text: const EventEmitter = require('events')
  const ObservableStore = require('obs-store')
  const ethUtil = require('ethereumjs-util')
  const { errors: rpcErrors } = require('eth-json-rpc-errors')
  const createId = require('./random-id')
  const hexRe = /^[0-9A-Fa-f]+$/g
  const log = require('loglevel')
  
  /**
   * Represents, and contains data about, an 'personal_sign' type signature request. These are created when a
   * signature for an personal_sign call is requested.
   *
   * @see {@link https://web3js.readthedocs.io/en/1.0/web3-eth-personal.html#sign}
   *
   * @typedef {Object} PersonalMessage
   * @property {number} id An id to track and identify the message object
   * @property {Object} msgParams The parameters to pass to the personal_sign method once the signature request is
   * approved.
   * @property {Object} msgParams.metamaskId Added to msgParams for tracking and identification within MetaMask.
   * @property {string} msgParams.data A hex string conversion of the raw buffer data of the signature request
   * @property {number} time The epoch time at which the this message was created
   * @property {string} status Indicates whether the signature request is 'unapproved', 'approved', 'signed' or 'rejected'
   * @property {string} type The json-prc signing method for which a signature request has been made. A 'Message' will
   * always have a 'personal_sign' type.
   *
   */
  
  module.exports = class PersonalMessageManager extends EventEmitter {
    /**
     * Controller in charge of managing - storing, adding, removing, updating - PersonalMessage.
     *
     * @typedef {Object} PersonalMessageManager
     * @param {Object} opts @deprecated
     * @property {Object} memStore The observable store where PersonalMessage are saved with persistance.
     * @property {Object} memStore.unapprovedPersonalMsgs A collection of all PersonalMessages in the 'unapproved' state
     * @property {number} memStore.unapprovedPersonalMsgCount The count of all PersonalMessages in this.memStore.unapprobedMsgs
     * @property {array} messages Holds all messages that have been created by this PersonalMessageManager
     *
     */
    constructor () {
      super()
      this.memStore = new ObservableStore({
        unapprovedPersonalMsgs: {},
        unapprovedPersonalMsgCount: 0,
      })
      this.messages = []
    }
  
    /**
     * A getter for the number of 'unapproved' PersonalMessages in this.messages
     *
     * @returns {number} The number of 'unapproved' PersonalMessages in this.messages
     *
     */
    get unapprovedPersonalMsgCount () {
      return Object.keys(this.getUnapprovedMsgs()).length
    }
  
    /**
     * A getter for the 'unapproved' PersonalMessages in this.messages
     *
     * @returns {Object} An index of PersonalMessage ids to PersonalMessages, for all 'unapproved' PersonalMessages in
     * this.messages
     *
     */
    getUnapprovedMsgs () {
      return this.messages.filter(msg => msg.status === 'unapproved')
        .reduce((result, msg) => { result[msg.id] = msg; return result }, {})
    }
  
    /**
     * Creates a new PersonalMessage with an 'unapproved' status using the passed msgParams. this.addMsg is called to add
     * the new PersonalMessage to this.messages, and to save the unapproved PersonalMessages from that list to
     * this.memStore.
     *
     * @param {Object} msgParams The params for the eth_sign call to be made after the message is approved.
     * @param {Object} req (optional) The original request object possibly containing the origin
     * @returns {promise} When the message has been signed or rejected
     *
     */
    addUnapprovedMessageAsync (msgParams, req) {
      return new Promise((resolve, reject) => {
        if (!msgParams.from) {
          reject(new Error('MetaMask Message Signature: from field is required.'))
        }
        const msgId = this.addUnapprovedMessage(msgParams, req)
        this.once(`${msgId}:finished`, (data) => {
          switch (data.status) {
            case 'signed':
              return resolve(data.rawSig)
            case 'rejected':
              return reject(rpcErrors.eth.userRejectedRequest('MetaMask Message Signature: User denied message signature.'))
            default:
              return reject(new Error(`MetaMask Message Signature: Unknown problem: ${JSON.stringify(msgParams)}`))
          }
        })
      })
    }
  
    /**
     * Creates a new PersonalMessage with an 'unapproved' status using the passed msgParams. this.addMsg is called to add
     * the new PersonalMessage to this.messages, and to save the unapproved PersonalMessages from that list to
     * this.memStore.
     *
     * @param {Object} msgParams The params for the eth_sign call to be made after the message is approved.
     * @param {Object} req (optional) The original request object possibly containing the origin
     * @returns {number} The id of the newly created PersonalMessage.
     *
     */
    addUnapprovedMessage (msgParams, req) {
      log.debug(`PersonalMessageManager addUnapprovedMessage: ${JSON.stringify(msgParams)}`)
      // add origin from request
      if (req) msgParams.origin = req.origin
      msgParams.data = this.normalizeMsgData(msgParams.data)
      // create txData obj with parameters and meta data
      var time = (new Date()).getTime()
      var msgId = createId()
      var msgData = {
        id: msgId,
        msgParams: msgParams,
        time: time,
        status: 'unapproved',
        type: 'personal_sign',
      }
      this.addMsg(msgData)
  
      // signal update
      this.emit('update')
      return msgId
    }
  
    /**
     * Adds a passed PersonalMessage to this.messages, and calls this._saveMsgList() to save the unapproved PersonalMessages from that
     * list to this.memStore.
     *
     * @param {Message} msg The PersonalMessage to add to this.messages
     *
     */
    addMsg (msg) {
      this.messages.push(msg)
      this._saveMsgList()
    }
  
