From a8646e0409cf24b26aabbd2d0640035da1bbf94e Mon Sep 17 00:00:00 2001
From: Vasia Ivanyshak <ivanyshak.vasia@gmail.com>
Date: Wed, 9 Jun 2021 18:06:23 +0300
Subject: [PATCH 1/3] Shop Cart implementation  - Order and OrderItem  - Cart
 list page :rocket:

---
 Gemfile                                       |  1 +
 Gemfile.lock                                  |  3 ++
 app/assets/stylesheets/app/application.scss   |  1 +
 app/assets/stylesheets/app/base/_base.scss    | 25 +++++++++++
 app/helpers/admin/events_helper.rb            |  2 -
 app/views/layouts/application.slim            |  1 +
 .../app/controllers/shop/base_controller.rb   |  4 ++
 .../app/controllers/shop/items_controller.rb  | 16 +++++++
 .../shop/order_items_controller.rb            | 44 +++++++++++++++++++
 .../shop/app/helpers/shop/item_helper.rb      |  6 +++
 components/shop/app/models/shop/item.rb       |  1 +
 components/shop/app/models/shop/order.rb      | 25 +++++++++++
 components/shop/app/models/shop/order_item.rb | 36 +++++++++++++++
 .../shop/app/uploaders/item_image_uploader.rb |  4 +-
 .../shop/app/views/shop/items/index.slim      | 15 ++++++-
 .../app/views/shop/order_items/index.slim     | 32 ++++++++++++++
 components/shop/config/routes.rb              |  1 +
 .../migrate/20210611210804_create_orders.rb   | 10 +++++
 .../20210611211002_create_order_items.rb      | 12 +++++
 components/shop/shop.gemspec                  |  2 +-
 .../app/assets/stylesheets/application.css    |  1 +
 components/shop/spec/dummy/db/schema.rb       | 16 ++++++-
 .../shop/spec/factories/order_factory.rb      |  7 +++
 .../shop/spec/factories/order_item_factory.rb |  7 +++
 .../spec/features/shop/add_to_cart_spec.rb    | 16 ++++++-
 .../shop/spec/features/shop/home_page_spec.rb |  4 +-
 .../spec/features/shop/shopping_cart_spec.rb  | 23 +++++++++-
 db/schema.rb                                  | 16 ++++++-
 28 files changed, 320 insertions(+), 11 deletions(-)
 create mode 100644 components/shop/app/controllers/shop/order_items_controller.rb
 create mode 100644 components/shop/app/helpers/shop/item_helper.rb
 create mode 100644 components/shop/app/models/shop/order.rb
 create mode 100644 components/shop/app/models/shop/order_item.rb
 create mode 100644 components/shop/app/views/shop/order_items/index.slim
 create mode 100644 components/shop/db/migrate/20210611210804_create_orders.rb
 create mode 100644 components/shop/db/migrate/20210611211002_create_order_items.rb
 create mode 100644 components/shop/spec/factories/order_factory.rb
 create mode 100644 components/shop/spec/factories/order_item_factory.rb

diff --git a/Gemfile b/Gemfile
index 8bd4dbb4f..ec41d2ff7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -23,6 +23,7 @@ gem 'redis', '~>3.2'
 gem 'sidekiq'
 gem 'sidekiq-scheduler', '~> 2.1.4'
 gem 'simple_form'
+gem 'font-awesome-rails'
 
 gem 'courses', path: 'components/courses'
 gem 'shop', path: 'components/shop'
diff --git a/Gemfile.lock b/Gemfile.lock
index 703e125f2..57febba2f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -226,6 +226,8 @@ GEM
     faraday (1.0.1)
       multipart-post (>= 1.2, < 3)
     ffi (1.12.2)
+    font-awesome-rails (4.7.0.7)
+      railties (>= 3.2, < 7)
     formatador (0.2.5)
     friendly_id (5.3.0)
       activerecord (>= 4.0.0)
@@ -650,6 +652,7 @@ DEPENDENCIES
   ez-settings
   factory_bot_rails
   faker
+  font-awesome-rails
   friendly_id (~> 5.1)
   gibbon (~> 3.0)
   groupdate (~> 4.0)
diff --git a/app/assets/stylesheets/app/application.scss b/app/assets/stylesheets/app/application.scss
index 784c887b6..699553472 100644
--- a/app/assets/stylesheets/app/application.scss
+++ b/app/assets/stylesheets/app/application.scss
@@ -14,6 +14,7 @@
 
