Merge remote-tracking branch 'origin/master' into error-info

# Conflicts:
#	app/controllers/concerns/submission_scoring.rb
#	app/views/application/_navigation.html.slim
#	config/locales/de.yml
#	config/locales/en.yml
#	db/schema.rb

app/models/comment.rb

@@ -1,7 +1,7 @@
 class Comment < ActiveRecord::Base
   # inherit the creation module: encapsulates that this is a polymorphic user, offers some aliases and makes sure that all necessary attributes are set.
   include Creation
-  attr_accessor :username, :date, :updated
+  attr_accessor :username, :date, :updated, :editable
 
   belongs_to :file, class_name: 'CodeOcean::File'
   belongs_to :user, polymorphic: true

app/models/exercise_collection.rb

@@ -2,4 +2,8 @@ class ExerciseCollection < ActiveRecord::Base
 
   has_and_belongs_to_many :exercises
 
-end
+  def to_s
+    "#{I18n.t('activerecord.models.exercise_collection.one')}: #{name} (#{id})"
+  end
+
+end

app/models/external_user.rb

@@ -5,11 +5,9 @@ class ExternalUser < ActiveRecord::Base
   validates :external_id, presence: true
 
   def displayname
-    result =  "User " + id.to_s
-    if(!consumer.nil? && consumer.name == 'openHPI')
-      result = Rails.cache.fetch("#{cache_key}/displayname", expires_in: 12.hours) do
-         Xikolo::UserClient.get(external_id.to_s)[:display_name]
-      end
+    result = name
+    if(result == nil || result == "")
+      result = "User " + id.to_s
     end
     result
   end

app/models/proxy_exercise.rb

@@ -37,35 +37,17 @@ class ProxyExercise < ActiveRecord::Base
           assigned_user_proxy_exercise.exercise
         else
           matching_exercise =
-            if (token.eql? "47f4c736")
-              Rails.logger.debug("Proxy exercise with token 47f4c736, split user in groups..")
-              group = UserGroupSeparator.getGroupWeek2Testing(user)
-              Rails.logger.debug("user assigned to group #{group}")
-              case group
-                when :group_a
-                  exercises.where(id: 348).first
-                when :group_b
-                  exercises.where(id: 349).first
-                when :group_c
-                  exercises.where(id: 350).first
-                when :group_d
-                  exercises.where(id: 351).first
-              end
-            else
               Rails.logger.debug("find new matching exercise for user #{user.id}" )
               begin
                 find_matching_exercise(user)
-              rescue #fallback
+              rescue => e #fallback
                 Rails.logger.error("finding matching exercise failed. Fall back to random exercise! Error: #{$!}" )
                 @reason[:reason] = "fallback because of error"
-                @reason[:error] = "#{$!}"
-                exercises.shuffle.first
+                @reason[:error] = "#{$!}:\n\t#{e.backtrace.join("\n\t")}"
+                exercises.where("expected_difficulty > 1").shuffle.first # difficulty should be > 1 to prevent dummy exercise from being chosen.
               end
-            end
           user.user_proxy_exercise_exercises << UserProxyExerciseExercise.create(user: user, exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
           matching_exercise
-
-
         end
       recommended_exercise
     end
@@ -136,6 +118,7 @@ class ProxyExercise < ActiveRecord::Base
           relative_knowledge_improvement[potex] += old_relative_loss_tag - new_relative_loss_tag
         end
       end
+
       highest_difficulty_user_has_accessed =  exercises_user_has_accessed.map{|e| e.expected_difficulty}.sort.last || 0
       best_matching_exercise = find_best_exercise(relative_knowledge_improvement, highest_difficulty_user_has_accessed)
       @reason[:reason] = "best matching exercise"

app/models/request_for_comment.rb

@@ -5,6 +5,7 @@ class RequestForComment < ActiveRecord::Base
   belongs_to :file, class_name: 'CodeOcean::File'
 
   has_many :comments, through: :submission
+  has_many :subscriptions
 
   scope :unsolved, -> { where(solved: [false, nil]) }
 
@@ -37,6 +38,14 @@ class RequestForComment < ActiveRecord::Base
     submission.files.map { |file| file.comments.size}.sum
   end
 
+  def commenters
+    commenters = []
+    comments.distinct.to_a.each {|comment|
+      commenters.append comment.user
+    }
+    commenters.uniq {|user| user.id}
+  end
+
   def to_s
     "RFC-" + self.id.to_s
   end

app/models/submission.rb

@@ -34,7 +34,7 @@ class Submission < ActiveRecord::Base
   end
 
   def normalized_score
-    ::NewRelic::Agent.add_custom_parameters({ unnormalized_score: score })
+    ::NewRelic::Agent.add_custom_attributes({ unnormalized_score: score })
     if !score.nil? && !exercise.maximum_score.nil? && (exercise.maximum_score > 0)
       score / exercise.maximum_score
     else

app/models/subscription.rb

@@ -0,0 +1,4 @@
+class Subscription < ActiveRecord::Base
+  belongs_to :user, polymorphic: true
+  belongs_to :request_for_comment
+end