// NexoUnite — makes the app installable: registers the service worker (public/sw.js) and keeps the browser's
// "install" offer for a button (Settings → Install the app). Nothing here runs on a page served over plain http,
// except on this computer (localhost), where browsers allow it for testing.

let offer = null;
const listeners = new Set();
const tell = () => listeners.forEach((fn) => { try { fn(); } catch { /* a closed view */ } });

const secure = typeof location !== 'undefined' && (location.protocol === 'https:' || ['localhost', '127.0.0.1'].includes(location.hostname));
if (secure && typeof navigator !== 'undefined' && 'serviceWorker' in navigator) {
  window.addEventListener('load', () => { navigator.serviceWorker.register('/sw.js').catch(() => { /* not installable here: the site works the same */ }); });
}
if (typeof window !== 'undefined') {
  // Chrome and Edge (computer and Android) offer the installation through this event; Safari does not have it.
  window.addEventListener('beforeinstallprompt', (e) => { e.preventDefault(); offer = e; tell(); });
  window.addEventListener('appinstalled', () => { offer = null; tell(); });
}

/** Is the page already running as the installed app? */
export const installed = () => typeof window !== 'undefined' && (window.matchMedia?.('(display-mode: standalone)').matches || navigator.standalone === true);
/** Can this browser show its install window now (Chrome, Edge)? */
export const canInstall = () => Boolean(offer);
/** Shows the browser's install window. Resolves with true when the person installed the app. */
export async function install() {
  if (!offer) return false;
  const e = offer;
  offer = null;
  e.prompt();
  const choice = await e.userChoice.catch(() => null);
  tell();
  return choice?.outcome === 'accepted';
}
export const onInstallChange = (fn) => { listeners.add(fn); return () => listeners.delete(fn); };