export function fmtDuration(sec: number): string {
  if (!isFinite(sec) || sec < 0) sec = 0;
  const s = Math.floor(sec % 60);
  const m = Math.floor((sec / 60) % 60);
  const h = Math.floor(sec / 3600);
  const ss = String(s).padStart(2, '0');
  return h > 0 ? `${h}:${String(m).padStart(2, '0')}:${ss}` : `${m}:${ss}`;
}

// m:ss.t, for editing
export function fmtTimecode(sec: number): string {
  if (!isFinite(sec) || sec < 0) sec = 0;
  const tenths = Math.floor((sec * 10) % 10);
  return `${fmtDuration(sec)}.${tenths}`;
}

export function fmtDate(iso: string): string {
  const d = new Date(iso);
  return d.toLocaleDateString(undefined, { year: 'numeric', month: 'short', day: 'numeric' });
}

export function fmtDateTime(iso: string): string {
  const d = new Date(iso);
  return d.toLocaleString(undefined, { month: 'short', day: 'numeric', hour: 'numeric', minute: '2-digit' });
}

export function fmtBytes(n: number): string {
  if (n < 1024) return `${n} B`;
  if (n < 1024 ** 2) return `${(n / 1024).toFixed(0)} KB`;
  if (n < 1024 ** 3) return `${(n / 1024 ** 2).toFixed(1)} MB`;
  return `${(n / 1024 ** 3).toFixed(2)} GB`;
}

export function decodePeaks(data: string): Uint8Array {
  const bin = atob(data);
  const out = new Uint8Array(bin.length);
  for (let i = 0; i < bin.length; i++) out[i] = bin.charCodeAt(i);
  return out;
}

export function loadPref<T>(key: string, fallback: T): T {
  try {
    const s = localStorage.getItem(key);
    return s ? { ...fallback, ...JSON.parse(s) } : fallback;
  } catch {
    return fallback;
  }
}

export function savePref(key: string, value: unknown) {
  try {
    localStorage.setItem(key, JSON.stringify(value));
  } catch {
    // storage unavailable
  }
}