Level2

game.rb

  class Tic
  X = "x"
  O = "o"

  def initialize
    puts "Initialized"
    @board = [
      "-","-","-",
      "-","-","-",
      "-","-","-",
    ]

    @turn = X
  end

  def show_board
    puts "-------"
    @board.each_index do |i|
      print " #{@board[i]}"
      print "\n" if i % 3 == 2
    end
  end

  def set_board board
    @board = board
  end

  def markable_list
    markables = []
    @board.each_index do |i|
      markables.push(i) if @board[i] == "-"
    end 
    markables
  end

  def show_board_index
    puts "-------"
    @board.each_index do |i|
      print " #{if @board[i] == "-" then i else "-" end}"
      print "\n" if i % 3 == 2
    end
  end

  def markable? i
    return false unless i > -1 and i < 9
    return false unless @board[i] == "-"
    true
  end 

  def mark i
    @board[i] = @turn
  end

  def change_turn
    if @turn == X
      @turn = O
    else
      @turn = X
    end
  end

  def read_mark_index
    puts "type index of board"
    show_board_index
    i = gets.to_i

    while not markable?(i)
      puts "you choosed invalid value"
      i = gets.to_i
    end
    i
  end

  def start 
    puts "================="
    puts "Tic Tac Toe"
    puts "Copyright 2015, Kentaro Teramoto\n Released under the MIT Licenses. \n Date: Sat June 27 2015"
    puts "================="
    puts "\n 1: play with computer, \n 2: play with friend \n type 1 or 2"
    mode = gets.to_i

    while true 
      if @turn == X or mode == 2
        index = read_mark_index
      else 
        index = markable_list.sample
      end
      mark index
      show_board
      change_turn

      maybe_winner = who_is_winner? 
      unless maybe_winner == nil
        puts "#{maybe_winner} won"
        break
      end

      if markable_list.length == 0
        puts "Draw"
        break
      end
    end
  end

  def who_is_winner? 
    score_board = [0,0,0,0,0,0,0,0,0]
    @board.each_index do |i|
      if @board[i] == O
        score_board[i] = 1
      elsif @board[i] == X
        score_board[i] = -1
      end
    end

    result = []
    3.times do |i|
      result.push(score_board[i*3] + score_board[i*3+1] + score_board[i*3+2])
      result.push(score_board[i] + score_board[i+3] + score_board[i+6])
    end
    result.push(score_board[0] + score_board[4] + score_board[8])
    result.push(score_board[2] + score_board[4] + score_board[6])

    result.each do |i|
      return O if i == 3
      return X if i == -3
    end
    return nil
  end
end

game = Tic.new
game.start