export function formatRial(amount: number): string {
  return new Intl.NumberFormat('fa-IR').format(amount) + ' تومان';
}

export function formatNumber(n: number): string {
  return new Intl.NumberFormat('fa-IR').format(n);
}

export function toDate(val: string | number | null | undefined): Date | null {
  if (val == null || val === '') return null;
  if (typeof val === 'number') return new Date(val * 1000);
  // Y-m-d → treat as local noon to avoid UTC-off-by-one
  if (/^\d{4}-\d{2}-\d{2}$/.test(val)) return new Date(`${val}T12:00:00`);
  return new Date(val);
}

export function formatDate(val: string | number | null | undefined): string {
  const d = toDate(val);
  if (!d || isNaN(d.getTime())) return '—';
  return new Intl.DateTimeFormat('fa-IR-u-ca-persian', {
    year: 'numeric', month: '2-digit', day: '2-digit',
  }).format(d);
}

export function formatDateTime(val: string | number | null | undefined): string {
  const d = toDate(val);
  if (!d || isNaN(d.getTime())) return '—';
  return new Intl.DateTimeFormat('fa-IR-u-ca-persian', {
    year: 'numeric', month: '2-digit', day: '2-digit',
    hour: '2-digit', minute: '2-digit',
  }).format(d);
}

export function toGregorianDate(d: Date): string {
  const y = d.getFullYear();
  const m = String(d.getMonth() + 1).padStart(2, '0');
  const day = String(d.getDate()).padStart(2, '0');
  return `${y}-${m}-${day}`;
}

export function maskMobile(mobile: string): string {
  if (mobile.length < 7) return mobile;
  return mobile.slice(0, 4) + '***' + mobile.slice(-3);
}

export function cn(...classes: (string | undefined | null | false)[]): string {
  return classes.filter(Boolean).join(' ');
}