dirty commit: can't get references to work correctly between any tables

app/presenters/dashboard/response_rate_presenter.rb

@@ -0,0 +1,110 @@
+module Dashboard
+  class ResponseRatePresenter
+    attr_reader :focus, :academic_year, :school, :survey_items
+
+    def initialize(focus:, academic_year:, school:)
+      @focus = focus
+      @academic_year = academic_year
+      @school = school
+      if focus == :student
+        @survey_items = Measure.all.flat_map do |measure|
+          measure.student_survey_items_with_sufficient_responses(school:, academic_year:)
+        end
+      end
+      @survey_items = SurveyItem.teacher_survey_items if focus == :teacher
+    end
+
+    def date
+      SurveyItemResponse.where(survey_item: survey_items, school:,
+                               academic_year:).order(recorded_date: :DESC).first&.recorded_date
+    end
+
+    def percentage
+      return 0 if respondents_count.zero?
+
+      cap_at_100(actual_count.to_f / respondents_count.to_f * 100).round
+    end
+
+    def color
+      percentage > 75 ? "purple" : "gold"
+    end
+
+    def date_message
+      return "" if date.nil?
+
+      "Response rate as of #{date.to_date.strftime('%m/%d/%y')}"
+    end
+
+    def hover_message
+      return "" if date.nil?
+
+      "Percentages based on #{actual_count} out of #{respondents_count.round} #{focus}s completing at least 25% of the survey."
+    end
+
+    private
+
+    def cap_at_100(value)
+      value > 100 ? 100 : value
+    end
+
+    def actual_count
+      if focus == :teacher
+        response_count_for_survey_items(survey_items:)
+      else
+        non_early_ed_items = survey_items - SurveyItem.early_education_survey_items
+        non_early_ed_count = response_count_for_survey_items(survey_items: non_early_ed_items)
+
+        early_ed_items = survey_items & SurveyItem.early_education_survey_items
+        early_ed_count = SurveyItemResponse.where(school:, academic_year:,
+                                                  survey_item: early_ed_items)
+                                           .group(:survey_item)
+                                           .select(:response_id)
+                                           .distinct
+                                           .count
+                                           .reduce(0) do |largest, row|
+          count = row[1]
+          if count > largest
+            count
+          else
+            largest
+          end
+        end
+
+        non_early_ed_count + early_ed_count
+      end
+    end
+
+    def response_count_for_survey_items(survey_items:)
+      SurveyItemResponse.where(school:, academic_year:,
+                               survey_item: survey_items).select(:response_id).distinct.count || 0
+    end
+
+    def respondents_count
+      return 0 if respondents.nil?
+
+      count = enrollment if focus == :student
+      count = respondents.total_teachers if focus == :teacher
+      count
+    end
+
+    def enrollment
+      SurveyItemResponse.where(school:, academic_year:, grade: grades,
+                               survey_item: SurveyItem.student_survey_items)
+                        .select(:grade)
+                        .distinct
+                        .pluck(:grade)
+                        .reject(&:nil?)
+                        .map do |grade|
+        respondents.enrollment_by_grade[grade]
+      end.sum.to_f
+    end
+
+    def respondents
+      @respondents ||= Respondent.by_school_and_year(school:, academic_year:)
+    end
+
+    def grades
+      respondents.enrollment_by_grade.keys
+    end
+  end
+end