/* 
 * Icons taken from http://p.yusukekamiyamane.com/
 * http://www.iconarchive.com/show/fugue-icons-by-yusuke-kamiyamane/document-image-icon.html
 */

import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JWindow;
import javax.swing.JInternalFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.JRadioButton;
import javax.swing.BorderFactory;
import javax.swing.border.TitledBorder;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.event.InternalFrameAdapter;
import javax.swing.event.InternalFrameEvent;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.GridLayout;
import java.awt.GraphicsEnvironment;
import java.awt.GraphicsDevice;
import java.awt.DisplayMode;
import java.awt.Window;

import java.io.InputStream;

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

import java.util.Properties;

public class Wallmagick {

	public static final double REQUIRED_JVM_VERSION = 1.7;

	public static final String CONFIGURATION_FILENAME = "config.xml";
	
	public static final String APPLICATION_ICON = "document-image-icon.png";

	// Wallpaper display styles
	public static final String STRETCH = "Stretch";
	public static final String PAD = "Pad";
	public static final String CROP = "Crop";

	private static void createAndShowGUI(Properties configuration) {
		// Create left panel with 5 radio buttons for display style of wallpaper
		JRadioButton stretchButton = new JRadioButton(STRETCH);
		JRadioButton padButton = new JRadioButton(PAD);
		JRadioButton cropButton = new JRadioButton(CROP);
		
		StyleSetter styleListener = new StyleSetter(configuration);
		stretchButton.addActionListener(styleListener);
		padButton.addActionListener(styleListener);
		cropButton.addActionListener(styleListener);

		switch (configuration.getProperty("style")) {
		case STRETCH:
			stretchButton.setSelected(true);
			break;
		case PAD:
			padButton.setSelected(true);
			break;
		case CROP:
			cropButton.setSelected(true);
			break;
		}

		ButtonGroup displayRadioButtons = new ButtonGroup();

		displayRadioButtons.add(stretchButton);
		displayRadioButtons.add(padButton);
		displayRadioButtons.add(cropButton);

		TitledBorder titledBorder = BorderFactory.createTitledBorder("Display");

		JPanel leftPanel = new JPanel(new GridLayout(0, 1));

		leftPanel.add(stretchButton);
		leftPanel.add(padButton);
		leftPanel.add(cropButton);

		leftPanel.setBorder(titledBorder);

		// Create right panel button with two standard buttons
		JButton wallpaperButton = new JButton("Wallpaper");
		wallpaperButton.setAlignmentX(Component.CENTER_ALIGNMENT);
		JButton applyButton = new JButton("Apply");
		applyButton.setAlignmentX(Component.CENTER_ALIGNMENT);
		
		// Select wallpaper using a JFileChooser
		wallpaperButton.addActionListener(new WallpaperChooser(configuration, wallpaperButton));
		// Set wallpaper using imagemagick's display command
		applyButton.addActionListener(new WallpaperSetter(configuration));

		JPanel rightPanel = new JPanel();
		rightPanel.setLayout(new BoxLayout(rightPanel, BoxLayout.Y_AXIS));

		rightPanel.add(Box.createVerticalGlue());
		rightPanel.add(wallpaperButton);
		rightPanel.add(applyButton);
		rightPanel.add(Box.createVerticalGlue());

		// Load application icon
		Path iconPath = null;
		try{
			iconPath = Paths.get(configuration.getProperty("config.path"), APPLICATION_ICON);
		}catch(Exception e){
			System.err.println("Unable to generate application icon path information.");
		}
		ImageIcon icon = new ImageIcon(iconPath.toString());

		JInternalFrame frame = new JInternalFrame("Wallmagick", false, true, false, false);
		frame.setDefaultCloseOperation(JInternalFrame.DISPOSE_ON_CLOSE);
		frame.getContentPane().add(leftPanel, BorderLayout.WEST);
		frame.getContentPane().add(rightPanel, BorderLayout.CENTER);
		frame.setFrameIcon(icon);
		frame.pack();
		frame.setVisible(true);
		
		frame.addInternalFrameListener(new InternalFrameAdapter() {
		    public void internalFrameClosed(InternalFrameEvent e) {
		    	for(Window windows : window.getWindows()){
		    		if(windows.getName().equals(e.getInternalFrame().getTopLevelAncestor().getName())){
		    			windows.dispose();
		    			break;
		    		}
		    	}
		        System.exit(0);
		    }
		});
		
		FrameDragManager frameDragManager = new FrameDragManager();
		frame.addComponentListener(frameDragManager);
		
		JWindow window = new JWindow();
		window.getContentPane().add(frame);
		window.pack();
		window.setLocationRelativeTo(null);
		window.setVisible(true);
	}

	public static Properties getConfiguration() {
		// Confirm Java Virtual Machine version
		try {
			double jvmversion = Double.parseDouble(System
					.getProperty("java.vm.specification.version"));
			if (jvmversion < REQUIRED_JVM_VERSION) {
				throw new Exception();
			}
		} catch (Exception e) {
			System.err.println("JVM version check failed.");
			System.exit(1);
		}

		// Determine config.xml path
		Path configPath = null;
		try {
			configPath = Paths.get(System.getProperty("java.class.path"), CONFIGURATION_FILENAME);
			configPath = configPath.toAbsolutePath();
		} catch (Exception e) {
			System.err.println("Unable to determine configuration path.");
			System.exit(1);
		}

		// Test if configuration is readable/exists
		boolean configReadable = false;

		try {
			configReadable = Files.isReadable(configPath);
		} catch (Exception e) {
			configReadable = false;
		}

