app.js

'use strict';

const SESSION_TTL = 8 * 60 * 60 * 1000;
const REMEMBERED_SESSION_TTL = 30 * 24 * 60 * 60 * 1000;
const SESSION_KEY = 'nexo-session';
const DEFAULT_RETURN_TARGET = '/upgrader-calculator/';

const loading = document.querySelector('#loading');
const loginView = document.querySelector('#login-view');
const dashboardView = document.querySelector('#dashboard-view');
const loginForm = document.querySelector('#login-form');
const formError = document.querySelector('#form-error');
const submitButton = document.querySelector('#submit-button');
const usernameInput = document.querySelector('#username');
const passwordInput = document.querySelector('#password');
const togglePassword = document.querySelector('#toggle-password');
const rememberSession = document.querySelector('#remember-session');
const logoutButton = document.querySelector('#logout-button');
const displayName = document.querySelector('#display-name');
const avatar = document.querySelector('.avatar');
const dashboardMessage = document.querySelector('#dashboard-message');
const sessionExpiry = document.querySelector('#session-expiry');

function getReturnTarget() {
  const target = new URLSearchParams(location.search).get('return');
  return target?.startsWith('/') && !target.startsWith('//') ? target : DEFAULT_RETURN_TARGET;
}

function continueAfterLogin(username, expiresAt) {
  const target = getReturnTarget();
  location.replace(target);
}

function showLogin() {
  loading.classList.add('hidden');
  dashboardView.classList.add('hidden');
  loginView.classList.remove('hidden');
  usernameInput.focus();
}

function showDashboard(username, expiresAt) {
  loading.classList.add('hidden');
  loginView.classList.add('hidden');
  dashboardView.classList.remove('hidden');
  displayName.textContent = username;
  avatar.textContent = username.charAt(0).toUpperCase();
  dashboardMessage.textContent = 'Entraste com sucesso. Esta sessão existe apenas neste navegador.';
  sessionExpiry.textContent = `Sessão válida até às ${new Date(expiresAt).toLocaleTimeString('pt-PT', { hour: '2-digit', minute: '2-digit' })}.`;
  dashboardView.focus();
}

function restoreSession() {
  try {
    const rawSession = localStorage.getItem(SESSION_KEY) || sessionStorage.getItem(SESSION_KEY);
    const session = JSON.parse(rawSession);
    if (session?.expiresAt > Date.now()) {
      continueAfterLogin(session.username, session.expiresAt);
      return;
    }
  } catch {
    // A sessão inválida é eliminada abaixo.
  }
  localStorage.removeItem(SESSION_KEY);
  sessionStorage.removeItem(SESSION_KEY);
  showLogin();
}

togglePassword.addEventListener('click', () => {
  const revealing = passwordInput.type === 'password';
  passwordInput.type = revealing ? 'text' : 'password';
  togglePassword.setAttribute('aria-label', revealing ? 'Ocultar palavra-passe' : 'Mostrar palavra-passe');
  passwordInput.focus();
});

loginForm.addEventListener('submit', async (event) => {
  event.preventDefault();
  formError.textContent = '';
  if (!loginForm.reportValidity()) return;

  submitButton.disabled = true;
  submitButton.querySelector('span').textContent = 'A entrar…';

  try {
    const username = usernameInput.value.trim();
    const expiresAt = Date.now() + (rememberSession.checked ? REMEMBERED_SESSION_TTL : SESSION_TTL);
    const session = JSON.stringify({ username, expiresAt });
    const storage = rememberSession.checked ? localStorage : sessionStorage;
    localStorage.removeItem(SESSION_KEY);
    sessionStorage.removeItem(SESSION_KEY);
    storage.setItem(SESSION_KEY, session);
    loginForm.reset();
    continueAfterLogin(username, expiresAt);
  } finally {
    submitButton.disabled = false;
    submitButton.querySelector('span').textContent = 'Entrar na minha conta';
  }
});

logoutButton.addEventListener('click', () => {
  localStorage.removeItem(SESSION_KEY);
  sessionStorage.removeItem(SESSION_KEY);
  showLogin();
});

restoreSession();