import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.awt.event.KeyListener;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;

class Manager implements KeyListener
{
    private final String USAGE =
        "------------------------------\n" +
        "Simple version of Flappy Bird\n" +
        "Press SPACE to jump!\n" +
        "------------------------------\n";
    private final Bird _bird;
    private final List<Drawable> _drawables;

    public Manager()
    {
        _drawables = new ArrayList<Drawable>();
        Turtle turtle = new Turtle();
        turtle.setzeGeschwindigkeit(10);

        JFrame fieldValue = new JFrame();
        // Modifying Turtle.java is forbidden so use reflection to get the JFrame and add
        // a KeyListener lol
        try
        {

            Field frameField = TurtleWelt.class.getDeclaredField("_frame");

            frameField.setAccessible(true);

            fieldValue = (JFrame) frameField.get(TurtleWelt.globaleWelt);
            fieldValue.addKeyListener(this);
        }
        catch (Exception ex)
        {
            System.out.println("Reflection hack failed");
            System.exit(-1);
        }

        System.out.print(USAGE);

        _bird = new Bird(this);
        Welt welt = new Welt(this);

        long lastNanos, elapsed;
        lastNanos = System.nanoTime();
        while (true)
        {
            elapsed = System.nanoTime() - lastNanos;
            lastNanos = System.nanoTime();

            _bird.update(elapsed * 1e-6d);
            welt.update(elapsed * 1e-6d);

            if (welt.checkCollision(_bird.getRect()))
            {
                welt.reset();
            }

            TurtleWelt.globaleWelt.bildschirmEinfaerben(255, 255, 255);
            for (var d : _drawables)
            {
                d.draw(turtle, elapsed * 1e-6d);
            }

            // Try to achieve approximately 60 FPS (1000ms / 60 FPS = 16.666ms)
            int missingMs = (int)(16 - (System.nanoTime() - lastNanos) * 1e-6d);
            if (missingMs > 0)
            {
                try
                {
                    Thread.sleep(missingMs);
                } catch (Exception e) {}
            }
        }
    }

    public void addDrawable(Drawable d)
    {
        _drawables.add(d);
    }

    public void keyPressed(KeyEvent e)
    {
        if (e.getKeyChar() == ' ')
        {
            _bird.jump();
        }
    }

    public void keyReleased(KeyEvent e) {}
    public void keyTyped(KeyEvent e) {}
}