import {z} from 'zod'

export type GetApiSuggestArgs = {projects: string, field: string, caret: number, full?: string | undefined, defs?: string | undefined, refs?: string | undefined, path?: string | undefined, hist?: string | undefined, type?: string | undefined};

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

export const suggestion = z.object({phrase: z.string().optional(), projects: z.array(z.string()).optional(), score: z.number().optional()});

export const suggestResponse = z.object({time: z.number().int().optional(), suggestions: z.array(suggestion).optional(), identifier: z.string().optional(), queryText: z.string().optional(), partialResult: z.boolean().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
};

/**
 * Return suggestions
 * 
 * GET /suggest
 */
export const getApiSuggest = async (args: GetApiSuggestArgs, options: GetApiSuggestOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

if (args.projects != null) query.append("projects", String(args.projects))
if (args.field != null) query.append("field", String(args.field))
if (args.caret != null) query.append("caret", String(args.caret))
if (args.full != null) query.append("full", String(args.full))
if (args.defs != null) query.append("defs", String(args.defs))
if (args.refs != null) query.append("refs", String(args.refs))
if (args.path != null) query.append("path", String(args.path))
if (args.hist != null) query.append("hist", String(args.hist))
if (args.type != null) query.append("type", String(args.type))

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