Fix duplicate key quiz when duplicate (#182)

* add quiz_responses association to user

* bugfix possible duplicate key entries in multi when adding quiz responses

* remove user_id from casting changeset in QuizResponse

* pass whole user to submit_quiz function

* update test to match changes

* simplify submit_quiz/3 function for inserting quiz response

---------

Co-authored-by: Dimitrije Dimitrijevic <me@dimitrijedimitrijevic.com>

Author: DimitrijeDimitrijevic

lib/claper/accounts/user.ex

@@ -30,6 +30,7 @@ defmodule Claper.Accounts.User do
 
     has_many :events, Claper.Events.Event
     has_one :lti_user, Lti13.Users.User
+    has_many :quiz_responses, Claper.Quizzes.QuizResponse
 
     timestamps()
   end

lib/claper/quizzes.ex

@@ -2,6 +2,8 @@ defmodule Claper.Quizzes do
   import Ecto.Query, warn: false
   alias Claper.Repo
 
+  alias Claper.Accounts.User
+
   alias Claper.Quizzes.Quiz
   alias Claper.Quizzes.QuizQuestion
   alias Claper.Quizzes.QuizQuestionOpt
@@ -265,37 +267,71 @@ defmodule Claper.Quizzes do
       {:ok, quiz}
 
   """
-  def submit_quiz(user_id, quiz_opts, quiz_id)
-      when is_number(user_id) and is_list(quiz_opts) do
-    case Enum.reduce(quiz_opts, Ecto.Multi.new(), fn opt, multi ->
-           Ecto.Multi.update(
-             multi,
-             {:update_quiz_opt, opt.id},
+
+  # Pattern match on user, from user we create QuizResponse struct
+  # def submit_quiz(user_id, quiz_opts, quiz_id)
+  #     when is_number(user_id) and is_list(quiz_opts) do
+  #   quiz_opts = Enum.with_index(quiz_opts)
+
+  #   case Enum.reduce(quiz_opts, Ecto.Multi.new(), fn {opt, index}, multi ->
+  #          unique_key = "#{opt.id}_#{user_id + index}"
+
+  #          multi
+  #          |> Ecto.Multi.update(
+  #            "update_quiz_opt_#{unique_key}",
+  #            QuizQuestionOpt.changeset(opt, %{"response_count" => opt.response_count + 1})
+  #          )
+  #          |> Ecto.Multi.insert(
+  #            "insert_quiz_response_#{unique_key}",
+  #            QuizResponse.changeset(%QuizResponse{}, %{
+  #              user_id: user_id,
+  #              quiz_question_opt_id: opt.id,
+  #              quiz_question_id: opt.quiz_question_id,
+  #              quiz_id: quiz_id
+  #            })
+  #          )
+  #        end)
+  #        |> Repo.transact() do
+  #     {:ok, _} ->
+  #       quiz = get_quiz!(quiz_id, [:quiz_questions, quiz_questions: :quiz_question_opts])
+  #       Lti13.QuizScoreReporter.report_quiz_score(quiz, user_id)
+  #       {:ok, quiz}
+  #   end
+  # end
+
+  def submit_quiz(%User{} = user, quiz_opts, quiz_id) do
+    quiz_opts = Enum.with_index(quiz_opts)
+
+    case Enum.reduce(quiz_opts, Ecto.Multi.new(), fn {opt, index}, multi ->
+           unique_key = "#{opt.id}_#{user.id + index}"
+
+           multi
+           |> Ecto.Multi.update(
+             "update_quiz_opt_#{unique_key}",
              QuizQuestionOpt.changeset(opt, %{"response_count" => opt.response_count + 1})
            )
            |> Ecto.Multi.insert(
-             {:insert_quiz_response, opt.id},
-             QuizResponse.changeset(%QuizResponse{}, %{
-               user_id: user_id,
+             "insert_quiz_response_#{unique_key}",
+             Ecto.build_assoc(user, :quiz_responses, %{
                quiz_question_opt_id: opt.id,
                quiz_question_id: opt.quiz_question_id,
                quiz_id: quiz_id
              })
            )
          end)
-         |> Repo.transaction() do
+         |> Repo.transact() do
       {:ok, _} ->
         quiz = get_quiz!(quiz_id, [:quiz_questions, quiz_questions: :quiz_question_opts])
-        Lti13.QuizScoreReporter.report_quiz_score(quiz, user_id)
+        Lti13.QuizScoreReporter.report_quiz_score(quiz, user.id)
         {:ok, quiz}
     end
   end
 
   def submit_quiz(attendee_identifier, quiz_opts, quiz_id)
       when is_binary(attendee_identifier) and is_list(quiz_opts) do
     case Enum.reduce(quiz_opts, Ecto.Multi.new(), fn opt, multi ->
-           Ecto.Multi.update(
-             multi,
+           multi
+           |> Ecto.Multi.update(
              {:update_quiz_opt, opt.id},
              QuizQuestionOpt.changeset(opt, %{"response_count" => opt.response_count + 1})
            )
@@ -309,7 +345,7 @@ defmodule Claper.Quizzes do
              })
            )
          end)
-         |> Repo.transaction() do
+         |> Repo.transact() do
       {:ok, _} ->
         quiz = get_quiz!(quiz_id, [:quiz_questions, quiz_questions: :quiz_question_opts])
         {:ok, quiz}

lib/claper/quizzes/quiz_response.ex

@@ -20,8 +20,7 @@ defmodule Claper.Quizzes.QuizResponse do
       :attendee_identifier,
       :quiz_id,
       :quiz_question_id,
-      :quiz_question_opt_id,
-      :user_id
+      :quiz_question_opt_id
     ])
     |> validate_required([:quiz_id, :quiz_question_id, :quiz_question_opt_id])
   end

lib/claper_web/live/event_live/show.ex

@@ -693,7 +693,7 @@ defmodule ClaperWeb.EventLive.Show do
       )
       when is_map(current_user) do
     case Claper.Quizzes.submit_quiz(
-           current_user.id,
+           current_user,
            opts,
            socket.assigns.current_interaction.id
          ) do

test/claper/quizzes_test.exs

@@ -113,14 +113,14 @@ defmodule Claper.QuizzesTest do
       assert length(new_question.quiz_question_opts) == 2
     end
 
-    test "submit_quiz/3 with user_id records responses and updates counts" do
+    test "submit_quiz/3 with user records responses and updates counts" do
       quiz = quiz_fixture()
       user = user_fixture()
       question = List.first(quiz.quiz_questions)
       option = List.first(question.quiz_question_opts)
 
       assert {:ok, updated_quiz} =
-               Quizzes.submit_quiz(user.id, [option], quiz.id)
+               Quizzes.submit_quiz(user, [option], quiz.id)
 
       updated_option =
         updated_quiz.quiz_questions
@@ -151,7 +151,7 @@ defmodule Claper.QuizzesTest do
       correct_option = Enum.find(question.quiz_question_opts, & &1.is_correct)
 
       # Submit correct answer
-      {:ok, _} = Quizzes.submit_quiz(user.id, [correct_option], quiz.id)
+      {:ok, _} = Quizzes.submit_quiz(user, [correct_option], quiz.id)
       assert {1, 1} = Quizzes.calculate_user_score(user.id, quiz.id)
     end