import {z} from 'zod'

export type ForexProduct = 'card_payouts' | 'daily_acquiring' | 'scheme_acquiring';

export type ForexSource = 'mastercard' | 'visa';

export type ForexProcessingChannelId = string;

export type GetApiForexRatesArgs = {product: ForexProduct, source: ForexSource, currency_pairs: string, processing_channel_id: ForexProcessingChannelId};

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

export const forexProduct = z.enum(["card_payouts", "daily_acquiring", "scheme_acquiring"]);

export const forexSource = z.enum(["mastercard", "visa"]);

export const timestamp = z.string();

export const forexRate = z.object({exchange_rate: z.number().optional(), currency_pair: z.string().optional(), valid_from: timestamp.optional()});

export const forexRatesResponse = z.object({product: forexProduct.optional(), source: forexSource.optional(), rates: z.array(forexRate).optional(), invalid_currency_pairs: z.array(z.string()).optional()});

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 FX rates
 * 
 * GET /forex/rates
 */
export const getApiForexRates = async (args: GetApiForexRatesArgs, options: GetApiForexRatesOptions) => {
const {baseUrl, fetch: fetchFn = fetch, OAuth} = options ?? {}

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

if (args.product != null) query.append("product", String(args.product))
if (args.source != null) query.append("source", String(args.source))
if (args.currency_pairs != null) query.append("currency_pairs", String(args.currency_pairs))
if (args.processing_channel_id != null) query.append("processing_channel_id", String(args.processing_channel_id))
if (OAuth !== undefined) headers.set('authorization', `Bearer ${OAuth}`)

const url = `${baseUrl.replace(/\/+$/, '')}/forex/rates${query.size > 0 ? `?${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(forexRatesResponse, await res.json())
};