export interface VatRateResponse {
  country: string;
  country_code: string;
  standard_rate: number;
  reduced_rates: number[];
  currency: string;
}

const FALLBACK_RATES: VatRateResponse[] = [
  {
    country: "Austria",
    country_code: "AT",
    standard_rate: 20,
    reduced_rates: [10, 13],
    currency: "EUR",
  },
  {
    country: "Belgium",
    country_code: "BE",
    standard_rate: 21,
    reduced_rates: [6, 12],
    currency: "EUR",
  },
  {
    country: "Bulgaria",
    country_code: "BG",
    standard_rate: 20,
    reduced_rates: [9],
    currency: "EUR",
  },
  {
    country: "Croatia",
    country_code: "HR",
    standard_rate: 25,
    reduced_rates: [5, 13],
    currency: "EUR",
  },
  {
    country: "Cyprus",
    country_code: "CY",
    standard_rate: 19,
    reduced_rates: [5, 9],
    currency: "EUR",
  },
  {
    country: "Czech Republic",
    country_code: "CZ",
    standard_rate: 21,
    reduced_rates: [12, 15],
    currency: "EUR",
  },
  {
    country: "Denmark",
    country_code: "DK",
    standard_rate: 25,
    reduced_rates: [],
    currency: "EUR",
  },
  {
    country: "Estonia",
    country_code: "EE",
    standard_rate: 22,
    reduced_rates: [9],
    currency: "EUR",
  },
  {
    country: "Finland",
    country_code: "FI",
    standard_rate: 25.5,
    reduced_rates: [10, 14],
    currency: "EUR",
  },
  {
    country: "France",
    country_code: "FR",
    standard_rate: 20,
    reduced_rates: [5.5, 10],
    currency: "EUR",
  },
  {
    country: "Germany",
    country_code: "DE",
    standard_rate: 19,
    reduced_rates: [7],
    currency: "EUR",
  },
  {
    country: "Greece",
    country_code: "GR",
    standard_rate: 24,
    reduced_rates: [6, 13],
    currency: "EUR",
  },
  {
    country: "Hungary",
    country_code: "HU",
    standard_rate: 27,
    reduced_rates: [5, 18],
    currency: "EUR",
  },
  {
    country: "Ireland",
    country_code: "IE",
    standard_rate: 23,
    reduced_rates: [9, 13.5],
    currency: "EUR",
  },
  {
    country: "Italy",
    country_code: "IT",
    standard_rate: 22,
    reduced_rates: [5, 10],
    currency: "EUR",
  },
  {
    country: "Latvia",
    country_code: "LV",
    standard_rate: 21,
    reduced_rates: [5, 12],
    currency: "EUR",
  },
  {
    country: "Lithuania",
    country_code: "LT",
    standard_rate: 21,
    reduced_rates: [5, 9],
    currency: "EUR",
  },
  {
    country: "Luxembourg",
    country_code: "LU",
    standard_rate: 17,
    reduced_rates: [8],
    currency: "EUR",
  },
  {
    country: "Malta",
    country_code: "MT",
    standard_rate: 18,
    reduced_rates: [5, 7],
    currency: "EUR",
  },
  {
    country: "Netherlands",
    country_code: "NL",
    standard_rate: 21,
    reduced_rates: [9],
    currency: "EUR",
  },
  {
    country: "Poland",
    country_code: "PL",
    standard_rate: 23,
    reduced_rates: [5, 8],
    currency: "EUR",
  },
  {
    country: "Portugal",
    country_code: "PT",
    standard_rate: 23,
    reduced_rates: [6, 13],
    currency: "EUR",
  },
  {
    country: "Romania",
    country_code: "RO",
    standard_rate: 19,
    reduced_rates: [5, 9],
    currency: "EUR",
  },
  {
    country: "Slovakia",
    country_code: "SK",
    standard_rate: 23,
    reduced_rates: [5, 10],
    currency: "EUR",
  },
  {
    country: "Slovenia",
    country_code: "SI",
    standard_rate: 22,
    reduced_rates: [5, 9.5],
    currency: "EUR",
  },
  {
    country: "Spain",
    country_code: "ES",
    standard_rate: 21,
    reduced_rates: [4, 10],
    currency: "EUR",
  },
  {
    country: "Sweden",
    country_code: "SE",
    standard_rate: 25,
    reduced_rates: [6, 12],
    currency: "EUR",
  },
];

const TWENTY_FOUR_HOURS = 24 * 60 * 60 * 1000;

let cache: { data: VatRateResponse[]; date: string; fetchedAt: number } | null =
  null;

function todayDateString(): string {
  return new Date().toISOString().slice(0, 10);
}

function isCacheValid(): boolean {
  if (!cache) return false;
  const age = Date.now() - cache.fetchedAt;
  return age < TWENTY_FOUR_HOURS && cache.date === todayDateString();
}

function transformVatstackResponse(vatstackRates: any[]): VatRateResponse[] {
  return vatstackRates.map((r: any) => ({
    country: r.country_name ?? "",
    country_code: r.country_code ?? "",
    standard_rate: r.standard_rate ?? 0,
    reduced_rates: r.reduced_rates ?? [],
    currency: "EUR",
  }));
}

export async function getAllRates(): Promise<VatRateResponse[]> {
  if (isCacheValid()) return cache!.data;

  const apiKey = "pk_live_3038ce089ee7197879fcf95e624da019";

  try {
    const response: any = await $fetch("https://api.vatstack.com/v1/rates", {
      headers: { "X-API-Key": apiKey },
      query: { member_state: true, limit: 100 },
    });

    const items: any[] = response.rates ?? response;
    const euOnly = items.filter((r: any) => r.member_state === true);
    const rates = transformVatstackResponse(euOnly);
    cache = { data: rates, date: todayDateString(), fetchedAt: Date.now() };
    return rates;
  } catch {
    // Fall back to hardcoded rates on fetch failure
    cache = {
      data: FALLBACK_RATES,
      date: todayDateString(),
      fetchedAt: Date.now(),
    };
    return FALLBACK_RATES;
  }
}

export async function getRateByCode(
  code: string,
): Promise<VatRateResponse | undefined> {
  const rates = await getAllRates();
  return rates.find((r) => r.country_code === code.toUpperCase());
}