Display Popular Vote Leaderboard (#1066)

* Added new col for popular vote score and compatible with frontend

* rename new table col from relative_score to popular_score

* Fix an issue which causes test cases to fail due to nil

* changed test cases to include popularVoteLeaderboard

* Fixed formatting

* Fix credo error

---------

Co-authored-by: Richard Dominick <[email protected]>

lib/cadet/assessments/answer.ex

@@ -16,6 +16,7 @@ defmodule Cadet.Assessments.Answer do
   schema "answers" do
     # used to compare answers with others
     field(:relative_score, :float, default: 0.0)
+    field(:popular_score, :float, default: 0.0)
     field(:xp, :integer, default: 0)
     field(:xp_adjustment, :integer, default: 0)
     field(:comments, :string)
@@ -122,4 +123,12 @@ defmodule Cadet.Assessments.Answer do
     answer
     |> cast(contest_score_param, [:relative_score])
   end
+
+  @doc """
+  Used to update popular_score of answer to contest_score
+  """
+  def popular_score_update_changeset(answer, popular_score_param) do
+    answer
+    |> cast(popular_score_param, [:popular_score])
+  end
 end

lib/cadet/assessments/assessments.ex

@@ -1006,6 +1006,18 @@ defmodule Cadet.Assessments do
           # fetch top 10 contest voting entries with the contest question id
           question_id = fetch_associated_contest_question_id(course_id, q)
 
+          # fetch top 10 contest coting entries with contest question id based on popular score
+          popular_results =
+            if is_nil(question_id) do
+              []
+            else
+              if leaderboard_open?(assessment, q) or role in @open_all_assessment_roles do
+                fetch_top_popular_score_answers(question_id, 10)
+              else
+                []
+              end
+            end
+
           leaderboard_results =
             if is_nil(question_id) do
               []
@@ -1025,6 +1037,10 @@ defmodule Cadet.Assessments do
               :contest_leaderboard,
               leaderboard_results
             )
+            |> Map.put(
+              :popular_leaderboard,
+              popular_results
+            )
 
           Map.put(q, :question, voting_question)
         else
@@ -1097,6 +1113,37 @@ defmodule Cadet.Assessments do
     |> Repo.all()
   end
 
+  @doc """
+  Fetches top answers for the given question, based on the contest popular_score
+
+  Used for contest leaderboard fetching
+  """
+  def fetch_top_popular_score_answers(question_id, number_of_answers) do
+    Answer
+    |> where(question_id: ^question_id)
+    |> where(
+      [a],
+      fragment(
+        "?->>'code' like ?",
+        a.answer,
+        "%return%"
+      )
+    )
+    |> order_by(desc: :popular_score)
+    |> join(:left, [a], s in assoc(a, :submission))
+    |> join(:left, [a, s], student in assoc(s, :student))
+    |> join(:inner, [a, s, student], student_user in assoc(student, :user))
+    |> where([a, s, student], student.role == "student")
+    |> select([a, s, student, student_user], %{
+      submission_id: a.submission_id,
+      answer: a.answer,
+      popular_score: a.popular_score,
+      student_name: student_user.name
+    })
+    |> limit(^number_of_answers)
+    |> Repo.all()
+  end
+
   @doc """
   Computes rolling leaderboard for contest votes that are still open.
   """
@@ -1181,6 +1228,7 @@ defmodule Cadet.Assessments do
       |> Repo.get_by(id: contest_voting_question_id)
 
     entry_scores = map_eligible_votes_to_entry_score(eligible_votes, token_divider)
+    normalized_scores = map_eligible_votes_to_popular_score(eligible_votes, token_divider)
 
     entry_scores
     |> Enum.map(fn {ans_id, relative_score} ->
@@ -1195,6 +1243,20 @@ defmodule Cadet.Assessments do
     end)
     |> Enum.reduce(Multi.new(), &Multi.append/2)
     |> Repo.transaction()
+
+    normalized_scores
+    |> Enum.map(fn {ans_id, popular_score} ->
+      %Answer{id: ans_id}
+      |> Answer.popular_score_update_changeset(%{
+        popular_score: popular_score
+      })
+    end)
+    |> Enum.map(fn changeset ->
+      op_key = "answer_#{changeset.data.id}"
+      Multi.update(Multi.new(), op_key, changeset)
+    end)
+    |> Enum.reduce(Multi.new(), &Multi.append/2)
+    |> Repo.transaction()
   end
 
   defp map_eligible_votes_to_entry_score(eligible_votes, token_divider) do
@@ -1220,14 +1282,46 @@ defmodule Cadet.Assessments do
     )
   end
 
