import {z} from 'zod'

export type GetApiV1OrderbookSymbolBboArgs = {symbol: string};

export type GetApiV1OrderbookSymbolBboOptions = {baseUrl?: string | undefined, XPMAccessKey?: string | undefined, XPMTimestamp?: string | undefined, XPMSignature?: string | undefined, fetch?: typeof fetch | undefined};

export const bookEntry = z.object({px: z.string().optional(), qty: z.string().optional()});

export const instrumentState = z.enum(["INSTRUMENT_STATE_CLOSED", "INSTRUMENT_STATE_OPEN", "INSTRUMENT_STATE_PREOPEN", "INSTRUMENT_STATE_SUSPENDED", "INSTRUMENT_STATE_EXPIRED", "INSTRUMENT_STATE_TERMINATED", "INSTRUMENT_STATE_HALTED", "INSTRUMENT_STATE_MATCH_AND_CLOSE_AUCTION", "INSTRUMENT_STATE_PENDING"]);

export const getBBOResponse = z.object({symbol: z.string().optional(), bestBid: bookEntry.optional(), bestOffer: bookEntry.optional(), spread: z.string().optional(), midPrice: z.string().optional(), state: instrumentState.optional(), transactTime: 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
};

/**
 * Get best bid/offer
 * 
 * GET /v1/orderbook/{symbol}/bbo
 */
export const getApiV1OrderbookSymbolBbo = async (args: GetApiV1OrderbookSymbolBboArgs, options?: GetApiV1OrderbookSymbolBboOptions) => {
const {baseUrl = "https://api.polymarket.us", fetch: fetchFn = fetch, XPMAccessKey, XPMTimestamp, XPMSignature} = options ?? {}

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

if (XPMAccessKey !== undefined) headers.set("X-PM-Access-Key", XPMAccessKey)
if (XPMTimestamp !== undefined) headers.set("X-PM-Timestamp", XPMTimestamp)
if (XPMSignature !== undefined) headers.set("X-PM-Signature", XPMSignature)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/orderbook/${encodeURIComponent(String(args.symbol))}/bbo${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(getBBOResponse, await res.json())
};