dcaliri

class Bill
  def assign_rps_number_and_serial(save_it = nil)
    rps = Bill.order(:rps_serial, :rps_number).where('rps_number IS NOT NULL').select(:rps_number, :rps_serial).last
    number = rps.try(:rps_number) || 1
    serial = rps.try(:rps_serial) || 'A'

    self.rps_number, self.rps_serial = if number < 999999999999
                                         [number + 1, serial]
                                       else
                                         [1, serial + 'A']