import {z} from 'zod'

export type GetApiAnswersSlugJsonArgs = {slug: string};

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

export const answerPage = z.object({agent_next_steps: z.array(z.string()).optional(), aliases: z.array(z.string()).optional(), answer: z.string().optional(), answer_policy: z.record(z.string(), z.unknown()).optional(), api: z.string().optional(), api_method: z.enum(["GET", "POST"]).optional(), canonical_url: z.string().optional(), citation_targets: z.array(z.object({})).optional(), cta: z.string().optional(), description: z.string().optional(), evidence_checks: z.array(z.string()).optional(), generated_at: z.string().optional(), json_url: z.string().optional(), name: z.string().optional(), primary_url: z.string().optional(), related: z.array(z.object({})).optional(), schema: z.string().optional(), search_intent: 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
};

/**
 * x402 answer page JSON mirror
 * 
 * GET /answers/{slug}.json
 */
export const getApiAnswersSlugJson = async (args: GetApiAnswersSlugJsonArgs, options?: GetApiAnswersSlugJsonOptions) => {
const {baseUrl = "https://ontarioprotocol.com", fetch: fetchFn = fetch} = options ?? {}

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

const url = `${baseUrl.replace(/\/+$/, '')}/answers/${encodeURIComponent(String(args.slug))}.json${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(answerPage, await res.json())
};