#!/usr/bin/env python

#
# a 4x4 square number puzzle
#


# load pygame libraries and screen
import pygame
from pygame.locals import *
from sys import exit

pygame.init()

my_font = pygame.font.SysFont("arial", 48)

screen = pygame.display.set_mode((240,240), 0, 24)

pygame.display.set_caption("Number Puzzle");

# set the background screen to white
screen.fill((255,255,255))

# initialize mouse values
mouse_x, mouse_y = pygame.mouse.get_pos()
leftbutton, middlebutton, rightbutton = pygame.mouse.get_pressed()

# game board array, zero is the blank square
game_array = ([6,1,2,3,4,5,0,7,8,9,10,11,12,13,14,15])


while True:

    # event loop
    for event in pygame.event.get():
        if event.type == QUIT:
            exit()
        if event.type == MOUSEMOTION:
            mouse_x, mouse_y = pygame.mouse.get_pos()
        if event.type == MOUSEBUTTONDOWN:
            leftbutton, middlebutton, rightbutton = pygame.mouse.get_pressed()
            mouse_x, mouse_y = pygame.mouse.get_pos()
        if event.type == MOUSEBUTTONUP:
            leftbutton, middlebutton, rightbutton = pygame.mouse.get_pressed()
            
        # fill white over everyting
        screen.fill((255,255,255))
                
        # starting values for the puzzle box drawing
        x1 = 0
        y1 = 0
        xwidth = 60
        yheight = 60

        for i in range(16):
            newsquare = pygame.Rect(x1, y1, xwidth, yheight)

            # check if you clicked on something and swap those values
            if leftbutton & newsquare.collidepoint((mouse_x,mouse_y)):
                if i - 4 in range(16):
                    if game_array[i - 4] == 0:
                        swap1 = game_array[i]
                        swap2 = game_array[i - 4]
                        game_array[i - 4] = swap1
                        game_array[i] = swap2
                if i + 4 in range(16):
                    if game_array[i + 4] == 0:
                        swap1 = game_array[i]
                        swap2 = game_array[i + 4]
                        game_array[i + 4] = swap1
                        game_array[i] = swap2
                if i - 1 in range(16):
                    if game_array[i - 1] == 0:
                        if i in (1,2,3,5,6,7,9,10,11,13,14,15):
                            swap1 = game_array[i]
                            swap2 = game_array[i - 1]
                            game_array[i - 1] = swap1
                            game_array[i] = swap2
                if i + 1 in range(16):
                    if game_array[i + 1] == 0:
                        if i in (0,1,2,4,5,6,8,9,10,12,13,14):
                            swap1 = game_array[i]
                            swap2 = game_array[i + 1]
                            game_array[i + 1] = swap1
                            game_array[i] = swap2
                            
            # draw the square itself
            # if width is zero, then rectangle will be filled, used for
            # the empty space in the puzzle
            if game_array[i] == 0:
                rwidth = 0
            else:
                rwidth = 1    
            pygame.draw.rect(screen, (0,0,0), newsquare, rwidth)

            # draw the number in the square
            numvalue = str(game_array[i])
            if len(numvalue) == 2:
                xoffset = 10
                yoffset = 15
            else:
                xoffset = 20
                yoffset = 15
            numtext = my_font.render(numvalue, True, (0,0,0))
            screen.blit(numtext,(x1+xoffset,y1+yoffset))
            x1 = x1 + xwidth
            # when you hit the end of 4 boxes move to the next line
            if i in (3,7,11):
                y1 = y1 + yheight
                x1 = 0
                

        pygame.display.update()