class ActiveRecord::Associations::BelongsToPolymorphicAssociation

def association_class
  @owner[@reflection.options[:foreign_type]].present? ? @owner[@reflection.options[:foreign_type]].constantize : nil
end

def conditions
  @conditions ||= @reflection.options[:conditions] && interpolate_and_sanitize_sql(@reflection.options[:conditions], nil, association_class)
end

def find_target
  return nil if association_class.nil?
  target =
    if @reflection.options[:conditions]
      association_class.find(
        @owner[@reflection.primary_key_name],
        :select     => @reflection.options[:select],
        :conditions => conditions,
        :include    => @reflection.options[:include]
      )
    else
      association_class.find(@owner[@reflection.primary_key_name], :select => @reflection.options[:select], :include => @reflection.options[:include])
    end
  set_inverse_instance(target, @owner)
  target
end

def foreign_key_present
  !@owner[@reflection.primary_key_name].nil?
end

def record_id(record)
  record.send(@reflection.options[:primary_key] || :id)
end

def replace(record)
  if record.nil?
    @target = @owner[@reflection.primary_key_name] = @owner[@reflection.options[:foreign_type]] = nil
  else
    @target = (AssociationProxy === record ? record.target : record)
    @owner[@reflection.primary_key_name] = record_id(record)
    @owner[@reflection.options[:foreign_type]] = record.class.base_class.name.to_s
    @updated = true
  end
  set_inverse_instance(record, @owner)
  loaded
  record
end

def set_inverse_instance(record, instance)
  return if record.nil? || !we_can_set_the_inverse_on_this?(record)
  inverse_relationship = @reflection.polymorphic_inverse_of(record.class)
  unless inverse_relationship.nil?
    record.send(:"set_#{inverse_relationship.name}_target", instance)
  end
end

def updated?
  @updated
end

def we_can_set_the_inverse_on_this?(record)
  if @reflection.has_inverse?
    inverse_association = @reflection.polymorphic_inverse_of(record.class)
    inverse_association && inverse_association.macro == :has_one
  else
    false
  end
end