feat(User): add Datastore support

docs/scripting.md

@@ -623,6 +623,21 @@ robot.respond /sleep it off/i, (res) ->
    res.reply 'zzzzz'
```

The datastore also allows setting and getting values which are scoped to individual users:

```coffeescript
module.exports = (robot) ->

  robot.respond /who is @?([\w .\-]+)\?*$/i, (res) ->
    name = res.match[1].trim()

    users = robot.brain.usersForFuzzyName(name)
    if users.length is 1
      user = users[0]
      user.get('roles').then (roles) ->
        res.send "#{name} is #{roles.join(', ')}"
```

## Script Loading

There are three main sources to load scripts from:

src/brain.js

@@ -10,7 +10,7 @@ const User = require('./user')
// 2. If the original object was a User object, the original object
// 3. If the original object was a plain JavaScript object, return
//    a User object with all of the original object's properties.
let reconstructUserIfNecessary = function (user) {
let reconstructUserIfNecessary = function (user, robot) {
  if (!user) {
    return null
  }
@@ -20,6 +20,9 @@ let reconstructUserIfNecessary = function (user) {
    delete user.id
    // Use the old user as the "options" object,
    // populating the new user with its values.
    // Also add the `robot` field so it gets a reference.
    user.robot = robot

    return new User(id, user)
  } else {
    return user
@@ -36,6 +39,7 @@ class Brain extends EventEmitter {
      users: {},
      _private: {}
    }
    this.robot = robot

    this.autoSave = true

@@ -142,7 +146,7 @@ class Brain extends EventEmitter {
    if (data && data.users) {
      for (let k in data.users) {
        let user = this.data.users[k]
        this.data.users[k] = reconstructUserIfNecessary(user)
        this.data.users[k] = reconstructUserIfNecessary(user, this.robot)
      }
    }

@@ -161,6 +165,10 @@ class Brain extends EventEmitter {
  // Returns a User instance of the specified user.
  userForId (id, options) {
    let user = this.data.users[id]
    if (!options) {
      options = {}
    }
    options.robot = this.robot

    if (!user) {
      user = new User(id, options)

src/user.js

@@ -1,5 +1,7 @@
'use strict'

const DataStoreUnavailable = require('./datastore').DataStoreUnavailable

class User {
  // Represents a participating user in the chat.
  //
@@ -12,6 +14,17 @@ class User {
      options = {}
    }

    // Define a getter method so we don't actually store the
    // robot itself on the user object, preventing it from
    // being serialized into the brain.
    if (options.robot) {
      let robot = options.robot
      delete options.robot
      this._getRobot = function () { return robot }
    } else {
      this._getRobot = function () { }
    }

    Object.keys(options).forEach((key) => {
      this[key] = options[key]
    })
@@ -20,6 +33,33 @@ class User {
      this.name = this.id.toString()
    }
  }

  set (key, value) {
    this._checkDatastoreAvailable()
    return this._getDatastore()._set(this._constructKey(key), value, 'users')
  }

  get (key) {
    this._checkDatastoreAvailable()
    return this._getDatastore()._get(this._constructKey(key), 'users')
  }

  _constructKey (key) {
    return `${this.id}+${key}`
  }

  _checkDatastoreAvailable () {
    if (!this._getDatastore()) {
      throw new DataStoreUnavailable('datastore is not initialized')
    }
  }

  _getDatastore () {
    let robot = this._getRobot()
    if (robot) {
      return robot.datastore
    }
  }
}

module.exports = User

test/datastore_test.js

@@ -113,4 +113,38 @@ describe('Datastore', function () {
      })
    })
  })

  describe('User scope', function () {
    it('has access to the robot object', function () {
      let user = this.robot.brain.userForId('1')
      expect(user._getRobot()).to.equal(this.robot)
    })

    it('can store user data which is separate from global data', function () {
      let user = this.robot.brain.userForId('1')
      return user.set('blah', 'blah').then(() => {
        return user.get('blah').then((userBlah) => {
          return this.robot.datastore.get('blah').then((datastoreBlah) => {
            expect(userBlah).to.not.equal(datastoreBlah)
            expect(userBlah).to.equal('blah')
            expect(datastoreBlah).to.be.an('undefined')
          })
        })
      })
    })

    it('stores user data separate per-user', function () {
      let userOne = this.robot.brain.userForId('1')
      let userTwo = this.robot.brain.userForId('2')
      return userOne.set('blah', 'blah').then(() => {
        return userOne.get('blah').then((valueOne) => {
          return userTwo.get('blah').then((valueTwo) => {
            expect(valueOne).to.not.equal(valueTwo)
            expect(valueOne).to.equal('blah')
            expect(valueTwo).to.be.an('undefined')
          })
        })
      })
    })
  })
})