document.getElementById('signin').onsubmit = async event => {
  event.preventDefault();
  const form = event.currentTarget;
  const status = document.getElementById('status');
  const action = event.submitter.value;
  const password = document.getElementById('password');
  const payload = {name: document.getElementById('name').value, password: password.value};
  password.value = '';
  for (const button of form.querySelectorAll('button')) button.disabled = true;
  try {
    const response = await fetch('/api/auth/' + action, {
      method: 'POST', credentials: 'same-origin',
      headers: {'Content-Type': 'application/json'}, body: JSON.stringify(payload)
    });
    payload.password = '';
    if (!response.ok) throw new Error();
    location.assign('/');
  } catch {
    payload.password = '';
    status.textContent = 'Sign-in unavailable. Check details and retry.';
    for (const button of form.querySelectorAll('button')) button.disabled = false;
  }
};

fetch('/api/session', {credentials: 'same-origin', cache: 'no-store'})
  .then(response => { if (response.ok) location.replace('/'); }).catch(() => {});