// Bell → attention: desktop notification, favicon badge and a title prefix while
// the tab is in the background. Claude rings the bell (preferredNotifChannel:
// terminal_bell) when it finishes a turn or needs input.

import { FAVICON, FAVICON_BADGE } from './icon.js';

let unread = 0;
let baseTitle = document.title;
let statusPrefix = '';

function attentive() {
  return !document.hidden && document.hasFocus();
}

function render() {
  document.title = `${unread ? `(${unread}) ` : ''}${statusPrefix}${baseTitle}`;
  const link = document.getElementById('favicon');
  if (link) link.href = unread ? FAVICON_BADGE : FAVICON;
}

export function setBaseTitle(title) {
  baseTitle = title;
  render();
}

// "⏳ 3m · " while Claude works on a turn in this tab's session (devdesk#48).
export function setStatusPrefix(prefix) {
  if (prefix === statusPrefix) return;
  statusPrefix = prefix;
  render();
}

export function notificationsState() {
  if (!('Notification' in window)) return 'unsupported';
  return Notification.permission; // granted | denied | default
}

export async function requestNotifications() {
  if (notificationsState() !== 'default') return notificationsState();
  return Notification.requestPermission();
}

const MUTE_KEY = 'devdesk.notify.muted';

export function isMuted() {
  try {
    return localStorage.getItem(MUTE_KEY) === '1';
  } catch {
    return false;
  }
}

export function setMuted(muted) {
  try {
    localStorage.setItem(MUTE_KEY, muted ? '1' : '0');
  } catch {
    // Private mode: the mute just won't persist.
  }
}

export function ring(session, detail) {
  if (attentive()) return;
  unread += 1;
  render();
  if (notificationsState() === 'granted' && !isMuted()) {
    const note = new Notification(`Claude · ${session || 'devdesk'}`, {
      body: detail || 'Claude needs your attention',
      tag: `devdesk-${session}`,
      renotify: true,
      icon: FAVICON,
    });
    note.onclick = () => {
      window.focus();
      note.close();
    };
  }
}

function clear() {
  if (!unread || !attentive()) return;
  unread = 0;
  render();
}

window.addEventListener('focus', clear);
document.addEventListener('visibilitychange', clear);