/backend/app/controllers/spree/admin/promotions_controller.rb

module Spree
  module Admin
    class PromotionsController < ResourceController
      before_action :load_data

      helper 'spree/admin/promotion_rules'

      protected

      def location_after_save
        spree.edit_admin_promotion_url(@promotion)
      end

      def load_data
        @calculators = Rails.application.config.spree.calculators.promotion_actions_create_adjustments
        @promotion_categories = Spree::PromotionCategory.order(:name)
      end

      def collection
        return @collection if defined?(@collection)
        params[:q] ||= HashWithIndifferentAccess.new
        params[:q][:s] ||= 'id desc'

        @collection = super
        @search = @collection.ransack(params[:q])
        @collection = @search.result(distinct: true).
                      includes(promotion_includes).
                      page(params[:page]).
                      per(params[:per_page] || Spree::Config[:admin_promotions_per_page])
      end

      def promotion_includes
        [:promotion_actions]
      end
    end
  end
end