/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.actions;


import org.eclipse.jface.action.*;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.util.PropertyChangeEvent;

/**
 * A <code>LabelRetargetAction</code> extends the behavior of
 * RetargetAction.  It will track the enable state, label, and 
 * tool tip text of the target action..
 * <p>
 * This class may be instantiated. It is not intented to be subclassed.
 * </p>
 *
 * @since 2.0 
 */
public class LabelRetargetAction extends RetargetAction {
	private String defaultText;
	private String defaultToolTipText;
	private ImageDescriptor defaultHoverImage;
	private ImageDescriptor defaultImage;
	private ImageDescriptor defaultDisabledImage;
	private String acceleratorText;
	
/**
 * Constructs a LabelRetargetAction.
 */
public LabelRetargetAction(String actionID, String text) {
	super(actionID, text);
	this.defaultText = text;
	this.defaultToolTipText = text;
	acceleratorText = extractAcceleratorText(text);
}
/**
 * The action handler has changed.  Update self.
 */
protected void propagateChange(PropertyChangeEvent event) {
	super.propagateChange(event);
	String prop = event.getProperty();
	if (prop.equals(Action.TEXT)) {
		String str = (String) event.getNewValue();
		super.setText(appendAccelerator(str));
	} 
	else if (prop.equals(Action.TOOL_TIP_TEXT)) {
		String str = (String) event.getNewValue();
		super.setToolTipText(str);
	}
	else if (prop.equals(Action.IMAGE)) {
		updateImages(getActionHandler());
	}
}
/**
 * Sets the action handler.  Update self.
 */
protected void setActionHandler(IAction handler) {
	// Run the default behavior.
	super.setActionHandler(handler);

	// Now update the label, tooltip and images.
	if (handler == null) {
		super.setText(defaultText);
		super.setToolTipText(defaultToolTipText);
	} else {
		// If no text is specified by the handler, use the default text.  Fixes 22529.
		String handlerText = handler.getText();
		if (handlerText == null || handlerText.length() == 0) {
			handlerText = defaultText;
		}
		super.setText(appendAccelerator(handlerText));
		super.setToolTipText(handler.getToolTipText());
	}
	updateImages(handler);
}

/* (non-Javadoc)
 * Method declared on IAction.
 */
public void setDisabledImageDescriptor(ImageDescriptor image) {
	super.setDisabledImageDescriptor(image);
	defaultDisabledImage = image;
}

/* (non-Javadoc)
 * Method declared on IAction.
 */
public void setHoverImageDescriptor(ImageDescriptor image) {
	super.setHoverImageDescriptor(image);
	defaultHoverImage = image;
}

/* (non-Javadoc)
 * Method declared on IAction.
 */
public void setImageDescriptor(ImageDescriptor image) {
	super.setImageDescriptor(image);
	defaultImage = image;
}

/**
 * Sets the action's label text to the given value.
 */
public void setText(String text) {
	super.setText(text);
	acceleratorText = extractAcceleratorText(text);
	defaultText = text;
}
/**
 * Sets the tooltip text to the given text.
 * The value <code>null</code> clears the tooltip text.
 */
public void setToolTipText(String text) {
	super.setToolTipText(text);
	defaultToolTipText = text;
}
/**
 * Ensures the accelerator is correct in the text (handlers are not
 * allowed to change the accelerator).
 */
private String appendAccelerator(String newText) {
	if (newText == null)
		return null;
		
	// Remove any accelerator
	String str = removeAcceleratorText(newText);
	// Append our accelerator
	if (acceleratorText != null)
		str = str + acceleratorText;
	return str;
}
/**
 * Extracts the accelerator text from the given text.
 * Returns <code>null</code> if there is no accelerator text,
 * and the empty string if there is no text after the accelerator delimeter (tab or '@').
 *
 * @param text the text for the action
 * @return the accelerator text including '@' or '\t', or <code>null</code>
 */
private String extractAcceleratorText(String text) {
	if (text == null)
		return null;
		
	int index = text.lastIndexOf('\t');
	if (index == -1)
		index = text.lastIndexOf('@');
	if (index >= 0)
		return text.substring(index);
	return null;
}

/**
 * Updates the images for this action based on the given handler.
 */
private void updateImages(IAction handler) {
	if (handler == null) {
		super.setHoverImageDescriptor(defaultHoverImage);
		super.setImageDescriptor(defaultImage);
		super.setDisabledImageDescriptor(defaultDisabledImage);
	}
	else {
		// use the default images if the handler has no images set
		ImageDescriptor hoverImage = handler.getHoverImageDescriptor();
		ImageDescriptor image = handler.getImageDescriptor();
		ImageDescriptor disabledImage = handler.getDisabledImageDescriptor();
		if (hoverImage != null || image != null || disabledImage != null) {
			super.setHoverImageDescriptor(hoverImage);
			super.setImageDescriptor(image);
			super.setDisabledImageDescriptor(disabledImage);
		}
		else {
			super.setHoverImageDescriptor(defaultHoverImage);
			super.setImageDescriptor(defaultImage);
			super.setDisabledImageDescriptor(defaultDisabledImage);
		}
	}
}

}