import {z} from 'zod'

export type AccessGrantType = 'client_credentials';

export type AccessScopes = 'service-provider:read' | 'service-provider:write' | 'crb:read' | 'point-of-sale:read' | 'point-of-sale:write' | 'trace' | 'admin' | 'ein:read' | 'crb-id-request:read' | 'create-crb-api-key:write' | 'connect-crb-to-sp:write';

export type TokenRequestBody = {client_id: string, client_secret: string, grant_type: AccessGrantType, scope?: Array<AccessScopes> | undefined};

export type CreateApiAuthTokenArgs = {body: TokenRequestBody};

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

export const accessScopes = z.enum(["service-provider:read", "service-provider:write", "crb:read", "point-of-sale:read", "point-of-sale:write", "trace", "admin", "ein:read", "crb-id-request:read", "create-crb-api-key:write", "connect-crb-to-sp:write"]);

export const authResponse = z.object({access_token: z.string(), token_type: z.literal("Bearer"), scope: z.array(accessScopes), expires_at: z.number(), client_id: z.string(), issued_at: z.number()});

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 Bearer Token
 * 
 * POST /auth/token
 */
export const createApiAuthToken = async (args: CreateApiAuthTokenArgs, options?: CreateApiAuthTokenOptions) => {
const {baseUrl = "https://sandbox-api.greencheckverified.com", 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 = `${baseUrl.replace(/\/+$/, '')}/auth/token${query.size > 0 ? `?${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(authResponse, await res.json())
};