feat(2629): Add stat cards to group view

CHANGELOG.md

@@ -1,4 +1,6 @@
 ## Unreleased
+
+- Added stat cards to the group view
 - Added stat cards to the student view
 - Added stat cards to organization view
 - Added a clear icon to search input and removed dead student performance view

app/controllers/groups_controller.rb

@@ -1,3 +1,4 @@
+# rubocop:disable Metrics/ClassLength
 class GroupsController < HtmlController
   include Pagy::Method
 
@@ -22,6 +23,8 @@ def show
         lesson_url: lesson_path(Lesson.find_by(id: summary.lesson_id))
       }
     end
+    @current_average_score = @group_summaries.last&.dig(:average_mark)
+    populate_skill_growth
   end
 
   def new
@@ -107,6 +110,35 @@ def confirm_enrollments
 
   private
 
+  def populate_skill_growth
+    growths = average_growth_per_skill
+    @most_improved_skill = growths.min_by { |g| [-g[:growth], g[:skill_name], g[:skill_id]] }
+    @least_improved_skill = growths.min_by { |g| [g[:growth], g[:skill_name], g[:skill_id]] }
+  end
+
+  def average_growth_per_skill
+    deltas_by_skill = Hash.new { |hash, key| hash[key] = [] }
+    marks_by_student_and_skill.each do |(_student_id, skill_id, skill_name), marks|
+      next if marks.size < 2
+
+      deltas_by_skill[[skill_id, skill_name]] << (marks.last - marks.first)
+    end
+
+    deltas_by_skill.map { |(skill_id, skill_name), deltas| { skill_id:, skill_name:, growth: deltas.sum.to_f / deltas.size } }
+  end
+
+  def marks_by_student_and_skill
+    marks = Hash.new { |hash, key| hash[key] = [] }
+    active_student_ids = @group.active_students.pluck(:id)
+    @group.valid_grades
+          .where(student_id: active_student_ids)
+          .joins(:skill)
+          .order('lessons.date ASC')
+          .pluck(:student_id, 'skills.id', 'skills.skill_name', :mark)
+          .each { |student_id, skill_id, skill_name, mark| marks[[student_id, skill_id, skill_name]] << mark }
+    marks
+  end
+
   def group_params
     params.require(:group).permit :group_name, :mlid, :chapter_id
   end
@@ -121,3 +153,4 @@ def new_params
     params.permit :chapter_id
   end
 end
+# rubocop:enable Metrics/ClassLength

app/helpers/application_helper.rb

@@ -63,7 +63,7 @@ def name_or_email(user)
   end
 
   def lesson_student_average_grade
-    t :student_not_graded
+    t :not_graded
   end
 
   def student_mini_thumbnail(student)

app/models/enrollment.rb

@@ -28,6 +28,7 @@ class Enrollment < ApplicationRecord
 
   scope :by_student, ->(student_id) { where student_id: }
   scope :by_group, ->(group_id) { where group_id: }
+  scope :active, ->(as_of = Time.zone.now) { where('active_since <= ? AND (inactive_since IS NULL OR inactive_since > ?)', as_of, as_of) }
 
   validates :active_since, presence: true
   validates :inactive_since, comparison: { greater_than: :active_since, message: I18n.t(:enrollment_end_before_start) }, allow_nil: true

app/models/group.rb

@@ -88,4 +88,28 @@ def students_with_grades_outside_enrollment
               SQL
             )
   end
+
+  def active_students(as_of: Time.zone.today)
+    Student
+      .joins(:enrollments)
+      .merge(enrollments.active(as_of))
+      .where(enrollments: { group_id: id }, students: { deleted_at: nil })
+      .distinct
+  end
+
+  def valid_grades
+    Grade.joins(:lesson)
+         .where(deleted_at: nil, lessons: { group_id: id, deleted_at: nil })
+         .where(
+           <<~SQL.squish
+             EXISTS (
+               SELECT 1
+               FROM enrollments e
+               WHERE e.student_id = grades.student_id
+                 AND e.group_id = lessons.group_id
+                 AND lessons.date BETWEEN e.active_since AND COALESCE(e.inactive_since, 'infinity')
+             )
+           SQL
+         )
+  end
 end

