(function () {
  var count = document.getElementById('online-count');
  var status = document.getElementById('refresh-status');
  var graphs = document.querySelectorAll('.js-live-graph');
  var lightbox = document.getElementById('graph-lightbox');
  var lightboxImage = document.getElementById('lightbox-image');
  var openers = document.querySelectorAll('.js-graph-open');
  var closeButtons = document.querySelectorAll('[data-lightbox-close]');

  function refresh() {
    if (status) status.textContent = 'Odświeżanie…';

    if (count) {
      fetch('/stats/live', {cache: 'no-store'})
        .then(function (response) {
          if (!response.ok) throw new Error('stats');
          return response.json();
        })
        .then(function (data) {
          if (typeof data.current === 'number') count.textContent = String(data.current);
          if (status) status.textContent = 'Dane aktualne';
        })
        .catch(function () {
          if (status) status.textContent = 'Nie udało się odświeżyć';
        });
    }

    var stamp = Date.now();
    graphs.forEach(function (img) {
      var src = img.dataset.src;
      if (src) img.src = src + '?v=' + stamp;
    });
  }

  function openLightbox(src) {
    if (!lightbox || !lightboxImage) return;
    lightboxImage.src = src + (src.indexOf('?') === -1 ? '?' : '&') + 'v=' + Date.now();
    lightbox.hidden = false;
    lightbox.setAttribute('aria-hidden', 'false');
    document.body.classList.add('lightbox-open');
  }

  function closeLightbox() {
    if (!lightbox || !lightboxImage) return;
    lightbox.hidden = true;
    lightbox.setAttribute('aria-hidden', 'true');
    lightboxImage.src = '';
    document.body.classList.remove('lightbox-open');
  }

  openers.forEach(function (button) {
    button.addEventListener('click', function () {
      var src = button.getAttribute('data-full');
      if (src) openLightbox(src);
    });
  });

  closeButtons.forEach(function (button) {
    button.addEventListener('click', closeLightbox);
  });

  document.addEventListener('keydown', function (event) {
    if (event.key === 'Escape' && lightbox && !lightbox.hidden) closeLightbox();
  });

  window.setInterval(refresh, 60000);
})();