module Bullet
  module ActiveRecord
    def self.enable
      ::ActiveRecord::Base.class_eval do
        class << self
          alias_method :origin_find_every, :find_every
          # if select a collection of objects, then these objects have possible to cause N+1 query
          # if select only one object, then the only one object has impossible to cause N+1 query
          def find_every(options)
            records = origin_find_every(options)

            if records 
              if records.size > 1
                Bullet::Association.add_possible_objects(records)
              elsif records.size == 1
                Bullet::Association.add_impossible_object(records.first)
              end
            end

            records
          end
        end
      end

      ::ActiveRecord::AssociationPreload::ClassMethods.class_eval do
        alias_method :origin_preload_associations, :preload_associations
        # add include for one to many associations query
        def preload_associations(records, associations, preload_options={})
          records = [records].flatten.compact.uniq
          return if records.empty?
          records.each do |record|
            Bullet::Association.add_association(record, associations)
          end
          Bullet::Association.add_eager_loadings(records, associations)
          origin_preload_associations(records, associations, preload_options={})
        end
      end

      ::ActiveRecord::Associations::ClassMethods.class_eval do
        # define one to many associations
        alias_method :origin_collection_reader_method, :collection_reader_method
        def collection_reader_method(reflection, association_proxy_class)
          Bullet::Association.define_association(self, reflection.name)
          origin_collection_reader_method(reflection, association_proxy_class)
        end
      end

      ::ActiveRecord::Associations::AssociationCollection.class_eval do
        # call one to many associations
        alias_method :origin_load_target, :load_target
        def load_target
          Bullet::Association.call_association(@owner, @reflection.name)
          origin_load_target
        end  
      end
      
      ::ActiveRecord::Associations::AssociationProxy.class_eval do
        # call has_one and belong_to association
        alias_method :origin_load_target, :load_target
        def load_target
          Bullet::Association.call_association(@owner, @reflection.name)
          origin_load_target
        end
      end
    end
  end
end