let appConfigCache = null;
let doctorsCache = null;
let topicsCache = null;

async function loadAppConfig() {
  if (appConfigCache) return appConfigCache;
  const data = await apiGet("config.php");
  appConfigCache = data;
  return data;
}

async function loadDoctors() {
  if (doctorsCache) return doctorsCache;
  const res = await apiGet("doctors.php");
  doctorsCache = res.data || [];
  return doctorsCache;
}

async function loadTopics() {
  if (topicsCache) return topicsCache;
  const res = await apiGet("topics.php");
  topicsCache = res.data || [];
  return topicsCache;
}

function getDoctorById(doctors, id) {
  return doctors.find((d) => d.id === id) || null;
}