import {z} from 'zod'

export type Timestamp = string;

export type ServerMeasurement = {time: Timestamp, cpu_percent?: number | undefined, loadavg_norm?: Array<number> | undefined, iowait_percent?: number | undefined, memory_used_percent?: number | undefined, avg_processor_queue_length?: number | undefined, avg_disk_queue_length?: number | undefined, duration: number};

export type ServerMeasurements = Array<ServerMeasurement>;

export type CreateApiServersSelfMetricsArgs = {body: ServerMeasurements};

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

export const timestamp = z.string();

export const serverMeasurement = z.object({time: timestamp, cpu_percent: z.number().optional(), loadavg_norm: z.array(z.number()).optional(), iowait_percent: z.number().optional(), memory_used_percent: z.number().optional(), avg_processor_queue_length: z.number().optional(), avg_disk_queue_length: z.number().optional(), duration: z.number().int()});

export const serverMeasurements = z.array(serverMeasurement);

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
};

/**
 * Post server metrics to analyze scaling conditions
 * 
 * POST /servers/self/metrics
 */
export const createApiServersSelfMetrics = async (args: CreateApiServersSelfMetricsArgs, options?: CreateApiServersSelfMetricsOptions) => {
const {baseUrl = "https://api.webscale.com/v2", fetch: fetchFn = fetch} = options ?? {}

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

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