import { ValidationError } from '@segment/analytics-core'
import { HTTPClient, HTTPFetchFn } from '../lib/http-client'

export interface AnalyticsSettings {
  /**
   * Key that corresponds to your Segment.io project
   */
  writeKey: string
  /**
   * The base URL of the API. Default: "https://api.segment.io"
   */
  host?: string
  /**
   * The API path route. Default: "/v1/batch"
   */
  path?: string
  /**
   * The number of times to retry flushing a batch. Default: 3
   */
  maxRetries?: number
  /**
   * The number of events to enqueue before flushing. Default: 15.
   */
  flushAt?: number
  /**
   * @deprecated
   * The number of events to enqueue before flushing. This is deprecated in favor of `flushAt`. Default: 15.
   */
  maxEventsInBatch?: number
  /**
   * The number of milliseconds to wait before flushing the queue automatically. Default: 10000
   */
  flushInterval?: number
  /**
   * The maximum number of milliseconds to wait for an http request. Default: 10000
   */
  httpRequestTimeout?: number
  /**
   * Disable the analytics library. All calls will be a noop. Default: false.
   */
  disable?: boolean
  /**
   * Supply a default http client implementation (such as one supporting proxy).
   * Accepts either an HTTPClient instance or a fetch function.
   * Default: an HTTP client that uses globalThis.fetch, with node-fetch as a fallback.
   */
  httpClient?: HTTPFetchFn | HTTPClient
}

export const validateSettings = (settings: AnalyticsSettings) => {
  if (!settings.writeKey) {
    throw new ValidationError('writeKey', 'writeKey is missing.')
  }
}