app/views/groups/show.html.erb

@@ -26,13 +26,29 @@ end %>
 <% end %>
 
 <section>
-   <div class="w-1/2">
-       <%= render CommonComponents::Card.new(title: t(:average_performance_for_last_30_lessons).capitalize) do |card| %>
-             <% card.with_card_content do %>
-               <div id="group-chart" class="ct-chart ct-octave bg-white full-width"></div>
-             <% end %>
-       <% end %>
+  <div class="flex gap-4">
+    <div class="w-1/2">
+        <%= render CommonComponents::Card.new(title: t(:average_performance_for_last_30_lessons).capitalize) do |card| %>
+              <% card.with_card_content do %>
+                <div id="group-chart" class="ct-chart ct-octave bg-white full-width"></div>
+              <% end %>
+        <% end %>
     </div>
+    <div class="w-1/2">
+      <div class="mt-6">
+        <%= render CommonComponents::StatCards.new(
+          label: t(:overview).capitalize,
+          columns: 2,
+          stats: [
+            { title: t(:nr_of_active_students), value: @group.active_students.count },
+            { title: t(:current_average_score_for_group), value: @current_average_score&.round(2) || t(:not_graded) },
+            { title: t(:most_improved_skill), value: @most_improved_skill&.dig(:skill_name) || t(:not_graded) },
+            { title: t(:least_improved_skill), value: @least_improved_skill&.dig(:skill_name) || t(:not_graded) }
+          ]
+        ) %>
+      </div>
+    </div>
+  </div>
 </section>
 <turbo-frame id="students-table">
   <%= render GroupEnrolledStudentsComponent.new(students: @group.students, group: @group, students_with_invalid_grades: @students_with_invalid_grades) %>

app/views/students/show.html.erb

@@ -32,9 +32,9 @@ end %>
             label: t(:student_statistics),
             stats: [
               { title: t(:nr_of_lessons_present), value: @nr_of_lessons_present },
-              { title: t(:total_average_score), value: @total_average_score&.round(2) || t(:student_not_graded) },
-              { title: t(:most_improved_skill), value: @most_improved_skill&.dig(:skill_name) || t(:student_not_graded) },
-              { title: t(:least_improved_skill), value: @least_improved_skill&.dig(:skill_name) || t(:student_not_graded) }
+              { title: t(:total_average_score), value: @total_average_score&.round(2) || t(:not_graded) },
+              { title: t(:most_improved_skill), value: @most_improved_skill&.dig(:skill_name) || t(:not_graded) },
+              { title: t(:least_improved_skill), value: @least_improved_skill&.dig(:skill_name) || t(:not_graded) }
             ]
           ) %>
         </div>

config/locales/en.yml

@@ -228,7 +228,7 @@ en:
   student_grades: Student Grades
   student_graded: Student graded.
   student_graded_text: Student %{student} graded.
-  student_not_graded: Not Graded
+  not_graded: Not Graded
   add_grade: Add Grade
   graded_vs_students_in_group: Graded / Students in Group
   back_to_subjects: Back to All Subjects
@@ -409,6 +409,7 @@ en:
   nr_of_users_with_role: Number of users with a role within the Organization
   nr_of_lessons_present: Number of lessons present
   total_average_score: Total average score
+  current_average_score_for_group: Current average score for group
   most_improved_skill: Most improved skill
   least_improved_skill: Least improved skill
   overview: Overview

spec/controllers/groups_controller_spec.rb

@@ -133,6 +133,39 @@
 
       it { should respond_with 200 }
     end
+
+    context 'group statistics' do
+      context 'when the group has graded lessons' do
+        before :each do
+          subject = create :subject_with_skills, skill_names: %w[Memorization Grit], organization: @group.chapter.organization
+          create :lesson_with_grades, group: @group, subject:, date: 2.days.ago,
+                                      student_grades: { @student1.id => { 'Memorization' => 1, 'Grit' => 3 } }
+          create :lesson_with_grades, group: @group, subject:, date: 1.day.ago,
+                                      student_grades: { @student1.id => { 'Memorization' => 3, 'Grit' => 6 } }
+
+          get :show, params: { id: @group.id }
+        end
+
+        it 'assigns the current average score and the most/least improved skill' do
+          expect(assigns(:current_average_score)).to be_a(Numeric)
+          expect(assigns(:most_improved_skill)[:skill_name]).to eq 'Grit'
+          expect(assigns(:least_improved_skill)[:skill_name]).to eq 'Memorization'
+        end
+      end
+
+      context 'when the group has no graded lessons' do
+        before :each do
+          @ungraded_group = create :group
+          get :show, params: { id: @ungraded_group.id }
+        end
+
+        it 'assigns nil for the current average score and the skill growth statistics' do
+          expect(assigns(:current_average_score)).to be_nil
+          expect(assigns(:most_improved_skill)).to be_nil
+          expect(assigns(:least_improved_skill)).to be_nil
+        end
+      end
+    end
   end
 
