'use strict';

const moment = require('moment');

class IdGenerator {
  constructor() {
    this._lastUsedTimestamp = null;
    this._counter = 0;
  }

  nextId() {
    const currentTimestamp = moment().valueOf();
    if (currentTimestamp === this._lastUsedTimestamp) {
      return currentTimestamp.toString(36) + '.' + (++this._counter).toString(36);
    } else {
      this._counter = 0;
      this._lastUsedTimestamp = currentTimestamp;
      return currentTimestamp.toString(36);
    }
  }
}

module.exports = IdGenerator;