import {z} from 'zod'

export type Description = string;

export type TransactionId = unknown;

export type InstalmentPlanType = 'BUY_NOW_PAY_LATER' | 'INTEREST_FREE' | 'FIXED_INTEREST';

export type PlanShift = number;

export type PaymentType = 'TENOR' | 'PORTION';

export type BaseInterestOptions = {paymentPlan: {type: PaymentType, value: number}};

export type PlanOptions = {type: InstalmentPlanType, shift: PlanShift} | BaseInterestOptions | BaseInterestOptions;

export type CreateInstalmentRequest = {from: 'TRANSACTION', description?: Description | undefined, transactionId: TransactionId, planOptions: PlanOptions};

export type CreateApiV1Args = {auditUser: string, body: CreateInstalmentRequest};

export type CreateApiV1Options = {baseUrl: string, fetch?: typeof fetch | undefined};

export const resourceResponse = z.object({description: z.string().optional(), id: z.string().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
};

/**
 * Create an instalment
 * 
 * POST /v1
 */
export const createApiV1 = async (args: CreateApiV1Args, options: CreateApiV1Options) => {
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")

if (args.auditUser != null) query.append("auditUser", String(args.auditUser))

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