import {z} from 'zod'

export type BaseIn = 'AUD' | 'BGN' | 'BRL' | 'CAD' | 'CHF' | 'CNY' | 'CZK' | 'DKK' | 'EUR' | 'GBP' | 'HKD' | 'HUF' | 'IDR' | 'ILS' | 'INR' | 'ISK' | 'JPY' | 'KRW' | 'MXN' | 'MYR' | 'NOK' | 'NZD' | 'PHP' | 'PLN' | 'RON' | 'SEK' | 'SGD' | 'THB' | 'TRY' | 'USD' | 'ZAR';

export type Base = 'AUD' | 'BGN' | 'BRL' | 'CAD' | 'CHF' | 'CNY' | 'CZK' | 'DKK' | 'EUR' | 'GBP' | 'HKD' | 'HUF' | 'IDR' | 'ILS' | 'INR' | 'ISK' | 'JPY' | 'KRW' | 'MXN' | 'MYR' | 'NOK' | 'NZD' | 'PHP' | 'PLN' | 'RON' | 'SEK' | 'SGD' | 'THB' | 'TRY' | 'USD' | 'ZAR';

export type GetApiLatestArgs = {base?: BaseIn | undefined, symbols?: Array<Base> | undefined};

export type GetApiLatestOptions = {baseUrl?: string | undefined, fetch?: typeof fetch | undefined};

export const amount = z.number().gt(0);

export const base = z.enum(["AUD", "BGN", "BRL", "CAD", "CHF", "CNY", "CZK", "DKK", "EUR", "GBP", "HKD", "HUF", "IDR", "ILS", "INR", "ISK", "JPY", "KRW", "MXN", "MYR", "NOK", "NZD", "PHP", "PLN", "RON", "SEK", "SGD", "THB", "TRY", "USD", "ZAR"]);

export const date = z.string();

export const rates = z.record(z.string(), z.number().gt(0).multipleOf(0.00001));

export const ratesOnDate = z.object({amount: amount.optional(), base: base, date: date, rates: rates});

export const validateResponse = async <Output>(
  schema: {
    readonly '~standard': {
      readonly validate: (value: unknown) => ({ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }) | Promise<{ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }>
    }
  },
  value: unknown
): Promise<Output> => {
  const result = await schema['~standard'].validate(value)

  if (result.issues !== undefined) {
    const detail = result.issues
      .map(({ message, path }) =>
        path?.length
          ? `${path.map((segment) => String(typeof segment === 'object' ? segment.key : segment)).join('.')}: ${message}`
          : message
      )
      .join('; ')

    throw new Error(`Response does not match the schema: ${detail}`, { cause: { issues: result.issues } })
  }

  return result.value
};

/**
 * Get the latest rates
 * 
 * GET /latest
 */
export const getApiLatest = async (args: GetApiLatestArgs, options?: GetApiLatestOptions) => {
const {baseUrl = "https://api.frankfurter.dev/v1", fetch: fetchFn = fetch} = options ?? {}

const query = new URLSearchParams()
const headers = new Headers()
headers.set('accept', "application/json")

if (args.base != null) query.append("base", String(args.base))
if (args.symbols != null) query.append("symbols", args.symbols.join(','))

const url = `${baseUrl.replace(/\/+$/, '')}/latest${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "GET", headers})

if (!res.ok) throw new Error(`Request failed with status ${res.status}`, {cause: {status: res.status, body: await res.text()}})

return validateResponse(ratesOnDate, await res.json())
};