Extract review stats query as a service.

app/controllers/quiz_templates_controller.rb

@@ -72,7 +72,7 @@ class QuizTemplatesController < ApplicationController
 
     unless @quiz_template.editable?
       @editable = false
-      term = @quiz_template.was_visible_to_students ? "was previosly" : "is"
+      term = @quiz_template.was_visible_to_students ? "was previously" : "is"
       @form_modal_body = "Quiz cannot be edited; it #{term} visible to students"
     else
       @editable = true
@@ -118,40 +118,9 @@ class QuizTemplatesController < ApplicationController
   def review_stats
     get_quiz_level_params
 
-    @form_modal_title = "Review Statistics Q#{@quiz_id}"
+    @review_stats_data = ReviewStatsService.new(@quiz_template, @course, current_user).generate_stats
 
-    @review_stats_query = QuizInstance.where({ :course_id => @course_id, :quiz_number => @quiz_id }).map_reduce(map_stats_js, reduce_stats_js).out(inline: true).entries
-
-    ap @review_stats_query
-
-    @review_stats_data = ["FreeTextQuestion", "FillInTheBlankQuestion", "DrawQuestion"].map do |type|
-      stats = @review_stats_query.select{|s| s["_id"]["type"] == type && !s["_id"]["scored"] }
-      groups = stats.map{|s| s["_id"]["group_name"] }.uniq
-      questions = stats.map{|s| s["_id"]["question_number"] }.uniq.sort
-
-      question_number_to_column = {}
-      questions.each_with_index{ |e, i| question_number_to_column[e] = i }
-
-      rows = groups.map do |group|
-          question_columns = Array.new(questions.length, 0)
-          stats.select{|s| s["_id"]["group_name"] == group }.map do |s|
-            question_columns[question_number_to_column[s["_id"]["question_number"]]] += s["value"].to_i
-          end
-          [group].concat question_columns
-        end
-
-      { :type => type.gsub("Question", ""),
-        :questions => questions,
-        :rows => rows
-      }
-    end
-
-    ap @review_stats_data
-
-    respond_to do |format|
-      format.html
-      format.js
-    end
+    respond_with_dialog "Review Statistics Q#{@quiz_id}"
   end
 
   def review_questions
@@ -309,34 +278,6 @@ class QuizTemplatesController < ApplicationController
     end
   end
 
-  def map_stats_js
-   %Q{
-    function map_stats() {
-      for (var q_no in this.sections) {
-        var q = this.sections[q_no]
-        print(q)
-        if (q._type && (q._type == 'FreeTextQuestion' || q._type == 'FillInTheBlankQuestion' || q._type == 'DrawQuestion')) {
-          emit({
-              type: q._type,
-              question_number: q_no,
-              group_name: this.group_name,
-              scored: q.answers[0].answer_kind !== undefined,
-            },
-            1);
-        }
-      }
-    }
-  }
-  end
-
-  def reduce_stats_js
-  %Q{
-    function reduce_stats(id, docs) {
-      return Array.sum(docs);
-    }
-  }
-  end
-
   def exec_quiz_service(&block)
     return unless get_quiz_level_params
 

app/services/review_stats_service.rb

+class ReviewStatsService
+  attr_accessor(
+                :course,
+                :quiz_template,
+                :user)
+
+  def initialize(quiz_template, course, user)
+    @quiz_template = quiz_template
+    @course = course
+    @user = user
+  end
+
+  def generate_stats    
+    @review_stats_query = QuizInstance.where({ :course_id => @course._id, :quiz_number => @quiz_template.quiz_number }).map_reduce(map_stats_js, reduce_stats_js).out(inline: true).entries
+
+    Rails.logger.info "Review stats query: #{ap @review_stats_query}"
+
+    review_stats_data = ["FreeTextQuestion", "FillInTheBlankQuestion", "DrawQuestion"].map do |type|
+      stats = @review_stats_query.select{|s| s["_id"]["type"] == type && !s["_id"]["scored"] }
+      groups = stats.map{|s| s["_id"]["group_name"] }.uniq
+      questions = stats.map{|s| s["_id"]["question_number"] }.uniq.sort
+
+      question_number_to_column = {}
+      questions.each_with_index{ |e, i| question_number_to_column[e] = i }
+
+      rows = groups.map do |group|
+          question_columns = Array.new(questions.length, 0)
+          stats.select{|s| s["_id"]["group_name"] == group }.map do |s|
+            question_columns[question_number_to_column[s["_id"]["question_number"]]] += s["value"].to_i
+          end
+          [group].concat question_columns
+        end
+
+      next if rows.count == 0
+
+      { :type => type.gsub("Question", ""),
+        :questions => questions,
+        :rows => rows
+      }
+    end.reject(&:nil?)
+
+    Rails.logger.info "Review stats data: #{ap review_stats_data}"
+
+    review_stats_data
+  end
+
+  private
+
+  def map_stats_js
+   %Q{
+    function map_stats() {
+      for (var q_no in this.sections) {
+        var q = this.sections[q_no]
+        print(q)
+        if (q._type && (q._type == 'FreeTextQuestion' || q._type == 'FillInTheBlankQuestion' || q._type == 'DrawQuestion')) {
+          emit({
+              type: q._type,
+              question_number: q_no,
+              group_name: this.group_name,
+              scored: q.answers[0].answer_kind !== undefined,
+            },
+            1);
+        }
+      }
+    }
+  }
+  end
+
+  def reduce_stats_js
+  %Q{
+    function reduce_stats(id, docs) {
+      return Array.sum(docs);
+    }
+  }
+  end
+end
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