# Tk_conways_game_of_life.py

# Tk_conways_game_of_life.py

import random
from Tkinter import *

def num_neighbors(grid, pos):
    neighbors = 0
    x,y = pos

    neighbors += grid[x-1][y-1] # Top Left
    neighbors += grid[x-1][y]   # Top
    neighbors += grid[x-1][y+1] # Top Right

    neighbors += grid[x][y-1]   # Left
    neighbors += grid[x][y+1]   # Right

    neighbors += grid[x+1][y-1] # Bottom Left
    neighbors += grid[x+1][y]   # Bottom
    neighbors += grid[x+1][y+1] # Bottom Right

    return neighbors


def update_state(grid):
    global xy
    crowded = len(xy) > 1600
    # print len(xy)
    xy = []
    h, w = len(grid)-1, len(grid[0])-1
    new_grid = eval(str([[0]*(w+1)]*(h+1)))

    for x in range(h):
        for y in range(w):
            n = num_neighbors(grid, [x,y])
            cell = grid[x][y]
            t = 0
            if crowded and cell:
                if n > 3 or n < 2:
                    new_grid[x][y] = 0
                else:
                    t = 1
            elif cell == 0 and n == 3:
                t = 1
            elif cell == 1 and n < 4:
                t = 1
            if t:
                new_grid[x][y] = 1
                xy.append((x,y))

    return new_grid


def print_grid():
    for x,y in xy:
        canvas.create_text(x*4+10,y*4+10,text='.', font=fff)
    canvas.update()
    canvas.delete('all')

fff = ('Times New Roman', 16, "bold")
if 1:
    ww = 500
    hh = 500
    xy = []
    lives = [0]*int((ww*hh/4)*0.9)+[1]*int((ww*hh/4)*0.2)
    random.shuffle(lives)
    grid = [[lives.pop() for x in range(ww/4-3)] for y in range(hh/4-4)]
    root = Tk()
    canvas = Canvas(root, bg='blue', height=hh, width=ww)
    canvas.pack()

    while 1:
        print_grid()
        grid = update_state(grid)