/* ================================================================
   GYANI GURU — Auth Manager (auth.js)
   Handles: login, register, session, user state
   ================================================================ */

const AuthManager = {

  // ---- Storage Keys ----
  KEYS: {
    user: 'gg_user',
    session: 'gg_session',
    cart: 'gg_cart',
    wishlist: 'gg_wishlist'
  },

  // ---- Initialize (redirect if logged in visiting auth pages) ----
  init() {
    // If logged in and on auth page, redirect to account
    const currentPage = window.location.pathname.split('/').pop();
    const authPages = ['login.html', 'register.html'];
    if (authPages.includes(currentPage) && this.isLoggedIn()) {
      window.location.href = 'account.html';
      return;
    }
    // Update navbar across all pages
    this.updateNavbar();
  },

  // ---- Check Login State ----
  isLoggedIn() {
    return !!localStorage.getItem(this.KEYS.user);
  },

  // ---- Get User ----
  getUser() {
    try {
      return JSON.parse(localStorage.getItem(this.KEYS.user)) || null;
    } catch { return null; }
  },

  // ---- Set User ----
  setUser(userData) {
    localStorage.setItem(this.KEYS.user, JSON.stringify(userData));
    // Also store extended profile if not existing
    const profile = this.getProfile();
    if (!profile) {
      this.setProfile({
        firstName: userData.name ? userData.name.split(' ')[0] : 'User',
        lastName: userData.name ? userData.name.split(' ').slice(1).join(' ') : '',
        email: userData.email || '',
        phone: userData.phone || '+91 98765 43210',
        dob: userData.dob || '',
        gender: userData.gender || 'Male',
        city: userData.city || 'India',
        joinedDate: userData.joinedDate || new Date().toLocaleDateString('en-IN', { month: 'long', year: 'numeric' })
      });
    }
  },

  // ---- Profile ----
  getProfile() {
    try { return JSON.parse(localStorage.getItem('gg_profile')) || null; } catch { return null; }
  },
  setProfile(data) {
    localStorage.setItem('gg_profile', JSON.stringify(data));
  },

  // ---- Logout ----
  logout() {
    localStorage.removeItem(this.KEYS.user);
    localStorage.removeItem('gg_profile');
    window.location.href = 'login.html';
  },

  // ---- Login Form Handler ----
  login() {
    const email = document.getElementById('loginEmail')?.value?.trim();
    const password = document.getElementById('loginPassword')?.value;
    const alertEl = document.getElementById('loginAlert');
    const alertMsg = document.getElementById('loginAlertMsg');
    const successEl = document.getElementById('loginSuccess');
    const btn = document.getElementById('loginBtn');

    // Clear previous errors
    this.clearFieldErrors(['emailError', 'passwordError']);
    if (alertEl) alertEl.style.display = 'none';

    let valid = true;

    if (!email || !this.isValidEmail(email)) {
      this.showFieldError('emailError', 'Please enter a valid email address');
      document.getElementById('loginEmail')?.classList.add('input-error');
      valid = false;
    }
    if (!password || password.length < 6) {
      this.showFieldError('passwordError', 'Password must be at least 6 characters');
      document.getElementById('loginPassword')?.classList.add('input-error');
      valid = false;
    }

    if (!valid) return;

    // Show loader
    this.setButtonLoading(btn, true);

    // Simulate async login
    setTimeout(() => {
      this.setButtonLoading(btn, false);

      // Demo: accept any valid email/password combo
      const userData = {
        name: email.split('@')[0].replace(/[._]/g, ' ').replace(/\b\w/g, c => c.toUpperCase()),
        email: email,
        loginTime: new Date().toISOString()
      };
      this.setUser(userData);

      if (successEl) successEl.style.display = 'flex';

      // Redirect
      const returnUrl = new URLSearchParams(window.location.search).get('from') || 'account.html';
      setTimeout(() => { window.location.href = returnUrl; }, 1200);
    }, 1500);
  },

