import {z} from 'zod'

export type NLU = {input?: string | undefined, skill_id?: string | undefined, lang?: string | undefined};

export type CreateApiNluArgs = {body: NLU};

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

export const nLUGet = z.object({corrected_input: z.string().optional(), intents: z.string().optional(), intent_id: z.string().optional(), intent_slug: z.string().optional(), confidence: z.string().optional(), confidence_threshold: z.string().optional(), understood: z.boolean().optional(), custom_entities: z.object({}).optional(), system_entities: z.object({}).optional(), sentiment_polarity: z.object({}).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
};

/**
 * Parse
 * 
 * POST /nlu/
 */
export const createApiNlu = async (args: CreateApiNluArgs, options?: CreateApiNluOptions) => {
const {baseUrl = "https://apis.smartly.ai", fetch: fetchFn = fetch, Bearer} = options ?? {}

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

if (Bearer !== undefined) headers.set("Authorization", Bearer)

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