internetee-registry/app/controllers/admin/sessions_controller.rb

module Admin
  class SessionsController < Devise::SessionsController
    skip_authorization_check only: :create

    def login
      @admin_user = AdminUser.new
    end

    def create
      if params[:admin_user].blank?
        @admin_user = AdminUser.new
        flash[:alert] = 'Something went wrong'
        return render 'login'
      end

      @admin_user = AdminUser.find_by(username: params[:admin_user][:username])
      @admin_user ||= AdminUser.new(username: params[:admin_user][:username])

      if @admin_user.valid_password?(params[:admin_user][:password])
        sign_in @admin_user, event: :authentication
        redirect_to admin_root_url, notice: I18n.t(:welcome)
      else
        flash[:alert] = 'Authorization error'
        render 'login'
      end
    end
  end
end