(function (root, factory) {
  if (typeof module === 'object' && module.exports) module.exports = factory;
  else root.createMobileTaskDock = factory;
})(typeof self !== 'undefined' ? self : this, function createMobileTaskDock(options) {
  const nav = options.nav;
  const buttons = options.buttons;
  const overlays = options.overlays || [];
  let launcher = null;
  let wasHidden = false;

  function select(name) {
    Object.entries(buttons).forEach(([key, button]) => {
      if (key === name) button.setAttribute('aria-current', 'page');
      else button.removeAttribute('aria-current');
    });
  }

  function refreshVisibility() {
    const hidden = overlays.some(overlay => overlay.classList.contains('open'));
    nav.hidden = hidden;
    if (wasHidden && !hidden && launcher) launcher.focus();
    wasHidden = hidden;
  }

  function start() {
    Object.entries(buttons).forEach(([name, button]) => {
      button.addEventListener('click', event => {
        launcher = event.currentTarget;
        select(name);
        options.actions[name]();
      });
    });
    options.observe(refreshVisibility, overlays);
    refreshVisibility();
  }

  function updateAttention(count) {
    const total = Math.max(0, Number(count) || 0);
    const badge = options.attentionBadge;
    if (badge) {
      badge.textContent = String(total);
      badge.hidden = total === 0;
    }
    if (buttons.work) {
      buttons.work.setAttribute(
        'aria-label',
        total ? 'Work, ' + total + ' items need attention' : 'Work'
      );
    }
  }

  return {start, refreshVisibility, updateAttention};
});