// Type definitions for Split JavaScript Sync Tools
// Project: https://www.split.io/
// Definitions by: Emiliano Sanchez <https://github.com/EmilianoSanchez/>

import '@splitsoftware/splitio-commons';
import { RequestOptions } from 'http';

/**
 * JavaScript synchronizer tool.
 *
 * @see {@link https://help.split.io/hc/en-us/articles/4421513571469-Split-JavaScript-synchronizer-tools}.
 */
export class Synchronizer {
  /**
   * Creates a new Synchronizer instance
   *
   * @param config - The synchronizer config object
   */
  constructor(config: ISynchronizerSettings);
  /**
   * Execute synchronization
   *
   * @param cb - Optional error-first callback to be invoked when the synchronization ends. The callback will be invoked with an error as first argument if the synchronization fails.
   * @returns A promise that resolves when the operation ends, with a boolean indicating if operation succeeded or not. The promise never rejects.
   */
  execute(cb?: (err?: Error) => void): Promise<boolean>;
  // @TODO expose settings eventually
  // settings: ISettings
}

/**
 * Settings interface for Synchronizer instances.
 *
 * @see {@link https://help.split.io/hc/en-us/articles/4421513571469-Split-JavaScript-synchronizer-tools#configuration}
 */
export interface ISynchronizerSettings {
  /**
   * Core settings.
   */
  core: {
    /**
     * Your SDK key.
     *
     * @see {@link https://help.split.io/hc/en-us/articles/360019916211-API-keys}
     */
    authorizationKey: string
  }
  /**
   * Defines which kind of storage we should instantiate.
   */
  storage: {
    /**
     * Storage type. The only possible value is `'PLUGGABLE'`, which is the default.
     */
    type?: 'PLUGGABLE',
    /**
     * A valid storage instance.
     */
    wrapper: Object
    /**
     * Optional prefix added to the storage keys to prevent any kind of data collision between SDK versions.
     *
     * @defaultValue `'SPLITIO'`
     */
    prefix?: string
  }
  /**
   * List of URLs that the Synchronizer will use as base for it's synchronization functionalities.
   * Do not change these settings unless you're working an advanced use case, like connecting to a proxy.
   */
  urls?: SplitIO.UrlSettings
  /**
   * Boolean value to indicate whether the logger should be enabled or disabled by default, or a log level string.
   *
   * Examples:
   * ```
   * config.debug = true
   * config.debug = 'WARN'
   * ```
   *
   * @defaultValue `false`
   */
  debug?: boolean | SplitIO.LogLevel
  /**
   * Synchronization settings.
   */
  sync?: {
    /**
     * List of feature flag filters. These filters are used to fetch a subset of the feature flag definitions in your environment.
     *
     * Example:
     * ```
     * splitFilter: [
     *   { type: 'byName', values: ['my_feature_flag_1', 'my_feature_flag_2'] }, // will fetch feature flags named 'my_feature_flag_1' and 'my_feature_flag_2'
     * ]
     * ```
     */
    splitFilters?: SplitIO.SplitFilter[]
    /**
     * Feature Flag Spec version. Option to determine which version of the feature flag definitions are fetched and stored.
     * Possible values are `'1.0'`, `'1.1'`, `'1.2'`, and `'1.3'`.
     *
     * @defaultValue `'1.3'`
     */
    flagSpecVersion?: '1.0' | '1.1' | '1.2' | '1.3'
    /**
     * Impressions Collection Mode. Option to determine how impressions are going to be sent to Split Servers.
     *
     * Possible values are `'DEBUG'` and `'OPTIMIZED'`.
     * - DEBUG: will send all the impressions generated (recommended only for debugging purposes).
     * - OPTIMIZED: will send unique impressions to Split Servers avoiding a considerable amount of traffic that duplicated impressions could generate.
     *
     * @defaultValue `'OPTIMIZED'`
     */
    impressionsMode?: SplitIO.ImpressionsMode
    /**
     * Custom options object for HTTP(S) requests in Node.js.
     * If provided, this object is merged with the options object passed for Node-Fetch calls.
     *
     * @see {@link https://www.npmjs.com/package/node-fetch#options}
     */
    requestOptions?: {
      /**
       * Custom function called before each request, allowing you to add or update headers in Synchronizer HTTP requests.
       * Some headers, such as `SplitSDKVersion`, are required by the Synchronizer and cannot be overridden.
       * To pass multiple headers with the same name, combine their values into a single line, separated by commas. Example: `{ 'Authorization': 'value1, value2' }`
       * Or provide keys with different cases since headers are case-insensitive. Example: `{ 'authorization': 'value1', 'Authorization': 'value2' }`
       *
       * @defaultValue `undefined`
       *
       * @param context - The context for the request, which contains the `headers` property object representing the current headers in the request.
       * @returns An object representing a set of headers to be merged with the current headers.
       *
       * @example
       * ```
       * const getHeaderOverrides = (context) => {
       *   return {
       *     'Authorization': context.headers['Authorization'] + ', other-value',
       *     'custom-header': 'custom-value'
       *   };
       * };
       * ```
       */
      getHeaderOverrides?: (context: { headers: Record<string, string> }) => Record<string, string>;
      /**
       * Custom Node.js HTTP(S) Agent used for HTTP(S) requests.
       *
       * You can use it, for example, for certificate pinning or setting a network proxy:
       *
       * ```
       * const { HttpsProxyAgent } = require('https-proxy-agent');
       *
       * const proxyAgent = new HttpsProxyAgent(process.env.HTTPS_PROXY || 'http://10.10.1.10:1080');
       *
       * const synchronizer = Synchronizer({
       *   ...
       *   sync: {
       *     requestOptions: {
       *       agent: proxyAgent
       *     }
       *   }
       * })
       * ```
       *
       * @see {@link https://nodejs.org/api/https.html#class-httpsagent}
       *
       * @defaultValue `undefined`
       */
      agent?: RequestOptions['agent']
    },
  }
  /**
   * Scheduler settings.
   */
  scheduler?: {
    /**
     * Maximum number of impressions to send per POST request.
     *
     * @defaultValue `1000`
     */
    impressionsPerPost?: number
    /**
     * Maximum number of events to send per POST request.
     *
     * @defaultValue `1000`
     */
    eventsPerPost?: number
    /**
     * Maximum number of retry attempts for posting impressions and events.
     *
     * @defaultValue `3`
     */
    maxRetries?: number
  }
}