"""启动路由网关服务（后台、无窗口）。

用法：
    python scripts/serve.py [--port 8000] [--stop]
"""
import argparse
import os
import subprocess
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
PID_FILE = ROOT / "_gateway.pid"


def start(port: int):
    if PID_FILE.exists():
        old = PID_FILE.read_text().strip()
        if old:
            print(f"已有服务运行 (pid={old})，先执行 --stop 再启动。")
            return
    out = open(ROOT / "_gateway.out.log", "ab", buffering=0)
    err = open(ROOT / "_gateway.err.log", "ab", buffering=0)
    flags = 0x00000008 | 0x08000000  # DETACHED_PROCESS | CREATE_NO_WINDOW
    proc = subprocess.Popen(
        [sys.executable, "-m", "uvicorn", "gateway.api:app",
         "--host", "127.0.0.1", "--port", str(port)],
        cwd=str(ROOT),
        stdout=out,
        stderr=err,
        creationflags=flags,
        close_fds=True,
    )
    PID_FILE.write_text(str(proc.pid))
    print(f"gateway 已启动 pid={proc.pid} port={port}，日志: _gateway.out.log")


def stop():
    if not PID_FILE.exists():
        print("没有运行中的服务。")
        return
    pid = int(PID_FILE.read_text().strip())
    try:
        import signal
        os.kill(pid, signal.SIGTERM)
        print(f"已发送终止信号 pid={pid}")
    except ProcessLookupError:
        print(f"进程 {pid} 不存在，清理 pid 文件。")
    PID_FILE.unlink(missing_ok=True)


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--port", type=int, default=8000)
    parser.add_argument("--stop", action="store_true", help="停止服务")
    args = parser.parse_args()
    if args.stop:
        stop()
    else:
        start(args.port)