function parseId(raw) {
  const n = Number(raw);
  if (!Number.isInteger(n) || n <= 0) return null;
  return n;
}

const DATE_RE = /^\d{4}-\d{2}-\d{2}$/;

function isValidDate(str) {
  if (!DATE_RE.test(str)) return false;
  const d = new Date(str + 'T00:00:00');
  return !isNaN(d.getTime());
}

function parseLimit(raw, max = 1000) {
  const n = Number(raw);
  if (!Number.isInteger(n) || n <= 0) return null;
  return Math.min(n, max);
}

module.exports = { parseId, isValidDate, parseLimit };