const inr = new Intl.NumberFormat("en-IN", {
  minimumFractionDigits: 2,
  maximumFractionDigits: 2,
});

/** Indian-grouped number, e.g. 25000 -> "25,000.00" */
export function formatAmount(amount: number): string {
  const value = Number.isFinite(amount) ? amount : 0;
  return inr.format(value);
}

/** Currency string with the rupee symbol, e.g. "₹25,000.00" */
export function formatCurrency(amount: number, symbol = "₹"): string {
  return `${symbol}${formatAmount(amount)}`;
}

/** "2024-06-13" -> "13 Jun 2024" (falls back to the raw value if unparseable). */
export function formatDate(iso: string): string {
  if (!iso) return "";
  const date = new Date(`${iso}T00:00:00`);
  if (Number.isNaN(date.getTime())) return iso;
  return date.toLocaleDateString("en-GB", { day: "2-digit", month: "short", year: "numeric" });
}

/** Today as an ISO date (YYYY-MM-DD) in local time. */
export function todayIso(): string {
  const now = new Date();
  const offset = now.getTimezoneOffset();
  return new Date(now.getTime() - offset * 60_000).toISOString().slice(0, 10);
}

/** ISO date `days` from `iso` (defaults to today). */
export function addDays(iso: string, days: number): string {
  const base = iso ? new Date(`${iso}T00:00:00`) : new Date();
  base.setDate(base.getDate() + (Number.isFinite(days) ? days : 0));
  const offset = base.getTimezoneOffset();
  return new Date(base.getTime() - offset * 60_000).toISOString().slice(0, 10);
}

export function round2(n: number): number {
  return Math.round((Number.isFinite(n) ? n : 0) * 100) / 100;
}