package examples;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
/*
 * @author Kenneth J. Goldman, Washington University, kjg@wustl.edu
 * Created: Feb 2, 2005
 */
public class Dragger extends MouseAdapter implements MouseMotionListener {
	PanelWithOverlay panel;
	Container oldParent;           // the old parent of component being dragged
	Point offset = new Point();  // the offset of the cursor from the upper left corner of the component being dragged
	
	public Dragger(PanelWithOverlay panel) {
		this.panel = panel;
	}
	
	public void control(Component x) {
		x.addMouseListener(this);
		x.addMouseMotionListener(this);
	}
	
	public void mouseDragged(MouseEvent me) {
		Component c = me.getComponent();
		if (c.getParent() != panel) {  // not yet in the overlay?
			oldParent = c.getParent();
			offset = me.getPoint();
			panel.raiseToOverlay(c);
		}
		Point p = c.getLocation();
		c.setLocation(p.x + me.getX() - offset.x, p.y + me.getY() - offset.y);
		c.repaint();
	}
	
	public void mouseReleased(MouseEvent me) {
		Component c = me.getComponent();
		Point cursor = new Point(c.getX() + me.getX(), c.getY() + me.getY());
		if (!panel.dropToContainerBeneath(c, cursor)) {
			oldParent.add(c);
			panel.revalidate();
			panel.repaint();
		}
	}

	public void mouseMoved(MouseEvent arg0) {}

	/*
	 * Test program.
	 */
	public static void main(String args[]) {
		JPanel mainPanel = new JPanel(new GridLayout(1,0));
		
		JPanel left = new JPanel();
		left.setBackground(Color.GREEN);
		mainPanel.add(left);
		JButton one = new JButton("one");
		one.setOpaque(false);
		left.add(one);
		
		JPanel right = new JPanel();
		right.setBackground(Color.ORANGE);
		mainPanel.add(right);
		JButton two = new JButton("two");
		two.setOpaque(false);
		right.add(two);	
		
		PanelWithOverlay layeredPanel = new PanelWithOverlay(mainPanel);
		
		Dragger dragger = new Dragger(layeredPanel);
		dragger.control(one);
		dragger.control(two);

		JFrame f = new JFrame("Dragger test");
		//f.setContentPane(layeredPanel);
		f.setLayout(new BorderLayout());
		f.add(layeredPanel);
		f.pack();
		f.setVisible(true);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
}