import javax.swing.JFrame;
import javax.swing.JPanel;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.Dimension;

import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.KeyListener;
import java.awt.event.KeyEvent;
import java.awt.event.ComponentListener;
import java.awt.event.ComponentEvent;

import java.lang.Runnable;
import java.lang.Thread;

import java.awt.Toolkit;


public class Subconscious 
    extends JPanel 
    implements Runnable, MouseListener, KeyListener,
               ComponentListener, MouseWheelListener {

    public static final String TITLE = "Subconscious";
    public static final long RENDER_PERIOD_MS = 10;

    /* graphics */
    private JFrame window;
    private Scene currentScene;

    private Graphics dbg = null; // double buffered graphics
    private Image dbImage = null; // double buffered image

    private Thread animator = null;

    /* game */
    // private volatile boolean gamePaused = false;
    private volatile boolean gameOver = false;
    private volatile boolean running = false;

    public Subconscious() {
        createWindow();

        // setup component
        addMouseListener(this);
        addKeyListener(this);
        addComponentListener(this);
        addMouseWheelListener(this);
        setFocusable(true);
        requestFocus();

        // TODO remove demo
        currentScene = new WorldScene(new Dimension(200, 200), 50);
    }

    private void createWindow() {
        window = new JFrame(TITLE);
        window.setSize(new Dimension(800, 600));
        window.setMinimumSize(getSize());
        window.setLocationRelativeTo(null); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.add(this);
    }

    /* game logic */
    private void gameLoop() {

    }

    private void gameRender() {
        if (dbImage == null) {
            dbImage = createImage(getWidth(), getHeight());
            if (dbImage == null) {
                System.out.println("ERROR: Cannot create image");
                return;
            }
        }

        dbg = dbImage.getGraphics();
        dbg.fillRect(0, 0, getWidth(), getHeight());

        currentScene.render(dbg);
    }

    public void gameStart() {
        if (animator == null || !running) {
            animator = new Thread(this);
            animator.start();
        }
    }

    /* animator and game thread */
    @Override
    public void run() {
        long beforeTime, afterTime, sleepTime;
        int skipFrame = 0;

        window.setVisible(true);
        beforeTime = System.currentTimeMillis();

        running = true;
        while (running) {
            gameLoop();
            gameRender();
            repaint(); 
            // could be better with NanoSeconds, but this is
            // probably enough for this
            afterTime = System.currentTimeMillis();
            sleepTime = RENDER_PERIOD_MS - (beforeTime - afterTime);

            if (sleepTime < 0) {
                skipFrame++;
                continue;
            }

            if (skipFrame > 0)
                skipFrame--;

            try {
                Thread.sleep(sleepTime);
            } catch (InterruptedException ex) {}

            beforeTime = System.currentTimeMillis();
        }

        window.dispose();
        System.exit(0);
    }

    /* graphics */
    @Override
    public void paintComponent(Graphics g) {
        if (dbImage != null) {
            g.drawImage(dbImage, 0, 0, null);
        }

        Toolkit.getDefaultToolkit().sync(); // needed on linux
        g.dispose();
    }

    /* listeners */
    @Override public void mousePressed(MouseEvent e) {}
    @Override public void mouseReleased(MouseEvent e) {}
    @Override public void mouseEntered(MouseEvent e) {}
    @Override public void mouseExited(MouseEvent e) {}
    @Override
    public void mouseClicked(MouseEvent e) {
        currentScene.mouseClicked(e.getX(), e.getY());
    }

    @Override public void keyPressed(KeyEvent e) {}
    @Override public void keyTyped(KeyEvent e) {}
    @Override
    public void keyReleased(KeyEvent e) {
        int keyCode = e.getKeyCode();

        if (keyCode == KeyEvent.VK_Q && e.isControlDown()) {
            running = false;
        }

        if (keyCode == KeyEvent.VK_DOWN) {
            currentScene.pan(0, -10);
            //rerender
            dbImage = null;
        }

        if (keyCode == KeyEvent.VK_UP) {
            currentScene.pan(0, 10);
            //rerender
            dbImage = null;
        }

        if (keyCode == KeyEvent.VK_LEFT) {
            currentScene.pan(10, 0);
            //rerender
            dbImage = null;
        }

        if (keyCode == KeyEvent.VK_RIGHT) {
            currentScene.pan(-10, 0);
            //rerender
            dbImage = null;
        }
    }

    @Override
    public void mouseWheelMoved(MouseWheelEvent e) {
        int value = e.getWheelRotation();
        currentScene.zoom(value * -1);
        //rerender
        dbImage = null;
    }

    @Override public void componentHidden(ComponentEvent e) {}
    @Override public void componentShown(ComponentEvent e) {}
    @Override public void componentMoved(ComponentEvent e) {}
    @Override
    public void componentResized(ComponentEvent e) {
        dbImage = null; // create new image with the correct size
    }

    /* main */
    public static void main(String args[]) {
        Subconscious g = new Subconscious();
        g.gameStart();
    }
}