 @import "https://fonts.googleapis.com/css2?family=Oswald&display=swap'";
 @import "local_fonts";
+@import "font-awesome";
 
 @import "normalize";
 
diff --git a/app/assets/stylesheets/app/base/_base.scss b/app/assets/stylesheets/app/base/_base.scss
index e13171aa0..00a4046df 100644
--- a/app/assets/stylesheets/app/base/_base.scss
+++ b/app/assets/stylesheets/app/base/_base.scss
@@ -134,3 +134,28 @@ q {
 .pk-no-display {
   display: none !important;
 }
+
+.shopping_cart-icon {
+  display: inline-block;
+  position: fixed;
+  left: 1450px;
+  opacity: 80%;
+
+  &:hover {
+    opacity: 100%;
+  }
+}
+
+.cart_table {
+  margin: 40px;
+
+  table {
+    border-collapse: collapse;
+    width: 100%;
+  }
+
+  th, td {
+    text-align: left;
+    padding: 8px;
+  }
+}
\ No newline at end of file
diff --git a/app/helpers/admin/events_helper.rb b/app/helpers/admin/events_helper.rb
index cbe427952..08621ae74 100644
--- a/app/helpers/admin/events_helper.rb
+++ b/app/helpers/admin/events_helper.rb
@@ -42,7 +42,6 @@ def event_status_label(event)
                   class: ['ui label', BG_STATUS_CLASS[event.status.to_sym]]
     end
 
-    # rubocop:disable Metrics/AbcSize
     def event_visitors(event)
       requested = event.pending_visit_requests.length
       approved  = event.approved_visit_requests.length
@@ -56,7 +55,6 @@ def event_visitors(event)
         t('events.index.visitors.visited')   => visited
       }
     end
-    # rubocop:enable Metrics/AbcSize
 
     def event_verified_user_data(event)
       verified = event.verified_visitors.length
diff --git a/app/views/layouts/application.slim b/app/views/layouts/application.slim
index 1d80e12f7..27ed3352f 100644
--- a/app/views/layouts/application.slim
+++ b/app/views/layouts/application.slim
@@ -13,6 +13,7 @@ html
     link rel="icon" type="image/png" href="/favicon-16x16.png" sizes="16x16"
     link rel="manifest" href="/manifest.json"
     link rel="mask-icon" href="/safari-pinned-tab.svg" color="#5bbad5"
+    link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.13.0/css/all.css"
     == render 'layouts/ga/head' if Rails.env.production?
 
   body.pk-main-layout class="#{yield(:main_body_class)}"
diff --git a/components/shop/app/controllers/shop/base_controller.rb b/components/shop/app/controllers/shop/base_controller.rb
index bc4a29bb8..96d7ec022 100644
--- a/components/shop/app/controllers/shop/base_controller.rb
+++ b/components/shop/app/controllers/shop/base_controller.rb
@@ -4,6 +4,10 @@ module Shop
   class BaseController < ApplicationController
     before_action :authenticate_user!
 
+    def current_order
+      session[:order_id] ? Shop::Order.find(session[:order_id]) : []
+    end
+
     private
 
     def render_form
diff --git a/components/shop/app/controllers/shop/items_controller.rb b/components/shop/app/controllers/shop/items_controller.rb
index a3dfaa367..6898d69f4 100644
--- a/components/shop/app/controllers/shop/items_controller.rb
+++ b/components/shop/app/controllers/shop/items_controller.rb
@@ -3,6 +3,22 @@
 module Shop
   class ItemsController < BaseController
     helper_method :items
+    helper_method :current_order
+
+    # @deprecated
+    # def add_to_cart
+    #   cart = session[:cart] || []
+    #   cart << item.id unless cart.include?(item.id)
+
+    #   session[:cart] = cart
+
+    #   redirect_back(fallback_location: root_path, notice: "#{item.name} was successfully added to cart")
+    # end
+
+    # def remove_from_cart
+    #   session[:cart].delete(item.id)
+    #   redirect_back(fallback_location: root_path, notice: "#{item.name} was successfully removed from cart")
+    # end
 
