"""SonicForge DAW — Desktop engine launcher (PyInstaller entry point).

Chay FastAPI backend duoi dang tien trinh nen (sidecar) cho ban cai Standalone
Windows (Tauri v2 shell). Tu chon port 8000-8010 (fallback neu bi chiem), tu
thoat khi tien trinh cha (Tauri) ket thuc — Graceful Shutdown.
"""
import logging
import os
import socket
import sys
import threading
import time

PORT_RANGE = (8000, 8010)
APP_DATA_DIR_NAME = "SonicForgeDAW"


def _pick_port():
    for port in range(PORT_RANGE[0], PORT_RANGE[1] + 1):
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
            # KHONG dung SO_REUSEADDR: tren Windows no CHO PHEP bind trung port
            # (2 engine cung 8000 -> request roi vao engine ngau nhien -> UI loi).
            # Listen socket khong can SO_REUSEADDR (TIME_WAIT chi ap dung cho
            # connection socket, khong phai listen socket).
            try:
                s.bind(("127.0.0.1", port))
                return port
            except OSError:
                continue
    return PORT_RANGE[0]


def _parent_alive(pid):
    # Windows: os.kill(pid, 0) KHONG kiem tra ton tai — no goi
    # TerminateProcess (giai thich: moi sig khac CTRL_C/BREAK deu terminate).
    # => watchdog se GIET LUON tien trinh cha (Tauri) sau 1s dau tien.
    # Dung OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION): tra ve NULL khi
    # pid khong con ton tai.
    if os.name == "nt":
        import ctypes
        PROCESS_QUERY_LIMITED_INFORMATION = 0x1000
        h = ctypes.windll.kernel32.OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, False, pid)
        if not h:
            return False  # tien trinh da chet
        ctypes.windll.kernel32.CloseHandle(h)
        return True
    try:
        os.kill(pid, 0)
        return True
    except OSError:
        return False


def main():
    os.environ.setdefault("SF_DESKTOP", "1")

    # Log dir tao SOM de stderr co the tro vao file (xem duoi).
    log_dir = os.path.join(
        os.environ.get("APPDATA") or os.path.expanduser("~"),
        APP_DATA_DIR_NAME, "logs",
    )
    try:
        os.makedirs(log_dir, exist_ok=True)
    except OSError:
        log_dir = os.path.expanduser("~")

    # Windowed app (engine.spec console=False): Windows khong tao console ->
    # sys.stdout/sys.stderr = None -> uvicorn logging crash
    # ('NoneType' object has no attribute 'isatty'). Tro stdout/stderr vao
    # FILE (KHONG phai devnull) — neu devnull thi moi exception bi nuot im
    # lang (trieu chung 'stuck khong logs, khong loi').
    if sys.stdout is None:
        sys.stdout = open(os.path.join(log_dir, "stdout.log"), "w", encoding="utf-8")
    if sys.stderr is None:
        sys.stderr = open(os.path.join(log_dir, "stderr.log"), "w", encoding="utf-8")

    port = _pick_port()
    os.environ["SF_PORT"] = str(port)

    # Log ra file — khi dong goi console=False, stdout khong nhin thay duoc.
    try:
        logging.basicConfig(
            level=logging.INFO,
            format="%(asctime)s %(levelname)s %(name)s: %(message)s",
            handlers=[
                logging.FileHandler(os.path.join(log_dir, "engine.log"), encoding="utf-8"),
                logging.StreamHandler(),
            ],
        )
    except Exception:
        logging.basicConfig(level=logging.INFO)

    import uvicorn
    import app.main  # noqa: F401 — import tuong minh de PyInstaller bundle du package app

    config = uvicorn.Config(app.main.app, host="127.0.0.1", port=port,
                            log_level="info", access_log=False)
    server = uvicorn.Server(config)

    parent_pid = os.environ.get("SF_PARENT_PID")
    if parent_pid:
        def _watchdog():
            pid = int(parent_pid)
            while True:
                time.sleep(1.0)
                if not _parent_alive(pid):
                    logging.getLogger("desktop_engine").info(
                        "Parent process exited — shutting down engine")
                    server.should_exit = True
                    return
        threading.Thread(target=_watchdog, daemon=True).start()

    logging.getLogger("desktop_engine").info(
        "SonicForge engine listening on 127.0.0.1:%d", port)
    server.run()


if __name__ == "__main__":
    main()