"""
操作系统信号和 Windows 控制台事件处理。
"""
import sys
import threading
import signal
from foundation.observability.logger.loggering import server_logger

_shutdown_lock = threading.Lock()
_shutdown_called = False


def _run_shutdown_once(shutdown_callback):
    """确保 shutdown 回调在整个进程生命周期内只执行一次。"""
    global _shutdown_called
    with _shutdown_lock:
        if _shutdown_called:
            return
        _shutdown_called = True
    shutdown_callback()


def setup_signal_handlers(shutdown_callback):
    """注册信号处理器，shutdown_callback 会在收到终止信号时调用（通过 _run_shutdown_once 确保只执行一次）。"""

    def handler(signum, frame):
        server_logger.info(f"收到信号 {signum}，正在停止服务...")
        _run_shutdown_once(shutdown_callback)

    try:
        signal.signal(signal.SIGINT, handler)
        signal.signal(signal.SIGTERM, handler)
    except AttributeError:
        pass

    if sys.platform == 'win32':
        _setup_windows_handler(shutdown_callback)


def _setup_windows_handler(shutdown_callback):
    try:
        import win32api
        def win32_handler(dwCtrlType):
            CTRL_C_EVENT = 0
            CTRL_BREAK_EVENT = 1
            CTRL_CLOSE_EVENT = 2
            CTRL_SHUTDOWN_EVENT = 6
            if dwCtrlType in (CTRL_C_EVENT, CTRL_BREAK_EVENT, CTRL_CLOSE_EVENT, CTRL_SHUTDOWN_EVENT):
                server_logger.info(f"收到Windows控制台事件 {dwCtrlType}，正在停止服务...")
                # 将耗时 shutdown 操作放到后台线程，避免阻塞 console handler 超时
                threading.Thread(
                    target=lambda: _run_shutdown_once(shutdown_callback),
                    daemon=True,
                ).start()
            return False
        win32api.SetConsoleCtrlHandler(win32_handler, True)
    except (ImportError, AttributeError) as e:
        server_logger.debug(f"Windows控制台事件处理不可用: {e}")