machine_readable_code_validation

machine_readable_code_validation.rb

# TPD<<T220001293<<<<<<<<<<<<<<<
# 6408125<2010315D<<<<<<<<<<<<<4
# MUSTERMAN<<ERIKA<<<<<<<<<<<<<<

class PersonalId

  attr_reader :code, :data
  # 9 alphanumeric
  def initialize(machinecode = "TPD<<2406055684D<<<<<<<<<<<<<<6810203<0705109D<<<<<<<<<<<<<6MUSTERMAN<<ERIKA<<<<<<<<<<<<<<")
    @code = machinecode
    @data = {
      # line 1
      :type          => @code[0..2],
      :id            => @code[5..13],
      :check_a       => @code.at(14),
      # line 2
      :date_of_birth => @code[30...36],
      :check_b       => @code.at(36),
      :expires_at    => @code[38...44],
      :check_c       => @code.at(44),
      :nationality   => @code.at(45),
      :check_d       => @code.at(59),
      # line 3
      :name          => @code[60...90]
    }
  end

  def full_name
    data[:name].sub("<<", " ").gsub("<", "")
  end

  def p1
    to_digits(data[:id] + data[:check_a])
  end

  def p2
    to_digits(data[:date_of_birth] + data[:check_b])
  end

  def p3
    to_digits(data[:expires_at] + data[:check_c])
  end

  def to_digits(string)
    string.split("").map(&:to_i)
  end

  def checksum_a
    checksum(p1[0...-1])
  end

  def checksum_b
    checksum(p2[0...-1])
  end

  def checksum_c
    checksum(p3[0...-1])
  end

  def checksum_d
    checksum([ p1, p2, p3 ].flatten)
  end

  def checksum(digits, i = 1)
    digits.map do |digit|
      wage = case (i % 3)
        when 1 then 7
        when 2 then 3
        when 0 then 1
      end
      i += 1

      digit * wage

    end.sum
  end

  def valid?
    (checksum_a == data[:check_a].to_i) && (checksum_b == data[:check_b].to_i) && (checksum_c == data[:check_c].to_i) && (checksum_d == data[:check_d].to_i)
  end

end