(() => {
  const auth = window.TrafficAuth;
  const $ = (id) => document.getElementById(id);
  const enrollmentByUser = new Map();
  let selectedUsername = '';

  function nextPage() {
    const next = new URLSearchParams(location.search).get('next');
    return ['link-generator.html', 'link-history.html'].includes(next) ? next : 'link-generator.html';
  }

  function showToast(message) {
    const toast = $('toast');
    toast.textContent = message; toast.classList.add('show');
    setTimeout(() => toast.classList.remove('show'), 1600);
  }

  function currentEnrollment() {
    if (!enrollmentByUser.has(selectedUsername)) enrollmentByUser.set(selectedUsername, auth.createEnrollment(selectedUsername));
    return enrollmentByUser.get(selectedUsername);
  }

  function renderQr(otpauthUrl) {
    const container = $('qrCode');
    container.innerHTML = '';
    if (typeof window.qrcode !== 'function') {
      container.innerHTML = '<span class="qr-error">二维码加载失败，请刷新页面重试</span>';
      return false;
    }
    try {
      const qr = window.qrcode(0, 'M');
      qr.addData(otpauthUrl);
      qr.make();
      container.innerHTML = qr.createSvgTag(5, 4);
      return true;
    } catch (_) {
      container.innerHTML = '<span class="qr-error">二维码生成失败，请刷新页面重试</span>';
      return false;
    }
  }

  function resetForms() {
    ['signinPassword','signinCode','newPassword','confirmPassword','setupCode'].forEach((id) => { $(id).value = ''; });
    $('accountMessage').textContent = '';
    $('signinMessage').textContent = '';
    $('enrollMessage').textContent = '';
  }

  function openAccount(username) {
    selectedUsername = username;
    const enrolled = auth.isEnrolled(username);
    $('accountForm').classList.add('hidden');
    $('confirmedAccount').classList.remove('hidden');
    $('confirmedUser').textContent = username;
    $('signinForm').classList.toggle('hidden', !enrolled);
    $('enrollForm').classList.toggle('hidden', enrolled);
    $('loginTitle').textContent = enrolled ? '欢迎回来' : '首次注册';
    $('loginSubtitle').textContent = enrolled ? '输入密码和动态验证码登录' : '扫描二维码并设置本机密码';
    if (!enrolled) {
      const ready = renderQr(currentEnrollment().otpauthUrl);
      $('enrollMessage').textContent = ready ? '' : '二维码组件加载失败，暂时无法完成注册';
    }
  }

  function changeAccount() {
    selectedUsername = '';
    resetForms();
    $('confirmedAccount').classList.add('hidden');
    $('signinForm').classList.add('hidden');
    $('enrollForm').classList.add('hidden');
    $('accountForm').classList.remove('hidden');
    $('loginTitle').textContent = 'Shareit ID 登录';
    $('loginSubtitle').textContent = '输入你的 Shareit ID 继续';
    $('loginUser').focus();
  }

  $('accountForm').addEventListener('submit', (event) => {
    event.preventDefault();
    const username = $('loginUser').value.trim().toLowerCase();
    if (!username) {
      $('accountMessage').textContent = '请输入 Shareit ID';
      return;
    }
    if (!auth.findUser(username)) {
      $('accountMessage').textContent = '该 Shareit ID 不在授权名单中';
      return;
    }
    resetForms();
    openAccount(username);
  });

  $('signinForm').addEventListener('submit', async (event) => {
    event.preventDefault();
    const button = event.submitter;
    button.disabled = true;
    $('signinMessage').textContent = '正在验证…';
    try {
      await auth.login(selectedUsername, $('signinPassword').value, $('signinCode').value);
      location.href = nextPage();
    } catch (error) {
      $('signinMessage').textContent = error.message;
      button.disabled = false;
    }
  });

  $('enrollForm').addEventListener('submit', async (event) => {
    event.preventDefault();
    const password = $('newPassword').value;
    if (password !== $('confirmPassword').value) {
      $('enrollMessage').textContent = '两次输入的密码不一致';
      return;
    }
    if (typeof window.qrcode !== 'function') {
      $('enrollMessage').textContent = '二维码组件尚未加载，请刷新页面重试';
      return;
    }
    const button = event.submitter;
    button.disabled = true;
    $('enrollMessage').textContent = '正在注册…';
    try {
      await auth.enroll(selectedUsername, password, currentEnrollment().secret, $('setupCode').value);
      location.href = nextPage();
    } catch (error) {
      $('enrollMessage').textContent = error.message;
      button.disabled = false;
    }
  });

  $('changeAccount').addEventListener('click', changeAccount);
  $('resetEnrollment').addEventListener('click', () => {
    if (!window.confirm(`确定清除 ${selectedUsername} 在当前浏览器的密码和 Authenticator 绑定吗？`)) return;
    try {
      auth.clearEnrollment(selectedUsername);
      enrollmentByUser.delete(selectedUsername);
      resetForms();
      openAccount(selectedUsername);
      showToast('本机绑定已清除，请重新注册');
    } catch (error) {
      $('signinMessage').textContent = error.message;
    }
  });

  if (auth.currentUser()) location.replace(nextPage());
  else $('loginUser').focus();
})();