import {z} from 'zod'

export type CreateApiServeArgs = {body: {serve_id: string, continuation_token?: string | undefined, max_events?: number | undefined, min_events?: number | undefined, timeout?: string | undefined, schema?: ('exact' | 'never' | 'name_and_type') | undefined}};

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

export const createApiServeResponse = z.object({next_continuation_token: z.string().nullable(), state: z.enum(["running", "completed", "failed"]), schemas: z.array(z.object({schema_id: z.string().optional(), type_id: z.string().optional(), definition: z.unknown()})).optional(), events: z.array(z.object({schema_id: z.string().optional(), schema: z.string().optional(), type_id: z.string().optional(), data: 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
};

/**
 * Read pipeline output
 * 
 * POST /serve
 */
export const createApiServe = async (args: CreateApiServeArgs, options: CreateApiServeOptions) => {
const {baseUrl, fetch: fetchFn = fetch, TenzirToken} = options ?? {}

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

if (TenzirToken !== undefined) headers.set("X-Tenzir-Token", TenzirToken)

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