"""
by Kristina Striegnitz
May 7, 2009
"""

import pygame
import random

def initialize():
    """
    This function sets some global constants (i.e., the values of these global
    variables never change).
    """
    pygame.init()

    # set up the display window
    global width, height, screen
    width = 800
    height = 800
    screen = pygame.display.set_mode((width,height))


def create_grid(rows, cols):
    """
    Creates a list of lists representing a rows x cols sized grid.
    Each cell holds an integer of value 0.
    Returns the grid.
    """
    grid = []
    for r in range(0,rows):
        row = [0] * cols
        grid = grid + [row]
    return grid




def run_game():

    # size of grid
    rows = 30
    cols = 30

    grid = create_grid(rows, cols)

    # values for drawing the grid.
    cell_width = 20
    x_offset = 20
    y_offset = 20
    padding = 3



    clock = pygame.time.Clock()
    
    keepGoing = True

    while (keepGoing):

        dt = clock.tick()

        # go through all events that happened and check ...
        for event in pygame.event.get():
            
            # ... whether the event was a quit event
            if event.type == pygame.QUIT:
                keepGoing = False

            # ... whether the event was a mouse click
            elif event.type == pygame.MOUSEBUTTONDOWN:

                (mouse_x, mouse_y) = event.pos

                # Find out whether mouse click was over one of the grid cells.
                # If so, flip the value of that cell.
                if (mouse_x >= x_offset and mouse_x <= x_offset + (padding + cell_width) * rows
                    and mouse_y >= y_offset and mouse_x <= y_offset + (padding + cell_width) * cols):

                    col = (mouse_x - x_offset) / (cell_width + padding)
                    row = (mouse_y - y_offset) / (cell_width + padding)
                    if grid[row][col] == 0:
                        grid[row][col] = 1
                    else:
                        grid[row][col] = 0


        screen.fill(pygame.color.Color("navy"))


        # draw the grid
        # cell value 0, becomes orange; cell value 1 becomes darkred
        for r in range(0,rows):
            for c in range(0,cols):
                if grid[r][c] == 0:
                    color = pygame.color.Color("orange")
                else:
                    color = pygame.color.Color("darkred")
                x = x_offset + (padding + cell_width) * c
                y = y_offset + (padding + cell_width) * r
                pygame.draw.rect(screen, color, (x, y, cell_width, cell_width))


        pygame.display.update()


def done():
    
    pygame.quit()
    


def main():

    initialize()

    run_game()

    done()



main()