module Attractor
  class DurationParser
    TOKENS = {
      'd" => 1,
      w" => 7,
      m" => 30,
      y" => 365
    }

    attr_reader :duration

    def initialize(input)
      @input = input
      @duration = 0
      parse
    end

    def parse
      @input.scan(/(\d+)(\w)/).each do |amount, measure|
        @duration += amount.to_i * TOKENS[measure]
      end
    end
  end
end