(function (global) {
  var deferredPrompt = null;

  function isStandalone() {
    return (
      (global.matchMedia && global.matchMedia("(display-mode: standalone)").matches) ||
      global.navigator.standalone === true
    );
  }

  function btn() {
    return document.getElementById("hub-install-btn");
  }

  function setHint(msg) {
    var el = document.getElementById("hub-install-hint");
    if (el) el.textContent = msg || "";
  }

  function showInstall() {
    var el = btn();
    if (!el || isStandalone()) return;
    el.hidden = false;
  }

  function hideInstall() {
    var el = btn();
    if (el) el.hidden = true;
    setHint("");
  }

  function downloadShortcut() {
    var origin = global.location.origin;
    var body = "[InternetShortcut]\r\nURL=" + origin + "/\r\n";
    var blob = new Blob([body], { type: "application/internet-shortcut" });
    var a = document.createElement("a");
    a.href = URL.createObjectURL(blob);
    a.download = "期权中控.url";
    document.body.appendChild(a);
    a.click();
    a.remove();
    setTimeout(function () {
      URL.revokeObjectURL(a.href);
    }, 1000);
  }

  async function onInstallClick() {
    setHint("");
    if (deferredPrompt) {
      deferredPrompt.prompt();
      try {
        var choice = await deferredPrompt.userChoice;
        deferredPrompt = null;
        if (choice && choice.outcome === "accepted") {
          hideInstall();
          return;
        }
      } catch (e) {
        deferredPrompt = null;
      }
    }
    downloadShortcut();
    setHint("已下载快捷方式，拖到桌面即可。Chrome / Edge 也可在地址栏右侧点「安装」。");
  }

  function boot() {
    if (isStandalone()) {
      hideInstall();
      return;
    }
    showInstall();
    global.addEventListener("beforeinstallprompt", function (ev) {
      ev.preventDefault();
      deferredPrompt = ev;
      showInstall();
    });
    global.addEventListener("appinstalled", function () {
      deferredPrompt = null;
      hideInstall();
    });
    var el = btn();
    if (el) el.addEventListener("click", onInstallClick);
    if ("serviceWorker" in navigator) {
      navigator.serviceWorker.register("/sw.js", { scope: "/" }).catch(function () {});
    }
  }

  global.HubPwa = { boot: boot };
})(window);