import {z} from 'zod'

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

export const classifierModel = z.object({id2label: z.record(z.string(), z.string()), label2id: z.record(z.string(), z.number().int().gte(0))});

export const embeddingModel = z.object({pooling: z.string()});

export const modelType = z.union([z.object({classifier: classifierModel}), z.object({embedding: embeddingModel}), z.object({reranker: classifierModel})]);

export const info = z.object({auto_truncate: z.boolean(), docker_label: z.string().nullable().optional(), max_batch_requests: z.number().int().gte(0).nullable().optional(), max_batch_tokens: z.number().int().gte(0), max_client_batch_size: z.number().int().gte(0), max_concurrent_requests: z.number().int().gte(0), max_input_length: z.number().int().gte(0), model_dtype: z.string(), model_id: z.string(), model_sha: z.string().nullable().optional(), model_type: modelType, sha: z.string().nullable().optional(), tokenization_workers: z.number().int().gte(0), version: z.string()});

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
};

/**
 * Text Embeddings Inference endpoint info
 * 
 * GET /info
 */
export const getApiInfo = async (options: GetApiInfoOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

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