/**
 * Navigation bar utility (shared across all pages)
 * Highlights current page link based on filename
 */
(function() {
  'use strict';

  // Determine current page
  var path = location.pathname;
  var currentPage = path.substring(path.lastIndexOf('/') + 1) || 'index.html';

  // Add active class to current nav link
  document.querySelectorAll('nav a[href]').forEach(function(link) {
    var href = link.getAttribute('href');
    if (href === currentPage || (currentPage === 'index.html' && href === '/')) {
      link.classList.add('active');
    }
  });

  // Update user display in nav if logged in
  function updateNavUser() {
    var userDisplay = document.getElementById('userDisplay');
    var loginBtn = document.getElementById('loginBtn');
    var logoutBtn = document.getElementById('logoutBtn');

    if (window.currentUser) {
      if (userDisplay) {
        userDisplay.textContent = window.currentUser.displayName || 'User';
        userDisplay.classList.remove('hidden');
      }
      if (loginBtn) loginBtn.classList.add('hidden');
      if (logoutBtn) logoutBtn.classList.remove('hidden');
    } else {
      if (userDisplay) userDisplay.classList.add('hidden');
      if (loginBtn) loginBtn.classList.remove('hidden');
      if (logoutBtn) logoutBtn.classList.add('hidden');
    }
  }

  // Run on DOM ready
  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', updateNavUser);
  } else {
    updateNavUser();
  }

  window.updateNavUser = updateNavUser;
})();