Refactor 2 iteration

app/controllers/api/experiments_controller.rb

@@ -2,24 +2,20 @@
 
 module Api
   class ExperimentsController < ApplicationController
-    before_action :device_header
+    before_action :validate_header!
 
     def index
-      if header_valid?
-        @experiments = Api::ExperimentService.call(@token)
-      else
-        render json: {}, status: :forbidden
-      end
+      @experiment = Api::ExperimentService.call(device_header)
     end
 
     private
 
-    def device_header
-      @token = request.headers['Device-Token']
+    def validate_header!
+      render(json: {}, status: :forbidden) unless device_header
     end
 
-    def header_valid?
-      request.headers.key? 'Device-Token'
+    def device_header
+      @device_header ||= request.headers['Device-Token']
     end
   end
 end

app/models/experiment.rb

@@ -1,25 +1,7 @@
 # frozen_string_literal: true
 
-require 'distribution'
-
 class Experiment < ApplicationRecord
   validates :token, presence: true, uniqueness: true # rubocop:disable Rails/UniqueValidationWithoutIndex
   validates :button_color, presence: true
   validates :price, presence: true
-
-  def self.colors
-    @colors ||= Color.new
-  end
-
-  def self.prices
-    @prices ||= Price.new
-  end
-
-  def self.color
-    @colors.distribution
-  end
-
-  def self.price
-    @prices.distribution
-  end
 end

app/services/api/experiment_service.rb

@@ -1,41 +1,22 @@
 # frozen_string_literal: true
 
+require 'distribution'
+
 module Api
   class ExperimentService < ApplicationService
+    attr_reader :token, :color_distribution, :price_distribution
+
     def initialize(token) # rubocop:disable Lint/MissingSuper: Call super to initialize state of the parent class.
       @token = token
+      @color_distribution = Distribution::Color.new
+      @price_distribution = Distribution::Price.new
     end
 
     def call
-      default_values
-      attribute_color if query_to_db_valid?
-      attribute_price if query_to_db_valid?
-      experiment_params
-      @experiment = Experiment.create experiment_params
-      @experiments = Experiment.select(:button_color, :price).where(token: @token)
-    end
-
-    private
-
-    def default_values
-      Experiment.colors
-      Experiment.prices
-    end
-
-    def attribute_color
-      @button_color = Experiment.color
-    end
-
-    def attribute_price
-      @price = Experiment.price
-    end
-
-    def query_to_db_valid?
-      !Experiment.exists?(token: @token)
-    end
-
-    def experiment_params
-      @params = { token: @token, button_color: @button_color, price: @price }
+      Experiment.find_or_create_by(token: token) do |experiment|
+        experiment.button_color = color_distribution.next_value
+        experiment.price = price_distribution.next_value
+      end
     end
   end
 end

app/views/api/experiments/index.json.jbuilder

@@ -1,4 +1,4 @@
 # frozen_string_literal: true
 
-json.experiments([{ value: @experiments.pluck(:button_color)[0], key: 'button_color' },
-                  { value: @experiments.pluck(:price)[0], key: 'price' }])
+json.experiments([{ value: @experiment.button_color, key: 'button_color' },
+                  { value: @experiment.price, key: 'price' }])

lib/distribution.rb

@@ -1,41 +1,43 @@
 # frozen_string_literal: true
 
-class Color
-  def initialize
-    @colors = []
-  end
+class Distribution
+  class Color
+    def initialize
+      @colors = []
+    end
 
-  def distribution
-    @colors = %w[#FF0000 #00FF00 #0000FF] if @colors.empty?
-    @colors.shift
+    def next_value
+      @colors = %w[#FF0000 #00FF00 #0000FF] if @colors.empty?
+      @colors.shift
+    end
   end
-end
 
-class Price
-  def initialize
-    @probability = [0.75, 0.1, 0.1, 0.05]
-    @prices = []
-    @counter = 0
-  end
+  class Price
+    def initialize
+      @probability = [0.75, 0.1, 0.1, 0.05]
+      @prices = []
+      @counter = 0
+    end
 
-  def distribution
-    @counter += 1
-    price1 = (@counter * @probability[0]).round
-    price2 = (@counter * @probability[1]).round
-    price3 = (@counter * @probability[2]).round
-    price4 = (@counter * @probability[3]).round
-    @prices << calculation_price(price1, price2, price3, price4)
-    @prices.last
-  end
+    def next_value
+      @counter += 1
+      price1 = (@counter * @probability[0]).round
+      price2 = (@counter * @probability[1]).round
+      price3 = (@counter * @probability[2]).round
+      price4 = (@counter * @probability[3]).round
+      @prices << calculation_price(price1, price2, price3, price4)
+      @prices.last
+    end
 
-  def calculation_price(price1, price2, price3, price4)
-    if @prices.count('10') < price1 then '10'
-    elsif @prices.count('20') < price2 then '20'
-    elsif @prices.count('5') < price3 then '5'
-    elsif @prices.count('50') < price4 then '50'
-    # rubocop:disable Lint/DuplicateBranch: Duplicate branch body detected.
-    else '10' # This is necessary logic
-      # rubocop:enable Lint/DuplicateBranch: Duplicate branch body detected.
+    def calculation_price(price1, price2, price3, price4)
+      if @prices.count('10') < price1 then '10'
+      elsif @prices.count('20') < price2 then '20'
+      elsif @prices.count('5') < price3 then '5'
+      elsif @prices.count('50') < price4 then '50'
+      # rubocop:disable Lint/DuplicateBranch: Duplicate branch body detected.
+      else '10' # This is necessary logic
+        # rubocop:enable Lint/DuplicateBranch: Duplicate branch body detected.
+      end
     end
   end
 end