total = monitor.get("total_downloaded", 0)
        size_mb = (monitor.get("total_size_bytes", 0) or 0) // 1024 // 1024
        body = f"""<div class=card><h2>下载记录 - {html_escape(monitor.get('channel_title',''))}</h2>
<p class=muted>累计：{total} 个文件，{size_mb} MB</p>
<div class=actions style='margin-bottom:16px'>
<a class='btn ok' href='/channel-media/{monitor_id}/check'>立即下载新内容</a>
<a class='btn' href='/channel-media'>返回列表</a></div>
<table><tr><th>ID</th><th>类型</th><th>文件名/说明</th><th>大小</th><th>时间</th></tr>{rows}</table></div>"""
        return layout("下载记录", body)

    return app


async def start_panel_server() -> uvicorn.Server | None:
    if not panel_enabled():
        logger.info("web panel disabled")
        return None
    host = os.getenv("WEB_PANEL_HOST", "127.0.0.1")
    port = int(os.getenv("WEB_PANEL_PORT", "8765"))
    server = uvicorn.Server(uvicorn.Config(create_panel_app(), host=host, port=port, log_level="info"))
    asyncio.create_task(server.serve())
    logger.info("web panel listening on http://%s:%s", host, port)
    return server

def validate_env() -> tuple[str, int]:
    load_dotenv(ENV_PATH)
    token = os.getenv("TELEGRAM_BOT_TOKEN", "").strip()
    admin = os.getenv("ADMIN_CHAT_ID", "").strip()
    if not token:
        raise RuntimeError(f"TELEGRAM_BOT_TOKEN is missing in {ENV_PATH}")
    if not admin:
        raise RuntimeError(f"ADMIN_CHAT_ID is missing in {ENV_PATH}")
    ids = parse_admin_chat_ids(admin)
    if not ids:
        raise RuntimeError(f"ADMIN_CHAT_ID is invalid in {ENV_PATH}")
    return token, ids[0]


def bot_env_configured() -> bool:
    load_dotenv(ENV_PATH, override=True)
    return bool(os.getenv("TELEGRAM_BOT_TOKEN", "").strip() and os.getenv("ADMIN_CHAT_ID", "").strip())


async def main_async(run_once: bool = False, panel_only: bool = False) -> None:
    global bot, admin_chat_id, admin_chat_ids, config, scheduler_ref, user_session_listener_task
    load_dotenv(ENV_PATH, override=True)
    config = load_config()
    setup_logging(os.getenv("LOG_LEVEL", "INFO"))
    init_db()
    if panel_only:
        await start_panel_server()
        logger.info("panel-only mode start")
        while True:
            await asyncio.sleep(3600)
    if run_once:
        try:
            token, admin_chat_id = validate_env()
            admin_chat_ids = parse_admin_chat_ids(os.getenv("ADMIN_CHAT_ID", ""))
            bot = Bot(token=token, default=DefaultBotProperties(parse_mode=ParseMode.HTML))
        except Exception as e:
            logger.warning("run-once without Telegram notification: %s", e)
        await run_all_monitors_once()
        if bot:
            await bot.session.close()
        return
    await start_panel_server()
    if not bot_env_configured():
        logger.warning(
            "Telegram bot is not configured. Web panel is available, but Telegram polling, monitor notifications, and admin/user messaging will not work until TELEGRAM_BOT_TOKEN and ADMIN_CHAT_ID are saved, then the service is restarted."
        )
        while True:
            await asyncio.sleep(3600)
    token, admin_chat_id = validate_env()
    admin_chat_ids = parse_admin_chat_ids(os.getenv("ADMIN_CHAT_ID", ""))
    bot = Bot(token=token, default=DefaultBotProperties(parse_mode=ParseMode.HTML))
    dp = Dispatcher()
    dp.include_router(router)
    scheduler = AsyncIOScheduler(timezone="Asia/Shanghai")
    scheduler_ref = scheduler
    schedule_monitors(scheduler)
    scheduler.start()
    asyncio.create_task(flush_pending_loop())
    asyncio.create_task(cleanup_monitor_loop())
    if group_monitors_need_user_session():
        if TelegramClient is None:
            logger.warning("group monitor with listen_source=user_session detected, but telethon is not installed")
        elif not user_session_ready():
            logger.warning(
                "group monitor with listen_source=user_session detected, but TG_API_ID/TG_API_HASH/TG_API_SESSION is not complete"
            )
        else:
            user_session_listener_task = asyncio.create_task(run_user_session_group_listener())
    if TelegramClient is not None and user_session_ready():
        asyncio.create_task(channel_media_monitor_loop())
        asyncio.create_task(channel_media_forward_listener())
        logger.info("channel media download + forward listeners started")
    else:
        logger.info("channel media listeners skipped: telethon not installed or user session not configured")
    await admin_send(f"tg-watchbot 已启动\n时间：{now_iso()}")
    logger.info("bot polling start")
    await dp.start_polling(bot, allowed_updates=dp.resolve_used_update_types())


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("--run-once", action="store_true", help="run all monitors once and exit; does not need Telegram token unless notification is sent")
    parser.add_argument("--panel-only", action="store_true", help="start only the web admin panel, useful before Telegram token is configured")
    args = parser.parse_args()
    try:
        asyncio.run(main_async(run_once=args.run_once, panel_only=args.panel_only))
    except KeyboardInterrupt:
        pass
    except Exception:
        logger.exception("fatal error")
        raise


if __name__ == "__main__":
    main()