Game.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Random;

/**
 * author smokeed_
 * project Snake
 */

public class Game extends JPanel implements ActionListener {

    static final int SCREEN_WIDTH = 600;
    static final int SCREEN_HEIGHT = 600;
    static final int UNIT_SIZE = 25;
    static final int GAME_UNITS = (SCREEN_WIDTH*SCREEN_HEIGHT)/UNIT_SIZE;
    static final int DELAY = 75;
    final int x[] = new int[GAME_UNITS];
    final int y[] = new int[GAME_UNITS];
    int bodyParts = 6;
    int applesEats;
    int appleX;
    int appleY;
    char direction = 'R';
    boolean running = false;
    Timer timer;
    Random random;

    Game() {
        random = new Random();
        this.setPreferredSize(new Dimension(SCREEN_WIDTH, SCREEN_HEIGHT));
        this.setBackground(Color.BLACK);
        this.setFocusable(true);
        this.addKeyListener(new MyKey());
        start();
    }
    @Override
    public void actionPerformed(ActionEvent e) {
        if (running) {
            move();
            checkApple();
            checkColl();
        }
        repaint();
    }
    public void start() {
        newApple();
        running = true;
        timer = new Timer(DELAY, this);
        timer.start();
    }
    public void paint(Graphics graphics) {
        super.paint(graphics);
        draw(graphics);
    }
    public void draw(Graphics graphics) {
        if (running) {
            for (int i = 0; i < SCREEN_HEIGHT / UNIT_SIZE; i++) {
                graphics.drawLine(i * UNIT_SIZE, 0, i * UNIT_SIZE, SCREEN_HEIGHT);
                graphics.drawLine(0, i * UNIT_SIZE, SCREEN_WIDTH, i * UNIT_SIZE);
            }
            graphics.setColor(Color.RED);
            graphics.fillOval(appleX, appleY, UNIT_SIZE, UNIT_SIZE);
            for (int i = 0; i < bodyParts; i++) {
                if (i == 0) {
                    graphics.setColor(Color.green);
                    graphics.fillRect(x[i], y[i], UNIT_SIZE, UNIT_SIZE);
                } else {
                    graphics.setColor(new Color(45, 180, 0));
                    graphics.fillRect(x[i], y[i], UNIT_SIZE, UNIT_SIZE);
                }
                graphics.setColor(Color.RED);
                graphics.setFont(new Font("Ink Free", Font.BOLD,45));
                FontMetrics metrics = getFontMetrics(graphics.getFont());
                graphics.drawString("O4KOV: "+applesEats, (SCREEN_WIDTH - metrics.stringWidth("O4KOV")+applesEats)/2, graphics.getFont().getSize());
            }
        } else {
            gameend(graphics);
        }
    }
    public void move() {
        for (int i = bodyParts;i>0;i--) {
            x[i] = x[i-1];
            y[i] = y[i-1];
        }
        switch (direction) {
            case 'U':
                y[0] = y[0] - UNIT_SIZE;
                break;
            case 'D':
                y[0] = y[0] + UNIT_SIZE;
                break;
            case 'L':
                x[0] = x[0] - UNIT_SIZE;
                break;
            case 'R':
                x[0] = x[0] + UNIT_SIZE;
                break;
        }
    }
    public void checkApple() {
        if ((x[0] == appleX) && (y[0] == appleY)) {
            bodyParts++;
            applesEats++;
            newApple();
        }
    }
    public void checkColl() {
        for (int i = bodyParts;i>0;i--) {
            if ((x[0] == x[i])&& (y[0] == y[i])) {
                running = false;
            }
        }
        if (x[0] < 0 ) {
            running = false;
        }
        if (x[0] > SCREEN_WIDTH) {
            running = false;
        }
        if (y[0] < 0) {
            running = false;
        }
        if (y[0] > SCREEN_HEIGHT) {
            running = false;
        }
        if (!running) {
            timer.start();
        }
    }
    public void newApple() {
        appleX = random.nextInt((int)(SCREEN_WIDTH/UNIT_SIZE))*UNIT_SIZE;
        appleY = random.nextInt((int)(SCREEN_HEIGHT/UNIT_SIZE))*UNIT_SIZE;
    }
    public void gameend(Graphics graphics) {
        graphics.setColor(Color.RED);
        graphics.setFont(new Font("Ink Free", Font.BOLD,75));
        FontMetrics metrics = getFontMetrics(graphics.getFont());
        graphics.drawString("LOX EBANNIY", (SCREEN_WIDTH - metrics.stringWidth("LOX EBANNIY"))/2, SCREEN_HEIGHT/2);
    }


    public class MyKey extends KeyAdapter {
        @Override
        public void keyPressed(KeyEvent event) {
            switch (event.getKeyCode()) {
                case KeyEvent.VK_LEFT:
                    if (direction != 'R') {
                        direction = 'L';
                    }
                    break;
                case KeyEvent.VK_RIGHT:
                    if (direction != 'L') {
                        direction = 'R';
                    }
                    break;
                case KeyEvent.VK_UP:
                    if (direction != 'D') {
                        direction = 'U';
                    }
                    break;
                case KeyEvent.VK_DOWN:
                    if (direction != 'U') {
                        direction = 'D';
                    }
            }
        }
    }
}