/*******************************************************************************
 * Copyright (c) 2000, 2009 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;


import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;

/**
 * Instances of this class represent a task item.
 * 
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>(none)</dd>
 * <dt><b>Events:</b></dt>
 * <dd>(none)</dd>
 * </dl>
 *
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * 
 * @since 3.6
 * 
 * @noextend This class is not intended to be subclassed by clients.
 */
public class TaskItem extends Item {
	TaskBar parent;
	Shell shell;
	int progress, progressState = SWT.DEFAULT;
	Image overlayImage;
	String overlayText = "";
	Menu menu;

	static final int PROGRESS_MAX = 100;
/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Tray</code>) and a style value
 * describing its behavior and appearance. The item is added
 * to the end of the items maintained by its parent.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a composite control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see SWT
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
TaskItem (TaskBar parent, int style) {
	super (parent, style);
	this.parent = parent;
	parent.createItem (this, -1);
}

@Override
protected void checkSubclass () {
	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
}

@Override
void destroyWidget () {
	parent.destroyItem (this);
	releaseHandle ();
}

/**
 * Returns the receiver's pop up menu if it has one, or null
 * if it does not.
 *
 * @return the receiver's menu
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Menu getMenu () {
	checkWidget ();
	return menu;
} 

/**
 * Returns the receiver's overlay image if it has one, or null
 * if it does not.
 *
 * @return the receiver's overlay image
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Image getOverlayImage () {
	checkWidget();
	return overlayImage;
}

/**
 * Returns the receiver's overlay text, which will be an empty
 * string if it has never been set.
 *
 * @return the receiver's overlay text
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getOverlayText () {
	checkWidget();
	return overlayText;
}

/**
 * Returns the receiver's parent, which must be a <code>TaskBar</code>.
 *
 * @return the receiver's parent
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 */
public TaskBar getParent () {
	checkWidget ();
	return parent;
}

/**
 * Returns the receiver's progress.
 *
 * @return the receiver's progress
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getProgress () {
	checkWidget ();
	return progress;
}

/**
 * Returns the receiver's progress state.
 *
 * @return the receiver's progress state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getProgressState () {
	checkWidget ();
	return progressState;
}

@Override
void releaseHandle () {
	super.releaseHandle ();
	parent = null;
}

@Override
void releaseWidget () {
	super.releaseWidget ();
	overlayImage = null;
	overlayText = null;
}

/**
 * Sets the receiver's pop up menu to the argument. The way the menu is
 * shown is platform specific.
 * 
 * <p>
 * This feature might not be available for the receiver on all
 * platforms. The application code can check if it is supported
 * by calling the respective get method. When the feature is not
 * available, the get method will always return the NULL.</p>
 *
 * <p>
 * For better cross platform support, the application code should
 * set this feature on the <code>TaskItem</code> for application.<br>
 * On Windows, this feature will only work on RCP applications.</p>
 *
 * <p>
 * The menu should be fully created before this method is called.
 * Dynamic changes to the menu after the method is called will not be reflected
 * in the native menu.</p> 
 *
 * @param menu the new pop up menu
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_MENU_NOT_POP_UP - the menu is not a pop up menu</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the menu has been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setMenu (Menu menu) {
	checkWidget ();
	if (menu != null) {
		if (menu.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
		if ((menu.style & SWT.POP_UP) == 0) {
			error (SWT.ERROR_MENU_NOT_POP_UP);
		}
	}
	this.menu = menu;
}

/**
 * Sets the receiver's overlay image, which may be null
 * indicating that no image should be displayed. The bounds
 * for the overlay image is determined by the platform and in 
 * general it should be a small image.
 *
 * <p>
 * This feature might not be available for the receiver on all
 * platforms. The application code can check if it is supported
 * by calling the respective get method. When the feature is not
 * available, the get method will always return the NULL.</p>
 *
 * <p>
 * For better cross platform support, the application code should
 * first try to set this feature on the <code>TaskItem</code> for the 
 * main shell then on the <code>TaskItem</code> for the application.</p>
 *
 * @param overlayImage the new overlay image (may be null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the overlayImage has been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setOverlayImage (Image overlayImage) {
	checkWidget ();
	if (overlayImage != null && overlayImage.isDisposed ()) error (SWT.ERROR_INVALID_ARGUMENT);
	this.overlayImage = overlayImage;
}

/**
 * Sets the receiver's overlay text. The space available to display the
 * overlay text is platform dependent and in general it should be no longer
 * than a few characters.
 *
 * <p>
 * This feature might not be available for the receiver on all
 * platforms. The application code can check if it is supported
 * by calling the respective get method. When the feature is not
 * available, the get method will always return an empty string.</p>
 *
 * <p>
 * For better cross platform support, the application code should
 * first try to set this feature on the <code>TaskItem</code> for the 
 * main shell then on the <code>TaskItem</code> for the application.</p>
 *
 * @param overlayText the new overlay text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the overlayText is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setOverlayText (String overlayText) {
	checkWidget ();
	if (overlayText == null) error (SWT.ERROR_NULL_ARGUMENT);
	this.overlayText = overlayText;
}

/**
 * Sets the receiver's progress state, the state can be one of
 * the following:
 * <p><ul>
 * <li>{@link SWT#DEFAULT}</li>
 * <li>{@link SWT#NORMAL}</li>
 * <li>{@link SWT#PAUSED}</li>
 * <li>{@link SWT#ERROR}</li>
 * <li>{@link SWT#INDETERMINATE}</li>
 * </ul></p>
 * 
 * The percentage of progress shown by the states <code>SWT#NORMAL</code>, <code>SWT#PAUSED</code>, 
 * <code>SWT#ERROR</code> is set with <code>setProgress()</code>. <br>
 * The state <code>SWT#DEFAULT</code> indicates that no progress should be shown.
 *
 * <p>
 * This feature might not be available for the receiver on all
 * platforms. The application code can check if it is supported
 * by calling the respective get method. When the feature is not
 * available, the get method will always return <code>SWT#DEFAULT</code>.</p>
 *
 * <p>
 * For better cross platform support, the application code should
 * first try to set this feature on the <code>TaskItem</code> for the 
 * main shell then on the <code>TaskItem</code> for the application.</p>
 *
 * @param progressState the new progress state 
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * #see {@link #setProgress(int)}
 */
public void setProgressState (int progressState) {
	checkWidget ();
	if (this.progressState == progressState) return;
	this.progressState = progressState;
}

/**
 * Sets the receiver's progress, the progress represents a percentage and
 * should be in range from 0 to 100. The progress is only shown when the progress
 * state is different than <code>SWT#DEFAULT</code>.
 *
 * <p>
 * This feature might not be available for the receiver on all
 * platforms. The application code can check if it is supported
 * by calling the respective get method. When the feature is not
 * available, the get method will always return zero.</p>
 *
 * <p>
 * For better cross platform support, the application code should
 * first try to set this feature on the <code>TaskItem</code> for the 
 * main shell then on the <code>TaskItem</code> for the application.</p>
 *
 * @param progress the new progress
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * #see {@link #setProgressState(int)}
 */
public void setProgress (int progress) {
	checkWidget ();
	progress = Math.max(0, Math.min(progress, PROGRESS_MAX));
	if (this.progress == progress) return;
	this.progress = progress;
}

}