     private
 
diff --git a/components/shop/app/controllers/shop/order_items_controller.rb b/components/shop/app/controllers/shop/order_items_controller.rb
new file mode 100644
index 000000000..8845096a9
--- /dev/null
+++ b/components/shop/app/controllers/shop/order_items_controller.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module Shop
+  class OrderItemsController < BaseController
+    helper_method :item
+    helper_method :order_items
+    helper_method :current_order
+
+    def create
+      order_item = ::Shop::OrderItem.new(item_id: item.id, order_id: order_id, price: item.price)
+      order_item.save
+
+      redirect_to shop_items_path
+    end
+
+    def update
+      order_item.increase_quantity!
+      redirect_to shop_order_items_path
+    end
+
+    def destroy
+      order_item.reduce_quantity!
+      redirect_to shop_order_items_path
+    end
+
+    private
+
+    def order_items
+      order_items = Shop::OrderItem.includes(:item)
+    end
+
+    def order_item
+      @order_items ||= Shop::OrderItem.find(params[:id])
+    end
+
+    def item
+      @items ||= Shop::Item.find(params[:item_id])
+    end
+
+    def order_id
+      session[:order_id] ||= Shop::Order.create.id
+    end
+  end
+end
diff --git a/components/shop/app/helpers/shop/item_helper.rb b/components/shop/app/helpers/shop/item_helper.rb
new file mode 100644
index 000000000..4913c5ad9
--- /dev/null
+++ b/components/shop/app/helpers/shop/item_helper.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module Shop
+  module ItemHelper
+  end
+end
diff --git a/components/shop/app/models/shop/item.rb b/components/shop/app/models/shop/item.rb
index daa6bdf13..d29ded302 100644
--- a/components/shop/app/models/shop/item.rb
+++ b/components/shop/app/models/shop/item.rb
@@ -5,6 +5,7 @@ class Item < ApplicationRecord
     self.table_name = 'shop_items'
 
     has_many :item_images
+    has_many :order_items
     accepts_nested_attributes_for :item_images
 
     scope :active, -> { where(published: true) }
diff --git a/components/shop/app/models/shop/order.rb b/components/shop/app/models/shop/order.rb
new file mode 100644
index 000000000..97a526c57
--- /dev/null
+++ b/components/shop/app/models/shop/order.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+# status: shopping_cart, placed, processing, shipping, complete, canceled
+# user: optional
+# buyer: anonymous user
+# shipment_address
+
+module Shop
+  class Order < ApplicationRecord
+    self.table_name = 'shop_orders'
+
+    enum status: { shopping_cart: 0, placed: 1, processing: 2, shipping: 3, complete: 4, canceled: 5 }
+
+    has_many :order_items
+    has_many :items, through: :order_items
+
+    def total_sum
+      order_items.map(&:price).sum.to_f
+    end
+
+    def order_items_count
+      order_items.count
+    end
+  end
+end
diff --git a/components/shop/app/models/shop/order_item.rb b/components/shop/app/models/shop/order_item.rb
new file mode 100644
index 000000000..c21ae7cce
--- /dev/null
+++ b/components/shop/app/models/shop/order_item.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Shop
+  class OrderItem < ApplicationRecord
+    self.table_name = 'shop_order_items'
+
+    validates_uniqueness_of :item_id
+
+    belongs_to :order
+    belongs_to :item
+
+    def increase_quantity!
+      self.quantity += 1
+      update_price(quantity)
+      save!
+    end
+
+    def reduce_quantity!
+      if self.quantity > 1
+        self.quantity -= 1
+        update_price(quantity)
+        save!
+      else
+        delete_order_item
+      end
+    end
+
+    def delete_order_item
+      destroy!
+    end
+
+    def update_price(qty)
+      self.price = item.price * qty
+    end
+  end
+end
diff --git a/components/shop/app/uploaders/item_image_uploader.rb b/components/shop/app/uploaders/item_image_uploader.rb
index 9e3f8f8ae..99745b955 100644
--- a/components/shop/app/uploaders/item_image_uploader.rb
+++ b/components/shop/app/uploaders/item_image_uploader.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 class ItemImageUploader < CarrierWave::Uploader::Base
-end
\ No newline at end of file
+end
diff --git a/components/shop/app/views/shop/items/index.slim b/components/shop/app/views/shop/items/index.slim
index d69d3fb48..1bb8c3031 100644
--- a/components/shop/app/views/shop/items/index.slim
+++ b/components/shop/app/views/shop/items/index.slim
@@ -1,5 +1,13 @@
 h2.main-header Shop
 
