class Rating < ActiveRecord::Base
  belongs_to :rateable, :polymorphic => true

  validates_presence_of :rateable_type, :rateable_id
  validates_numericality_of :value
  validate :maximum_value_is_not_breached
   
  before_save :delete_last_rating
 
  def self.find_similar(rating)
    Rating.find(
      :first, 
      :conditions => {
        :ip_address => rating.ip_address,
        :rateable_id => rating.rateable_id,
        :rateable_type => rating.rateable_type 
      }
    )
  end

  protected
    def maximum_value_is_not_breached
      errors.add('value', 'is not in the range') unless rateable.rating_range.include?(value)
    end
  
    def delete_last_rating
      if (rating = Rating.find_similar(self))
        rating.destroy
      end
    end
end