Persist reasons for notifications to db

app/models/anomaly_notification.rb

@@ -0,0 +1,5 @@
+class AnomalyNotification < ActiveRecord::Base
+  belongs_to :user, polymorphic: true
+  belongs_to :exercise
+  belongs_to :exercise_collection
+end

app/models/exercise.rb

@@ -66,21 +66,24 @@ class Exercise < ActiveRecord::Base
   end
 
   def user_working_time_query
-    """
+    "
       SELECT user_id,
+             user_type,
              sum(working_time_new) AS working_time
       FROM
         (SELECT user_id,
+                user_type,
                 CASE WHEN working_time >= '0:05:00' THEN '0' ELSE working_time END AS working_time_new
          FROM
             (SELECT user_id,
+                    user_type,
                     id,
                     (created_at - lag(created_at) over (PARTITION BY user_id, exercise_id
                                                         ORDER BY created_at)) AS working_time
             FROM submissions
             WHERE exercise_id=#{id}) AS foo) AS bar
-      GROUP BY user_id
-    """
+      GROUP BY user_id, user_type
+    "
   end
 
   def get_quantiles(quantiles)
@@ -203,7 +206,7 @@ class Exercise < ActiveRecord::Base
   def retrieve_working_time_statistics
     @working_time_statistics = {}
     self.class.connection.execute(user_working_time_query).each do |tuple|
-      @working_time_statistics[tuple["user_id"].to_i] = tuple
+      @working_time_statistics[tuple['user_id'].to_i] = tuple
     end
   end
 
@@ -373,6 +376,7 @@ class Exercise < ActiveRecord::Base
     Submission.joins("JOIN (
           SELECT
               user_id,
+              user_type,
               first_value(id) OVER (PARTITION BY user_id ORDER BY created_at DESC) AS fv
           FROM submissions
           WHERE exercise_id = #{id}

db/migrate/20180226131340_create_anomaly_notifications.rb

@@ -0,0 +1,11 @@
+class CreateAnomalyNotifications < ActiveRecord::Migration
+  def change
+    create_table :anomaly_notifications do |t|
+      t.belongs_to :user, polymorphic: true, index: true
+      t.belongs_to :exercise, index: true
+      t.belongs_to :exercise_collection, index: true
+      t.string :reason
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -11,11 +11,25 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20171210172208) do
+ActiveRecord::Schema.define(version: 20180226131340) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
+  create_table "anomaly_notifications", force: :cascade do |t|
+    t.integer  "user_id"
+    t.string   "user_type"
+    t.integer  "exercise_id"
+    t.integer  "exercise_collection_id"
+    t.string   "reason"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
+  add_index "anomaly_notifications", ["exercise_collection_id"], name: "index_anomaly_notifications_on_exercise_collection_id", using: :btree
+  add_index "anomaly_notifications", ["exercise_id"], name: "index_anomaly_notifications_on_exercise_id", using: :btree
+  add_index "anomaly_notifications", ["user_type", "user_id"], name: "index_anomaly_notifications_on_user_type_and_user_id", using: :btree
+
   create_table "code_harbor_links", force: :cascade do |t|
     t.string   "oauth2token", limit: 255
     t.datetime "created_at"

lib/tasks/detect_exercise_anomalies.rake

@@ -95,6 +95,8 @@ namespace :detect_exercise_anomalies do
   end
 
   def notify_users(collection, anomalies)
+    by_id_and_type = proc { |u| {user_id: u[:user_id], user_type: u[:user_type]} }
+
     puts "\t\tSending E-Mails to best and worst performing users of each anomaly..."
     anomalies.each do |exercise_id, average_working_time|
       puts "\t\tAnomaly in exercise #{exercise_id} (avg: #{average_working_time} seconds):"
@@ -107,33 +109,37 @@ namespace :detect_exercise_anomalies do
         users = users.merge(send(method, exercise, NUMBER_OF_USERS_PER_CLASS)) {|key, this, other| this + other}
       end
 
+      # write reasons for feedback emails to db
       users.keys.each do |key|
-        segment = users[key].uniq
-        puts "\t\t\t#{key.to_s} performers: #{segment}"
+        segment = users[key].uniq &by_id_and_type
         users_to_notify += segment
+        segment.each do |user|
+          reason = "{\"segment\": \"#{key.to_s}\", \"feature\": \"#{user[:reason]}\", value: \"#{user[:value]}\"}"
+          AnomalyNotification.create(user_id: user[:user_id], user_type: user[:user_type],
+                                     exercise: exercise, exercise_collection: collection, reason: reason)
+        end
       end
 
-      users_to_notify.uniq!
+      users_to_notify.uniq! &by_id_and_type
+      puts "\t\tAsked #{users_to_notify.size} users for feedback."
       # todo: send emails
     end
   end
 
   def performers_by_score(exercise, n)
-    submissions = exercise.last_submission_per_user.where('score is not null').order(:score)
-    best_performers = submissions.first(n).to_a.map {|item| item.user_id}
-    worst_performers = submissions.last(n).to_a.map {|item| item.user_id}
-
+    submissions = exercise.last_submission_per_user.where('score is not null').order(score: :desc)
+    map_block = proc {|item| {user_id: item.user_id, user_type: item.user_type, value: item.score, reason: 'score'}}
+    best_performers = submissions.first(n).to_a.map &map_block
+    worst_performers = submissions.last(n).to_a.map &map_block
     return {:best => best_performers, :worst => worst_performers}
   end
 
   def performers_by_time(exercise, n)
     working_times = get_user_working_times(exercise).values.map do |item|
-      {user_id: item['user_id'], time: time_to_f(item['working_time'])}
+      {user_id: item['user_id'], user_type: item['user_type'], value: time_to_f(item['working_time']), reason: 'time'}
     end
-    working_times.reject! {|item| item[:time].nil? or item[:time] <= MIN_USER_WORKING_TIME}
-    working_times.sort_by! {|item| item[:time]}
-
-    working_times.map! {|item| item[:user_id].to_i}
+    working_times.reject! {|item| item[:value].nil? or item[:value] <= MIN_USER_WORKING_TIME}
+    working_times.sort_by! {|item| item[:value]}
     return {:best => working_times.first(n), :worst => working_times.last(n)}
   end