class Cracker
  attr_accessor :current

  OPTS = [('a'..'z'),('A'..'Z'),('0'..'9')].map{|n| n.to_a }.flatten

  def initialize(pass)
    @current = OPTS.first
    crack while @current != pass
    puts "Password is #{@current}"
  end

  def crack
    current_array = @current.split(//)
    if current_array.all? {|o| o == OPTS.last}
      current_array = [OPTS.first]*(current_array.length+1)
    else
      poped = []
      poped << current_array.pop while current_array.last == OPTS.last
      last = current_array.pop
      current_array.push OPTS[OPTS.index(last)+1]
      current_array += ([OPTS.first]*poped.length)
    end
    @current = current_array.join
  end
end