module RailsTrade::PromoteBuyer
  extend ActiveSupport::Concern
  included do
    attribute :state, :string, default: 'unused'
    attribute :status, :string, default: 'available'
    attribute :effect_at, :datetime
    attribute :expire_at, :datetime
    attribute :trade_promotes_count, :integer, default: 0
    
    belongs_to :promote
    belongs_to :promote_good, optional: true
    belongs_to :buyer, polymorphic: true
    has_many :trade_promotes, dependent: :nullify
    
    enum state: {
      unused: 'unused',
      used: 'used'
    }

    scope :valid, -> { t = Time.current; unused.default_where('expire_at-gte': t, 'effect_at-lte': t) }
    
    before_validation do
      self.promote = self.promote_good.promote
    end
  end

end