path: root/dozentenmodul/src/main/java/util/GuiManager.java

package util;

import gui.intro.About_GUI;
import gui.intro.Login_GUI;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.HeadlessException;
import java.awt.Rectangle;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.plaf.basic.BasicInternalFrameUI;

import org.apache.log4j.Logger;

/**
 * An abstract class to organize the GUI.
 * Currently only provide a method for centering Window-objects.
 */
public abstract class GuiManager {

	private final static Logger LOGGER = Logger.getLogger(GuiManager.class);
	
	/**
	 * The rectangle representing the bounds of the primary display
	 */
	private static Rectangle rect = null;

	/**
	 * Gets the bounds of the primary display using
	 * AWT's GraphicsEnvironment class.
	 */
	private static boolean getDisplayBounds() {
		GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
		GraphicsDevice gd = null;
		try {
			gd = ge.getDefaultScreenDevice();
		} catch (HeadlessException he) {
			he.printStackTrace();
			JOptionPane.showMessageDialog(null, "Konnte kein Display ermittelt werden.",
					"Fehler", JOptionPane.ERROR_MESSAGE);
			return false;
		}

		GraphicsConfiguration gc = gd.getDefaultConfiguration();
		rect = gc.getBounds();

		if (rect == null) {
			JOptionPane.showMessageDialog(null, "Konnte die Resolution des Bildschirms nicht ermitteln!",
					"Fehler", JOptionPane.ERROR_MESSAGE);
			return false;
		} else {
			return true;
		}
	}

	/**
	 * Centers the given Window within the bounds of the display
	 * @param gui The Window object to be centered.
	 */
	public static void centerGUI(Window gui) {

		if (rect == null) getDisplayBounds();
		double width = rect.getWidth();
		double height = rect.getHeight();
		double xCenter = (width / 2 - gui.getWidth() / 2);
		double yCenter = (height / 2 - gui.getHeight() / 2);
		gui.setLocation((int) xCenter, (int) yCenter);
	}
	
	private static JFrame mainWindow = null;
	public static JFrame getMainWindow() {
		return mainWindow;
	}
	private static JInternalFrame currentFrame = null;
	// TODO use this formerFrame when going "back" in the gui
	private static JInternalFrame formerFrame = null;

	/**
	 * Starts the GUI by creating the main window
	 * and showing the Login_GUI as the first frame.
	 */
	public static void initGui() {
		// get the screen size
		getDisplayBounds();
		if (rect == null) {
			LOGGER.error("Could not get display size. Contact developper.");
			System.exit(1);
		}

		// create main window
		mainWindow = new JFrame("DozMod");
		mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		mainWindow.setResizable(false);
		
		// create login frame
		currentFrame = new Login_GUI();
		mainWindow.getContentPane().add(currentFrame, BorderLayout.CENTER);
		((BasicInternalFrameUI)currentFrame.getUI()).setNorthPane(null);
		mainWindow.pack();

		// size management
		mainWindow.setBounds(0, 0, 785, 430);
		mainWindow.setLocation((int) (rect.getWidth() / 2 - mainWindow.getWidth() / 2),
				(int) (rect.getHeight() / 2 - mainWindow.getHeight() / 2));
		
		try {
			UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
		} catch (Exception e) {
			// Non-critical - applying the look failed, but app will still work
		}
		
		// finally let's see the frames
		currentFrame.setVisible(true);
		mainWindow.setVisible(true);
	}

	/**
	 * Private function to add the menu bar to the main window.
	 * @return true if adding the menu bar worked, false otherwise
	 */
	private static boolean addMenuBar() {
		JMenuBar menuBar = new JMenuBar();
		mainWindow.setJMenuBar(menuBar);

		JMenu helpMenu = new JMenu("Hilfe");
		menuBar.add(helpMenu);