		// Instantiate Wallmagick properties
		Properties configuration = new Properties();
		configuration.setProperty("wallpaper.path", configPath.getParent().toString());
		configuration.setProperty("wallpaper.image", "wallmagick.png");
		configuration.setProperty("style", STRETCH);

		// Load properties from configuration file if possible
		if (configReadable) {
			try (InputStream configStream = Files.newInputStream(configPath)) {
				configuration.loadFromXML(configStream);
			} catch (Exception e) {
				System.err.println("Unable to read configuration file.");
				System.exit(1);
			}
		}

		// These configuration properties are dynamic
		configuration.setProperty("config.path", configPath.getParent()
				.toString());

		// Determine display's current resolution
		int height = 0;
		int width = 0;
		try {
			GraphicsDevice graphicsDevice = GraphicsEnvironment
					.getLocalGraphicsEnvironment().getDefaultScreenDevice();
			DisplayMode displayMode = graphicsDevice.getDisplayMode();
			height = displayMode.getHeight();
			width = displayMode.getWidth();
		} catch (Exception e) {
			System.err.println("System is running headless.");
			System.exit(1);
		}

		configuration.setProperty("display.width", String.valueOf(width));
		configuration.setProperty("display.height", String.valueOf(height));

		return configuration;
	}

	public static void main(String[] args) {

		// Event Dispatch Thread
		javax.swing.SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				// Set Nimbus L&F
				try {
					for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
						if ("Nimbus".equals(info.getName())) {
							UIManager.setLookAndFeel(info.getClassName());
							break;
						}
					}
				} catch (Exception e) {
					System.err.println("Nimbus L&F not supported.");
					System.exit(1);
				}

				// Display GUI
				createAndShowGUI(getConfiguration());
			}
		});

	}

}

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Properties;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class WallpaperSetter implements ActionListener {
	private Properties configuration;
	
	public WallpaperSetter(Properties configuration){
		this.configuration = configuration;
	}

	public void actionPerformed(ActionEvent e){
		
		Path wallpaperPath = null;
		try{
			wallpaperPath = Paths.get(
					configuration.getProperty("wallpaper.path"),
					configuration.getProperty("wallpaper.image")
				);
		}catch(Exception ex){
			System.err.println("Unable to determine wallpaper path.");
			System.exit(1);
		}
		
		int displayWidth = Integer.parseInt(configuration.getProperty("display.width"));
		int displayHeight = Integer.parseInt(configuration.getProperty("display.height"));
		
		String pipedCommand = "convert -resize ";
		pipedCommand += displayWidth;
		pipedCommand += "x";
		pipedCommand += displayHeight;
		
		switch(configuration.getProperty("style")){
		case Wallmagick.STRETCH:
			pipedCommand += "\\!";
			break;
		case Wallmagick.PAD:
			pipedCommand += "\\> -background black -gravity center -extent ";
			pipedCommand += displayWidth;
			pipedCommand += "x";
			pipedCommand += displayHeight;
			break;
		case Wallmagick.CROP:
			pipedCommand += "^ -gravity center -extent ";
			pipedCommand += displayWidth;
			pipedCommand += "x";
			pipedCommand += displayHeight;
			break;
		}
		
		pipedCommand += " ";
		pipedCommand += wallpaperPath.toString();
		pipedCommand += " - | display -window root -";
		
		String[] command = {
			"/bin/sh",
			"-c",
			pipedCommand
		};
		
		try {
			Runtime.getRuntime().exec(command);
		} catch(Exception ex) {
			System.err.println("Unable to execute imagemagick.");
			System.exit(1);
		}
		
		Path configPath = null;
		try{
			configPath = Paths.get(configuration.getProperty("config.path"), Wallmagick.CONFIGURATION_FILENAME);
		}catch(Exception ex){
			System.err.println("Unable to set configuration path information.");
			System.exit(1);
		}
		
		// Equivalent to Files.newOutputStream(configPath, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING)
		try(OutputStream configOut = Files.newOutputStream(configPath)){
			configuration.storeToXML(configOut, "Wallmagick configuration");
		}catch(Exception ex){
			System.err.println("Unable to store configuration.");
			System.exit(1);
		}
	}
}

import java.util.Properties;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFileChooser;
import javax.swing.filechooser.FileSystemView;
import javax.swing.JButton;

import java.nio.file.Path;
import java.nio.file.Paths;
//import java.nio.file.Files;


public class WallpaperChooser implements ActionListener {
	private Properties configuration;
	private JButton button;

	public WallpaperChooser(Properties configuration, JButton button){
		this.configuration = configuration;
		this.button = button;
	}
	
	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub
		Path wallpaperPath = null;
		try{
			wallpaperPath = Paths.get(
					configuration.getProperty("wallpaper.path"),
					configuration.getProperty("wallpaper.image")
				);
		}catch(Exception ex){
			System.err.println("Unable to generate chooser path information.");
			System.exit(1);
		}
		
		JFileChooser wallpaperChooser;
		wallpaperChooser = new JFileChooser(wallpaperPath.getParent().toString(), FileSystemView.getFileSystemView());
		try{
			if(wallpaperChooser.showOpenDialog(button) == JFileChooser.APPROVE_OPTION){
				wallpaperPath = Paths.get(
						wallpaperChooser.getSelectedFile().getAbsolutePath()
					);
				configuration.setProperty("wallpaper.path", wallpaperPath.getParent().toString());
				configuration.setProperty("wallpaper.image", wallpaperPath.getFileName().toString());
			}
		}catch(Exception ex){
			System.err.print("Unable to select wallpaper.");
			System.exit(1);
		}
	}

}