(function (A) {
  let deferredPrompt = null;
  let swRegistration = null;

  A.pwa = {
    isFileProtocol() {
      return location.protocol === 'file:';
    },
    isSupported() {
      return 'serviceWorker' in navigator && !A.pwa.isFileProtocol();
    },
    isStandalone() {
      return window.matchMedia('(display-mode: standalone)').matches
        || window.navigator.standalone === true;
    },
    getPlatform() {
      const ua = navigator.userAgent;
      const isIOS = /iPad|iPhone|iPod/.test(ua) && !window.MSStream;
      const isIPadOS = navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1;
      if (isIOS || isIPadOS) return 'ios';
      if (/Android/.test(ua)) return 'android';
      if (/Chrome|Chromium|Edg/.test(ua)) return 'desktop-chromium';
      if (/Firefox/.test(ua)) return 'firefox';
      if (/Safari/.test(ua)) return 'desktop-safari';
      return 'other';
    },
    canPromptInstall() {
      return deferredPrompt !== null;
    },
    async promptInstall() {
      if (!deferredPrompt) return { outcome: 'unavailable' };
      deferredPrompt.prompt();
      const choice = await deferredPrompt.userChoice;
      deferredPrompt = null;
      return choice;
    },
    async register() {
      if (!A.pwa.isSupported()) return null;
      try {
        swRegistration = await navigator.serviceWorker.register('./sw.js', { scope: './' });
        return swRegistration;
      } catch (err) {
        console.warn('Service worker registration failed:', err);
        return null;
      }
    }
  };

  window.addEventListener('beforeinstallprompt', (e) => {
    e.preventDefault();
    deferredPrompt = e;
    document.dispatchEvent(new CustomEvent('pwa:install-available'));
  });

  window.addEventListener('appinstalled', () => {
    deferredPrompt = null;
    document.dispatchEvent(new CustomEvent('pwa:installed'));
  });
})(window.App.Application);