import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;

import javax.swing.JOptionPane;
import javax.swing.JPanel;


public class SlidingPuzzlePanel extends JPanel {

    private static final long serialVersionUID = 4501938941435763747L;

    private static final int SIDE = 4;
    private static final int FONT_SIZE = 40;
    private static int LEVEL = 10;

    private Game game;
    private Font font;
    private Color background, foreground, borderColor;

    private int slotWidth, slotHeight, slotXOffset, slotYOffset;

    private int inX, inY, xOffset, yOffset;
    private boolean dragged;

    public SlidingPuzzlePanel() {
        game = new Game(SIDE, LEVEL);
        font = new Font(Font.SERIF, Font.BOLD, FONT_SIZE);

        slotWidth = SlidingPuzzle.WIDTH / SIDE;
        slotHeight = SlidingPuzzle.HEIGHT / SIDE;
        slotXOffset = slotWidth / 2 - FONT_SIZE / 4;
        slotYOffset = slotHeight / 2 + FONT_SIZE / 3;

        background = new Color(123, 155, 232);
        foreground = new Color(123, 255, 132);
        borderColor = new Color(223, 255, 132);
        dragged = false;

        setFocusable(true);
        requestFocus();

        addMouseMotionListener(new MouseMotionAdapter() {
            @Override
            public void mouseDragged(MouseEvent e) {
                if(dragged) {
                    inX = e.getXOnScreen() - xOffset;
                    inY = e.getYOnScreen() - yOffset;
                    SlidingPuzzle.frame.setLocation(inX, inY);
                }
                else {
                    dragged = true;
                    xOffset = e.getX();
                    yOffset = e.getY();
                }
            }

            @Override
            public void mouseMoved(MouseEvent e) {
                dragged = false;
            }
        });

        addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent e) {
                int key = e.getKeyCode();
                switch(key) {
                case KeyEvent.VK_ESCAPE:
                    SlidingPuzzle.frame.dispose();
                    break;
                default:
                    game.keyPressed(key);
                    repaint();
                    if(game.isCorrect()) {
                        JOptionPane.showMessageDialog(SlidingPuzzle.frame, "You Win!");
                        LEVEL += 10;
                        game = new Game(SIDE, LEVEL);
                        repaint();
                    }
                }
            }
        });
    }

    @Override
    public void paint(Graphics g) {
        Graphics2D g2d = (Graphics2D)g;
        g2d.setFont(font);
        g2d.setColor(background);
        g2d.fillRect(0, 0, getWidth(), getHeight());
        drawBorders(g2d);

        g2d.setColor(foreground);
        for(int i = 0; i < 4; i++) {
            for(int j = 0; j < 4; j++) {
                if(game.getValueAt(j, i) != 0)
                    g2d.drawString(""+game.getValueAt(j, i), slotXOffset + j * slotWidth,
                            slotYOffset + i * slotHeight);
            }
        }
    }
    private void drawBorders(Graphics2D g2d) {
        g2d.setColor(borderColor);
        for(int i = 0; i < 3; i++)
            g2d.drawRect(i, i, SlidingPuzzle.WIDTH - 1 - 2 * i, SlidingPuzzle.HEIGHT - 1 - 2 * i);

        for(int  i = 1; i < 4; i++) {
            int level = i * slotHeight;
            g2d.drawLine(0, level, SlidingPuzzle.WIDTH, level);
            g2d.drawLine(0, level + 1, SlidingPuzzle.WIDTH, level + 1);
            g2d.drawLine(0, level + 2, SlidingPuzzle.WIDTH, level + 2);

            g2d.drawLine(level, 0, level, SlidingPuzzle.HEIGHT);
            g2d.drawLine(level + 1, 0, level + 1, SlidingPuzzle.HEIGHT);
            g2d.drawLine(level + 2, 0, level + 2, SlidingPuzzle.HEIGHT);
        }
    }
}