matthew.moss.coder
4/30/2007 8:08:00 PM
Here is my version... Note that it is probably incorrect w.r.t. the
valid/invalid and known/unknown issue discussed earlier... However,
after finishing my initial version, and despite how easy it would be
to fix, I am pretty swamped with other tasks and so won't fix it.
class Integer
def digitSum
self.to_s.split(//).inject(0) { |s, d| s + d.to_i }
end
end
class CreditCard
TYPE_MATCH = {
:visa => /^4/,
:discover => /^6011/,
:amex => /^3(4|7)/,
:mastercard => /^5[1-5]/
}
SIZE_MATCH = {
:visa => [13, 16],
:discover => [16],
:amex => [15],
:mastercard => [16]
}
CARD_NAME = {
:visa => "Visa",
:discover => "Discover",
:amex => "American Express",
:mastercard => "MasterCard",
:unknown => "unknown",
nil => "invalid"
}
def initialize(cc)
@cc = cc.delete(" ")
end
def valid?
self.type && (self._luhn % 10).zero?
end
def type
TYPE_MATCH.each do |k, v|
if @cc =~ v
if SIZE_MATCH[k].find { |n| @cc.size == n }
return k
else
return nil
end
end
end
:unknown
end
def name
CARD_NAME[self.type]
end
def to_s
@cc
end
def _luhn
sum = 0
cc = @cc.split(//)
until cc.empty?
a, b = cc.pop.to_i, cc.pop.to_i
sum += a + (2 * b).digitSum
end
sum
end
end
cc = CreditCard.new(ARGV.join)
if !cc.valid?
puts "Card #{cc} is invalid."
elsif cc.type != :unknown
puts "Card #{cc} is a valid #{cc.name}."
else
puts "Card #{cc} is unknown type, may be valid."
end