+- if current_order.present?
+  span.shopping_cart-icon
+    = link_to shop_order_items_path do
+      i.fas.fa-shopping-cart.fa-8x
+      div.item_counts
+      span
+        = current_order.order_items_count
+
 .main
   ul.cards
     - items.each do |item|
@@ -9,4 +17,9 @@ h2.main-header Shop
           .card_content
             h2.card_title = item.name
             p.card_text = item.description
-            button.btn.card_btn Add to cart
+            - if current_order.present? && current_order.items.include?(item)
+              = link_to shop_order_items_path do
+                button.btn.card_btn Added to the cart
+            - else
+              = link_to shop_order_items_path(item_id: item.id), method: :post  do
+                button.btn.card_btn Add to cart
\ No newline at end of file
diff --git a/components/shop/app/views/shop/order_items/index.slim b/components/shop/app/views/shop/order_items/index.slim
new file mode 100644
index 000000000..a1731de61
--- /dev/null
+++ b/components/shop/app/views/shop/order_items/index.slim
@@ -0,0 +1,32 @@
+h2.main-header Cart
+
+.cart_table
+  - if current_order.present? && current_order.order_items.any?
+    table
+      thead
+        tr
+          th Image
+          th.company Name
+          th.company Price
+          th.count Count
+      tbody
+        - order_items.each do |item|
+          tr
+            td= image_tag item.item.item_images.first.image_url(:small).to_s, class: 'card_image' if item.item.item_images.first.try(:image_url)
+            td= item.item.name
+            td= item.price
+            td
+              div
+                = link_to shop_order_item_path(item.id), method: :delete  do
+                  i.fas.fa-minus
+
+                = item.quantity
+
+                = link_to shop_order_item_path(item.id), method: :put  do
+                  i.fas.fa-plus
+
+    .total_sum
+      h2 Total
+      h2= current_order.total_sum
+  - else
+    h1 Your cart is empty for now
\ No newline at end of file
diff --git a/components/shop/config/routes.rb b/components/shop/config/routes.rb
index 1a826fb9d..b1c6ad8f6 100644
--- a/components/shop/config/routes.rb
+++ b/components/shop/config/routes.rb
@@ -3,6 +3,7 @@
 Rails.application.routes.draw do
   namespace :shop do
     resources :items, only: %i[index]
+    resources :order_items, only: %i[index create update destroy]
   end
 
   namespace :admin do
diff --git a/components/shop/db/migrate/20210611210804_create_orders.rb b/components/shop/db/migrate/20210611210804_create_orders.rb
new file mode 100644
index 000000000..3ce78d97d
--- /dev/null
+++ b/components/shop/db/migrate/20210611210804_create_orders.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class CreateOrders < ActiveRecord::Migration[5.2]
+  def change
+    create_table :shop_orders do |t|
+      t.integer :status, default: 0
+      t.text :shipment_address
+    end
+  end
+end
diff --git a/components/shop/db/migrate/20210611211002_create_order_items.rb b/components/shop/db/migrate/20210611211002_create_order_items.rb
new file mode 100644
index 000000000..c8a214828
--- /dev/null
+++ b/components/shop/db/migrate/20210611211002_create_order_items.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class CreateOrderItems < ActiveRecord::Migration[5.2]
+  def change
+    create_table :shop_order_items do |t|
+      t.integer :quantity, default: 1
+      t.decimal :price, null: false
+      t.references :item
+      t.references :order
+    end
+  end
+end
diff --git a/components/shop/shop.gemspec b/components/shop/shop.gemspec
index 8f747a731..51f55983a 100644
--- a/components/shop/shop.gemspec
+++ b/components/shop/shop.gemspec
@@ -29,11 +29,11 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'rails', '~> 5.2.2', '>= 5.2.2.1'
 
+  spec.add_dependency 'carrierwave', '~> 1.2'
   spec.add_dependency 'friendly_id'
   spec.add_dependency 'kaminari'
   spec.add_dependency 'simple_form'
   spec.add_dependency 'slim-rails'
-  spec.add_dependency 'carrierwave', '~> 1.2'
 
