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

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

export function formatCurrency(value: number | null | undefined): string {
  if (value == null) return "R0.00";
  return new Intl.NumberFormat("en-ZA", {
    style: "currency",
    currency: "ZAR",
    minimumFractionDigits: 2,
  }).format(value);
}

export function formatNumber(value: number | null | undefined, decimals = 2): string {
  if (value == null) return "0";
  return new Intl.NumberFormat("en-ZA", {
    minimumFractionDigits: decimals,
    maximumFractionDigits: decimals,
  }).format(value);
}

export function formatDate(value: string | Date | null | undefined): string {
  if (!value) return "";
  const d = typeof value === "string" ? new Date(value) : value;
  if (isNaN(d.getTime())) return "";
  return new Intl.DateTimeFormat("en-ZA", {
    year: "numeric",
    month: "short",
    day: "2-digit",
  }).format(d);
}

export function formatDateInput(value: string | Date | null | undefined): string {
  if (!value) return "";
  const d = typeof value === "string" ? new Date(value) : value;
  if (isNaN(d.getTime())) return "";
  // YYYY-MM-DD for <input type="date">
  const yyyy = d.getFullYear();
  const mm = String(d.getMonth() + 1).padStart(2, "0");
  const dd = String(d.getDate()).padStart(2, "0");
  return `${yyyy}-${mm}-${dd}`;
}