module Pagy::GearboxExtra

def setup_offset_var
  return super if !@vars[:gearbox_extra] || @vars[:items_extra]
  gearbox_items = @vars[:gearbox_items]
  @offset       = if @page <= gearbox_items.count
                    gearbox_items[0, @page - 1].sum
                  else
                    gearbox_items.sum + (gearbox_items.last * (@page - gearbox_items.count - 1))
                  end + @outset
end