"use client";
import { useEffect, useState } from "react";

type InstallPrompt = Event & { prompt: () => Promise<void>; userChoice: Promise<{ outcome: "accepted" | "dismissed" }> };

export default function PwaRegister() {
  const [prompt, setPrompt] = useState<InstallPrompt | null>(null);
  const [isIos, setIsIos] = useState(false);

  useEffect(() => {
    if ("serviceWorker" in navigator) navigator.serviceWorker.register("/sw.js", { updateViaCache: "none" }).catch(() => undefined);
    setIsIos(/iphone|ipad|ipod/i.test(navigator.userAgent));
    const receivePrompt = (event: Event) => { event.preventDefault(); setPrompt(event as InstallPrompt); };
    window.addEventListener("beforeinstallprompt", receivePrompt);
    return () => window.removeEventListener("beforeinstallprompt", receivePrompt);
  }, []);

  if (!prompt && !isIos) return null;
  return <div className="pwa-install" role="status">
    <span>把打卡站点安装到桌面，打开更快捷。</span>
    {prompt ? <button onClick={async () => { await prompt.prompt(); const result = await prompt.userChoice; if (result.outcome === "accepted") setPrompt(null); }}>安装应用</button> : <span className="pwa-ios">Safari 点“分享”→“添加到主屏幕”</span>}
  </div>;
}