/**
 * Duration formatting utilities.
 *
 * Durations are milliseconds — the app's neutral time unit. The backend has
 * already converted any provider unit (e.g. Jellyfin ticks) before it reaches
 * the frontend, so no tick arithmetic lives here.
 */

/**
 * Convert a millisecond duration to a formatted string.
 * @param ms Duration in milliseconds
 * @param format Format type: "mm:ss" (default) or "hh:mm:ss"
 * @returns Formatted duration string or empty string if no duration
 */
export function formatDuration(
  ms?: number | null,
  format: "mm:ss" | "hh:mm:ss" | "h m" = "mm:ss",
): string {
  if (!ms) return "";

  const totalSeconds = Math.floor(ms / 1000);

  // "1h 23m" / "45m" — the shape a runtime is read at a glance, as opposed to
  // the clock shape a *position* is read at. Three components had hand-rolled
  // this identically; it belongs here with the other two.
  if (format === "h m") {
    const hours = Math.floor(totalSeconds / 3600);
    const minutes = Math.floor((totalSeconds % 3600) / 60);
    return hours > 0 ? `${hours}h ${minutes}m` : `${minutes}m`;
  }

  if (format === "hh:mm:ss") {
    const hours = Math.floor(totalSeconds / 3600);
    const minutes = Math.floor((totalSeconds % 3600) / 60);
    const seconds = totalSeconds % 60;

    return `${hours}:${minutes.toString().padStart(2, "0")}:${seconds.toString().padStart(2, "0")}`;
  }

  // Default "mm:ss" format
  const minutes = Math.floor(totalSeconds / 60);
  const seconds = totalSeconds % 60;
  return `${minutes}:${seconds.toString().padStart(2, "0")}`;
}