// Tiny className combiner (avoids an extra dependency).
export function cn(...parts: Array<string | false | null | undefined>): string {
  return parts.filter(Boolean).join(" ");
}

// Convert ASCII digits to Persian digits for display.
const FA_DIGITS = ["۰", "۱", "۲", "۳", "۴", "۵", "۶", "۷", "۸", "۹"];
export function toFa(value: string | number | null | undefined): string {
  if (value === null || value === undefined) return "";
  return String(value).replace(/\d/g, (d) => FA_DIGITS[Number(d)]);
}

// Seconds -> "م:ث" style label (e.g. 90 -> ۱:۳۰). Used by the timer presets,
// whose backend field is `duration_seconds`.
export function formatDuration(seconds?: number | null): string {
  if (!seconds && seconds !== 0) return "—";
  const m = Math.floor(seconds / 60);
  const s = Math.floor(seconds % 60);
  return toFa(`${m}:${String(s).padStart(2, "0")}`);
}

// Minutes -> Persian label. Media and music store `duration` in minutes.
export function formatMinutes(minutes?: number | null): string {
  if (minutes === null || minutes === undefined) return "—";
  const m = Math.floor(minutes);
  if (m < 60) return toFa(`${m} دقیقه`);
  const h = Math.floor(m / 60);
  const rem = m % 60;
  return rem ? toFa(`${h} ساعت و ${rem} دقیقه`) : toFa(`${h} ساعت`);
}