form_object_helpers.rb

module FormObjectHelpers
  extend ActiveSupport::Concern

  included do
    def form(klass, attributes = {}, options = {})
      form = klass.new(current_user, params, attributes)
      authorize_model(form, options)

      yield form if block_given?
      render action_name, locals: { form: form }
    end

    def run(klass, attributes = {}, options = {})
      form = klass.new(current_user, params, attributes)
      authorize_model(form, options)
      yield form if block_given?

      call_form(form, options)
    end

    private

    def authorize_model(form, options = {})
      authorize form.model if options.fetch(:authorize, true)
    end

    def call_form(form, options)
      on_success, on_fail, after_success, after_fail = extract_callbacks(options)

      if form.valid?
        form.call

        on_success.(form.model, form)
        after_success.(form.model, form)
      else
        on_fail.(form.model, form)
        after_fail.(form.model, form)
      end
    end

    def extract_callbacks(options = {})
      [
          options.fetch(:on_success, -> (model, _) { respond_with model, options.slice(:notice, :status) }),
          options.fetch(:on_fail, -> (model, _) { respond_with model, options.slice(:alert, :status) }),
          options.fetch(:after_success, -> (*) {}),
          options.fetch(:after_fail, -> (*) {})
      ]
    end
  end
end