// Keep the screen awake while a rewards barcode is on screen so the cashier
// can scan it without the display dimming or locking. This mirrors how wallet
// apps behave when showing a barcode. The Screen Wake Lock API is best-effort:
// it may be rejected (e.g. low battery) or auto-released when the tab is hidden,
// so we re-acquire whenever the page becomes visible again.
(function () {
  var wakeLock = null;

  function requestWakeLock() {
    if (!("wakeLock" in navigator)) return;
    navigator.wakeLock
      .request("screen")
      .then(function (sentinel) {
        wakeLock = sentinel;
      })
      .catch(function () {
        // Best-effort only; ignore failures (unsupported, low battery, etc.).
      });
  }

  // Re-acquire if the lock was released (e.g. the tab was hidden) and the user
  // returns to the page.
  document.addEventListener("visibilitychange", function () {
    if (document.visibilityState === "visible" && wakeLock === null) {
      requestWakeLock();
    }
  });

  requestWakeLock();
})();