(function () {
  function urlBase64ToUint8Array(base64String) {
    const padding = "=".repeat((4 - (base64String.length % 4)) % 4);
    const base64 = (base64String + padding).replace(/-/g, "+").replace(/_/g, "/");
    const rawData = atob(base64);
    const output = new Uint8Array(rawData.length);
    for (let i = 0; i < rawData.length; i++) {
      output[i] = rawData.charCodeAt(i);
    }
    return output;
  }

  function isPushSupported() {
    return "serviceWorker" in navigator && "PushManager" in window;
  }

  async function getSubscriptionState() {
    if (!isPushSupported()) return "unsupported";
    const reg = await navigator.serviceWorker.ready;
    const sub = await reg.pushManager.getSubscription();
    return sub ? "subscribed" : "unsubscribed";
  }

  async function subscribePush() {
    if (!isPushSupported()) {
      alert("이 브라우저는 알림을 지원하지 않아요.");
      return false;
    }
    const permission = await Notification.requestPermission();
    if (permission !== "granted") {
      alert("알림 권한이 허용되지 않았어요.");
      return false;
    }

    const reg = await navigator.serviceWorker.ready;
    const { publicKey } = await fetch("/api/push/vapid-public-key").then((r) => r.json());
    const sub = await reg.pushManager.subscribe({
      userVisibleOnly: true,
      applicationServerKey: urlBase64ToUint8Array(publicKey),
    });
    await fetch("/api/push/subscribe", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(sub.toJSON()),
    });
    return true;
  }

  async function unsubscribePush() {
    if (!isPushSupported()) return;
    const reg = await navigator.serviceWorker.ready;
    const sub = await reg.pushManager.getSubscription();
    if (!sub) return;
    await fetch("/api/push/unsubscribe", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ endpoint: sub.endpoint }),
    });
    await sub.unsubscribe();
  }

  window.habitPush = { getSubscriptionState, subscribePush, unsubscribePush };
})();