/*******************************************************************************
 * Copyright (c) 2007 IBM Corporation and Others
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Takashi ITOH - initial API and implementation
 *******************************************************************************/

package org.eclipse.actf.util.win32;

import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.ShellAdapter;
import org.eclipse.swt.events.ShellEvent;
import org.eclipse.swt.internal.win32.OS;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

/**
 * OverlayWindow is transparent window. The purpose of this class is to overlay
 * some labels and highlight borders on the application windows. The
 * OverlayWindow covers the entire screen. Currently it supports only the main
 * screen.
 */
@SuppressWarnings("restriction")
public class OverlayWindow implements Runnable {

	public static final String WINDOW_TEXT = "[Overlay Window]"; //$NON-NLS-1$
	public static final int INDEX_HIGHLIGHT = 0;
	public static final int INDEX_LABELS = 1;
	private static boolean visible = true;

	private Shell shell;

	private Display display;

	private static OverlayWindow[] instance = new OverlayWindow[2];

	private OverlayWindow(int index) {
		// Create OverlayWindow shell
		shell = new Shell(SWT.MODELESS | SWT.NO_TRIM | SWT.ON_TOP);
		shell.setText(WINDOW_TEXT);
		shell.setBackground(shell.getBackground()); // Fix for color change
		display = shell.getDisplay();
		Shell activeShell = display.getActiveShell();
		if (null != activeShell) {
			activeShell.addDisposeListener(new DisposeListener() {
				public void widgetDisposed(DisposeEvent e) {
					shell.dispose();
				}
			});
		}

		// Make shell window transparent
		OverlayWindow.setLayered(shell, INDEX_HIGHLIGHT == index);

		// Init the shell
		shell.setLayout(new GridLayout());
		GraphicsEnvironment env = GraphicsEnvironment
				.getLocalGraphicsEnvironment();
		Rectangle rect = env.getDefaultScreenDevice().getDefaultConfiguration()
				.getBounds();
		shell.setBounds(0, 0, rect.width, rect.height);
		// shell.setBounds(0, 0, OS.GetSystemMetrics(OS.SM_CXSCREEN),
		// OS.GetSystemMetrics(OS.SM_CYSCREEN));
		shell.setVisible(visible);

		//
		if (INDEX_LABELS == index) {
			shell.addShellListener(new ShellAdapter() {
				public void shellDeactivated(ShellEvent e) {
					OverlayLabel.removeAll();
				}
			});
		}
	}

	/**
	 * @param index
	 *            the index of the overlay, it must be INDEX_HIGHLIGHT or
	 *            INDEX_LABELS
	 * @param create
	 *            whether create a new instance or not
	 * @return the instance of the OverlayWindow
	 * @see #INDEX_HIGHLIGHT
	 * @see #INDEX_LABELS
	 */
	public static OverlayWindow getInstance(int index, boolean create) {
		if (index < instance.length) {
			if (create && null == instance[index]) {
				instance[index] = new OverlayWindow(index);
			}
			return instance[index];
		}
		return null;
	}

	/**
	 * @return whether the overlay window is visible or not
	 */
	public static boolean getVisible() {
		return visible;
	}

	/**
	 * @param newVisible
	 *            whether the overlay window is visible or not
	 */
	public static void setVisible(boolean newVisible) {
		if (visible != newVisible) {
			visible = newVisible;
			for (int i = 0; i < instance.length; i++) {
				if (null != instance[i]) {
					instance[i].shell.setVisible(visible);
				}
			}
		}
	}

	/**
	 * @return the internal composite object. OverlayLabel and
	 *         HighlightComposite are added to this composite.
	 */
	public Composite getComposite() {
		return shell;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Runnable#run()
	 */
	public void run() {
		if (!shell.isDisposed()) {
			Control[] children = shell.getChildren();
			for (int i = 0; i < children.length; i++) {
				if (children[i] instanceof IIntervalExec) {
					int nextInterval = ((IIntervalExec) children[i]).exec();
					if (nextInterval > 0) {
						display.timerExec(nextInterval, this);
					}
				}
			}
		}
	}

	/**
	 * 
	 * @param control
	 * @param transparent
	 */
	private static void setLayered(Control control, boolean transparent) {
		int ws = OS.GetWindowLongW(control.handle, OS.GWL_EXSTYLE);
		ws |= WindowUtil.WS_EX_LAYERED;
		if (transparent) {
			ws |= OS.WS_EX_TRANSPARENT;
		}
		OS.SetWindowLong(control.handle, OS.GWL_EXSTYLE, ws);
		WindowUtil.SetLayeredWindowAttributes(control.handle, control
				.getBackground().handle, (char) 0, WindowUtil.LWA_COLORKEY);
	}
}