import {z} from 'zod'

export type GetApiArgs = {q: string, gl?: string | undefined, hl?: string | undefined, start?: number | undefined, rawhtml?: (0 | 1) | undefined};

export type GetApiOptions = {baseUrl?: string | undefined, basicAuth?: {username: string, password: string} | undefined, fetch?: typeof fetch | undefined};

export const serpResultItem = z.object({title: z.string().optional(), url: z.string().optional(), description: z.string().optional(), moreinfo: z.string().optional(), rank: z.number().int().optional()});

export const getApiResponse = z.object({query: z.string().optional(), url: z.string().optional(), html: z.string().optional(), results: z.array(z.object({Organic: z.array(serpResultItem).optional(), PeopleAlsoSearchFor: z.array(serpResultItem).optional(), Places: z.array(serpResultItem).optional()})).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
};

/**
 * Search
 * 
 * GET /
 */
export const getApi = async (args: GetApiArgs, options?: GetApiOptions) => {
const {baseUrl = "https://api.proxyscrape.com", fetch: fetchFn = fetch, basicAuth} = options ?? {}

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

if (args.q != null) query.append("q", String(args.q))
if (args.gl != null) query.append("gl", String(args.gl))
if (args.hl != null) query.append("hl", String(args.hl))
if (args.start != null) query.append("start", String(args.start))
if (args.rawhtml != null) query.append("rawhtml", String(args.rawhtml))
if (basicAuth !== undefined) headers.set('authorization', `Basic ${btoa(`${basicAuth.username}:${basicAuth.password}`)}`)

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