# Each function defines a set of rules for the CA
# If you want to add new functions the syntax is:
#
# def func(GRID, X,Y, MAXX, MAXY)
#
# GRID - a 2D Numeric array
# X,Y - X,Y position of the current cell
# MAXX,MAXY - Size of the grid in X & Y diections
#
# The function must return 1 if the current cell is to live
# or 0 if it is to die
#
# An important point to note: Though the function will recieve the x
# and y coordinates, you need to use them reversed. That is x is actually
# y and y is actually x.

from random import *

def flipflop(grid, x,y, maxx, maxy):
    if grid[y][x] == 1:
        return 0
    else:
        return 1

def rca(grid,x,y,maxx,maxy):
    x = random()
    if x < .5: return 1
    else: return 0
    
def neighbor3(grid,x,y,maxx,maxy):

    # does'nt wrap around the grid

    c = 0
    cl = []

    cl.append( (x+1,y) )
    cl.append( (x-1,y) )
    cl.append( (x,y+1) )
    cl.append( (x,y-1) )

    for xx,yy in cl:
        if xx < 0 or xx >= maxx: continue
        if yy < 0 or yy >= maxy: continue

        if grid[yy][xx] == 1: c += 1
    
    if c >= 3:
        return 0
    else: 
        return 1
    
def nb(grid,x,y,maxx,maxy):

    # does'nt wrap around the grid

    c = 0
    cl = []

    total = add(grid)
    
    cl.append( (x+1,y) )
    cl.append( (x-1,y) )
    cl.append( (x,y+1) )
    cl.append( (x,y-1) )

    for xx,yy in cl:
        if xx < 0 or xx >= maxx: continue
        if yy < 0 or yy >= maxy: continue

        if grid[yy][xx] == 1: c += 1
    
    if c >= 1 and total < .9*maxx*maxy:
        return 1
    else: 
        return 0