text: 'use strict'
  
  /**
   * Module dependencies
   */
  var xtend = require('xtend')
  
  var Readable = require('readable-stream').Readable
  var streamsOpts = { objectMode: true }
  var defaultStoreOptions = {
    clean: true
  }
  
  /**
   * es6-map can preserve insertion order even if ES version is older.
   *
   * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map#Description
   * It should be noted that a Map which is a map of an object, especially
   * a dictionary of dictionaries, will only map to the object's insertion
   * order. In ES2015 this is ordered for objects but for older versions of
   * ES, this may be random and not ordered.
   *
   */
  var Map = require('es6-map')
  
  /**
   * In-memory implementation of the message store
   * This can actually be saved into files.
   *
   * @param {Object} [options] - store options
   */
  function Store (options) {
    if (!(this instanceof Store)) {
      return new Store(options)
    }
  
    this.options = options || {}
  
    // Defaults
    this.options = xtend(defaultStoreOptions, options)
  
    this._inflights = new Map()
  }
  
  /**
   * Adds a packet to the store, a packet is
   * anything that has a messageId property.
   *
   */
  Store.prototype.put = function (packet, cb) {
    this._inflights.set(packet.messageId, packet)
  
    if (cb) {
      cb()
    }
  
    return this
  }
  
  /**
   * Creates a stream with all the packets in the store
   *
   */
  Store.prototype.createStream = function () {
    var stream = new Readable(streamsOpts)
    var destroyed = false
    var values = []
    var i = 0
  
    this._inflights.forEach(function (value, key) {
      values.push(value)
    })
  
    stream._read = function () {
      if (!destroyed && i < values.length) {
        this.push(values[i++])
      } else {
        this.push(null)
      }
    }
  
    stream.destroy = function () {
      if (destroyed) {
        return
      }
  
      var self = this
  
      destroyed = true
  
      setTimeout(function () {
        self.emit('close')
      }, 0)
    }
  
    return stream
  }
  
  /**
   * deletes a packet from the store.
   */
  Store.prototype.del = function (packet, cb, buf) {
    packet = this._inflights.get(packet.messageId)
    // const bufs = buf.toString().indexOf('{') !== -1 ? JSON.parse('{' + buf.toString().substring(buf.toString().indexOf('{') + 1, buf.toString().length)) : buf
    if (packet) {
      this._inflights.delete(packet.messageId)
      // cb(null, packet, bufs)
      cb(null, packet, buf)
    } else if (cb) {
      cb(new Error('missing packet'))
    }
  
    return this
  }
  
  /**
   * get a packet from the store.
   */
  Store.prototype.get = function (packet, cb) {
    packet = this._inflights.get(packet.messageId)
    if (packet) {
      cb(null, packet)
    } else if (cb) {
      cb(new Error('missing packet'))
    }
  
    return this
  }
  
  /**
   * Close the store
   */
  Store.prototype.close = function (cb) {
    if (this.options.clean) {
      this._inflights = null
    }
    if (cb) {
      cb()
    }
  }
  
  module.exports = Store
  