+  defp map_eligible_votes_to_popular_score(eligible_votes, token_divider) do
+    # converts eligible votes to the {total cumulative score, number of votes, tokens}
+    entry_vote_data =
+      Enum.reduce(eligible_votes, %{}, fn %{ans_id: ans_id, score: score, ans: ans}, tracker ->
+        {prev_score, prev_count, _ans_tokens} = Map.get(tracker, ans_id, {0, 0, 0})
+
+        Map.put(
+          tracker,
+          ans_id,
+          # assume each voter is assigned 10 entries which will make it fair.
+          {prev_score + score, prev_count + 1, Lexer.count_tokens(ans)}
+        )
+      end)
+
+    # calculate the score based on formula {ans_id, score}
+    Enum.map(
+      entry_vote_data,
+      fn {ans_id, {sum_of_scores, number_of_voters, tokens}} ->
+        {ans_id,
+         calculate_normalized_score(sum_of_scores, number_of_voters, tokens, token_divider)}
+      end
+    )
+  end
+
   # Calculate the score based on formula
   # score(v,t) = v - 2^(t/token_divider) where v is the normalized_voting_score
   # normalized_voting_score = sum_of_scores / number_of_voters / 10 * 100
   defp calculate_formula_score(sum_of_scores, number_of_voters, tokens, token_divider) do
-    normalized_voting_score = sum_of_scores / number_of_voters / 10 * 100
+    normalized_voting_score =
+      calculate_normalized_score(sum_of_scores, number_of_voters, tokens, token_divider)
+
     normalized_voting_score - :math.pow(2, min(1023.5, tokens / token_divider))
   end
 
+  # Calculate the normalized score based on formula
+  # normalized_voting_score = sum_of_scores / number_of_voters / 10 * 100
+  defp calculate_normalized_score(sum_of_scores, number_of_voters, _tokens, _token_divider) do
+    sum_of_scores / number_of_voters / 10 * 100
+  end
+
   @doc """
   Function returning submissions under a grader. This function returns only the
   fields that are exposed in the /grading endpoint.
@@ -1509,7 +1603,8 @@ defmodule Cadet.Assessments do
       |> Enum.map(fn ans ->
         if ans.question.type == :voting do
           empty_contest_entries = Map.put(ans.question.question, :contest_entries, [])
-          empty_contest_leaderboard = Map.put(empty_contest_entries, :contest_leaderboard, [])
+          empty_popular_leaderboard = Map.put(empty_contest_entries, :popular_leaderboard, [])
+          empty_contest_leaderboard = Map.put(empty_popular_leaderboard, :contest_leaderboard, [])
           question = Map.put(ans.question, :question, empty_contest_leaderboard)
           Map.put(ans, :question, question)
         else

lib/cadet_web/helpers/assessments_helpers.ex

@@ -113,6 +113,18 @@ defmodule CadetWeb.AssessmentsHelpers do
     )
   end
 
+  defp build_popular_leaderboard_entry(leaderboard_ans) do
+    Map.put(
+      transform_map_for_view(leaderboard_ans, %{
+        submission_id: :submission_id,
+        answer: :answer,
+        student_name: :student_name
+      }),
+      "final_score",
+      Float.round(leaderboard_ans.popular_score, 2)
+    )
+  end
+
   defp build_choice(choice) do
     transform_map_for_view(choice, %{
       id: "choice_id",
@@ -183,6 +195,10 @@ defmodule CadetWeb.AssessmentsHelpers do
           scoreLeaderboard:
             &Enum.map(&1[:contest_leaderboard], fn entry ->
               build_contest_leaderboard_entry(entry)
+            end),
+          popularVoteLeaderboard:
+            &Enum.map(&1[:popular_leaderboard], fn entry ->
+              build_popular_leaderboard_entry(entry)
             end)
         })
     end

priv/repo/migrations/20240213081500_answers_add_popular_score_column.exs

@@ -0,0 +1,9 @@
+defmodule Cadet.Repo.Migrations.AnswersAddPopularScoreColumn do
+  use Ecto.Migration
+
+  def change do
+    alter table("answers") do
+      add(:popular_score, :float, default: 0.0)
+    end
+  end
+end

test/cadet_web/admin_controllers/admin_grading_controller_test.exs

@@ -400,7 +400,8 @@ defmodule CadetWeb.AdminGradingControllerTest do
                     "autogradingResults" => &1.autograding_results,
                     "answer" => nil,
                     "contestEntries" => [],
-                    "scoreLeaderboard" => []
+                    "scoreLeaderboard" => [],
+                    "popularVoteLeaderboard" => []
                   },
                   "grade" => %{
                     "xp" => &1.xp,
@@ -1075,7 +1076,8 @@ defmodule CadetWeb.AdminGradingControllerTest do
                     "autogradingResults" => &1.autograding_results,
                     "answer" => nil,
                     "contestEntries" => [],
-                    "scoreLeaderboard" => []
+                    "scoreLeaderboard" => [],
+                    "popularVoteLeaderboard" => []
                   },
                   "grade" => %{
                     "xp" => &1.xp,

test/cadet_web/controllers/assessments_controller_test.exs

@@ -444,8 +444,10 @@ defmodule CadetWeb.AssessmentsControllerTest do
             expected_voting_questions
             |> Enum.zip(contests_entries)
             |> Enum.map(fn {question, contest_entries} ->
-              question = Map.put(question, "contestEntries", contest_entries)
-              Map.put(question, "scoreLeaderboard", [])
+              question
+              |> Map.put("contestEntries", contest_entries)
+              |> Map.put("scoreLeaderboard", [])
+              |> Map.put("popularVoteLeaderboard", [])
             end)
 
           expected_questions =