import { authFetch } from "../../../utils/authFetch";

interface VatRate {
  countryCode: string;
  standardRate: number;
}

const normalizeVatRate = (rate: number | null | undefined): number | null => {
  if (rate == null || Number.isNaN(rate)) return null;
  return rate > 1 ? rate / 100 : rate;
};

/**
 * Fetches the standard VAT rate for a given ISO country code.
 * Returns null if not found or on any error.
 */
export async function getStandardVatRate(countryCode: string): Promise<number | null> {
  try {
    const res = await authFetch(`${process.env.NEXT_PUBLIC_API_BASE_URL}/api/tax/vat-rates`, { method: "GET" });
    if (!res.ok) return null;

    const data = await res.json().catch(() => null);
    if (!data || !Array.isArray(data)) return null;

    const upper = countryCode.toUpperCase();
    const match = (data as VatRate[]).find(r => r.countryCode.toUpperCase() === upper);
    return normalizeVatRate(match?.standardRate);
  } catch {
    return null;
  }
}