function supportsNotifications() {
  return typeof Notification !== "undefined";
}

function stripHtml(input) {
  const div = document.createElement("div");
  div.innerHTML = input;
  return div.textContent || div.innerText || "";
}

function primeNotifications() {
  if (!supportsNotifications()) return;
  if (Notification.permission === "default") {
    Notification.requestPermission();
  }
}

function showNotification(title, body) {
  if (!supportsNotifications()) return;
  const options = { body };
  if (Notification.permission === "granted") {
    new Notification(title, options);
  } else if (Notification.permission === "default") {
    Notification.requestPermission().then((perm) => {
      if (perm === "granted") new Notification(title, options);
    });
  }
}

function notifyNotice(content) {
  const text = stripHtml(content);
  if (!text) return;
  showNotification(`COMS`, text);
}

/**
 * Notify the user that someone replied directly to their thread.
 * @param {string} authorName
 * @param {string} content
 */
function notifyDirectReply(authorName, content) {
  const text = stripHtml(content);
  if (!text) return;
  const name = authorName || "Anon";
  showNotification(`${name} replied`, text);
}

export { primeNotifications, notifyNotice, notifyDirectReply };