class Rails::AppUpdater

def app_generator
  @app_generator ||= begin
    gen = Rails::Generators::AppGenerator.new ["rails"], generator_options, destination_root: Rails.root
    gen.send(:valid_const?) unless File.exist?(Rails.root.join("config", "application.rb"))
    gen
  end
end

def generator_options
  options = { api: !!Rails.application.config.api_only, update: true }
  options[:skip_active_job]     = !defined?(ActiveJob::Railtie)
  options[:skip_active_record]  = !defined?(ActiveRecord::Railtie)
  options[:skip_active_storage] = !defined?(ActiveStorage::Engine)
  options[:skip_action_mailer]  = !defined?(ActionMailer::Railtie)
  options[:skip_action_mailbox] = !defined?(ActionMailbox::Engine)
  options[:skip_action_text]    = !defined?(ActionText::Engine)
  options[:skip_action_cable]   = !defined?(ActionCable::Engine)
  options[:skip_test]           = !defined?(Rails::TestUnitRailtie)
  options[:skip_system_test]    = Rails.application.config.generators.system_tests.nil?
  options[:skip_asset_pipeline] = !defined?(Sprockets::Railtie) && !defined?(Propshaft::Railtie)
  options[:skip_bootsnap]       = !defined?(Bootsnap)
  options[:updating]            = true
  options
end

def invoke_from_app_generator(method)
  app_generator.send(method)
end