async function api(path, options = {}) {
  const config = {
    method: options.method || 'GET',
    headers: {},
    credentials: 'same-origin'
  };
  if (options.json !== undefined) {
    config.headers['Content-Type'] = 'application/json';
    config.body = JSON.stringify(options.json);
  } else if (options.body) {
    config.body = options.body;
  }
  const response = await fetch(`/api/${path}`, config);
  let data;
  try {
    data = await response.json();
  } catch (_) {
    data = { ok: false, message: '服务器响应异常，请刷新后重试' };
  }
  if (!response.ok && !data.message) data.message = `请求失败（${response.status}）`;
  return data;
}

function toast(message, isError = false) {
  let element = document.querySelector('#toast');
  if (!element) {
    element = document.createElement('div');
    element.id = 'toast';
    element.className = 'toast';
    document.body.appendChild(element);
  }
  element.textContent = message;
  element.classList.toggle('error', Boolean(isError));
  element.classList.add('show');
  clearTimeout(element.timer);
  element.timer = setTimeout(() => element.classList.remove('show'), 3800);
}

function text(value) {
  return String(value ?? '').replace(/[&<>"']/g, ch => ({
    '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;'
  }[ch]));
}

function requireConfirm(message) {
  return window.confirm(message);
}

function setButtonsDisabled(root, disabled) {
  root.querySelectorAll('button[data-working]').forEach(button => {
    button.disabled = disabled || button.dataset.alwaysDisabled === '1';
  });
}