class Vindetta::Calculator

Constants

InvalidCharacterError

Public Class Methods

check_digit(vin) click to toggle source
# File lib/vindetta/calculator.rb, line 7
def self.check_digit(vin)
  transliterator = lambda do |c|
    index = "0123456789.ABCDEFGH..JKLMN.P.R..STUVWXYZ".chars.index(c)

    raise InvalidCharacterError if index.nil?

    index % 10
  end

  summer = lambda do |sum, (a, b)|
    sum + (a * b)
  end

  sum = vin
        .chars
        .map(&transliterator)
        .zip([8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2])
        .reduce(0, &summer)

  "0123456789X"[sum % 11]
end