text: import EventEmitter from 'events'
  import ObservableStore from 'obs-store'
  import ethUtil from 'ethereumjs-util'
  import { ethErrors } from 'eth-json-rpc-errors'
  import createId from './random-id'
  
  /**
   * Represents, and contains data about, an 'eth_sign' type signature request. These are created when a signature for
   * an eth_sign call is requested.
   *
   * @see {@link https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign}
   *
   * @typedef {Object} Message
   * @property {number} id An id to track and identify the message object
   * @property {Object} msgParams The parameters to pass to the eth_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' with
   * always have a 'eth_sign' type.
   *
   */
  
  export default class MessageManager extends EventEmitter {
    /**
     * Controller in charge of managing - storing, adding, removing, updating - Messages.
     *
     * @typedef {Object} MessageManager
     * @param {Object} opts @deprecated
     * @property {Object} memStore The observable store where Messages are saved.
     * @property {Object} memStore.unapprovedMsgs A collection of all Messages in the 'unapproved' state
     * @property {number} memStore.unapprovedMsgCount The count of all Messages in this.memStore.unapprobedMsgs
     * @property {array} messages Holds all messages that have been created by this MessageManager
     *
     */
    constructor () {
      super()
      this.memStore = new ObservableStore({
        unapprovedMsgs: {},
        unapprovedMsgCount: 0,
      })
      this.messages = []
    }
  
    /**
     * A getter for the number of 'unapproved' Messages in this.messages
     *
     * @returns {number} - The number of 'unapproved' Messages in this.messages
     *
     */
    get unapprovedMsgCount () {
      return Object.keys(this.getUnapprovedMsgs()).length
    }
  
    /**
     * A getter for the 'unapproved' Messages in this.messages
     *
     * @returns {Object} - An index of Message ids to Messages, for all 'unapproved' Messages in this.messages
     *
     */
    getUnapprovedMsgs () {
      return this.messages
        .filter(msg => msg.status === 'unapproved')
        .reduce((result, msg) => {
          result[msg.id] = msg
          return result
        }, {})
    }
  
    /**
     * Creates a new Message with an 'unapproved' status using the passed msgParams. this.addMsg is called to add the
     * new Message to this.messages, and to save the unapproved Messages 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} - after signature has been
     *
     */
    addUnapprovedMessageAsync (msgParams, req) {
      return new Promise((resolve, reject) => {
        const msgId = this.addUnapprovedMessage(msgParams, req)
        // await finished
        this.once(`${msgId}:finished`, data => {
          switch (data.status) {
            case 'signed':
              return resolve(data.rawSig)
            case 'rejected':
              return reject(
                ethErrors.provider.userRejectedRequest(
                  'MetaMask Message Signature: User denied message signature.'
                )
              )
            default:
              return reject(
                new Error(
                  `MetaMask Message Signature: Unknown problem: ${JSON.stringify(
                    msgParams
                  )}`
                )
              )
          }
        })
      })
    }
  
    /**
     * Creates a new Message with an 'unapproved' status using the passed msgParams. this.addMsg is called to add the
     * new Message to this.messages, and to save the unapproved Messages 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 where the origin may be specificied
     * @returns {number} - The id of the newly created message.
     *
     */
    addUnapprovedMessage (msgParams, req) {
      // add origin from request
      if (req) {
        msgParams.origin = req.origin
      }
      msgParams.data = normalizeMsgData(msgParams.data)
      // create txData obj with parameters and meta data
      const time = new Date().getTime()
      const msgId = createId()
      const msgData = {
        id: msgId,
        msgParams: msgParams,
        time: time,
        status: 'unapproved',
        type: 'eth_sign',
      }
      this.addMsg(msgData)
  
      // signal update
      this.emit('update')
      return msgId
    }
  
    /**
     * Adds a passed Message to this.messages, and calls this._saveMsgList() to save the unapproved Messages from that
     * list to this.memStore.
     *
     * @param {Message} msg - The Message to add to this.messages
     *
     */
    addMsg (msg) {
      this.messages.push(msg)
      this._saveMsgList()
    }
  
    /**
     * Returns a specified Message.
     *
     * @param {number} msgId - The id of the Message to get
     * @returns {Message|undefined} - The Message with the id that matches the passed msgId, or undefined if no Message has that id.
     *
     */
    getMsg (msgId) {
      return this.messages.find(msg => msg.id === msgId)
    }
  
    /**
     * Approves a Message. 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 Message status to 'approved' via a call to this._setMsgStatus.
     *
     * @param {number} msgId - The id of the Message to approve.
     *
     */
    setMsgStatusApproved (msgId) {
      this._setMsgStatus(msgId, 'approved')
    }
  
    /**
     * Sets a Message status to 'signed' via a call to this._setMsgStatus and updates that Message in this.messages by
     * adding the raw signature data of the signature request to the Message
     *
     * @param {number} msgId - The id of the Message 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 Message status to 'rejected' via a call to this._setMsgStatus.
     *
     * @param {number} msgId - The id of the Message to reject.
     *
     */
    rejectMsg (msgId) {
      this._setMsgStatus(msgId, 'rejected')
    }
  
    /**
     * Updates the status of a Message in this.messages via a call to this._updateMsg
     *
     * @private
     * @param {number} msgId - The id of the Message to update.
     * @param {string} status - The new status of the Message.
     * @throws A 'MessageManager - Message not found for id: "${msgId}".' if there is no Message in this.messages with an
     * id equal to the passed msgId
     * @fires An event with a name equal to `${msgId}:${status}`. The Message is also fired.
     * @fires If status is 'rejected' or 'signed', an event with a name equal to `${msgId}:finished` is fired along with the message
     *
     */
    _setMsgStatus (msgId, status) {
      const msg = this.getMsg(msgId)
      if (!msg) {
        throw new Error('MessageManager - 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 Message in this.messages to the passed Message if the ids are equal. Then saves the unapprovedMsg list to
     * storage via this._saveMsgList
     *
     * @private
     * @param {msg} Message - A Message that will replace an existing Message (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 messages, and their count, to this.memStore
     *
     * @private
     * @fires 'updateBadge'
     *
     */
    _saveMsgList () {
      const unapprovedMsgs = this.getUnapprovedMsgs()
      const unapprovedMsgCount = Object.keys(unapprovedMsgs).length
      this.memStore.updateState({ unapprovedMsgs, unapprovedMsgCount })
      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
   *
   */
  function normalizeMsgData (data) {
    if (data.slice(0, 2) === '0x') {
      // data is already hex
      return data
    } else {
      // data is unicode, convert to hex
      return ethUtil.bufferToHex(Buffer.from(data, 'utf8'))
    }
  }
  