   spec.add_development_dependency 'capybara'
   spec.add_development_dependency 'faker'
diff --git a/components/shop/spec/dummy/app/assets/stylesheets/application.css b/components/shop/spec/dummy/app/assets/stylesheets/application.css
index 0ebd7fe82..3e01e3d08 100644
--- a/components/shop/spec/dummy/app/assets/stylesheets/application.css
+++ b/components/shop/spec/dummy/app/assets/stylesheets/application.css
@@ -12,4 +12,5 @@
  *
  *= require_tree .
  *= require_self
+ *= require font-awesome
  */
diff --git a/components/shop/spec/dummy/db/schema.rb b/components/shop/spec/dummy/db/schema.rb
index 285f33b28..12bb42d0c 100644
--- a/components/shop/spec/dummy/db/schema.rb
+++ b/components/shop/spec/dummy/db/schema.rb
@@ -12,7 +12,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20_210_514_113_103) do
+ActiveRecord::Schema.define(version: 20_210_611_211_002) do
   create_table 'shop_item_images', force: :cascade do |t|
     t.string 'image'
     t.integer 'item_id'
@@ -30,4 +30,18 @@
     t.datetime 'created_at', null: false
     t.datetime 'updated_at', null: false
   end
+
+  create_table 'shop_order_items', force: :cascade do |t|
+    t.integer 'quantity'
+    t.decimal 'price', null: false
+    t.integer 'item_id'
+    t.integer 'order_id'
+    t.index ['item_id'], name: 'index_shop_order_items_on_item_id'
+    t.index ['order_id'], name: 'index_shop_order_items_on_order_id'
+  end
+
+  create_table 'shop_orders', force: :cascade do |t|
+    t.integer 'status', default: 0
+    t.text 'shipment_address'
+  end
 end
diff --git a/components/shop/spec/factories/order_factory.rb b/components/shop/spec/factories/order_factory.rb
new file mode 100644
index 000000000..1811b47e5
--- /dev/null
+++ b/components/shop/spec/factories/order_factory.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :order, class: Shop::Order do
+    shipment_address { 'Lviv, Pivorak street' }
+  end
+end
diff --git a/components/shop/spec/factories/order_item_factory.rb b/components/shop/spec/factories/order_item_factory.rb
new file mode 100644
index 000000000..ce7fdc606
--- /dev/null
+++ b/components/shop/spec/factories/order_item_factory.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :order_item, class: Shop::OrderItem do
+    price { 12 }
+  end
+end
diff --git a/components/shop/spec/features/shop/add_to_cart_spec.rb b/components/shop/spec/features/shop/add_to_cart_spec.rb
index 5179920ef..f047ab6d8 100644
--- a/components/shop/spec/features/shop/add_to_cart_spec.rb
+++ b/components/shop/spec/features/shop/add_to_cart_spec.rb
@@ -1,2 +1,16 @@
 # frozen_string_literal: true
-# TODO
+
+require 'rails_helper'
+
+RSpec.describe '/shop' do
+  let!(:active_item) { create(:item, published: true) }
+
+  scenario 'display items' do
+    visit shop_items_path
+
+    click_button 'Add to cart'
+
+    expect(page).to have_current_path '/shop/items'
+    # expect(page).to have_button('Added to the cart')
+  end
+end
diff --git a/components/shop/spec/features/shop/home_page_spec.rb b/components/shop/spec/features/shop/home_page_spec.rb
index c7ff126f1..8e266a2e4 100644
--- a/components/shop/spec/features/shop/home_page_spec.rb
+++ b/components/shop/spec/features/shop/home_page_spec.rb
@@ -8,10 +8,10 @@
     let!(:item_b) { create(:item, published: false) }
 
     scenario 'display items' do
-      visit admin_shop_items_path
+      visit shop_items_path
 
       expect(page).to have_content item_a.name
-      expect(page).to have_content item_b.name
+      expect(page).to have_button('Add to cart')
     end
   end
 end
diff --git a/components/shop/spec/features/shop/shopping_cart_spec.rb b/components/shop/spec/features/shop/shopping_cart_spec.rb
index 464090415..203b33ba3 100644
--- a/components/shop/spec/features/shop/shopping_cart_spec.rb
+++ b/components/shop/spec/features/shop/shopping_cart_spec.rb
@@ -1 +1,22 @@
-# TODO
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Shop Cart list' do
+  let!(:active_item) { create(:item, published: true) }
+  let!(:order)       { create(:order) }
+  let!(:order_item)  { create(:order_item, order: order, item: active_item) }
+
+  # scenario 'display items' do
+  #   session[:order_id] = order.id
+  #   visit shop_order_items_path
+
+  #   expect(page).to have_content active_item.name
+  # end
+
+  scenario 'display empty cart' do
+    visit shop_order_items_path
+
+    expect(page).not_to have_content active_item.name
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index dd483650b..b6cfa8be6 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2021_05_14_113103) do
+ActiveRecord::Schema.define(version: 2021_06_11_211002) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -252,6 +252,20 @@
     t.datetime "updated_at", null: false
   end
 
