#!/usr/bin/ruby

# Game of Life
# basic (aka very inefficient) implementation
# copyright 2008 Yoann Guillot
# license: GPLv2

class World
	attr_accessor :w, :h, :table
	def initialize(w=32, h=w)
		@emptyl = "\0"*((w+7)/8)
		@w, @h = w, h
		@table = Array.new(h) { @emptyl.dup }
		@clear = `clear`
	end

	def iter
		counts = Array.new(h) { [] }
		@h.times { |y|
			@w.times { |x|
				counts[y][x] = countnb(x, y)
			}
		}
		puts counts.map { |c| c.join(' ') } if $DEBUG
		#@table = Array.new(h) { @emptyl.dup }
		@h.times { |y|
			@w.times { |x|
				case counts[y][x]
				when 3: set(x, y, true)
				when 2
				else set(x, y, false)
				end
			}
		}
	end

	def countnb(x, y)
		n = 0
		(-1..1).each { |i|
			n += 1 if get(x+i, y-1)
			n += 1 if get(x+i, y+1)
			n += 1 if i != 0 and get(x+i, y)
		}
		n
	end

	# true/false
	def get(x, y)
		x %= @w
		y %= @h
		@table[y][x/8][x%8] != 0
	end
	alias [] get

	def set_intable(t, x, y, v)
		x %= @w
		y %= @h
		if v
			t[y][x/8] |= 1<<(x%8)
		else
			t[y][x/8] &= 0xff ^ (1<<(x%8))
		end
	end
	def set(x, y, v)
		set_intable(@table, x, y, v)
	end
	alias []= set

	def display
		puts @clear, @table.map { |r| r.unpack('b*').first.tr('01', ' x').gsub(/(.)/, ' \1') }
		#puts '-'*@w*2
	end

	def finished?
		@table.all? { |r| r == @emptyl }
	end

	def run
		while not finished?
			display
			iter
		end
		display
	end

	def randomize
		@h.times { |y|
			@w.times { |x|
				set(x, y, rand(2) == 1)
			}
		}
	end
end

w = World.new(ARGV.empty? ? 32 : ARGV.shift.to_i)
w.randomize
#w[1, 0] = w[2, 1] = w[0, 2] = w[1, 2] = w[2, 2] = true
w.run