  // ---- Register Form Handler ----
  register() {
    const firstName = document.getElementById('regFirstName')?.value?.trim();
    const lastName = document.getElementById('regLastName')?.value?.trim();
    const email = document.getElementById('regEmail')?.value?.trim();
    const password = document.getElementById('regPassword')?.value;
    const confirmPwd = document.getElementById('regConfirmPassword')?.value;
    const agreeTerms = document.getElementById('agreeTerms')?.checked;
    const alertEl = document.getElementById('registerAlert');
    const alertMsg = document.getElementById('registerAlertMsg');
    const successEl = document.getElementById('registerSuccess');
    const btn = document.getElementById('registerBtn');

    // Clear
    this.clearFieldErrors(['firstNameError','lastNameError','regEmailError','regPwdError','regConfPwdError','termsError']);
    if (alertEl) alertEl.style.display = 'none';

    let valid = true;

    if (!firstName) { this.showFieldError('firstNameError', 'First name is required'); valid = false; }
    if (!lastName) { this.showFieldError('lastNameError', 'Last name is required'); valid = false; }
    if (!email || !this.isValidEmail(email)) { this.showFieldError('regEmailError', 'Enter a valid email'); valid = false; }
    if (!password || password.length < 8) { this.showFieldError('regPwdError', 'Password must be at least 8 characters'); valid = false; }
    if (password !== confirmPwd) { this.showFieldError('regConfPwdError', 'Passwords do not match'); valid = false; }
    if (!agreeTerms) { this.showFieldError('termsError', 'Please agree to the Terms of Service'); valid = false; }

    if (!valid) return;

    this.setButtonLoading(btn, true);

    setTimeout(() => {
      this.setButtonLoading(btn, false);
      const userData = { name: `${firstName} ${lastName}`, email, joinedDate: new Date().toLocaleDateString('en-IN', { month: 'long', year: 'numeric' }) };
      this.setUser(userData);
      if (successEl) successEl.style.display = 'flex';
      setTimeout(() => { window.location.href = 'account.html'; }, 1500);
    }, 1800);
  },

  // ---- Update Navbar Based on Login State ----
  updateNavbar() {
    // Find or inject the user/account nav icon
    const navIcons = document.querySelector('.nav-icons');
    if (!navIcons) return;

    let accountIcon = navIcons.querySelector('.nav-account-icon');
    if (!accountIcon) {
      accountIcon = document.createElement('a');
      accountIcon.className = 'nav-icon-btn nav-account-icon';
      accountIcon.title = 'My Account';
      navIcons.appendChild(accountIcon);
    }

    if (this.isLoggedIn()) {
      const user = this.getUser();
      const initials = user?.name ? user.name.split(' ').map(w => w[0]).join('').slice(0,2).toUpperCase() : '👤';
      accountIcon.href = 'account.html';
      accountIcon.innerHTML = `<i class="bi bi-person-fill"></i>`;
      accountIcon.style.background = 'rgba(212,175,55,0.2)';
      accountIcon.style.borderColor = 'var(--gold)';
    } else {
      accountIcon.href = 'login.html';
      accountIcon.innerHTML = `<i class="bi bi-person"></i>`;
    }
  },

  // ---- Helpers ----
  isValidEmail(email) {
    return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);
  },
  showFieldError(id, msg) {
    const el = document.getElementById(id);
    if (el) el.textContent = msg;
  },
  clearFieldErrors(ids) {
    ids.forEach(id => {
      const el = document.getElementById(id);
      if (el) el.textContent = '';
    });
    document.querySelectorAll('.auth-input').forEach(inp => {
      inp.classList.remove('input-error', 'input-success');
    });
  },
  setButtonLoading(btn, loading) {
    if (!btn) return;
    const text = btn.querySelector('.btn-text');
    const loader = btn.querySelector('.btn-loader');
    if (loading) {
      if (text) text.style.display = 'none';
      if (loader) loader.style.display = 'flex';
      btn.disabled = true;
    } else {
      if (text) text.style.display = 'flex';
      if (loader) loader.style.display = 'none';
      btn.disabled = false;
    }
  }
};

// Auto-run on every page
document.addEventListener('DOMContentLoaded', () => AuthManager.updateNavbar());