+  create_table "shop_order_items", force: :cascade do |t|
+    t.integer "quantity", default: 1
+    t.decimal "price", null: false
+    t.bigint "item_id"
+    t.bigint "order_id"
+    t.index ["item_id"], name: "index_shop_order_items_on_item_id"
+    t.index ["order_id"], name: "index_shop_order_items_on_order_id"
+  end
+
+  create_table "shop_orders", force: :cascade do |t|
+    t.integer "status", default: 0
+    t.text "shipment_address"
+  end
+
   create_table "taggings", id: :serial, force: :cascade do |t|
     t.integer "tag_id"
     t.string "taggable_type"

From a7cf6271b085be0110316987378146abfdfb808b Mon Sep 17 00:00:00 2001
From: Volodya Sveredyuk <sveredyuk@gmail.com>
Date: Wed, 16 Jun 2021 18:58:14 +0300
Subject: [PATCH 2/3] OrderItemService

---
 .../app/controllers/shop/base_controller.rb   |  6 +++-
 .../app/controllers/shop/items_controller.rb  | 16 ---------
 .../shop/order_items_controller.rb            | 12 +++----
 .../app/decorators/shop/base_decorator.rb     |  4 +++
 .../decorators/shop/order_item_decorator.rb   |  7 ++++
 components/shop/app/models/shop/order.rb      | 13 ++++----
 components/shop/app/models/shop/order_item.rb | 24 --------------
 .../app/services/shop/order_item_service.rb   | 21 ++++++++++++
 .../shop/app/views/shop/items/index.slim      |  2 +-
 .../app/views/shop/order_items/index.slim     |  4 +--
 .../spec/features/shop/add_to_cart_spec.rb    |  2 +-
 .../spec/features/shop/shopping_cart_spec.rb  | 11 ++++---
 .../services/shop/order_item_service_spec.rb  | 33 +++++++++++++++++++
 13 files changed, 93 insertions(+), 62 deletions(-)
 create mode 100644 components/shop/app/decorators/shop/base_decorator.rb
 create mode 100644 components/shop/app/decorators/shop/order_item_decorator.rb
 create mode 100644 components/shop/app/services/shop/order_item_service.rb
 create mode 100644 components/shop/spec/services/shop/order_item_service_spec.rb

diff --git a/components/shop/app/controllers/shop/base_controller.rb b/components/shop/app/controllers/shop/base_controller.rb
index 96d7ec022..c245b1929 100644
--- a/components/shop/app/controllers/shop/base_controller.rb
+++ b/components/shop/app/controllers/shop/base_controller.rb
@@ -4,8 +4,12 @@ module Shop
   class BaseController < ApplicationController
     before_action :authenticate_user!
 
+    helper_method :current_order
+
     def current_order
-      session[:order_id] ? Shop::Order.find(session[:order_id]) : []
+      return unless session[:order_id]
+
+      @current_order ||= Shop::Order.find(session[:order_id])
     end
 
     private
diff --git a/components/shop/app/controllers/shop/items_controller.rb b/components/shop/app/controllers/shop/items_controller.rb
index 6898d69f4..a3dfaa367 100644
--- a/components/shop/app/controllers/shop/items_controller.rb
+++ b/components/shop/app/controllers/shop/items_controller.rb
@@ -3,22 +3,6 @@
 module Shop
   class ItemsController < BaseController
     helper_method :items
-    helper_method :current_order
-
-    # @deprecated
-    # def add_to_cart
-    #   cart = session[:cart] || []
-    #   cart << item.id unless cart.include?(item.id)
-
-    #   session[:cart] = cart
-
-    #   redirect_back(fallback_location: root_path, notice: "#{item.name} was successfully added to cart")
-    # end
-
-    # def remove_from_cart
-    #   session[:cart].delete(item.id)
-    #   redirect_back(fallback_location: root_path, notice: "#{item.name} was successfully removed from cart")
-    # end
 
     private
 
diff --git a/components/shop/app/controllers/shop/order_items_controller.rb b/components/shop/app/controllers/shop/order_items_controller.rb
index 8845096a9..406905211 100644
--- a/components/shop/app/controllers/shop/order_items_controller.rb
+++ b/components/shop/app/controllers/shop/order_items_controller.rb
@@ -2,9 +2,7 @@
 
 module Shop
   class OrderItemsController < BaseController
-    helper_method :item
-    helper_method :order_items
-    helper_method :current_order
+    helper_method :item, :order_items
 
     def create
       order_item = ::Shop::OrderItem.new(item_id: item.id, order_id: order_id, price: item.price)
@@ -14,19 +12,21 @@ def create
     end
 
     def update
-      order_item.increase_quantity!
+      OrderItemService.new(order_item).increase_quantity!
       redirect_to shop_order_items_path
     end
 
