// from http://www.coderanch.com/t/341737/GUI/java/Expand-Collapse-Panels
package util;

import javax.swing.*;
import javax.imageio.*;

import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.image.*;
import java.io.*;

public class CollapsiblePanel extends JPanel {

	private boolean selected;
	JPanel contentPanel_;
	HeaderPanel headerPanel_;

	private class HeaderPanel extends JPanel implements MouseListener {
		String text_;
		Font font;
		BufferedImage open, closed;
		final int OFFSET = 30, PAD = 5;

		public HeaderPanel(String text) {
			addMouseListener(this);
			text_ = text;
			font = new Font("sans-serif", Font.PLAIN, 12);
			// setRequestFocusEnabled(true);
			setPreferredSize(new Dimension(200, 20));
			int w = getWidth();
			int h = getHeight();

			try {
				closed = ImageIO.read(getClass().getResourceAsStream("/toolbarButtonGraphics/navigation/Forward24.gif"));
				open = ImageIO.read(getClass().getResourceAsStream("/toolbarButtonGraphics/navigation/Down24.gif"));
			} catch (IOException e) {
				e.printStackTrace();
			}

		}

		protected void paintComponent(Graphics g) {
			super.paintComponent(g);
			Graphics2D g2 = (Graphics2D) g;
			g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
					RenderingHints.VALUE_ANTIALIAS_ON);
			int h = getHeight();
			if (selected)
				g2.drawImage(open, PAD, 0, h, h, this);
			else
				g2.drawImage(closed, PAD, 0, h, h, this);
                         // Uncomment once you have your own images
			g2.setFont(font);
			FontRenderContext frc = g2.getFontRenderContext();
			LineMetrics lm = font.getLineMetrics(text_, frc);
			float height = lm.getAscent() + lm.getDescent();
			float x = OFFSET;
			float y = (h + height) / 2 - lm.getDescent();
			g2.drawString(text_, x, y);
		}

		public void mouseClicked(MouseEvent e) {
			toggleSelection();
		}

		public void mouseEntered(MouseEvent e) {
		}

		public void mouseExited(MouseEvent e) {
		}

		public void mousePressed(MouseEvent e) {
		}

		public void mouseReleased(MouseEvent e) {
		}

	}

	public CollapsiblePanel(String text, JPanel panel) {
		super(new GridBagLayout());
		GridBagConstraints gbc = new GridBagConstraints();
		gbc.insets = new Insets(1, 3, 0, 3);
		gbc.weightx = 1.0;
		gbc.fill = gbc.HORIZONTAL;
		gbc.gridwidth = gbc.REMAINDER;

		selected = true;
		headerPanel_ = new HeaderPanel(text);

		setBackground(new Color(200, 200, 220));
		contentPanel_ = panel;

		add(headerPanel_, gbc);
		add(contentPanel_, gbc);
		contentPanel_.setVisible(selected);

		JLabel padding = new JLabel();
		gbc.weighty = 1.0;
		add(padding, gbc);

	}

	public void toggleSelection() {
		selected = !selected;

		if (contentPanel_.isShowing())
			contentPanel_.setVisible(false);
		else
			contentPanel_.setVisible(true);

		validate();

		headerPanel_.repaint();
	}
	
}