ThinkDeepTech/thinkdeep

import {validString} from '@thinkdeep/util';

/**
 * Commander implementation for microservice use.
 */
class Commander {
  /**
   * Construct an instance.
   * @param {Object} logger Logger to use.
   */
  constructor(logger) {
    this._commandMap = {};
    this._logger = logger;
  }

  /**
   * Execute the commands and associate them with the key provided.
   * @param {String} key - The key to associate with the commands.
   * @param {Array} commands - Command objects to execute.
   * @throws {Error} Will throw an error if the key is not a valid string.
   */
  async execute(key, commands) {
    if (!validString(key))
      throw new Error(`Key must be a valid string. Received: ${key}`);

    if (!Array.isArray(commands)) return;

    this._addCommands(key, commands);

    this._logger.info(`Executing commands for key ${key}`);
    for (const command of this._commands(key)) {
      await command.execute();
    }
  }

  /**
   * Check if a key has already been registered with the commander.
   * @param {String} key
   * @return {Boolean} True if the key has already been registered. False otherwise.
   */
  registered(key) {
    return key in this._commandMap;
  }

  /**
   * Stop all the running commands.
   */
  async stopAllCommands() {
    this._logger.info(`Stopping all commands`);
    for (const [key, commands] of Object.entries(this._commandMap)) {
      this._logger.info(`Clearing commands for key ${key}`);
      await this._stopCommands(commands);
    }
  }

  /**
   * Stop the passed commands.
   * @param {Array} commands - Command objects.
   */
  async _stopCommands(commands) {
    if (!Array.isArray(commands)) return;

    for (const command of commands) {
      await command.stop();
    }
  }

  /**
   * Track the specified commands with the key provided.
   * @param {String} key - Key to be used.
   * @param {Array} commands - Command objects.
   */
  _addCommands(key, commands) {
    if (!validString(key))
      throw new Error(`Key must be valid but was not. Received: ${key}`);

    if (!Array.isArray(commands)) return;

    this._logger.info(`Adding commands for key ${key}`);

    this._commandMap[key] = commands;
  }

  /**
   * Fetch the commands associated with the provided key.
   * @param {String} key
   * @return {Array} Command objects.
   */
  _commands(key) {
    if (!validString(key))
      throw new Error(`Key must be valid but was not. Received: ${key}`);

    return this._commandMap[key];
  }
}

export {Commander};