Replace Subclasses with Strategies: Step Ten

* Move state for first strategy out of root class

Author: jferris

example_app/app/controllers/questions_controller.rb

@@ -32,7 +32,7 @@ def update
 
   def build_question
     @question = type.constantize.new(question_params)
-    @question.build_submittable({})
+    @question.build_submittable(submittable_params)
     @question.survey = @survey
   end
 
@@ -43,6 +43,14 @@ def type
   def question_params
     params.
       require(:question).
-      permit(:title, :options_attributes, :minimum, :maximum)
+      permit(:title, :options_attributes)
+  end
+
+  def submittable_params
+    if submittable_attributes = params[:question][:submittable_attributes]
+      submittable_attributes.permit(:minimum, :maximum)
+    else
+      {}
+    end
   end
 end

example_app/app/controllers/types_controller.rb

@@ -3,11 +3,16 @@ def new
     @question = Question.find(params[:question_id])
     assign_type
     @new_question = type.constantize.new
+    @new_question.build_submittable({})
   end
 
   def create
     @question = Question.find(params[:question_id])
-    @new_question = @question.switch_to(type, params[:question], {})
+    @new_question = @question.switch_to(
+      type,
+      question_params,
+      submittable_attributes
+    )
 
     if @new_question.errors.empty?
       redirect_to @question.survey
@@ -23,6 +28,14 @@ def assign_type
     @new_type = type.underscore
   end
 
+  def question_params
+    params[:question].except(:submittable_attributes)
+  end
+
+  def submittable_attributes
+    params[:question][:submittable_attributes] || {}
+  end
+
   def type
     params[:question][:type]
   end

example_app/app/models/question.rb

@@ -3,13 +3,16 @@ class Question < ActiveRecord::Base
 
   QUESTION_TYPES = %w(OpenQuestion MultipleChoiceQuestion ScaleQuestion).freeze
 
+  validates :submittable, associated: true
   validates :type, presence: true, inclusion: QUESTION_TYPES
   validates :title, presence: true
 
   belongs_to :submittable, polymorphic: true
   belongs_to :survey
   has_many :answers
 
+  accepts_nested_attributes_for :submittable
+
   delegate :breakdown, :score, to: :submittable
   delegate :title, to: :survey, prefix: true
 

example_app/app/models/scale_question.rb

@@ -1,4 +1,2 @@
 class ScaleQuestion < Question
-  validates :maximum, presence: true
-  validates :minimum, presence: true
 end

example_app/app/models/scale_submittable.rb

@@ -1,6 +1,9 @@
 class ScaleSubmittable < ActiveRecord::Base
   has_one :question, as: :submittable
 
+  validates :maximum, presence: true
+  validates :minimum, presence: true
+
   def breakdown
     sprintf('Average: %.02f', answers.average('text'))
   end
@@ -10,7 +13,7 @@ def score(text)
   end
 
   def steps
-    (question.minimum..question.maximum).to_a
+    (minimum..maximum).to_a
   end
 
   private

example_app/app/views/scale_questions/_scale_question_form.html.erb

@@ -1,2 +1,4 @@
-<%= form.input :minimum %>
-<%= form.input :maximum %>
+<%= form.fields_for :submittable do |submittable_fields| -%>
+  <%= submittable_fields.input :minimum %>
+  <%= submittable_fields.input :maximum %>
+<% end -%>

example_app/db/migrate/20130131211856_move_scale_question_state_to_scale_submittable.rb

@@ -0,0 +1,50 @@
+class MoveScaleQuestionStateToScaleSubmittable < ActiveRecord::Migration
+  def up
+    add_column :scale_submittables, :minimum, :integer
+    add_column :scale_submittables, :maximum, :integer
+
+    connection.insert(<<-SQL)
+      INSERT INTO scale_submittables
+        (id, created_at, updated_at, minimum, maximum)
+      SELECT
+        id, created_at, updated_at, minimum, maximum
+      FROM questions
+      WHERE questions.type = 'ScaleQuestion'
+    SQL
+
+    connection.update(<<-SQL)
+      UPDATE questions
+      SET submittable_id = id, submittable_type = 'ScaleSubmittable'
+      WHERE type = 'ScaleQuestion'
+    SQL
+
+    remove_column :questions, :minimum
+    remove_column :questions, :maximum
+  end
+
+  def down
+    add_column :questions, :maximum, :integer
+    add_column :questions, :minimum, :integer
+
+    connection.update(<<-SQL)
+      UPDATE questions
+      SET
+        minimum = (
+          SELECT minimum
+          FROM scale_submittables
+          WHERE questions.submittable_id = scale_submittables.id
+        ),
+        maximum = (
+          SELECT maximum
+          FROM scale_submittables
+          WHERE questions.submittable_id = scale_submittables.id
+        )
+      WHERE questions.submittable_type = 'ScaleSubmittable'
+    SQL
+
+    connection.delete('DELETE FROM scale_submittables')
+
+    remove_column :scale_submittables, :maximum
+    remove_column :scale_submittables, :minimum
+  end
+end

example_app/db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20130131205918) do
+ActiveRecord::Schema.define(:version => 20130131211856) do
 
   create_table "answers", :force => true do |t|
     t.integer  "completion_id", :null => false
@@ -72,15 +72,15 @@
     t.integer  "survey_id",        :null => false
     t.datetime "created_at",       :null => false
     t.datetime "updated_at",       :null => false
-    t.integer  "minimum"
-    t.integer  "maximum"
     t.integer  "submittable_id"
     t.string   "submittable_type"
   end
 
   create_table "scale_submittables", :force => true do |t|
     t.datetime "created_at", :null => false
     t.datetime "updated_at", :null => false
+    t.integer  "minimum"
+    t.integer  "maximum"
   end
 
   create_table "surveys", :force => true do |t|

example_app/spec/factories/application.rb

@@ -43,14 +43,13 @@
     end
 
     factory :scale_question, class: 'ScaleQuestion' do
-      minimum 1
-      maximum 2
-
       submittable factory: :scale_submittable
     end
   end
 
   factory :scale_submittable do
+    minimum 1
+    maximum 2
   end
 
   factory :survey do

example_app/spec/features/user_answers_scale_question_spec.rb

@@ -3,10 +3,11 @@
 feature 'user answers scale question' do
   scenario 'with valid answer' do
     sign_in
-    view_survey_with_question :scale,
-      title: 'How many fingers do you have?',
-      minimum: 0,
-      maximum: 10
+    view_survey_with_question(
+      :scale,
+      { title: 'How many fingers do you have?' },
+      { minimum: 0, maximum: 10 }
+    )
     choose '10'
     submit_answers
     answer_to_question('How many fingers do you have?').