rubocop corrections

app/controllers/application_controller.rb

@@ -1,3 +1,6 @@
+# frozen_string_literal: true
+
+# Base for application controllers
 class ApplicationController < ActionController::Base
   helper_method :current_user
   helper_method :logged_in?
@@ -5,7 +8,7 @@ class ApplicationController < ActionController::Base
   def current_user
     User.find_by(id: session[:user_id])
   end
-  
+
   def logged_in?
     !current_user.nil?
   end
@@ -13,15 +16,13 @@ class ApplicationController < ActionController::Base
   protected
 
   def notices_from_errors(record)
-    messages = record.errors.messages.map do |attribute, messages|
+    errors = record.errors.messages.map do |attribute, messages|
       messages.map { |message| "#{attribute} #{message}".capitalize }
     end
-    messages.flatten
+    errors.flatten
   end
 
   def ensure_admin
-    unless current_user&.admin?
-      redirect_to '/welcome', notice: 'You are not allowed to perform this action'
-    end
+    redirect_to '/welcome', notice: 'You are not allowed to perform this action' unless current_user&.admin?
   end
 end

app/controllers/authors_controller.rb

@@ -1,6 +1,9 @@
+# frozen_string_literal: true
+
+# Authors controller
 class AuthorsController < ApplicationController
   before_action :ensure_admin
-  before_action :set_author, only: [:edit, :update]
+  before_action :set_author, only: %i[edit update]
 
   def index
     @authors = Author.all
@@ -11,9 +14,7 @@ class AuthorsController < ApplicationController
   end
 
   def update
-    if @author.update(author_params)
-      redirect_to '/authors'
-    end
+    redirect_to '/authors' if @author.update(author_params)
   end
 
   private

app/controllers/books_controller.rb

@@ -1,26 +1,25 @@
+# frozen_string_literal: true
+
+# Books controller
 class BooksController < ApplicationController
-  before_action :set_book, only: [:show, :edit, :update, :add_to_cart]
-  before_action :ensure_admin, only: [:edit, :update]
+  before_action :set_book, only: %i[show edit update add_to_cart]
+  before_action :ensure_admin, only: %i[edit update]
 
   def index
-    if current_user&.admin?
-      books = Book.all
-    else
-      books = Book.published
-    end
+    books = if current_user&.admin?
+              Book.all
+            else
+              Book.published
+            end
     @books = books.map { |book| BooksPresenter.new(book) }
   end
 
-  def show
-  end
+  def show; end
 
-  def edit
-  end
+  def edit; end
 
   def update
-    if @book.update(book_params)
-      redirect_to '/books'
-    end
+    redirect_to '/books' if @book.update(book_params)
   end
 
   def add_to_cart

app/controllers/sessions_controller.rb

@@ -1,23 +1,18 @@
+# frozen_string_literal: true
+
+# Sessions controller
 class SessionsController < ApplicationController
-  def new
-  end
+  def new; end
 
   def create
     @user = User.find_by(email: params[:email])
-    unless @user
-      redirect_to '/welcome', notice: 'Wrong email address'
-      return
+    problem = problem_with_login
+    if problem
+      redirect_to '/welcome', notice: problem
+    else
+      session[:user_id] = @user.id
+      redirect_to '/welcome'
     end
-    unless @user.authenticate(params[:password])
-      redirect_to '/welcome', notice: 'Wrong password'
-      return
-    end
-    if @user.blocked?
-      redirect_to '/welcome', notice: 'You are blocked, please contact support'
-      return
-    end
-    session[:user_id] = @user.id
-    redirect_to '/welcome'
   end
 
   def delete
@@ -25,6 +20,17 @@ class SessionsController < ApplicationController
     redirect_to '/welcome', notice: 'Logged out properly'
   end
 
-  def welcome
+  def welcome; end
+
+  private
+
+  def problem_with_login
+    if !@user
+      'Wrong email address'
+    elsif !@user.authenticate(params[:password])
+      'Wrong password'
+    elsif @user.blocked?
+      'You are blocked, please contact support'
+    end
   end
 end

app/controllers/users_controller.rb

@@ -1,5 +1,8 @@
+# frozen_string_literal: true
+
+# Users controller
 class UsersController < ApplicationController
-  before_action :ensure_admin, only: [:destroy, :block]
+  before_action :ensure_admin, only: %i[destroy block]
 
   def index
     @users = User.all
@@ -21,15 +24,14 @@ class UsersController < ApplicationController
 
   def password_recovery_request
     @user = User.where(email: params['email']).first
-    recovery_password = ('a'..'z').to_a.shuffle[0,8].join
+    recovery_password = ('a'..'z').to_a.sample(8).join
     @user.recovery_password = recovery_password
     @user.save
     UserMailer.with(user: @user, recovery_password: recovery_password).password_recovery.deliver_now
     redirect_to '/welcome', notice: "Recovery email sent to #{params['email']}"
   end
 
-  def password_recovery_request_form
-  end
+  def password_recovery_request_form; end
 
   def recover_password_form
     @recovery_password = params[:recovery_password]