class Nvr

# File lib/nvr.rb, line 11
def initialize(value)
  self.nip = value
end

# File lib/nvr.rb, line 15
def nip=(value)
  @nip = value.to_s.delete(" ").delete("-")
end

# File lib/nvr.rb, line 20
def checksum
  errors.add(:nip) unless control_number == nip[9].to_i
end

# File lib/nvr.rb, line 30
def control_array
  [6, 5, 7, 2, 3, 4, 5, 6, 7]
end

# File lib/nvr.rb, line 24
def control_number
  s = 0
  (0..8).each { |i| s += (nip[i].to_i*control_array[i]) }
  s % 11
end