import { todayLocalDate } from "@/api/hooks/reads";

/**
 * Local-calendar [from, to] bounds (`YYYY-MM-DD`, matching `?from=&to=`) for
 * the month `offset` months from `base` — 0 = `base`'s own month, -1 = the
 * month before, +1 = the month after. Powers the Тооцоо month navigator.
 */
export function monthRange(offset: number, base: Date = new Date()): { from: string; to: string } {
  const year = base.getFullYear();
  const month = base.getMonth() + offset;
  const first = new Date(year, month, 1);
  const last = new Date(year, month + 1, 0); // day 0 of next month = this month's last day
  return { from: todayLocalDate(first), to: todayLocalDate(last) };
}

/** "2026 оны 8-р сар" for the month `offset` months from `base`. */
export function monthLabel(offset: number, base: Date = new Date()): string {
  const year = base.getFullYear();
  const month = base.getMonth() + offset;
  const d = new Date(year, month, 1);
  return `${d.getFullYear()} оны ${d.getMonth() + 1}-р сар`;
}