import pygame, sys, random, math, time
from pygame.locals import *
#defines some key variables
cell_x_coord = list()
cell_y_coord = list()
x_coord = 0
y_coord = 0
counter = 0
left = bool()
right = bool()
upwards = bool()
downwards = bool()
x_coord_for_food = list()
y_coord_for_food = list()
x_coord_list = list()
y_coord_list = list()

pygame.init()
#defining variables for the width and length of screen
LENGTH = 500
WIDTH = 500
FPS = 1
#this makes the screen appear
DISPLAYSURF = pygame.display.set_mode((WIDTH,LENGTH), 0, 32)
#the class to split up the screen (refer to line 84 for more information)
class split_up:
    def __init__(self):
        t = 10
        WIDTH = 490
        self.width_split_list = []
        WIDTH = int(WIDTH/10)
        for i in range(WIDTH):
            self.width_split_list.append(t)
            t+=10
        self.length_split_list = []
        j = 10
        LENGTH = 490
        LENGTH = int(LENGTH/10)
        for i in range((LENGTH)):
            self.length_split_list.append(j)
            j+=10
        return
#defines the csolors
WHITE = (255,255,255)
RED = (255,0,0)
BLACK = (0,0,0)
FOODCOLOR = (180, 159, 7)
#pygame.draw.rect(foo) is complicated and ineficiant, therefore this function creates the snake
def draw_square_snake(area,x_coord,y_coord,COLOR):
    area = math.sqrt(area)
    pygame.draw.rect(DISPLAYSURF, COLOR, (x_coord, y_coord, area, area))
    return
#this function draws black for the ares where the snake used to be, and the ares where the snake ate the food
def draw_square_background(area, x_coord, y_coord, COLOR):
    area = math.sqrt(area)
    pygame.draw.rect(DISPLAYSURF, COLOR, (x_coord, y_coord, area , area))
    return
#this class makes the food
class make_food:
    def __init__(self, area,COLOR):
        self.color = COLOR
        self.area = math.sqrt(area)
        split_up_object = split_up()
        self.random_width = random.choice(split_up_object.width_split_list)
        self.random_length = random.choice(split_up_object.length_split_list)
        pygame.draw.rect(DISPLAYSURF, self.color, (self.random_width, self.random_length, 10,10))
        return
def main():
    #defining varaibles for the loop
    area = 100
    clock = pygame.time.Clock()
    count = 0
    counter = 0
    left = bool()
    right = bool()
    upwards = bool()
    downwards = bool()
    x_coord = 20
    y_coord = 20
    eat_counter = 0
    eaten = bool()
    cell_x_coord = list()
    cell_y_coord = list()
    speed = 10
    var = 10
    food_eaten = bool()
    cell_count = 0
    #splits up the screen into squares of 10 (area = math.sqrt(WIDTH)/ math.sqrt(LENGTH))
    split_up_object = split_up()
    random_width = random.choice(split_up_object.width_split_list)
    random_length = random.choice(split_up_object.length_split_list)
    timer_event = pygame.USEREVENT+1
    pygame.time.set_timer(timer_event, 250)
    while True:

        #these 'try' statements will do things, if it is the first iteration of the loop, it will pass
        try:
            draw_square_background(500, cell_x_coord[0], cell_y_coord[0], BLACK)
        except IndexError:
            time.sleep(0.0000000000000001)
        try:
            del cell_x_coord[0]
            del cell_y_coord[0]
        except IndexError:
            time.sleep(0.0000000000000001)

        #this will set the FPS to 30
        clock.tick(30)

        #the only things that will happen in this event handler is if the user wants to quit, the program will end
        for event in pygame.event.get():
            if event.type == QUIT:
                pygame.quit()
                sys.exit()
            pygame.display.update()

        #these will check if the user has pressed any of the arrow keys, any other event will be sent to the event handler, (above this comment) and since the only algorithm in that is the QUIT, nothing will happen
        if pygame.key.get_pressed()[pygame.K_UP] == True:
            upwards = True
            downwards = False
            left = False
            right = False
        elif pygame.key.get_pressed()[pygame.K_DOWN] == True:
            downwards = True
            upwards = False
            left = False
            right = False
        elif pygame.key.get_pressed()[pygame.K_LEFT] == True:
            left = True
            upwards = False
            downwards = False
            right = False
        elif pygame.key.get_pressed()[pygame.K_RIGHT] == True:

            right = True
            left = False
            downwards = False
            upwards = False
        #passes if none of the arrow keys are pressed
        else:
            pass
        #the reason why the x_coord and y_coord don't go higher in the first statements is because the program needs to continue even if no keys are pressed, therefore they have their own seperate statements
        if upwards == False and downwards == False and right == False and left == False:
            x_coord+=0
            y_coord+=0
        if upwards == True:
            x_coord+=0
            y_coord-=speed
        elif downwards == True:
            x_coord+=0
            y_coord+=speed
        elif right == True:
            x_coord+=speed
            y_coord+=0
        elif left == True:
            x_coord-=speed
            y_coord+=0
        if x_coord >=int((WIDTH-19)):
            pygame.quit()
            sys.exit()
        elif x_coord <=-2:
            pygame.quit()
            sys.exit()
        elif y_coord >=int((LENGTH-19)):
            pygame.quit()
            sys.exit()
        elif y_coord<=-2:
            pygame.quit()
            sys.exit()
        #although this is only 2 lines, it could be the most important part of the program
        cell_x_coord.append(x_coord)
        cell_y_coord.append(y_coord)
        #draws the food if the loop has only been through one iteration
        if eat_counter == 0:
            area = math.sqrt(area)
            split_up_object = split_up()
            random_width = random.choice(split_up_object.width_split_list)
            random_length = random.choice(split_up_object.length_split_list)
            pygame.draw.rect(DISPLAYSURF, FOODCOLOR, (20, 20, 1,1))
            food_for_snake = make_food(10, FOODCOLOR)
            eat_counter+=1
        #length_x_coord=len(x_coord)
        #checks if the head of the snake is in the range of the food
        #print(len(x_coord))
        #print(len(cell_x_coord))
        if (((cell_x_coord[0] <= food_for_snake.random_width and cell_x_coord[0] >= (food_for_snake.random_width-var)) and (cell_y_coord[0] <= food_for_snake.random_length and cell_y_coord[0] >= (food_for_snake.random_length-var))) or ((cell_y_coord[0] <=food_for_snake.random_length and cell_y_coord[0] >= (food_for_snake.random_length-var)) and cell_x_coord[0] <= food_for_snake.random_width and cell_x_coord[0] >= (food_for_snake.random_width-var)) and food_eaten !=True):
            food_eaten = True
        last_in_list_x = int((len(cell_x_coord)-1))
        last_in_list_y = int((len(cell_y_coord)-1))
        last_element_x = cell_x_coord[last_in_list_x]
        last_element_y = cell_y_coord[last_in_list_y]
        for i in range((len(cell_x_coord))):
            draw_square_snake(500, cell_x_coord[i], cell_y_coord[i], RED)
        if food_eaten == 1:
            cell_x_coord.append((x_coord-1000))
            cell_y_coord.append((y_coord))
            food_for_snake = make_food(10, FOODCOLOR)
            food_eaten = False
        #print(cell_count)
        #cell_count+=1
        pygame.display.update()
if __name__== '__main__':
    #executes the 'main' function
    main()