Rock, Paper, Scissors Winner Algorithm

rps.rb

class RPSAlgorithm

  # Let Paper = 1, Rock = 2, Scissors = 3
  def initialize(values={})
    @values = {paper: 1, rock: 2, scissors: 3}
  end

  def set_values(values)
    @values = values
  end

  # get_winner(:rock, :paper) => :paper
  # Takes the sum of the two choices, based on the values hash above.
  # If the sum is even, the greater value of the two choices is the winner.
  # If the sum is odd, the lesser value of the two choices is the winner.
  def get_winner(choice_one, choice_two)
    return "tie" if choice_one == choice_two

    choice_values = [@values[choice_one], @values[choice_two]]
    choice_sum = choice_values.inject(0, :+)

    winning_value = choice_sum.even? ? choice_values.max : choice_values.min
    return @values.key(winning_value)
  end

end