two_player_math_game.rb

class Player
  attr_accessor :name, :score, :lives

  def initialize(name,score=0,lives=3)
    @name = name
    @score = score
    @lives = lives
  end

  def resurrect
    self.lives = 3
  end

  def dead?
    self.lives == 0
  end 

  def score_point
    self.score += 1
  end

  def lose_a_life
    self.lives -= 1
  end
end

class Question
  attr_reader :answer, :string

  def initialize(player)
    question_type = rand(3)
    # 0 == Addition, 1 == Subtraction, 2 == Multiplication, 
    case(question_type)
    when(0)
      type = "plus"
      num1 = rand(1..30)
      num2 = rand(1..30)
    when(1)
      type = "minus"
      num1 = rand(1..20)
      num2 = rand(1..20)
    when(2)
      type = "times"
      num1 = rand(2..10)
      num2 = rand(2..10)
    else
      exit
    end
    @answer = num1 + num2
    @string = "#{player.name}, what is #{num1} #{type} #{num2}?"
  end
end

@game_on = true
@first_time = true

def validate_name(name)
  name.length > 0 
end

def setup_players
  puts "What's your name?"
  p1_name = gets.chomp 
  if validate_name(p1_name)
    @p1 = Player.new(p1_name)
    puts "Okay, #{@p1.name}, what's your opponent's name?"
    p2_name = gets.chomp
    if validate_name(p2_name)
      @p2 = Player.new(p2_name)
      puts "Welcome, #{@p2.name}!"
    else
      puts "Sorry, that name is too short!"
      exit
    end
  else
    puts "Sorry, your name is too short!"
    exit
  end
end

def ask_question(player)
  question = Question.new(player)
  puts question.string
  response = gets.chomp.to_i
  if response == question.answer
    puts "CORRECT!"
    player.score_point
  else
    puts "WRONG! The answer is #{question.answer}"
    player.lose_a_life
    puts "#{player.name}, you have #{player.lives} #{player.lives == 1 ? 'life' : 'lives'} left."
  end
  check_lives(player)
end

def check_lives(player)
  if player.dead?
    puts "Game over, #{player.name}, you lost! :("
    offer_another_round
  end
end

def offer_another_round
  puts "Wanna play again? (y/n)"
  response = gets.chomp
  if response == "y"
    puts "Alright! Once again..."
    resurrection(@p1,@p2)
  else
    @game_on = false 
    puts "OK! #{@p1.name}, you scored #{@p1.score} points, and, #{@p2.name}, you scored #{@p2.score} points."
  end
end

def resurrection(*players)
  players.each {|p| p.resurrect } 
end

def repl
  if @first_time == true
    puts "It's the MATH GAME!"
    setup_players 
    @first_time = false
  end
  [@p1,@p2].each do |player|
    ask_question(player) if @game_on
  end
end

while @game_on
  repl
end