{# ── PWA install banner + service-worker registration (shared) ── #}
<div id="pwaInstall" class="pwa-install" hidden role="dialog" aria-label="{{ t('pwa_install_title') | default('Install FIGHTSKILL') }}">
  <img class="pwa-install-appicon" src="{{ url_for('static', filename='icons/icon-192.png') }}" alt="" width="44" height="44">
  <div class="pwa-install-body">
    <div class="pwa-install-title" id="pwaInstallTitle">{{ t('pwa_install_title') | default('Install FIGHTSKILL') }}</div>
    <div class="pwa-install-text" id="pwaInstallText">{{ t('pwa_install_text') | default('Install the app on your device for a faster, full-screen experience.') }}</div>
  </div>
  <button class="pwa-install-btn" id="pwaInstallBtn" type="button">{{ t('pwa_install_btn') | default('Install') }}</button>
  <button class="pwa-install-close" id="pwaInstallClose" type="button" aria-label="✕">✕</button>
</div>
<script>
(function () {
  'use strict';
  /* ── 1) Service worker registration ── */
  if ('serviceWorker' in navigator) {
    window.addEventListener('load', function () {
      navigator.serviceWorker.register('/sw.js', { scope: '/' })
        .catch(function () { /* PWA is progressive enhancement — never block the app */ });
    });
  }

  /* ── 2) Custom install banner ──
     • Chromium/Android: shown when `beforeinstallprompt` fires
     • iOS Safari:       shown as an "Add to Home Screen" guide
     • Already standalone, recently dismissed, or logged-in admins: hidden */
  var banner = document.getElementById('pwaInstall');
  if (!banner) return;

  var DISMISS_KEY = 'fightskill_pwa_dismissed_at';
  var DISMISS_TTL = 7 * 24 * 3600 * 1000; /* ask again after a week */

  var isStandalone = window.matchMedia('(display-mode: standalone)').matches ||
                     window.navigator.standalone === true;
  if (isStandalone) return;

  var dismissedAt = 0;
  try { dismissedAt = parseInt(localStorage.getItem(DISMISS_KEY) || '0', 10) || 0; } catch (e) {}
  if (dismissedAt && Date.now() - dismissedAt < DISMISS_TTL) return;
  if (document.body.dataset.pwaHide === '1') return; /* escape hatch for special pages */

  var deferredPrompt = null;
  var isIOS = /iphone|ipad|ipod/i.test(navigator.userAgent) && !window.MSStream;

  function show(mode) {
    var titleEl = document.getElementById('pwaInstallTitle');
    var textEl = document.getElementById('pwaInstallText');
    var btn = document.getElementById('pwaInstallBtn');
    if (!titleEl || !textEl || !btn) return;
    if (mode === 'ios') {
      titleEl.textContent = {{ t('pwa_ios_title') | default('Install on iOS') | tojson }};
      textEl.textContent = {{ t('pwa_ios_text') | default('Tap the Share icon, then choose "Add to Home Screen" to install the app.') | tojson }};
      btn.style.display = 'none';
    }
    banner.hidden = false;
    document.body.classList.add('pwa-banner-open');
  }

  function hide() {
    banner.hidden = true;
    document.body.classList.remove('pwa-banner-open');
  }

  window.addEventListener('beforeinstallprompt', function (e) {
    e.preventDefault();
    deferredPrompt = e;
    show('default');
  });

  /* iOS Safari never fires beforeinstallprompt → guide the user once */
  if (isIOS) {
    setTimeout(function () { show('ios'); }, 2500);
  }

  document.getElementById('pwaInstallBtn').addEventListener('click', function () {
    if (!deferredPrompt) return;
    deferredPrompt.prompt();
    deferredPrompt.userChoice.then(function () {
      deferredPrompt = null;
      hide();
    }).catch(function () { deferredPrompt = null; hide(); });
  });

  document.getElementById('pwaInstallClose').addEventListener('click', function () {
    try { localStorage.setItem(DISMISS_KEY, String(Date.now())); } catch (e) {}
    hide();
  });

  window.addEventListener('appinstalled', hide);
})();
</script>