     def destroy
-      order_item.reduce_quantity!
+      OrderItemService.new(order_item).reduce_quantity!
       redirect_to shop_order_items_path
     end
 
     private
 
     def order_items
-      order_items = Shop::OrderItem.includes(:item)
+      @order_items ||= Shop::OrderItem.includes(:item).map do |order_item|
+        Shop::OrderItemDecorator.new(order_item)
+      end
     end
 
     def order_item
diff --git a/components/shop/app/decorators/shop/base_decorator.rb b/components/shop/app/decorators/shop/base_decorator.rb
new file mode 100644
index 000000000..190764d04
--- /dev/null
+++ b/components/shop/app/decorators/shop/base_decorator.rb
@@ -0,0 +1,4 @@
+module Shop
+  class BaseDecorator < SimpleDelegator
+  end
+end
diff --git a/components/shop/app/decorators/shop/order_item_decorator.rb b/components/shop/app/decorators/shop/order_item_decorator.rb
new file mode 100644
index 000000000..aef29d376
--- /dev/null
+++ b/components/shop/app/decorators/shop/order_item_decorator.rb
@@ -0,0 +1,7 @@
+module Shop
+  class OrderItemDecorator < BaseDecorator
+    def sum
+      price * quantity
+    end
+  end
+end
diff --git a/components/shop/app/models/shop/order.rb b/components/shop/app/models/shop/order.rb
index 97a526c57..ceb328584 100644
--- a/components/shop/app/models/shop/order.rb
+++ b/components/shop/app/models/shop/order.rb
@@ -14,12 +14,13 @@ class Order < ApplicationRecord
     has_many :order_items
     has_many :items, through: :order_items
 
-    def total_sum
-      order_items.map(&:price).sum.to_f
-    end
+    # TODO: OrderDecorator
+    # def total_sum
+    #   order_items.map(&:price).sum.to_f
+    # end
 
-    def order_items_count
-      order_items.count
-    end
+    # def order_items_count
+    #   order_items.count
+    # end
   end
 end
diff --git a/components/shop/app/models/shop/order_item.rb b/components/shop/app/models/shop/order_item.rb
index c21ae7cce..16af4dcf6 100644
--- a/components/shop/app/models/shop/order_item.rb
+++ b/components/shop/app/models/shop/order_item.rb
@@ -8,29 +8,5 @@ class OrderItem < ApplicationRecord
 
     belongs_to :order
     belongs_to :item
-
-    def increase_quantity!
-      self.quantity += 1
-      update_price(quantity)
-      save!
-    end
-
-    def reduce_quantity!
-      if self.quantity > 1
-        self.quantity -= 1
-        update_price(quantity)
-        save!
-      else
-        delete_order_item
-      end
-    end
-
-    def delete_order_item
-      destroy!
-    end
-
-    def update_price(qty)
-      self.price = item.price * qty
-    end
   end
 end
diff --git a/components/shop/app/services/shop/order_item_service.rb b/components/shop/app/services/shop/order_item_service.rb
new file mode 100644
index 000000000..eeb891fd9
--- /dev/null
+++ b/components/shop/app/services/shop/order_item_service.rb
@@ -0,0 +1,21 @@
+module Shop
+  class OrderItemService
+    attr_reader :order_item
+
+    def initialize(order_item)
+      @order_item = order_item
+    end
+
+    def increase_quantity!
+      order_item.increment!(:quantity)
+    end
+
+    def reduce_quantity!
+      if order_item.quantity > 1
+        order_item.decrement!(:quantity)
+      else
+        order_item.destroy!
+      end
+    end
+  end
+end
diff --git a/components/shop/app/views/shop/items/index.slim b/components/shop/app/views/shop/items/index.slim
index 1bb8c3031..e3224d4d9 100644
--- a/components/shop/app/views/shop/items/index.slim
+++ b/components/shop/app/views/shop/items/index.slim
@@ -22,4 +22,4 @@ h2.main-header Shop
                 button.btn.card_btn Added to the cart
             - else
               = link_to shop_order_items_path(item_id: item.id), method: :post  do
-                button.btn.card_btn Add to cart
\ No newline at end of file
+                button.btn.card_btn Add to cart
diff --git a/components/shop/app/views/shop/order_items/index.slim b/components/shop/app/views/shop/order_items/index.slim
index a1731de61..95fee80f9 100644
--- a/components/shop/app/views/shop/order_items/index.slim
+++ b/components/shop/app/views/shop/order_items/index.slim
@@ -14,7 +14,7 @@ h2.main-header Cart
           tr
             td= image_tag item.item.item_images.first.image_url(:small).to_s, class: 'card_image' if item.item.item_images.first.try(:image_url)
             td= item.item.name
-            td= item.price
+            td= item.sum
             td
               div
                 = link_to shop_order_item_path(item.id), method: :delete  do
@@ -29,4 +29,4 @@ h2.main-header Cart
       h2 Total
       h2= current_order.total_sum
   - else
-    h1 Your cart is empty for now
\ No newline at end of file
+    h1 Your cart is empty for now
diff --git a/components/shop/spec/features/shop/add_to_cart_spec.rb b/components/shop/spec/features/shop/add_to_cart_spec.rb
index f047ab6d8..da51b5e6d 100644
--- a/components/shop/spec/features/shop/add_to_cart_spec.rb
+++ b/components/shop/spec/features/shop/add_to_cart_spec.rb
@@ -11,6 +11,6 @@
     click_button 'Add to cart'
 
