import {z} from 'zod'

export type InferenceDocument = {[key: string]: unknown};

export type InferenceRerankRequest = {model: string, query: string, top_n?: number | undefined, return_documents?: boolean | undefined, rank_fields?: Array<string> | undefined, documents: Array<InferenceDocument>, parameters?: {[key: string]: unknown} | undefined};

export type CreateApiRerankArgs = {'X-Pinecone-Api-Version': string, body: InferenceRerankRequest};

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

export const inferenceDocument = z.record(z.string(), z.unknown());

export const inferenceRankedDocument = z.object({index: z.number().int(), score: z.number(), document: inferenceDocument.optional()});

export const inferenceRerankResult = z.object({model: z.string(), data: z.array(inferenceRankedDocument), usage: z.object({rerank_units: z.number().int().gte(0).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
};

/**
 * Rerank results
 * 
 * POST /rerank
 */
export const createApiRerank = async (args: CreateApiRerankArgs, options?: CreateApiRerankOptions) => {
const {baseUrl = "https://api.pinecone.io", fetch: fetchFn = fetch, ApiKeyAuth} = options ?? {}

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

if (args['X-Pinecone-Api-Version'] != null) headers.set("X-Pinecone-Api-Version", String(args['X-Pinecone-Api-Version']))
if (ApiKeyAuth !== undefined) headers.set("Api-Key", ApiKeyAuth)

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