'use strict'

/**
 * This is apparently a bit like a Jquery deferred, hence the name
 */

class Deferred {

  constructor (Promise) {
    this._state = Deferred.PENDING
    this._resolve = undefined
    this._reject = undefined

    this._promise = new Promise((resolve, reject) => {
      this._resolve = resolve
      this._reject = reject
    })
  }

  get state () {
    return this._state
  }

  get promise () {
    return this._promise
  }

  reject (reason) {
    if (this._state !== Deferred.PENDING) {
      return
    }
    this._state = Deferred.REJECTED
    this._reject(reason)
  }

  resolve (value) {
    if (this._state !== Deferred.PENDING) {
      return
    }
    this._state = Deferred.FULFILLED
    this._resolve(value)
  }
}

// TODO: should these really live here? or be a seperate 'state' enum
Deferred.PENDING = 'PENDING'
Deferred.FULFILLED = 'FULFILLED'
Deferred.REJECTED = 'REJECTED'

module.exports = Deferred