module Kaminari::ActiveRecord

def self.inherited(kls)
  # TERRIBLE HORRIBLE NO GOOD VERY BAD HACK: inheritable_attributes is not yet set here on AR 3.0
  unless kls.default_scoping
    new_inheritable_attributes = Hash[inheritable_attributes.map do |key, value|
      [key, value.duplicable? ? value.dup : value]
    end]
    kls.instance_variable_set('@inheritable_attributes', new_inheritable_attributes)
  end
  kls.class_eval do
    # page(5)
    scope :page, lambda {|num|
      offset(PER_PAGE * ([num.to_i, 1].max - 1)).limit(PER_PAGE)
    } do
      # page(3).per(10)
      def per(num)
        offset(offset_value / limit_value * num).limit(num)
      end
      def num_pages
        (except(:offset, :limit).count.to_f / limit_value).ceil
      end
      def current_page
        (offset_value / limit_value) + 1
      end
    end
  end
end

def current_page
  (offset_value / limit_value) + 1
end

def num_pages
  (except(:offset, :limit).count.to_f / limit_value).ceil
end

def per(num)
  offset(offset_value / limit_value * num).limit(num)
end