import {z} from 'zod'

export type GetApiCurrenciesV1ConvertArgs = {from: string, to: string, amount?: number | undefined, pretty?: boolean | undefined};

export type GetApiCurrenciesV1ConvertOptions = {baseUrl?: string | undefined, BearerAuth?: string | undefined, fetch?: typeof fetch | undefined};

export const currency = z.object({code: z.string(), name: z.string(), symbol: z.string().nullable()});

export const convertObject = z.object({from: currency.optional(), to: currency.optional(), amount: z.number().optional(), rate: z.number().optional(), result: z.number().optional(), as_of: z.number().int().optional()});

export const resultMeta = z.object({total: z.number().int(), request_id: z.string(), duration: z.number().int()});

export const convertResponse = z.object({data: z.object({objects: z.array(convertObject), meta: resultMeta.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
};

/**
 * Convert an amount between currencies
 * 
 * GET /currencies/v1/convert
 * 
 * Also accepts auth: KeyQuery
 */
export const getApiCurrenciesV1Convert = async (args: GetApiCurrenciesV1ConvertArgs, options?: GetApiCurrenciesV1ConvertOptions) => {
const {baseUrl = "https://api.restcountries.com", fetch: fetchFn = fetch, BearerAuth} = options ?? {}

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

if (args.from != null) query.append("from", String(args.from))
if (args.to != null) query.append("to", String(args.to))
if (args.amount != null) query.append("amount", String(args.amount))
if (args.pretty != null) query.append("pretty", String(args.pretty))
if (BearerAuth !== undefined) headers.set('authorization', `Bearer ${BearerAuth}`)

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