit('LL2_START_FAILED')

ABOVE_NORMAL_PRIORITY_CLASS = 0x00008000

try:

    ok = bool(ctypes.windll.kernel32.SetPriorityClass(int(new._handle), ABOVE_NORMAL_PRIORITY_CLASS))

except Exception:

    ok = False

print('SWITCH_OK')

print('OLD_PID=' + str(OLD_PID))

print('NEW_PID=' + str(new.pid))

print('REVISION=20260830-107-LL2')

print('PRIORITY_ABOVE_NORMAL=' + str(ok))