import {z} from 'zod'

export type Currency = string;

export type Source = string;

export type RateType = 'MID' | 'BUY' | 'SELL';

export type GetApiV1RatesBaseArgs = {base: Currency, as_of?: string | undefined, source?: Source | undefined, type?: RateType | undefined, limit?: number | undefined, offset?: number | undefined};

export type GetApiV1RatesBaseOptions = {baseUrl: string, fetch?: typeof fetch | undefined};

export const currency = z.string();

export const rateType = z.enum(["MID", "BUY", "SELL"]);

export const source = z.string().max(50);

export const exchangeRate = z.object({as_of: z.string(), fetched_at: z.string(), base: currency, target: currency, rate_type: rateType, source: source, rate: z.number()});

export const pageExchangeRate = z.object({results: z.array(exchangeRate), total: z.number().int()});

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 rates for a base currency effective from a specific time
 * 
 * GET /v1/rates/{base}
 */
export const getApiV1RatesBase = async (args: GetApiV1RatesBaseArgs, options: GetApiV1RatesBaseOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

if (args.as_of != null) query.append("as_of", String(args.as_of))
if (args.source != null) query.append("source", String(args.source))
if (args.type != null) query.append("type", String(args.type))
if (args.limit != null) query.append("limit", String(args.limit))
if (args.offset != null) query.append("offset", String(args.offset))

const url = `${baseUrl.replace(/\/+$/, '')}/v1/rates/${encodeURIComponent(String(args.base))}${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(pageExchangeRate, await res.json())
};