/*******************************************************************************
 * Copyright (c) 2000, 2005 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.examples.logicdesigner.actions;

import java.util.List;

import org.eclipse.ui.IWorkbenchPart;
import org.eclipse.ui.actions.ActionFactory;

import org.eclipse.draw2d.geometry.Point;

import org.eclipse.gef.GraphicalEditPart;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.requests.CreateRequest;
import org.eclipse.gef.requests.CreationFactory;
import org.eclipse.gef.ui.actions.Clipboard;
import org.eclipse.gef.ui.actions.SelectionAction;

import org.eclipse.gef.examples.logicdesigner.LogicMessages;

/**
 * If the current object on the clipboard is a valid template, this action will paste 
 * the template to the viewer.
 * 
 * @author Eric Bordeau, Pratik Shah
 * @see org.eclipse.gef.ui.actions.CopyTemplateAction
 */
public abstract class PasteTemplateAction
	extends SelectionAction 
{

/**
 * Constructor for PasteTemplateAction.
 * @param editor
 */
public PasteTemplateAction(IWorkbenchPart editor) {
	super(editor);
}

/**
 * @return <code>true</code> if {@link #createPasteCommand()} returns an executable command
 * @see org.eclipse.gef.ui.actions.WorkbenchPartAction#calculateEnabled()
 */
protected boolean calculateEnabled() {
	// TODO Workaround for Bug 82622/39369.  Should be removed when 39369 is fixed.
	return true;
}

/**
 * Creates and returns a command (which may be <code>null</code>) to create a new EditPart
 * based on the template on the clipboard.
 * @return the paste command
 */
protected Command createPasteCommand() {
	Command result = null;
	List selection = getSelectedObjects();
	if (selection != null && selection.size() == 1) {
		Object obj = selection.get(0);
		if (obj instanceof GraphicalEditPart) {
			GraphicalEditPart gep = (GraphicalEditPart)obj;
			Object template = getClipboardContents();
			if (template != null) {
				CreationFactory factory = getFactory(template);
				if (factory != null) {
					CreateRequest request = new CreateRequest();
					request.setFactory(factory);
					request.setLocation(getPasteLocation(gep));
					result = gep.getCommand(request);
				}
			}
		}
	}
	return result;
}

/**
 * Returns the template on the clipboard, if there is one.  Note that the template on
 * the clipboard might be from a palette from another type of editor.
 * @return the clipboard's contents
 */
protected Object getClipboardContents() {
	return Clipboard.getDefault().getContents();
}

/**
 * Returns the appropriate Factory object to be used for the specified template. This
 * Factory is used on the CreateRequest that is sent to the target EditPart.  Note that
 * the given template might be from a palette for a different GEF-based editor.  In that
 * case, this method can return <code>null</code>.
 * @param template the template Object; it will never be <code>null</code>
 * @return a Factory
 */
protected CreationFactory getFactory(Object template) {
	if (template instanceof CreationFactory)
		return (CreationFactory)template;
	return null;
}

/**
 * @param container the parent of the new part that is being pasted
 * @return the location at which  
 */
protected abstract Point getPasteLocation(GraphicalEditPart container);

/**
 * @see org.eclipse.gef.ui.actions.EditorPartAction#init()
 */
protected void init() {
	setId(ActionFactory.PASTE.getId());
	setText(LogicMessages.PasteAction_ActionLabelText);
}

/**
 * Executes the command returned by {@link #createPasteCommand()}.
 */
public void run() {
	execute(createPasteCommand());
}

}