module Spree
  class Referral < Spree::Base
    belongs_to :user, class_name: Spree.user_class.to_s
    has_many :referred_records

    validates_presence_of :user_id, :code

    before_validation :attach_code, on: :create

    def referred_users
      referred_records.includes(:user).collect(&:user).compact
    end

    def referred_orders
      referred_records_with_user_orders.collect{|u| u.user.orders }.flatten.compact
    end

    def referral_activated_users
      referred_records_with_user_orders.select{|u| post_referral_order?(u) }.collect(&:user)
    end

    protected
      def attach_code
        self.code = loop do
          code =  (0...8).map { (65 + rand(26)).chr }.join
          break code unless Referral.exists?(code: code)
        end
      end

   private

    def referred_records_with_user_orders
      referred_records.includes({:user => :orders})
    end

    def post_referral_order?(referred_record)
      referred_record.user.orders.where('completed_at > ?', self.user.created_at).any?
    end
  end
end