import {z} from 'zod'

export type Header = {service: string, issuerCode: string, subIssuerCode: string, requestId: string, keyTag?: string | undefined, iv?: string | undefined};

export type EchoBody = {timestamp: unknown};

export type Signature = string;

export type EchoMessage = {header: Header, body: EchoBody, signature?: Signature | undefined};

export type CreateApiEchoArgs = {body: EchoMessage};

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

export const header = z.object({service: z.string().min(1).max(255), issuerCode: z.string().min(5).max(5), subIssuerCode: z.string().min(5).max(5), requestId: z.string(), keyTag: z.string().min(2).max(2).optional(), iv: z.string().min(24).max(32).optional()});

export const echoBody = z.object({timestamp: z.string().min(14).max(14)});

export const signature = z.string();

export const echoMessage = z.object({header: header, body: echoBody, signature: signature.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
};

/**
 * Test the availability of the web service. Timestamps are exchanged between the client and the server.
 * 
 * POST /echo
 */
export const createApiEcho = async (args: CreateApiEchoArgs, options: CreateApiEchoOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

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

const res = await fetchFn(url, {method: "POST", headers, body: JSON.stringify(args.body)})

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

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