gol.rb

class GOL
  attr_accessor :size
  attr_accessor :board

  def initialize(size)
    @size = size
    reset_board
  end

  def reset_board
    @numbers = (0...size).to_a
    @board = Array.new(size*size, 0)
    randomize(size*size/2)
  end

  def randomize(n)
    (1..n).each do |i|
      x = @numbers.sample
      y = @numbers.sample
      board[x*size + y] = 1
    end
  end

  def printboard
    system('clear')
    char_map = [' ', '@']
    board.each.with_index do |cell, index|
      print char_map[cell]
      print "\n" if index % size == size - 1
    end
  end

  def neighbor_by_index(index)
    x = index / size
    y = index % size
    xs = ((x-1)..(x+1)).to_a.map{|x| (x + size) % size }
    ys = ((y-1)..(y+1)).to_a.map{|y| (y + size) % size }
    neighbor = []
    xs.each do |x|
      ys.each do |y|
        neighbor << board[x*size + y]
      end
    end
    neighbor
  end

  def step
    @board = @board.map.with_index do |cell, index|
      neighbor = neighbor_by_index(index)
      rule(neighbor)
    end
  end

  def rule(neighbor)
    count = neighbor.sum - neighbor[4]
    return 0 if count < 2 || count > 3
    return 1 if neighbor[4] == 0 && count == 3
    neighbor[4]
  end

  # def rule(neighbor)
  #   neighbor[1]
  # end

  # def rule(neighbor)
  #   neighbor[3]
  # end

  def run
    while true do
      printboard
      sleep(1.0 / 4)
      step
    end
  end
end

gol = GOL.new(20)
gol.run