##
## gol.py
##
## by Kristina Striegnitz
##
## version 2/12/2010
##
## Conway's game of life.
##
from gol_display import run_game

ROWS = 20
COLS = 20
DEAD = 0
ALIFE = 1

def create_grid(rows, cols):
    """
    This function creates and returns a list of lists, intended to
    represent a grid. All of the grid cells are filled with 0.
    """
    grid = []
    for r in range(0,rows):
        row = []
        for c in range(0, cols):
            row = row + [DEAD]
        grid = grid + [row]
    return grid

def read_grid_from_file(filename):
    global ROWS
    global COLS
    file_obj = open(filename, "r")


    ## ADD code here.

    ## Add code that reads the content of the file and builds a grid
    ## representations (list of lists) from it. 0 indicates DEAD and 1
    ## ALIFE.


    file_obj.close()

    ROWS = len(grid)
    if ROWS > 0:
        COLS = len(grid[0])

    return grid


def play_gol():

    grid = create_grid(ROWS, COLS)

    cell_size = 10
    run_game(grid, cell_size, on_click, next_gen)

def play_gol_file_input(filename):
    grid = read_grid_from_file(filename)

    cell_size = 10
    run_game(grid, cell_size, on_click, next_gen)


def on_click(grid, row, col):

    if grid[row][col] == DEAD:
        grid[row][col] = ALIFE
    else:
        grid[row][col] = DEAD

    return grid

def life_neighbors(board,r,c):
    """
    This function counts how many life neighbors a given cell in a
    Game of Life grid has.

    Parameters: the grid representation, the row number and column
    number we are interested in, the overall number of rows and
    columns.
    """
    n = 0
    for i in range(c-1,c+2):
        for j in range(r-1,r+2):
            if board[j%ROWS][i%COLS]==1 and (i != c or j != r):
                n += 1
    return n

def next_gen(grid):
    """
    This function applies the Game of Life rules to a given grid. It
    returns the next generation of the grid.
    """
    new_grid = create_grid(ROWS, COLS)
    for r in range(0,ROWS):
        for c in range(0,COLS):
            n = life_neighbors(grid,r,c)
            if grid[r][c]==ALIFE:
                if n < 2 or n > 3:
                    new_grid[r][c] = DEAD
                else:
                    new_grid[r][c] = ALIFE
            else:
                if n == 3:
                    new_grid[r][c] = ALIFE
                else:
                    new_grid[r][c] = DEAD
    return new_grid

## Start it:
#play_gol_file_input("gol_input_mini.txt")
play_gol_file_input("gol_glider_gun.txt")