snake.py

import random
import time

import pygame

from app import App
from food import Food


class Snake(App):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.snake_length = 1

        # Snake starts at the center of the display
        self.x_pos = self.display_width / 2
        self.y_pos = self.display_height / 2
        self.snake = [(self.x_pos, self.y_pos)]

        # Snake will not move until an arrow key is pressed
        self.x_speed = 0
        self.y_speed = 0

        self.snake_food = Food(
            display_width=self.display_width, display_height=self.display_height
        )

    def start(self):
        super().start()
        self.play_game()

    def play_game(self):
        self.snake_food.generate_food()
        while (self.snake_food.x_pos, self.snake_food.y_pos) in self.snake:
            self.snake_food.generate_food()

        while not self.game_over:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    self.game_over = True
                if event.type == pygame.KEYDOWN:
                    if event.key in (pygame.K_DOWN, pygame.K_s):
                        self.move_down(event.key)
                    elif event.key in (pygame.K_LEFT, pygame.K_a):
                        self.move_left(event.key)
                    elif event.key in (pygame.K_UP, pygame.K_w):
                        self.move_up(event.key)
                    elif event.key in (pygame.K_RIGHT, pygame.K_d):
                        self.move_right(event.key)
            self.display.fill(self.color["gray"])
            self.x_pos += self.x_speed
            self.y_pos += self.y_speed
            self.snake.append((self.x_pos, self.y_pos))

            if len(self.snake) > self.snake_length:
                del self.snake[0]

            if (
                self.x_pos > self.display_width - 10
                or self.x_pos < 0
                or self.y_pos > self.display_height - 10
                or self.y_pos < 0
                or self.snake_length != len(list(set(s for s in self.snake)))
            ):
                time.sleep(0.5)
                self.game_over = True
                print(f"Final score: {self.score}")
                self.reset_game()

            if (
                self.x_pos == self.snake_food.x_pos
                and self.y_pos == self.snake_food.y_pos
            ):
                self.snake_food.generate_food()
                self.snake_length += 1
                self.score += 1
                self.update_caption()

            pygame.draw.rect(
                self.display,
                self.color["white"],
                [self.snake_food.x_pos, self.snake_food.y_pos, 10, 10],
            )
            for x, y in self.snake:
                pygame.draw.rect(self.display, self.color["lime"], [x, y, 10, 10])
            pygame.display.update()

            # Runs game at 30 FPS
            self.clock.tick(30)

    def move_right(self, event_key):
        if self.snake_length == 1 or self.prev_key not in (pygame.K_LEFT, pygame.K_a):
            self.x_speed = 10
            self.y_speed = 0
            self.prev_key = event_key

    def move_left(self, event_key):
        if self.snake_length == 1 or self.prev_key not in (pygame.K_RIGHT, pygame.K_d):
            self.x_speed = -10
            self.y_speed = 0
            self.prev_key = event_key

    def move_down(self, event_key):
        if self.snake_length == 1 or self.prev_key not in (pygame.K_UP, pygame.K_w):
            self.x_speed = 0
            self.y_speed = 10
            self.prev_key = event_key

    def move_up(self, event_key):
        if self.snake_length == 1 or self.prev_key not in (pygame.K_DOWN, pygame.K_s):
            self.x_speed = 0
            self.y_speed = -10
            self.prev_key = event_key

    def reset_game(self):
        self.game_over = False
        self.snake.clear()
        self.snake_length = 1
        self.x_pos = self.display_width / 2
        self.y_pos = self.display_height / 2
        self.x_speed = 0
        self.y_speed = 0
        self.score = 0
        self.snake_food.generate_food()
        self.update_caption()


snake = Snake()
snake.start()