// Show or hide the offline status banner.
function setOfflineBannerVisible(visible, message) {
  if (window.__pulseThumbnailPreview) {
    return;
  }
  var normalizedVisible = Boolean(visible);
  var bannerMessage = String(message || 'Offline mode: using cached playlist.').trim();
  if (normalizedVisible) {
    if (!offlineBanner) {
      offlineBanner = document.createElement('div');
      offlineBanner.className = 'player-offline-banner';
      offlineBanner.style.position = 'fixed';
      offlineBanner.style.right = '0';
      offlineBanner.style.bottom = '0';
      offlineBanner.style.left = 'auto';
      offlineBanner.style.top = 'auto';
      offlineBanner.style.width = '1.25rem';
      offlineBanner.style.height = '1.25rem';
      offlineBanner.style.zIndex = '9999';
      offlineBanner.style.background = 'linear-gradient(135deg, #ff4d4f 0%, #b00020 100%)';
      offlineBanner.style.clipPath = 'circle(100% at 100% 100%)';
      offlineBanner.style.webkitClipPath = 'circle(100% at 100% 100%)';
      offlineBanner.style.boxShadow = '0 0 0 1px rgba(0, 0, 0, 0.16), 0 4px 12px rgba(0, 0, 0, 0.18)';
      offlineBanner.style.pointerEvents = 'none';
      document.body.appendChild(offlineBanner);
    }
    offlineBanner.textContent = '';
    offlineBanner.setAttribute('aria-label', bannerMessage);
    offlineBanner.setAttribute('role', 'img');
    offlineBanner.title = bannerMessage;
    offlineBannerVisible = true;
    return;
  }

  offlineBannerVisible = false;
  if (offlineBanner && offlineBanner.parentNode) {
    offlineBanner.parentNode.removeChild(offlineBanner);
  }
  offlineBanner = null;
}

// Update the offline banner based on connectivity or playlist availability.
function syncOfflineBanner() {
  if (window.__pulseThumbnailPreview) {
    return;
  }
  if (!window.navigator.onLine) {
    setOfflineBannerVisible(true, 'Offline mode: using cached playlist.');
    return;
  }
  if (offlineBannerVisible) {
    setOfflineBannerVisible(false);
  }
}

// Clear any pending playlist refresh retry.
function clearRefreshRetry() {
  if (refreshRetryTimer) {
    window.clearTimeout(refreshRetryTimer);
    refreshRetryTimer = null;
  }
}

// Retry playlist refresh with a short backoff while the player is offline.
function scheduleRefreshRetry() {
  if (window.__pulseThumbnailPreview) {
    return;
  }
  if (refreshRetryTimer) {
    return;
  }
  if (window.navigator.onLine === false) {
    refreshRetryDelayMs = refreshRetryDelayMs ? Math.min(refreshRetryDelayMs * 2, 15000) : 3000;
  } else {
    refreshRetryDelayMs = refreshRetryDelayMs ? Math.min(refreshRetryDelayMs * 2, 8000) : 3000;
  }
  refreshRetryTimer = window.setTimeout(function () {
    refreshRetryTimer = null;
    refresh();
  }, refreshRetryDelayMs);
}

function clearScreenWakeLockRetry() {
  if (screenWakeLockRetryTimer) {
    window.clearTimeout(screenWakeLockRetryTimer);
    screenWakeLockRetryTimer = null;
  }
}

function supportsScreenWakeLock() {
  return Boolean(window.navigator && window.navigator.wakeLock && typeof window.navigator.wakeLock.request === 'function');
}

function scheduleScreenWakeLockRetry() {
  if (screenWakeLockRetryTimer) {
    return;
  }
  if (!supportsScreenWakeLock() || document.visibilityState !== 'visible') {
    return;
  }
  screenWakeLockRetryTimer = window.setTimeout(function () {
    screenWakeLockRetryTimer = null;
    acquireScreenWakeLock();
  }, 2000);
}

function releaseScreenWakeLock() {
  if (screenWakeLock && typeof screenWakeLock.release === 'function') {
    try {
      screenWakeLock.release();
    } catch (_error) {
      // ignore wake lock release errors
    }
  }
  screenWakeLock = null;
  screenWakeLockRequestPromise = null;
  clearScreenWakeLockRetry();
}

function acquireScreenWakeLock() {
  if (!supportsScreenWakeLock() || document.visibilityState !== 'visible') {
    return Promise.resolve(null);
  }
  if (screenWakeLockRequestPromise) {
    return screenWakeLockRequestPromise;
  }
  if (screenWakeLock && screenWakeLock.released === false) {
    return Promise.resolve(screenWakeLock);
  }

  screenWakeLockRequestPromise = window.navigator.wakeLock.request('screen').then(function (sentinel) {
    screenWakeLock = sentinel;
    screenWakeLock.addEventListener('release', function () {
      screenWakeLock = null;
      if (document.visibilityState === 'visible') {
        scheduleScreenWakeLockRetry();
      }
    });
    clearScreenWakeLockRetry();
    return screenWakeLock;
  }).catch(function (error) {
    screenWakeLock = null;
    if (error && error.name !== 'NotAllowedError') {
      scheduleScreenWakeLockRetry();
    }
    return null;
  }).finally(function () {
    screenWakeLockRequestPromise = null;
  });

  return screenWakeLockRequestPromise;
}

function syncScreenWakeLock() {
  if (!supportsScreenWakeLock()) {
    return;
  }
  if (document.visibilityState === 'visible') {
    acquireScreenWakeLock();
    return;
  }
  releaseScreenWakeLock();
}

// Clear the retry cadence after a successful refresh.
function markRefreshHealthy() {
  refreshRetryDelayMs = 0;
  clearRefreshRetry();
}