const UNITS: [Intl.RelativeTimeFormatUnit, number][] = [
  ["year", 365 * 24 * 3600e3],
  ["month", 30 * 24 * 3600e3],
  ["week", 7 * 24 * 3600e3],
  ["day", 24 * 3600e3],
  ["hour", 3600e3],
  ["minute", 60e3],
];

const rtf = new Intl.RelativeTimeFormat("en", { numeric: "auto" });

export function timeAgo(ms: number) {
  const diff = ms - Date.now();
  for (const [unit, size] of UNITS) {
    if (Math.abs(diff) >= size) return rtf.format(Math.round(diff / size), unit);
  }
  return "just now";
}

export function formatDate(ms: number) {
  return new Date(ms).toLocaleDateString("en", { month: "short", day: "numeric", year: "numeric" });
}

export function formatBytes(n: number) {
  if (n < 1024) return `${n} Bytes`;
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`;
  if (n < 1024 * 1024 * 1024) return `${(n / 1024 / 1024).toFixed(1)} MB`;
  return `${(n / 1024 / 1024 / 1024).toFixed(2)} GB`;
}

export function shortSha(sha: string) {
  return sha.slice(0, 7);
}

/** Encodes each path segment but keeps the slashes. */
export function encodePath(p: string) {
  return p.split("/").map(encodeURIComponent).join("/");
}

/** A run's length: "45s", "3m 12s", "1h 4m". */
export function formatDuration(ms: number) {
  const s = Math.max(0, Math.round(ms / 1000));
  if (s < 60) return `${s}s`;
  const m = Math.floor(s / 60);
  if (m < 60) return `${m}m ${s % 60}s`;
  return `${Math.floor(m / 60)}h ${m % 60}m`;
}