Add checks to keep User purchased.gems from becoming NaN

Also sought to more thoroughly protect earned.gems.

server/handlers/payment_handler.coffee

@@ -377,6 +377,9 @@ PaymentHandler = class PaymentHandler extends Handler
   #- Incrementing/recalculating gems
 
   incrementGemsFor: (user, gems, done) ->
+    if not gems
+      return done()
+      
     purchased = _.clone(user.get('purchased'))
     if not purchased?.gems
       purchased ?= {}

server/handlers/subscription_handler.coffee

@@ -176,7 +176,7 @@ class SubscriptionHandler extends Handler
                 purchased = _.clone(req.user.get('purchased'))
                 purchased ?= {}
                 purchased.gems ?= 0
-                purchased.gems += parseInt(charge.metadata.gems)
+                purchased.gems += parseInt(charge.metadata.gems) if charge.metadata.gems
                 req.user.set('purchased', purchased)
 
                 req.user.save (err, user) =>
@@ -257,7 +257,7 @@ class SubscriptionHandler extends Handler
             purchased = _.clone(req.user.get('purchased'))
             purchased ?= {}
             purchased.gems ?= 0
-            purchased.gems += product.get('gems') * months
+            purchased.gems += product.get('gems') * months if product.get('gems')
             req.user.set('purchased', purchased)
 
             req.user.save (err, user) =>
@@ -440,7 +440,7 @@ class SubscriptionHandler extends Handler
         purchased = _.clone(user.get('purchased'))
         purchased ?= {}
         purchased.gems ?= 0
-        purchased.gems += product.get('gems')
+        purchased.gems += product.get('gems') if product.get('gems')
         user.set('purchased', purchased)
 
       user.save (err) =>
@@ -550,7 +550,7 @@ class SubscriptionHandler extends Handler
               purchased = _.clone(recipient.get('purchased'))
               purchased ?= {}
               purchased.gems ?= 0
-              purchased.gems += product.get('gems')
+              purchased.gems += product.get('gems') if product.get('gems')
               recipient.set('purchased', purchased)
             recipient.save (err) =>
               if err

server/models/EarnedAchievement.coffee

@@ -59,7 +59,7 @@ EarnedAchievementSchema.statics.createForAchievement = (achievement, doc, origin
         earned.achievedAmount = newAmount
         #console.log 'earnedPoints is', (expFunction(newAmount) - expFunction(originalAmount)) * pointWorth, 'was', earned.earnedPoints, earned.previouslyAchievedAmount, 'got exp function for new amount', newAmount, expFunction(newAmount), 'for original amount', originalAmount, expFunction(originalAmount), 'with point worth', pointWorth
         earnedPoints = earned.earnedPoints = (expFunction(newAmount) - expFunction(originalAmount)) * pointWorth
-        earnedGems = earned.earnedGems = (expFunction(newAmount) - expFunction(originalAmount)) * gemWorth
+        earnedGems = earned.earnedGems = (expFunction(newAmount) - expFunction(originalAmount)) * gemWorth ? 0
         earned.previouslyAchievedAmount = originalAmount
         EarnedAchievement.update {achievement: earned.achievement, user: earned.user}, earned, {upsert: true}, (err) ->
           return log.error err if err?

server/models/User.coffee

@@ -9,6 +9,7 @@ AnalyticsUsersActive = require './AnalyticsUsersActive'
 Classroom = require '../models/Classroom'
 languages = require '../routes/languages'
 _ = require 'lodash'
+errors = require '../commons/errors'
 
 config = require '../../server_config'
 stripe = require('stripe')(config.stripe.secretKey)
@@ -347,6 +348,8 @@ UserSchema.methods.saveActiveUser = (event, done=null) ->
     done?()
 
 UserSchema.pre('save', (next) ->
+  if _.isNaN(@get('purchased')?.gems)
+    return next(new errors.InternalServerError('Attempting to save NaN to user')) 
   Classroom = require './Classroom'
   if @isTeacher() and not @wasTeacher
     Classroom.update({members: @_id}, {$pull: {members: @_id}}, {multi: true}).exec (err, res) ->

server/models/UserPollsRecord.coffee

@@ -47,6 +47,7 @@ updateUserProperty = (userID, userProperty, answer) ->
     return log.error err if err
 
 updateUserGems = (userID, gemDelta) ->
+  return unless gemDelta
   update = $inc: {'earned.gems': gemDelta}
   User.update {_id: mongoose.Types.ObjectId(userID)}, update, (err, result) ->
     return log.error err if err

server/routes/stripe.coffee

@@ -101,7 +101,7 @@ module.exports.setup = (app) ->
               # Update purchased gems
               # TODO: is this correct for a resub?
               Payment.find({recipient: recipient._id, gems: {$exists: true}}).select('gems').exec (err, payments) ->
-                gems = _.reduce payments, ((sum, p) -> sum + p.get('gems')), 0
+                gems = _.reduce payments, ((sum, p) -> sum + (p.get('gems') or 0)), 0
                 purchased = _.clone(recipient.get('purchased'))
                 purchased ?= {}
                 purchased.gems = gems