rpsls-functional.rb

HANDS = [:rock, :paper, :scissors, :lizard, :spock]
HANDS.freeze

RESULTS = {
  rock: {
    lizard: 'crushes',
    scissors: 'crushes'
  },
  paper: {
    rock: 'covers',
    spock: 'disproves'
  },
  scissors: {
    paper: 'cuts',
    lizard: 'decapitate'
  },
  lizard: {
    paper: 'eats',
    spock: 'poisons'
  },
  spock: {
    scissors: 'smashes',
    vaporizes: 'rock'
  }
}
RESULTS.freeze

def rpsls(first, second)
  return unless validate_hand(first) && validate_hand(second)

  first.to_sym!
  second.to_sym!

  if RESULTS[first].keys.include?(second)
    winner, loser = first, second
  else
    winner, loser = second, first
  end

  "#{winner.capitalize} #{RESULTS[winner][loser]} #{loser.capitalize}"
end

def validate_hand(hand)
  HANDS.include?(hand.to_sym)
end