import {z} from 'zod'

export type GetApiV1VerificationUpiArgs = {vpa: string, name?: string | undefined};

export type GetApiV1VerificationUpiOptions = {baseUrl: string, Oauth2ClientCredentials?: string | undefined, fetch?: typeof fetch | undefined};

export const vPASUCCESS = z.object({account_exists: z.boolean(), name_at_bank: z.string().optional()});

export const rESPONSEUPIVERIFICATIONSUCCESSFUL = z.object({code: z.number().int(), timestamp: z.number().int(), transaction_id: z.string(), data: vPASUCCESS});

export const vPAFAIL = z.object({account_exists: z.boolean()});

export const rESPONSEUPIVERIFICATIONFAILURE = z.object({code: z.number().int(), timestamp: z.number().int(), transaction_id: z.string(), data: vPAFAIL});

export const getApiV1VerificationUpiResponse = z.union([rESPONSEUPIVERIFICATIONSUCCESSFUL, rESPONSEUPIVERIFICATIONFAILURE]);

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
};

/**
 * Upi Verification
 * 
 * GET /v1/verification/upi
 */
export const getApiV1VerificationUpi = async (args: GetApiV1VerificationUpiArgs, options: GetApiV1VerificationUpiOptions) => {
const {baseUrl, fetch: fetchFn = fetch, Oauth2ClientCredentials} = options ?? {}

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

if (args.vpa != null) query.append("vpa", String(args.vpa))
if (args.name != null) query.append("name", String(args.name))
if (Oauth2ClientCredentials !== undefined) headers.set('authorization', `Bearer ${Oauth2ClientCredentials}`)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/verification/upi${query.size > 0 ? `?${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(getApiV1VerificationUpiResponse, await res.json())
};