    /**
     * Returns a specified PersonalMessage.
     *
     * @param {number} msgId The id of the PersonalMessage to get
     * @returns {PersonalMessage|undefined} The PersonalMessage with the id that matches the passed msgId, or undefined
     * if no PersonalMessage has that id.
     *
     */
    getMsg (msgId) {
      return this.messages.find(msg => msg.id === msgId)
    }
  
    /**
     * Approves a PersonalMessage. Sets the message status via a call to this.setMsgStatusApproved, and returns a promise
     * with any the message params modified for proper signing.
     *
     * @param {Object} msgParams The msgParams to be used when eth_sign is called, plus data added by MetaMask.
     * @param {Object} msgParams.metamaskId Added to msgParams for tracking and identification within MetaMask.
     * @returns {Promise<object>} Promises the msgParams object with metamaskId removed.
     *
     */
    approveMessage (msgParams) {
      this.setMsgStatusApproved(msgParams.metamaskId)
      return this.prepMsgForSigning(msgParams)
    }
  
    /**
     * Sets a PersonalMessage status to 'approved' via a call to this._setMsgStatus.
     *
     * @param {number} msgId The id of the PersonalMessage to approve.
     *
     */
    setMsgStatusApproved (msgId) {
      this._setMsgStatus(msgId, 'approved')
    }
  
    /**
     * Sets a PersonalMessage status to 'signed' via a call to this._setMsgStatus and updates that PersonalMessage in
     * this.messages by adding the raw signature data of the signature request to the PersonalMessage
     *
     * @param {number} msgId The id of the PersonalMessage to sign.
     * @param {buffer} rawSig The raw data of the signature request
     *
     */
    setMsgStatusSigned (msgId, rawSig) {
      const msg = this.getMsg(msgId)
      msg.rawSig = rawSig
      this._updateMsg(msg)
      this._setMsgStatus(msgId, 'signed')
    }
  
    /**
     * Removes the metamaskId property from passed msgParams and returns a promise which resolves the updated msgParams
     *
     * @param {Object} msgParams The msgParams to modify
     * @returns {Promise<object>} Promises the msgParams with the metamaskId property removed
     *
     */
    prepMsgForSigning (msgParams) {
      delete msgParams.metamaskId
      return Promise.resolve(msgParams)
    }
  
    /**
     * Sets a PersonalMessage status to 'rejected' via a call to this._setMsgStatus.
     *
     * @param {number} msgId The id of the PersonalMessage to reject.
     *
     */
    rejectMsg (msgId) {
      this._setMsgStatus(msgId, 'rejected')
    }
  
    /**
     * Updates the status of a PersonalMessage in this.messages via a call to this._updateMsg
     *
     * @private
     * @param {number} msgId The id of the PersonalMessage to update.
     * @param {string} status The new status of the PersonalMessage.
     * @throws A 'PersonalMessageManager - PersonalMessage not found for id: "${msgId}".' if there is no PersonalMessage
     * in this.messages with an id equal to the passed msgId
     * @fires An event with a name equal to `${msgId}:${status}`. The PersonalMessage is also fired.
     * @fires If status is 'rejected' or 'signed', an event with a name equal to `${msgId}:finished` is fired along
     * with the PersonalMessage
     *
     */
    _setMsgStatus (msgId, status) {
      const msg = this.getMsg(msgId)
      if (!msg) throw new Error(`PersonalMessageManager - Message not found for id: "${msgId}".`)
      msg.status = status
      this._updateMsg(msg)
      this.emit(`${msgId}:${status}`, msg)
      if (status === 'rejected' || status === 'signed') {
        this.emit(`${msgId}:finished`, msg)
      }
    }
  
    /**
     * Sets a PersonalMessage in this.messages to the passed PersonalMessage if the ids are equal. Then saves the
     * unapprovedPersonalMsgs index to storage via this._saveMsgList
     *
     * @private
     * @param {msg} PersonalMessage A PersonalMessage that will replace an existing PersonalMessage (with the same
     * id) in this.messages
     *
     */
    _updateMsg (msg) {
      const index = this.messages.findIndex((message) => message.id === msg.id)
      if (index !== -1) {
        this.messages[index] = msg
      }
      this._saveMsgList()
    }
  
    /**
     * Saves the unapproved PersonalMessages, and their count, to this.memStore
     *
     * @private
     * @fires 'updateBadge'
     *
     */
    _saveMsgList () {
      const unapprovedPersonalMsgs = this.getUnapprovedMsgs()
      const unapprovedPersonalMsgCount = Object.keys(unapprovedPersonalMsgs).length
      this.memStore.updateState({ unapprovedPersonalMsgs, unapprovedPersonalMsgCount })
      this.emit('updateBadge')
    }
  
    /**
     * A helper function that converts raw buffer data to a hex, or just returns the data if it is already formatted as a hex.
     *
     * @param {any} data The buffer data to convert to a hex
     * @returns {string} A hex string conversion of the buffer data
     *
     */
    normalizeMsgData (data) {
      try {
        const stripped = ethUtil.stripHexPrefix(data)
        if (stripped.match(hexRe)) {
          return ethUtil.addHexPrefix(stripped)
        }
      } catch (e) {
        log.debug(`Message was not hex encoded, interpreting as utf8.`)
      }
  
      return ethUtil.bufferToHex(Buffer.from(data, 'utf8'))
    }
  
  }
  