codecombat/server/middleware/course-instances.coffee

errors = require '../commons/errors'
wrap = require 'co-express'
Promise = require 'bluebird'
database = require '../commons/database'
mongoose = require 'mongoose'
TrialRequest = require '../models/TrialRequest'
CourseInstance = require '../models/CourseInstance'
Classroom = require '../models/Classroom'
Course = require '../models/Course'
User = require '../models/User'
Level = require '../models/Level'
parse = require '../commons/parse'

module.exports =
  addMembers: wrap (req, res) ->
    if req.body.userID
      userIDs = [req.body.userID]
    else if req.body.userIDs
      userIDs = req.body.userIDs
    else
      throw new errors.UnprocessableEntity('Must provide userID or userIDs')
    
    for userID in userIDs
      unless _.all userIDs, database.isID
        throw new errors.UnprocessableEntity('Invalid list of user IDs')
      
    courseInstance = yield database.getDocFromHandle(req, CourseInstance)
    if not courseInstance
      throw new errors.NotFound('Course Instance not found.')
      
    classroom = yield Classroom.findById courseInstance.get('classroomID')
    if not classroom
      throw new errors.NotFound('Classroom not found.')
    
    classroomMembers = (userID.toString() for userID in classroom.get('members'))
    unless _.all(userIDs, (userID) -> _.contains classroomMembers, userID)
      throw new errors.Forbidden('Users must be members of classroom')
      
    ownsClassroom = classroom.get('ownerID').equals(req.user._id)
    addingSelf = userIDs.length is 1 and userIDs[0] is req.user.id
    unless ownsClassroom or addingSelf
      throw new errors.Forbidden('You must own the classroom to add members')
      
    # Only the enrolled users
    users = yield User.find({ _id: { $in: userIDs }}).select('coursePrepaidID')
    usersArePrepaid = _.all((user.get('coursePrepaidID') for user in users))
    
    course = yield Course.findById courseInstance.get('courseID')
    throw new errors.NotFound('Course referenced by course instance not found') unless course
    
    if not (course.get('free') or usersArePrepaid)
      throw new errors.PaymentRequired('Cannot add users to a course instance until they are added to a prepaid')
    
    userObjectIDs = (mongoose.Types.ObjectId(userID) for userID in userIDs)
    
    courseInstance = yield CourseInstance.findByIdAndUpdate(
      courseInstance._id,
      { $addToSet: { members: { $each: userObjectIDs } } }
      { new: true }
    )
    
    userUpdateResult = yield User.update(
      { _id: { $in: userObjectIDs } },
      { $addToSet: { courseInstances: courseInstance._id } }
    )
    
    res.status(200).send(courseInstance.toObject({ req }))


  fetchNextLevel: wrap (req, res) ->
    levelOriginal = req.params.levelOriginal
    if not database.isID(levelOriginal)
      throw new errors.UnprocessableEntity('Invalid level original ObjectId')
    
    courseInstance = yield database.getDocFromHandle(req, CourseInstance)
    if not courseInstance
      throw new errors.NotFound('Course Instance not found.')
    courseID = courseInstance.get('courseID')

    classroom = yield Classroom.findById courseInstance.get('classroomID')
    if not classroom
      throw new errors.NotFound('Classroom not found.')
      
    nextLevelOriginal = null
    foundLevelOriginal = false
    for course in classroom.get('courses') or []
      if not courseID.equals(course._id)
        continue
      for level, index in course.levels
        if level.original.toString() is levelOriginal
          foundLevelOriginal = true
          nextLevelOriginal = course.levels[index+1]?.original
          break
          
    if not foundLevelOriginal
      throw new errors.NotFound('Level original ObjectId not found in Classroom courses')
    
    if not nextLevelOriginal
      res.status(200).send({})
      
    dbq = Level.findOne({original: mongoose.Types.ObjectId(nextLevelOriginal)})
    dbq.sort({ 'version.major': -1, 'version.minor': -1 })
    dbq.select(parse.getProjectFromReq(req))
    level = yield dbq
    level = level.toObject({req: req})
    res.status(200).send(level)
    
    
  fetchClassroom: wrap (req, res) ->
    courseInstance = yield database.getDocFromHandle(req, CourseInstance)
    if not courseInstance
      throw new errors.NotFound('Course Instance not found.')

    classroom = yield Classroom.findById(courseInstance.get('classroomID')).select(parse.getProjectFromReq(req))
    if not classroom
      throw new errors.NotFound('Classroom not found.')

    isOwner = classroom.get('ownerID')?.equals req.user?._id
    isMember = _.any(classroom.get('members') or [], (memberID) -> memberID.equals(req.user.get('_id')))
    if not (isOwner or isMember)
      throw new errors.Forbidden('You do not have access to this classroom')

    classroom = classroom.toObject({req: req})

    res.status(200).send(classroom)