package org.rr.commons.swing.dialogs;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;

import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JPanel;

import org.rr.commons.utils.ReflectionFailureException;
import org.rr.commons.utils.ReflectionUtils;

public class JImageFileChooser extends JFileChooser {

	private static final long serialVersionUID = 1456173962722237346L;
	
	public JImageFileChooser() {
		super();
		ImagePreviewPanel imagePreviewPanel = new ImagePreviewPanel();
		setAccessory(imagePreviewPanel);
		addPropertyChangeListener(imagePreviewPanel);
	}
	
	/**
	 * Get the return value from a previous showOpenDialog call.
	 * @return The desired return value. (CANCEL_OPTION or APPROVE_OPTION ...)
	 */
	public int getReturnValue() {
		try {
			return ((Integer) ReflectionUtils.getFieldValue(this, "returnValue", false)).intValue();
		} catch (ReflectionFailureException e) {
			throw new RuntimeException(e);
		}
	}
	
	private static class ImagePreviewPanel extends JPanel implements PropertyChangeListener {

		private static final long serialVersionUID = 3262711734796955424L;

		private int width, height;
		private ImageIcon icon;
		private Image image;
		private static final int ACCSIZE = 155;
		private Color bg;

		public ImagePreviewPanel() {
			setPreferredSize(new Dimension(ACCSIZE, -1));
			bg = getBackground();
		}

		public void propertyChange(PropertyChangeEvent e) {
			String propertyName = e.getPropertyName();

			// Make sure we are responding to the right event.
			if (propertyName.equals(JFileChooser.SELECTED_FILE_CHANGED_PROPERTY)) {
				File selection = (File) e.getNewValue();
				String name;

				if (selection == null)
					return;
				else
					name = selection.getAbsolutePath();

				/*
				 * Make reasonably sure we have an image format that AWT can handle so we don't try to draw something silly.
				 */
				if ((name != null) && name.toLowerCase().endsWith(".jpg") || name.toLowerCase().endsWith(".jpeg") || name.toLowerCase().endsWith(".gif")
						|| name.toLowerCase().endsWith(".png")) {
					icon = new ImageIcon(name);
					image = icon.getImage();
					scaleImage();
					repaint();
				}
			}
		}

		private void scaleImage() {
			width = image.getWidth(this);
			height = image.getHeight(this);
			double ratio = 1.0;

			/*
			 * Determine how to scale the image. Since the accessory can expand vertically make sure we don't go larger than 150 when scaling vertically.
			 */
			if (width >= height) {
				ratio = (double) (ACCSIZE - 5) / width;
				width = ACCSIZE - 5;
				height = (int) (height * ratio);
			} else {
				if (getHeight() > 150) {
					ratio = (double) (ACCSIZE - 5) / height;
					height = ACCSIZE - 5;
					width = (int) (width * ratio);
				} else {
					ratio = (double) getHeight() / height;
					height = getHeight();
					width = (int) (width * ratio);
				}
			}
			if(width>0 && height>0) {
				image = image.getScaledInstance(width, height, Image.SCALE_DEFAULT);
			}
		}

		public void paintComponent(Graphics g) {
			g.setColor(bg);

			/*
			 * If we don't do this, we will end up with garbage from previous images if they have larger sizes than the one we are currently drawing. Also, it seems
			 * that the file list can paint outside of its rectangle, and will cause odd behavior if we don't clear or fill the rectangle for the accessory before
			 * drawing. This might be a bug in JFileChooser.
			 */
			g.fillRect(0, 0, ACCSIZE, getHeight());
			g.drawImage(image, getWidth() / 2 - width / 2 + 5, getHeight() / 2 - height / 2, this);
		}

	}
	

}