scrabble score

scrabble_score.rb

require 'set'

class Scrabble
  class Letter
    attr_reader :point_value
    def initialize(input)
      @input = input
      @point_value = find_value
    end

    private
    attr_reader :input

    LETTER_VALUES = {
      1 => Set.new(["a", "e", "i", "o", "u", "l", "n", "r", "s", "t"]),
      2 => Set.new(["d", "g"]),
      3 => Set.new(["b", "c", "m", "p"]),
      4 => Set.new(["f", "h", "v", "w", "y"]),
      5 => Set.new(["k"]),
      8 => Set.new(["j", "x"]),
      10 => Set.new(["q", "z"])
    }.freeze

    # runtime here is not much of a concern and using #find with a Set should be fine for
    # 99.9% of words
    def find_value
      LETTER_VALUES.find { |_, letters| letters.include?(input.downcase) }.first
    end
  end

end

class Scrabble
  class Bonus
    attr_reader :multiplier_value
    def initialize(bonus_type)
      @bonus_type = bonus_type
      @multiplier_value = find_value
    end

    private
    attr_reader :bonus_type

    BONUS_VALUES = {
      single: 1,
      double: 2,
      triple: 3
    }.freeze

    def find_value
      BONUS_VALUES[bonus_type]
    end
  end
end

class Scrabble
  attr_reader :input, :bonus
  def initialize(raw_word, bonus = :single)
    @input = sanitize(raw_word)
    @bonus = Bonus.new(bonus)
  end

  def score
    return 0 if input.size == 0

    letters = input.chars.map { |char| Letter.new(char) }
    letters.map(&:point_value).reduce(:+) * bonus.multiplier_value
  end

  def self.score(input)
    new(input).score
  end

  private

  def sanitize(raw_word)
    return "" unless raw_word
    raw_word.gsub(/\t| |\n/, "")
  end
end