     expect(page).to have_current_path '/shop/items'
-    # expect(page).to have_button('Added to the cart')
+    expect(page).to have_button('Added to the cart')
   end
 end
diff --git a/components/shop/spec/features/shop/shopping_cart_spec.rb b/components/shop/spec/features/shop/shopping_cart_spec.rb
index 203b33ba3..944671411 100644
--- a/components/shop/spec/features/shop/shopping_cart_spec.rb
+++ b/components/shop/spec/features/shop/shopping_cart_spec.rb
@@ -7,12 +7,13 @@
   let!(:order)       { create(:order) }
   let!(:order_item)  { create(:order_item, order: order, item: active_item) }
 
-  # scenario 'display items' do
-  #   session[:order_id] = order.id
-  #   visit shop_order_items_path
+  fscenario 'display items' do
+    # TODO: Mock controller session object
+    # session[:order_id] = order.id
+    visit shop_order_items_path
 
-  #   expect(page).to have_content active_item.name
-  # end
+    expect(page).to have_content active_item.name
+  end
 
   scenario 'display empty cart' do
     visit shop_order_items_path
diff --git a/components/shop/spec/services/shop/order_item_service_spec.rb b/components/shop/spec/services/shop/order_item_service_spec.rb
new file mode 100644
index 000000000..fa7e8f077
--- /dev/null
+++ b/components/shop/spec/services/shop/order_item_service_spec.rb
@@ -0,0 +1,33 @@
+require 'rails_helper'
+
+RSpec.describe Shop::OrderItemService do
+  let(:order)       { create(:order) }
+  let(:item)        { create(:item) }
+  let!(:order_item) { create(:order_item, quantity: 1, order: order, item: item) }
+
+  describe '#increase_quantity!' do
+    subject { described_class.new(order_item).increase_quantity! }
+
+    it 'increase order item qty' do
+      expect { subject }.to change { order_item.quantity }.from(1).to(2)
+    end
+  end
+
+  describe '#reduce_quantity!' do
+    subject { described_class.new(order_item).reduce_quantity! }
+
+    context 'when > 1' do
+      let(:order_item) { create(:order_item, quantity: 3, order: order, item: item) }
+
+      it 'increase order item qty' do
+        expect { subject }.to change { order_item.quantity }.from(3).to(2)
+      end
+    end
+
+    context 'when eq 1' do
+      it 'increase order item qty' do
+        expect { subject }.to change { Shop::OrderItem.count }.from(1).to(0)
+      end
+    end
+  end
+end

From a0571f8efdd673a531152a3b0a0f44e49fb361df Mon Sep 17 00:00:00 2001
From: Volodya Sveredyuk <sveredyuk@gmail.com>
Date: Wed, 16 Jun 2021 18:59:12 +0300
Subject: [PATCH 3/3] Find current order by id without 404 error

---
 components/shop/app/controllers/shop/base_controller.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/components/shop/app/controllers/shop/base_controller.rb b/components/shop/app/controllers/shop/base_controller.rb
index c245b1929..7fde64dba 100644
--- a/components/shop/app/controllers/shop/base_controller.rb
+++ b/components/shop/app/controllers/shop/base_controller.rb
@@ -9,7 +9,7 @@ class BaseController < ApplicationController
     def current_order
       return unless session[:order_id]
 
-      @current_order ||= Shop::Order.find(session[:order_id])
+      @current_order ||= Shop::Order.find_by(id: session[:order_id])
     end
 
     private