import {z} from 'zod'

export type GetApiV1ExchangeQuoteArgs = {from_amount?: number | undefined, from_account: string, to_amount?: number | undefined, to_account: string};

export type GetApiV1ExchangeQuoteOptions = {baseUrl?: string | undefined, fetch?: typeof fetch | undefined};

export const currency = z.enum(["AED", "USD", "JOD", "EGP", "SAR", "GBP", "EUR", "HKD", "CNH", "SGD"]);

export const getExchangeRateResponse = z.object({exchange_rate: z.number(), from_amount: z.number().int().gte(0), from_currency: currency, to_amount: z.number().int().gte(0), to_currency: currency});

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 a quote for an exchange between two currencies
 * 
 * GET /v1/exchange/quote
 */
export const getApiV1ExchangeQuote = async (args: GetApiV1ExchangeQuoteArgs, options?: GetApiV1ExchangeQuoteOptions) => {
const {baseUrl = "https://auth-sandbox.fuse.me", fetch: fetchFn = fetch} = options ?? {}

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

if (args.from_amount != null) query.append("from_amount", String(args.from_amount))
if (args.from_account != null) query.append("from_account", String(args.from_account))
if (args.to_amount != null) query.append("to_amount", String(args.to_amount))
if (args.to_account != null) query.append("to_account", String(args.to_account))

const url = `${baseUrl.replace(/\/+$/, '')}/v1/exchange/quote${query.size > 0 ? `?${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(getExchangeRateResponse, await res.json())
};