/** Pad number to 2 digits */
export function pad(n) {
  return n.toString().padStart(2, "0");
}

/** Format seconds as M:SS (e.g. 1:05) */
export function formatTime(seconds) {
  if (!seconds || isNaN(seconds)) return "0:00";
  const m = Math.floor(seconds / 60);
  const s = Math.floor(seconds % 60).toString().padStart(2, "0");
  return `${m}:${s}`;
}

/** Format seconds as human duration (e.g. 2m 30s) */
export function formatDuration(seconds) {
  if (!seconds) return "";
  const m = Math.floor(seconds / 60);
  const s = Math.round(seconds % 60);
  return m > 0 ? `${m}m ${s}s` : `${s}s`;
}

/** Format ISO timestamp as D Mon HH:MM (e.g. 15 Mar 18:11) */
export function formatTimestamp(iso) {
  if (!iso) return "";
  const d = new Date(iso);
  return d.toLocaleDateString("en-GB", { day: "numeric", month: "short" }) +
    " " + d.toLocaleTimeString("en-GB", { hour: "2-digit", minute: "2-digit" });
}

/** Format seconds as SRT timestamp (HH:MM:SS,mmm) */
export function formatTimeSRT(seconds) {
  const h = Math.floor(seconds / 3600);
  const m = Math.floor((seconds % 3600) / 60);
  const s = Math.floor(seconds % 60);
  const ms = Math.floor((seconds % 1) * 1000);
  return `${pad(h)}:${pad(m)}:${pad(s)},${ms.toString().padStart(3, "0")}`;
}

/** Format seconds as VTT timestamp (HH:MM:SS.mmm) */
export function formatTimeVTT(seconds) {
  const h = Math.floor(seconds / 3600);
  const m = Math.floor((seconds % 3600) / 60);
  const s = Math.floor(seconds % 60);
  const ms = Math.floor((seconds % 1) * 1000);
  return `${pad(h)}:${pad(m)}:${pad(s)}.${ms.toString().padStart(3, "0")}`;
}