   describe '#edit' do

spec/features/group_features_spec.rb

@@ -239,4 +239,36 @@
       expect(page).to have_selector('span.group > .tooltip', visible: :all, text: expected_alert_text)
     end
   end
+
+  describe 'Group statistics' do
+    it 'shows active student count, current average, and most/least improved skill for the current roster only' do
+      group = create :group, group_name: 'Growth Stats Group'
+      subject = create :subject_with_skills, skill_names: %w[Memorization Grit], organization: group.chapter.organization
+
+      active_student = create :student, organization: group.chapter.organization
+      create :enrollment, student: active_student, group: group, active_since: 1.month.ago.to_date
+      second_active_student = create :student, organization: group.chapter.organization
+      create :enrollment, student: second_active_student, group: group, active_since: 1.month.ago.to_date
+
+      # This student already left the group. Their grades were valid while they were enrolled, and show a huge
+      # improvement in Memorization -- if they were wrongly counted, that swing would hijack "most improved".
+      left_student = create :student, organization: group.chapter.organization
+      create :enrollment, student: left_student, group: group, active_since: 1.year.ago.to_date, inactive_since: 1.month.ago.to_date
+      create :lesson_with_grades, group: group, subject:, date: 11.months.ago, student_grades: { left_student.id => { 'Memorization' => 1 } }
+      create :lesson_with_grades, group: group, subject:, date: 10.months.ago, student_grades: { left_student.id => { 'Memorization' => 7 } }
+
+      create :lesson_with_grades, group: group, subject:, date: 2.days.ago,
+                                  student_grades: { active_student.id => { 'Memorization' => 1 }, second_active_student.id => { 'Grit' => 1 } }
+      create :lesson_with_grades, group: group, subject:, date: 1.day.ago,
+                                  student_grades: { active_student.id => { 'Memorization' => 2 }, second_active_student.id => { 'Grit' => 3 } }
+
+      visit "/groups/#{group.id}"
+
+      stat_values = all('dd.tracking-tight').map(&:text)
+      expect(stat_values[0]).to eq '2' # active students: left_student excluded
+      expect(stat_values[1]).to eq '2.5' # average of the two active students' marks on the most recent lesson
+      expect(stat_values[2]).to eq 'Grit' # most improved, among active students only (delta +2, vs Memorization's +1)
+      expect(stat_values[3]).to eq 'Memorization' # would lose to Memorization's +6 if left_student were wrongly counted
+    end
+  end
 end

spec/models/group_spec.rb

@@ -139,5 +139,34 @@
         expect(result).not_to include @students[4]
       end
     end
+
+    describe '#active_students' do
+      before :each do
+        @group = create :group
+        @currently_enrolled = create :student, organization: @group.chapter.organization
+        create :enrollment, group: @group, student: @currently_enrolled, active_since: 1.week.ago
+
+        @already_left = create :student, organization: @group.chapter.organization
+        create :enrollment, group: @group, student: @already_left, active_since: 1.year.ago.to_date, inactive_since: 1.month.ago.to_date
+
+        @not_yet_started = create :student, organization: @group.chapter.organization
+        create :enrollment, group: @group, student: @not_yet_started, active_since: 1.month.from_now.to_date
+
+        @deleted_student = create :student, organization: @group.chapter.organization, deleted_at: Time.zone.now
+        create :enrollment, group: @group, student: @deleted_student, active_since: 1.week.ago
+      end
+
+      it 'returns only students with an open enrollment covering the given date who are not deleted' do
+        result = @group.active_students
+
+        expect(result).to contain_exactly @currently_enrolled
+      end
+
+      it 'accepts an as_of date to check enrollment at a different point in time' do
+        result = @group.active_students(as_of: 6.months.ago)
+
+        expect(result).to contain_exactly @already_left
+      end
+    end
   end
 end