import pygame  #pip install pygame
import sys     #pip install sys
import random  #pip install random
import time    #pip install time

# game initialization
errors = pygame.init()

if errors[1] > 0:
    print('(!) Got {0} errors during initializing pygame \
        exiting...'.format(errors[1]))
    sys.exit(-1)
else:
    print('(+) pygame successfully initialized.')

# game screen
width = 750   #Screen width
height = 495   #Screen Height
screen = pygame.display.set_mode((width, height))
pygame.display.set_caption('Snake game')

# colors
red = pygame.Color(255, 0, 0)  # game over
grey_blue = pygame.Color(77, 126, 118)  # snake body
green = pygame.Color(12, 182, 128)  # player score
white = pygame.Color(237, 226, 202)  # game background
brown = pygame.Color(109, 50, 4)  # food

# FPS controller
fps_controller = pygame.time.Clock()

# game variables
start_x = 300
start_y = 150
step = 15  # block width is 10
body_length = 3
head = [start_x, start_y]  # snake start position [x, y]
# initialize snake body, index 0 contains the snake head
body = [[start_x - i * step, start_y] for i in range(body_length)]
score = 0
level = 1

foodPos = [random.randrange(2, width / step - 1) * step, \
            random.randrange(2, height / step - 1) * step]  # don't put food at the border of the screen
foodSpawn = True

direction = 'RIGHT'
next = direction  # new direction after user hits keyboard


def draw_game_menu():
    count = 3
    font = pygame.font.SysFont('ds-digital', 60)
    while True:
        screen.fill(white)

        start_surface = font.render('Start in {0} seconds.'.format(count), True, green)
        start_rect = start_surface.get_rect()
        start_rect.midtop = (width / 2, 80)
        screen.blit(start_surface, start_rect)

        esc_surface = font.render('''Press Esc to exit during game.''', True, green)
        esc_rect = esc_surface.get_rect()
        esc_rect.midtop = (width / 2, 150)
        screen.blit(esc_surface, esc_rect)

        pause_surface = font.render('''Press Space to pause the game.''', True, green)
        pause_rect = pause_surface.get_rect()
        pause_rect.midtop = (width / 2, 220)
        screen.blit(pause_surface, pause_rect)

        pygame.display.flip()  # update the game screen
        time.sleep(1)
        fps_controller.tick()
        count -= 1
        if count == 0: break

def draw_game_pause():
    font = pygame.font.SysFont('ds-digital', 18)
    while True:
        pause_surface = font.render('Press Space to continue.', True, green)
        pause_rect = pause_surface.get_rect()
        pause_rect.midtop = (width / 2, 150)
        screen.blit(pause_surface, pause_rect)
        pygame.display.flip()
        fps_controller.tick()
        for move in pygame.event.get():
            if move.type == pygame.KEYDOWN:
                if move.key == pygame.K_SPACE: return

def show_score(game_over=False):
    font = pygame.font.SysFont('ds-digital', 18)
    score_surface = font.render('Score: {0}'.format(score), True, green)
    score_rect = score_surface.get_rect()
    if game_over == False:
        score_rect.midtop = (75, 10)
    else:
        score_rect.midtop = (width / 2, 130)
    screen.blit(score_surface, score_rect)

# game over function
def draw_game_over():
    font = pygame.font.SysFont('ds-digital', 24)
    surface = font.render('Game Over !', True, red)
    GO_rect = surface.get_rect()
    GO_rect.midtop = (width/2, 60)
    screen.blit(surface, GO_rect)

    show_score(game_over=True)
    pygame.display.flip()  # update the game screen

    time.sleep(4)
    pygame.quit()  # quit the game
    sys.exit()  # exit the console

def get_food(foodPos, body):
    for block in body:
        if block[0] == foodPos[0] and block[1] == foodPos[1]:
            return True
    return False


# game start menu
draw_game_menu()

# main logic of the game
while True:
    for move in pygame.event.get():
        if move.type == pygame.KEYDOWN:  # if user press any button
            if move.key == pygame.K_RIGHT or move.key == ord('d'):
                next = 'RIGHT'
            elif move.key == pygame.K_LEFT or move.key == ord('a'):
                next = 'LEFT'
            elif move.key == pygame.K_UP or move.key == ord('w'):
                next = 'UP'
            elif move.key == pygame.K_DOWN or move.key == ord('s'):
                next = 'DOWN'
            elif move.key == pygame.K_ESCAPE:  # if user choose to quit the game
                pygame.event.post(pygame.event.Event(pygame.QUIT))
            elif move.key == pygame.K_SPACE:
                draw_game_pause()
        if move.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    # move snake head
    if direction == 'RIGHT':
        head[0] += step
    elif direction == 'LEFT':
        head[0] -= step
    elif direction == 'DOWN':
        head[1] += step
    elif direction == 'UP':
        head[1] -= step

    # validation of direction
    if next == 'RIGHT' and direction != 'LEFT':
        direction = 'RIGHT'
    elif next == 'LEFT' and direction != 'RIGHT':
        direction = 'LEFT'
    elif next == 'DOWN' and direction != 'UP':
        direction = 'DOWN'
    elif next == 'UP' and direction != 'DOWN':
        direction = 'UP'



    # move snake body mechanism
    # insert a new block at the beginning of the body
   
    body.insert(0, list(head))
    if head[0] == foodPos[0] and head[1] == foodPos[1]:
        foodSpawn = False
        score += 1
    else:
        body.pop()

    while foodSpawn == False:
        foodPos = [random.randrange(2, width / step - 1) * step,
                    random.randrange(2, height / step - 1) * step]
        if get_food(foodPos, body) == True:
            foodSpawn = False
        else:
            foodSpawn = True

    # fill game background
    screen.fill(white)

    # draw snake body
    for pos in body:
        pygame.draw.rect(screen, grey_blue, pygame.Rect(pos[0], pos[1], step, step))

    # draw food
    pygame.draw.rect(screen, brown, pygame.Rect(foodPos[0], foodPos[1], step, step))

    # check if snake hits the border
    if (head[0] > width - step) or (head[0] < 0) or \
            (head[1] > height - step) or (head[1] < 0):
        draw_game_over()

    # check if snake hits itself
    for block in body[1:]:
        if head[0] == block[0] and head[1] == block[1]:
            draw_game_over()

    level = score//5 + 1
    if level > 3:
        level = 3

    show_score(game_over=False)
    pygame.display.flip()

    if level == 1:
        fps_controller.tick(8)
    elif level == 2:
        fps_controller.tick(10)
    elif level == 3:
        fps_controller.tick(12)


#--------------------------------End Of Code--------------------------------#