enhancement(elixir): Preload all questions

aion/lib/aion/room_channel/question_set.ex

@@ -0,0 +1,35 @@
+defmodule Aion.RoomChannel.QuestionSet do
+  @moduledoc """
+  This module provides logic for generating new question set
+  """
+  alias Aion.{Question, Answer}
+  require Logger
+
+  @type t :: %__MODULE__{questions: (list Question.t), current_question: Question.t, answers: (list Answer.t)}
+
+  defstruct questions: [],
+            current_question: nil,
+            answers: []
+
+  @spec create((list Question.t), integer) :: __MODULE__.t
+  def create(questions, room_id) do
+    case questions do
+      [] ->
+        %{questions: [], current_question: nil, answers: []}
+
+      [last_question] ->
+        remaining_questions = Question.get_questions_by_room_id(room_id)
+        build_new(last_question, remaining_questions)
+
+      [next_question | remaining_questions] ->
+        build_new(next_question, remaining_questions)
+    end
+  end
+
+  @spec build_new(Question.t, (list Question.t)) :: __MODULE__.t
+  defp build_new(current_question, remaining_questions) do
+    answers = Answer.get_answers(current_question.id)
+    Logger.debug fn -> "Answers: #{inspect(Enum.map(answers, fn answer -> answer.content end))}" end
+    %{questions: remaining_questions, current_question: current_question, answers: answers}
+  end
+end

aion/lib/aion/room_channel/room.ex

@@ -3,28 +3,31 @@ defmodule Aion.RoomChannel.Room do
   This module represents one game room, and fetches resources from the db
   """
   alias Aion.{Question, Answer}
-  alias Aion.RoomChannel.{Room, UserRecord}
+  alias Aion.RoomChannel.{Room, UserRecord, QuestionSet}
   require Logger
 
   @type t :: %__MODULE__{users: %{String.t => UserRecord.t},
                          users_count: integer,
-                         question: Question.t,
-                         answers: list Answer.t}
+                         questions: (list Question.t),
+                         current_question: Question.t,
+                         answers: (list Answer.t)}
 
   defstruct users: %{},
             users_count: 0,
-            question: nil,
+            questions: [],
+            current_question: nil,
             answers: []
 
-  @spec new(integer, [question: nil | Question.t]) :: %__MODULE__{}
+  @spec new(integer, [current_question: nil | Question.t]) :: %__MODULE__{}
   def new(room_id, state \\ []) do
     case state do
       [] ->
         %Room{}
+        |> load_questions(room_id)
         |> change_question(room_id)
 
-      {:question, question} ->
-        %Room{question: question}
+      {:current_question, question} ->
+        %Room{current_question: question}
 
       _ -> Logger.error fn -> "Unexpected state passed to Room.new: #{state}" end
            %Room{}
@@ -50,8 +53,17 @@ defmodule Aion.RoomChannel.Room do
   """
   @spec change_question(%__MODULE__{}, integer) :: __MODULE__.t
   def change_question(room, room_id) do
-    room
-    |> struct(get_new_question_with_answers(room_id))
+    new_questions_with_answers = QuestionSet.create(room.questions, room_id)
+    struct(room, new_questions_with_answers)
+  end
+
+  @spec load_questions(%__MODULE__{}, integer) :: __MODULE__.t
+  def load_questions(room, room_id) do
+    questions =
+      room_id
+      |> Question.get_questions_by_room_id()
+      |> Enum.shuffle()
+    struct(room, %{questions: questions})
   end
 
   @spec add_user(__MODULE__.t, UserRecord.t) :: __MODULE__.t
@@ -73,15 +85,6 @@ defmodule Aion.RoomChannel.Room do
 
   @spec get_current_question(__MODULE__.t) :: Question.t
   def get_current_question(room) do
-    room.question
-  end
-
-  @spec get_new_question_with_answers(integer) :: %{question: Question.t, answers: list Answer.t}
-  defp get_new_question_with_answers(room_id) do
-      question = Question.get_random_question(room_id)
-      answers = Answer.get_answers(question.id)
-      Logger.debug fn -> "Answers: #{inspect(Enum.map(answers, fn answer -> answer.content end))}" end
-
-      %{question: question, answers: answers}
+    room.current_question
   end
 end

aion/test/lib/room_channel/monitor_test.exs

@@ -8,7 +8,7 @@ defmodule Aion.MonitorTest do
   @question %Question{content: "Content"}
 
   setup do
-    Monitor.create(@room_id, question: @question)
+    Monitor.create(@room_id, current_question: @question)
     :ok
   end
 

aion/test/models/question_test.exs

@@ -1,7 +1,7 @@
 defmodule Aion.QuestionTest do
   use Aion.ModelCase
 
-  alias Aion.Question
+  alias Aion.{Question, RoomCategory, Room, Category}
 
   @valid_attrs %{content: "some content", image_name: "some content"}
   @invalid_attrs %{}
@@ -16,6 +16,29 @@ defmodule Aion.QuestionTest do
     refute changeset.valid?
   end
 
+  test "get_questions_by_room_id when there are no questions" do
+    room1 = Repo.insert! %Room{}
+
+    result = Question.get_questions_by_room_id(room1.id)
+    assert length(result) == 0
+  end
+
+  test "get_questions_by_room_id when there are some questions" do
+    room1 = Repo.insert! %Room{}
+    room2 = Repo.insert! %Room{}
+
+    question_1 = Repo.insert! %Question{category: (Repo.insert! %Category{})}
+    question_2 = Repo.insert! %Question{category: (Repo.insert! %Category{})}
+    question_3 = Repo.insert! %Question{category: (Repo.insert! %Category{})}
+
+    room_category1 = Repo.insert! %RoomCategory{room_id: room1.id, category_id: question_1.category_id}
+    room_category2 = Repo.insert! %RoomCategory{room_id: room1.id, category_id: question_2.category_id}
+    room_category2 = Repo.insert! %RoomCategory{room_id: room2.id, category_id: question_3.category_id}
+
+    result = Question.get_questions_by_room_id(room1.id)
+    assert length(result) == 2
+  end
+
   def get_question(question_id) do
     Repo.get(Question, question_id)
   end

aion/web/models/question.ex

@@ -6,7 +6,7 @@ defmodule Aion.Question do
 
   use Aion.Web, :model
   alias Aion.Repo
-  alias Aion.{Question, Category}
+  alias Aion.{Question, Category, RoomCategory, Room}
 
   schema "questions" do
     field :content, :string
@@ -36,6 +36,16 @@ defmodule Aion.Question do
     Repo.get(Question, question_id)
   end
 
+  @spec get_questions_by_room_id(integer) :: Question.t
+  def get_questions_by_room_id(room_id) do
+    Repo.all(
+      from q in Question,
+      join: rc in RoomCategory, on: rc.category_id == q.category_id,
+      join: r in Room, on: r.id == rc.room_id,
+      where: r.id == ^room_id
+    )
+  end
+
   @spec get_random_question(integer) :: Question.t
   def get_random_question(room_id) do
     query = Repo.query("