import { clsx, type ClassValue } from "clsx";
import { twMerge } from "tailwind-merge";

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs));
}

export function formatBytes(n: number): string {
  if (n < 1024) return `${n} B`;
  const u = ["KB", "MB", "GB"];
  let v = n / 1024;
  let i = 0;
  while (v >= 1024 && i < u.length - 1) { v /= 1024; i++; }
  return `${v.toFixed(v < 10 ? 1 : 0)} ${u[i]}`;
}

export function coverHref(image: { id: number; code: string | null }): string {
  if (image.code && image.code.trim()) return `/id/${encodeURIComponent(image.code)}`;
  return `/image/${image.id}`;
}

export function relativeTime(ms: number): string {
  const diff = Date.now() - ms;
  const s = Math.floor(diff / 1000);
  if (s < 60) return "just now";
  const m = Math.floor(s / 60);
  if (m < 60) return `${m}m ago`;
  const h = Math.floor(m / 60);
  if (h < 24) return `${h}h ago`;
  const d = Math.floor(h / 24);
  if (d < 30) return `${d}d ago`;
  const mo = Math.floor(d / 30);
  if (mo < 12) return `${mo}mo ago`;
  return `${Math.floor(mo / 12)}y ago`;
}