let cachedConfig = null;
let expiresAt = 0;

function getPublicSystemConfigCache(now = Date.now()) {
  if (!cachedConfig || expiresAt <= now) {
    return null;
  }

  return cachedConfig;
}

function getStalePublicSystemConfigCache() {
  return cachedConfig;
}

function setPublicSystemConfigCache(config, ttlMs, now = Date.now()) {
  cachedConfig = config;
  expiresAt = now + Math.max(Number(ttlMs) || 0, 0);
  return cachedConfig;
}

function clearPublicSystemConfigCache() {
  cachedConfig = null;
  expiresAt = 0;
}

module.exports = {
  clearPublicSystemConfigCache,
  getPublicSystemConfigCache,
  getStalePublicSystemConfigCache,
  setPublicSystemConfigCache,
};