(function () {
  const TOKEN_KEYS = {
    access: 'access_token',
    refresh: 'refresh_token',
    preAuth: 'pre_auth_token',
  };

  function isRotateMode() {
    return new URLSearchParams(window.location.search).get('rotate') === '1';
  }

  function getReturnUrl() {
    const params = new URLSearchParams(window.location.search);
    const next = params.get('next');
    if (next && next.startsWith('/') && !next.startsWith('//')) {
      return next;
    }
    return '/';
  }

  function getPreAuthToken() {
    return sessionStorage.getItem(TOKEN_KEYS.preAuth);
  }

  function getAccessToken() {
    return localStorage.getItem(TOKEN_KEYS.access);
  }

  function getAuthToken() {
    return isRotateMode() ? getAccessToken() : getPreAuthToken();
  }

  function setTokens(accessToken, refreshToken) {
    sessionStorage.removeItem(TOKEN_KEYS.preAuth);
    localStorage.setItem(TOKEN_KEYS.access, accessToken);
    if (refreshToken) {
      localStorage.setItem(TOKEN_KEYS.refresh, refreshToken);
    }
  }

  function applyPageMode() {
    if (!isRotateMode()) return;
    document.getElementById('setupTitle').textContent = 'Google OTP 재등록';
    document.getElementById('setupSubtitle').textContent =
      '새 기기·앱으로 다시 연결합니다. 등록 완료 후 이전 OTP 코드는 사용할 수 없습니다.';
    document.getElementById('setupConfirmBtn').textContent = '재등록 완료';
  }

  function showError(message) {
    const el = document.getElementById('setupError');
    if (!message) {
      el.classList.add('hidden');
      el.textContent = '';
      return;
    }
    el.textContent = message;
    el.classList.remove('hidden');
  }

  function showScanStep(data) {
    document.getElementById('setupLoading').classList.add('hidden');
    document.getElementById('setupStepScan').classList.remove('hidden');
    document.getElementById('setupSecret').textContent = data.secret;
    const qr = document.getElementById('setupQr');
    if (data.qr_data_url) {
      qr.src = data.qr_data_url;
    } else {
      qr.src = `https://api.qrserver.com/v1/create-qr-code/?size=200x200&data=${encodeURIComponent(data.provisioning_uri)}`;
    }
    document.getElementById('setupOtpCode').focus();
  }

  function loginNextUrl() {
    const suffix = isRotateMode() ? '?rotate=1' : '';
    return `/setup-2fa${suffix}`;
  }

  async function beginSetup() {
    const rotate = isRotateMode();
    const token = getAuthToken();
    if (!token) {
      window.location.href = `/login?next=${encodeURIComponent(loginNextUrl())}`;
      return;
    }

    const url = rotate ? '/api/v1/auth/setup-2fa' : '/api/v1/auth/setup-2fa/begin';
    const res = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Bearer ${token}`,
      },
    });
    const data = await res.json();
    if (!res.ok) {
      const detail = data.detail || '';
      if (res.status === 401) {
        if (rotate) {
          localStorage.removeItem(TOKEN_KEYS.access);
          localStorage.removeItem(TOKEN_KEYS.refresh);
        } else {
          sessionStorage.removeItem(TOKEN_KEYS.preAuth);
          localStorage.removeItem(TOKEN_KEYS.access);
          localStorage.removeItem(TOKEN_KEYS.refresh);
        }
        window.location.href = `/login?next=${encodeURIComponent(loginNextUrl())}`;
        return;
      }
      showError(detail || 'OTP 설정을 시작할 수 없습니다. 다시 로그인하세요.');
      return;
    }
    showScanStep(data);
  }

  async function confirmSetup() {
    const code = document.getElementById('setupOtpCode').value.trim();
    if (code.length < 6) {
      showError('인증 코드 6자리를 입력하세요.');
      return;
    }
    showError('');
    const rotate = isRotateMode();
    const token = getAuthToken();
    const url = rotate ? '/api/v1/auth/setup-2fa/activate' : '/api/v1/auth/setup-2fa/confirm';
    const res = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Bearer ${token}`,
      },
      body: JSON.stringify({ code }),
    });
    const data = await res.json();
    if (!res.ok) {
      showError(
        data.detail === 'Invalid OTP'
          ? 'OTP 코드가 올바르지 않습니다.'
          : (data.detail || '등록에 실패했습니다.'),
      );
      return;
    }
    setTokens(data.access_token, data.refresh_token);
    window.location.href = getReturnUrl();
  }

  applyPageMode();
  document.getElementById('setupConfirmBtn').addEventListener('click', confirmSetup);
  document.getElementById('setupOtpCode').addEventListener('keydown', (e) => {
    if (e.key === 'Enter') confirmSetup();
  });

  beginSetup().catch(() => {
    showError('네트워크 오류가 발생했습니다.');
  });
})();