From 0f67297e2cc966f3f10436bec41486524a425c45 Mon Sep 17 00:00:00 2001
From: Thomas Hille <thomahi@gmx.de>
Date: Thu, 23 Feb 2017 13:38:42 +0100
Subject: [PATCH] recommendation also now returns easiest exercise as
 recommendation if no tag matched could be found findMatchingExercises only
 searched for assessed submissions to get processed exercises, fixed this to
 look at all submissions

---
 app/models/proxy_exercise.rb | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/app/models/proxy_exercise.rb b/app/models/proxy_exercise.rb
index 970286e7..31a0a8eb 100644
--- a/app/models/proxy_exercise.rb
+++ b/app/models/proxy_exercise.rb
@@ -41,7 +41,8 @@ class ProxyExercise < ActiveRecord::Base
 
     def findMatchingExercise(user)
       #exercises.shuffle.first
-      exercisesUserHasAccessed = user.submissions.where(cause: :assess).map{|s| s.exercise}.uniq
+      # hier vielleicht nur betrachten wenn der user die aufgabe assessed oder submitted hat
+      exercisesUserHasAccessed = user.submissions.map{|s| s.exercise}.uniq
       tagsUserHasSeen = exercisesUserHasAccessed.map{|ex| ex.tags}.uniq.flatten
       puts "exercisesUserHasAccessed #{exercisesUserHasAccessed}"
 
@@ -54,15 +55,19 @@ class ProxyExercise < ActiveRecord::Base
           potentialRecommendedExercises << ex
         end
       end
-      puts "potentialRecommendedExercises: #{potentialRecommendedExercises}"
-      recommendedExercise = selectBestMatchingExercise(user, exercisesUserHasAccessed, potentialRecommendedExercises)
-      recommendedExercise
+      if potentialRecommendedExercises.empty?
+        getEasiestExercise(exercises)
+      else
+        puts "potentialRecommendedExercises: #{potentialRecommendedExercises}"
+        recommendedExercise = selectBestMatchingExercise(user, exercisesUserHasAccessed, potentialRecommendedExercises)
+        recommendedExercise
+      end
     end
 
     def selectBestMatchingExercise(user, exercisesUserHasAccessed, potentialRecommendedExercises)
       topic_knowledge_user_and_max = getUserKnowledgeAndMaxKnowledge(user, exercisesUserHasAccessed)
       puts "topic_knowledge_user_and_max: #{topic_knowledge_user_and_max}"
-      puts "potentialRecommendedExercises: #{potentialRecommendedExercises.size}"
+      puts "potentialRecommendedExercises: #{potentialRecommendedExercises.size}: #{potentialRecommendedExercises.map{|p| p.title}}"
       topic_knowledge_user = topic_knowledge_user_and_max[:user_topic_knowledge]
       topic_knowledge_max = topic_knowledge_user_and_max[:max_topic_knowledge]
       relative_knowledge_improvement = {}
@@ -80,8 +85,8 @@ class ProxyExercise < ActiveRecord::Base
         end
       end
       puts "relative improvements #{relative_knowledge_improvement}"
-      exercise_with_greatest_improvements = relative_knowledge_improvement.max_by{|k,v| v}
-      exercise_with_greatest_improvements.first
+      exercise_with_greatest_improvements = relative_knowledge_improvement.max_by{|k,v| v}.first
+      exercise_with_greatest_improvements
     end
 
     # [score][quantile]
@@ -166,4 +171,8 @@ class ProxyExercise < ActiveRecord::Base
       {user_topic_knowledge: topic_knowledge_loss_user, max_topic_knowledge: topic_knowledge_max}
     end
 
+    def getEasiestExercise(exercises)
+      exercises.order(:expected_difficulty).first
+    end
+
 end
\ No newline at end of file