/* Auth state helpers shared across all pages */

const Auth = (() => {
  const KEY = 'bb_token';
  const USER_KEY = 'bb_user';

  function getToken() { return localStorage.getItem(KEY); }

  function saveToken(token) { localStorage.setItem(KEY, token); }

  function getUser() {
    const raw = localStorage.getItem(USER_KEY);
    return raw ? JSON.parse(raw) : null;
  }

  function saveUser(user) { localStorage.setItem(USER_KEY, JSON.stringify(user)); }

  function logout() {
    localStorage.removeItem(KEY);
    localStorage.removeItem(USER_KEY);
    window.location.href = '/index.html';
  }

  function isLoggedIn() { return !!getToken(); }

  /* Redirect to login if not authenticated */
  function requireAuth() {
    if (!isLoggedIn()) {
      window.location.href = '/login.html';
      return false;
    }
    return true;
  }

  /* Redirect away from auth pages if already logged in */
  function redirectIfLoggedIn() {
    if (isLoggedIn()) {
      window.location.href = '/dashboard.html';
    }
  }

  /* Render the nav user area; call after DOM ready */
  async function renderNav(activePage) {
    const navLinksEl = document.getElementById('nav-links');
    const navUserEl  = document.getElementById('nav-user');
    if (!navLinksEl || !navUserEl) return;

    if (isLoggedIn()) {
      let user = getUser();
      if (!user) {
        try { user = await API.users.me(); saveUser(user); } catch (_) {}
      }
      navLinksEl.innerHTML = `
        <a href="/dashboard.html" class="${activePage === 'dashboard' ? 'active' : ''}">My Bottle</a>
        <a href="/log.html" class="${activePage === 'log' ? 'active' : ''}">Log Entry</a>
      `;
      navUserEl.innerHTML = `
        <a href="/profile.html" class="nav-user">${user?.display_name || user?.email || 'Account'}</a>
        <a href="#" class="btn btn-ghost btn-sm" id="logout-btn">Logout</a>
      `;
      document.getElementById('logout-btn')?.addEventListener('click', (e) => {
        e.preventDefault();
        logout();
      });
    } else {
      navLinksEl.innerHTML = '';
      navUserEl.innerHTML = `<a href="/login.html" class="btn btn-primary btn-sm">Login</a>`;
    }
  }

  return { getToken, saveToken, getUser, saveUser, logout, isLoggedIn, requireAuth, redirectIfLoggedIn, renderNav };
})();