/*******************************************************************************
 * Copyright (c) 2000, 2010 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.gef.ui.actions;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.actions.ActionFactory;

import org.eclipse.gef.EditPart;
import org.eclipse.gef.internal.GEFMessages;
import org.eclipse.gef.palette.CombinedTemplateCreationEntry;
import org.eclipse.gef.palette.PaletteTemplateEntry;

/**
 * Copies the currently selected template in the palatte to the system
 * clipboard.
 * 
 * @author Eric Bordeau
 */
public class CopyTemplateAction extends WorkbenchPartAction implements
		ISelectionChangedListener {

	private Object template;

	/**
	 * Constructs a new CopyTemplateAction. You must manually add this action to
	 * the palette viewer's list of selection listeners. Otherwise, this
	 * action's enabled state won't be updated properly.
	 * 
	 * @param editor
	 *            the workbench part
	 * @see org.eclipse.gef.ui.actions.EditorPartAction#EditorPartAction(IEditorPart)
	 */
	public CopyTemplateAction(IEditorPart editor) {
		super(editor);
		setId(ActionFactory.COPY.getId());
		setText(GEFMessages.CopyAction_Label);
	}

	/**
	 * Returns whether the selected EditPart is a TemplateEditPart.
	 * 
	 * @return whether the selected EditPart is a TemplateEditPart
	 */
	protected boolean calculateEnabled() {
		return template != null;
	}

	/**
	 * @see org.eclipse.gef.ui.actions.EditorPartAction#dispose()
	 */
	public void dispose() {
		template = null;
	}

	/**
	 * Sets the default {@link Clipboard Clipboard's} contents to be the
	 * currently selected template.
	 */
	public void run() {
		Clipboard.getDefault().setContents(template);
	}

	/**
	 * Sets the selected EditPart and refreshes the enabled state of this
	 * action.
	 * 
	 * @see ISelectionChangedListener#selectionChanged(SelectionChangedEvent)
	 */
	public void selectionChanged(SelectionChangedEvent event) {
		ISelection s = event.getSelection();
		if (!(s instanceof IStructuredSelection))
			return;
		IStructuredSelection selection = (IStructuredSelection) s;
		template = null;
		if (selection != null && selection.size() == 1) {
			Object obj = selection.getFirstElement();
			if (obj instanceof EditPart) {
				Object model = ((EditPart) obj).getModel();
				if (model instanceof CombinedTemplateCreationEntry)
					template = ((CombinedTemplateCreationEntry) model)
							.getTemplate();
				else if (model instanceof PaletteTemplateEntry)
					template = ((PaletteTemplateEntry) model).getTemplate();
			}
		}
		refresh();
	}

}
