Rock Paper Scissors in Ruby

rock_paper_scissors.rb

class WrongNumberOfPlayersError < StandardError ; end
class NoSuchStrategyError < StandardError ; end

VALID_MOVES = %w{R P S}

def rps_game_winner(game)
  raise WrongNumberOfPlayersError unless game.count == 2

  game.each do |move|
    unless VALID_MOVES.include?(move[1])
      raise NoSuchStrategyError
    end
  end

  p1 = game[0][0]
  v1 = game[0][1]

  p2 = game[1][0]
  v2 = game[1][1]

  return [p1, v1] if v1 == v2

  if v1 == "R"
    return [p1, v1] if v2 == "S"
    return [p2, v2] if v2 == "P"
  elsif v1 == "P"
    return [p1, v1] if v2 == "R"
    return [p2, v2] if v2 == "S"
  elsif v1 == "S"
    return [p1, v1] if v2 == "P"
    return [p2, v2] if v2 == "R"
  end
  
end

def rps_tournament_winner(node)
  if node.flatten.length == 4
    rps_game_winner(node) 
  elsif node.first.is_a?(Array)
    node = [ rps_tournament_winner(node[0]), rps_tournament_winner(node[1]) ]
    rps_tournament_winner(node)
  end
end

# 2 player game
two =  ["Armando", "P"], ["Dave", "S"]

# 4 player game
four = [
        [ ["Armando", "P"], ["Dave", "S"] ],
        [ ["Richard", "R"],  ["Michael", "S"] ],
]

# 8 player game
eight =
[
    [
        [ ["Armando", "P"], ["Dave", "S"] ],
        [ ["Richard", "R"],  ["Michael", "S"] ],
    ],
    [
        [ ["Allen", "S"], ["Omer", "P"] ],
        [ ["David E.", "R"], ["Richard X.", "P"] ]
    ]
]

sixteen =
[
  [[[["Armando", "P"], ["Dave", "S"]], [["Richard", "R"], ["Michael", "S"]]], [[["Allen", "S"], ["Omer", "P"]], [["David E.", "R"], ["Richard X.", "P"]]]],
  [[[["Mike", "S"], ["DJ", "P"]], [["Isaiah", "S"], ["Steve", "P"]]], [[["Alan", "P"], ["Mahmoud", "R"]], [["Bill E.", "S"], ["Loraine", "R"]]]]
  
]

 
p rps_tournament_winner(two)
p rps_tournament_winner(four)
p rps_tournament_winner(eight)
p rps_tournament_winner(sixteen)