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

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

export function formatDateTime(value?: string | null) {
  if (!value) return "Never";
  return new Intl.DateTimeFormat(undefined, {
    month: "short",
    day: "numeric",
    hour: "2-digit",
    minute: "2-digit",
  }).format(new Date(value));
}

export function relativeTime(value?: string | null) {
  if (!value) return "Never";
  const deltaSeconds = Math.round((new Date(value).getTime() - Date.now()) / 1000);
  const units: Array<[Intl.RelativeTimeFormatUnit, number]> = [
    ["year", 31536000],
    ["month", 2592000],
    ["day", 86400],
    ["hour", 3600],
    ["minute", 60],
    ["second", 1],
  ];
  const formatter = new Intl.RelativeTimeFormat(undefined, { numeric: "auto" });
  const [unit, seconds] = units.find(([, amount]) => Math.abs(deltaSeconds) >= amount) ?? ["second", 1];
  return formatter.format(Math.round(deltaSeconds / seconds), unit);
}

export function truncateMiddle(value: string, max = 18) {
  if (value.length <= max) return value;
  const keep = Math.max(4, Math.floor((max - 3) / 2));
  return `${value.slice(0, keep)}...${value.slice(-keep)}`;
}

export async function copyToClipboard(value: string) {
  await navigator.clipboard.writeText(value);
}

export function slugifyName(value: string, fallback = "item") {
  const slug = value
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, "_")
    .replace(/^_+|_+$/g, "");
  return slug || `${fallback}_${Date.now().toString(36)}`;
}