Refactor UsersController#create

* Simplify controller action
* Extract service classes

app/services/user_activator.rb

@@ -0,0 +1,70 @@
+class UserActivator
+  attr_reader :user, :request, :session, :cookies, :message
+
+  def initialize(user, request, session, cookies)
+    @user = user
+    @session = session
+    @cookies = cookies
+    @request = request
+    @settings = SiteSetting
+    @hub = DiscourseHub
+    @message = nil
+  end
+
+  def start
+    register_nickname
+  end
+
+  def finish
+    @message = activator.activate
+  end
+
+  private
+
+  def activator
+    factory.new(user, request, session, cookies)
+  end
+
+  def factory
+    if @settings.must_approve_users?
+      ApprovalActivator
+    elsif !user.active?
+      EmailActivator
+    else
+      LoginActivator
+    end
+  end
+
+  def register_nickname
+    if user.valid? && @settings.call_discourse_hub?
+      @hub.register_nickname(user.username, user.email)
+    end
+  end
+end
+
+class ApprovalActivator < UserActivator
+  def activate
+    I18n.t("login.wait_approval")
+  end
+end
+
+class EmailActivator < UserActivator
+  def activate
+    Jobs.enqueue(:user_email,
+      type: :signup,
+      user_id: user.id,
+      email_token: user.email_tokens.first.token
+    )
+    I18n.t("login.activate_email", email: user.email)
+  end
+end
+
+class LoginActivator < UserActivator
+  include CurrentUser
+
+  def activate
+    log_on_user(user)
+    user.enqueue_welcome_message('welcome_user')
+    I18n.t("login.active")
+  end
+end

app/services/user_authenticator.rb

@@ -0,0 +1,39 @@
+class UserAuthenticator
+  def initialize(user, session, authenticator_finder = Users::OmniauthCallbacksController)
+    @user = user
+    @session = session[:authentication]
+    @authenticator_finder = authenticator_finder
+  end
+
+  def start
+    if authenticated?
+      @user.active = true
+    else
+      @user.password_required!
+    end
+  end
+
+  def finish
+    if authenticator
+      authenticator.after_create_account(@user, @session)
+    end
+
+    @session = nil
+  end
+
+  private
+
+  def authenticated?
+    @session && @session[:email] == @user.email && @session[:email_valid]
+  end
+
+  def authenticator
+    if authenticator_name
+      @authenticator ||= @authenticator_finder.find_authenticator(authenticator_name)
+    end
+  end
+
+  def authenticator_name
+    @session && @session[:authenticator_name]
+  end
+end