		// FAQ Field
		JMenuItem mntmFaq = new JMenuItem("FAQ");
		mntmFaq.addMouseListener(new MouseAdapter() {
			@Override
			public void mousePressed(MouseEvent arg0) {
				OpenLinks.openWebpage("faq");
			}
		});
		helpMenu.add(mntmFaq);
		// OTRS Field
		JMenuItem mntmOtrs = new JMenuItem("OTRS");
		mntmOtrs.addMouseListener(new MouseAdapter() {
			@Override
			public void mousePressed(MouseEvent arg0) {
					OpenLinks.openWebpage("otrs");
			}
		});
		helpMenu.add(mntmOtrs);
		// About Field
		JMenuItem mntmAbout = new JMenuItem("About");
		mntmAbout.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				GuiManager.openPopup(new About_GUI());
			}
		});
		helpMenu.add(mntmAbout);
		return true;
	}
	/**
	 * Private function to determine whether the currentFrame has a
	 * 'HELP_MESSAGE' defined and to add it to the menu bar if found one.
	 * @return true if setting the help button to the menu bar worked, false otherwise
	 */
	private static boolean addHelp() {
		// let's see if we have a HELP_MESSAGE variable defined in
		// the class of the currentFrame, if so we need to show it by pressing "Hilfe"
		String test = "";
		try {
			test = (String) (currentFrame.getClass().getDeclaredField("HELP_MESSAGE").get(currentFrame));
		} catch (NoSuchFieldException e) {
			// only this case if interesting for us, 
			// since we now we don't have a help message to show
			return false;
		} catch (IllegalArgumentException|IllegalAccessException|SecurityException e) {
			LOGGER.error("Failed to check for 'HELP_MESSAGE' variable in '"
					+ currentFrame.getClass() + "' class, see trace: " + e);
			// just do nothing
		}
		// print it for debugging purposes
		// still here? means we have a HELP_MESSAGE to display
		JMenu mnNewMenu_Info = new JMenu("Info");
		mnNewMenu_Info.addMouseListener(new MouseAdapter() {
			@Override
			public void mousePressed(MouseEvent arg0) {
				String helpMessage = null;
				try {
					helpMessage = (String) currentFrame.getClass().getField("HELP_MESSAGE").get(currentFrame);
				} catch (IllegalArgumentException | IllegalAccessException
						| NoSuchFieldException | SecurityException e) {
					LOGGER.error("Failed to check for 'HELP_MESSAGE' variable in '"
							+ currentFrame.getClass() + "' class, see trace: " + e);
				}
				JOptionPane.showMessageDialog(currentFrame, helpMessage != null ? helpMessage : "No help message.",
						"Hilfe zu dieser Oberfläche", JOptionPane.INFORMATION_MESSAGE);
			}
		});
		mainWindow.getJMenuBar().add(mnNewMenu_Info);
		return true;
	}

	/**
	 * Public function to show the given frame, replacing the current frame
	 * @param newFrame the new frame to show
	 */
	public static void show(JInternalFrame newFrame) {
		// first remove the current component
		currentFrame.setVisible(false);
		mainWindow.getContentPane().remove(currentFrame);
		// save it as formerFrame in case we need it
		formerFrame = currentFrame;
		// from now on currentFrame is newFrame !!!
		currentFrame = newFrame;
		currentFrame.setBorder(null);

		// show the menu bar for everything but the Login_GUI
		if (!(currentFrame instanceof Login_GUI)) {
			if (mainWindow.getMenuBar() == null) {
				if (!addMenuBar()) {
					LOGGER.error("Failed to add menu to main window. See logs.");
				}
			}
			// add help if needed
			if (!addHelp()) {
				LOGGER.error("Failed to add help to main window's menu. See logs.");
			}
		}
		// prepare the switch
		if (currentFrame.getUI() instanceof BasicInternalFrameUI) {
			BasicInternalFrameUI bar = ((BasicInternalFrameUI) currentFrame.getUI());
			if (bar.getNorthPane() != null) bar.setNorthPane(null);
		}
		// TODO else case
		
		mainWindow.setTitle(newFrame.getTitle() != null ? newFrame.getTitle() : "bwLehrpool Suite");
		mainWindow.getContentPane().add(currentFrame, BorderLayout.CENTER);
		mainWindow.setBounds((int)mainWindow.getLocationOnScreen().getX(), (int)mainWindow.getLocationOnScreen().getY(),
				currentFrame.getWidth(), currentFrame.getHeight());
		currentFrame.setVisible(true);
		
	}
	/**
	 * Public function to show the given frame, replacing the current frame
	 * @param newFrame the new frame to show
	 * @param center true if the main window is to be centered, false otherwise
	 */
	public static void show(JInternalFrame newFrame, boolean center) {
		show(newFrame);
		if (center) {
			double xCenter = (rect.getWidth() / 2 - newFrame.getWidth() / 2);
			double yCenter = (rect.getHeight() / 2 - newFrame.getHeight() / 2);
			mainWindow.setBounds((int) xCenter, (int) yCenter,
					newFrame.getWidth(), newFrame.getHeight());
		}
	}
	/**
	 * 
	 */
	public static void openPopup(Component popup) {
		if (!(popup instanceof JFrame)) {
			LOGGER.error("Popup classes need to be JFrame, given a: " + popup.getClass().getName());
			return;
		}
		((JFrame)popup).setLocation((int)(rect.getWidth() / 2 - popup.getWidth() / 2), (int)(rect.getHeight() / 2 - popup.getHeight() / 2));
		((JFrame)popup).setVisible(true);
	}
}