/*******************************************************************************
 * 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:
 *     IBM Corporation - initial API and implementation
 ******************************************************************************/

package org.eclipse.ui.internal;

import org.eclipse.ui.IPageService;
import org.eclipse.ui.IPartService;
import org.eclipse.ui.ISelectionService;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchPartSite;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.progress.IProgressService;
import org.eclipse.ui.progress.IWorkbenchSiteProgressService;
import org.eclipse.ui.services.AbstractServiceFactory;
import org.eclipse.ui.services.IServiceLocator;

/**
 * Create singleton services to make the Workbench singletons available. This is
 * a "hack" to provide access to the Workbench singletons.
 * 
 * @since 3.4
 */
public class WorkbenchSupportFactory extends AbstractServiceFactory {

	public Object create(Class serviceInterface, IServiceLocator parentLocator,
			IServiceLocator locator) {

		final IWorkbench wb = (IWorkbench) locator.getService(IWorkbench.class);
		if (wb == null) {
			return null;
		}
		final IWorkbenchWindow window = (IWorkbenchWindow) locator
				.getService(IWorkbenchWindow.class);
		final IWorkbenchPartSite site = (IWorkbenchPartSite) locator
				.getService(IWorkbenchPartSite.class);
		Object parent = parentLocator.getService(serviceInterface);

		if (parent == null) {
			// return top level services
			if (IProgressService.class.equals(serviceInterface)) {
				return wb.getProgressService();
			}
			if (IWorkbenchSiteProgressService.class.equals(serviceInterface)) {
				if (site instanceof PartSite) {
					return ((PartSite) site).getSiteProgressService();
				}
			}
			if (IPartService.class.equals(serviceInterface)) {
				if (window != null) {
					return window.getPartService();
				}
			}
			if (IPageService.class.equals(serviceInterface)) {
				if (window != null) {
					return window;
				}
			}
			if (ISelectionService.class.equals(serviceInterface)) {
				if (window != null) {
					return window.getSelectionService();
				}
			}
			return null;
		}

		if (ISelectionService.class.equals(serviceInterface)) {
			if (parent instanceof WindowSelectionService && window != null
					&& window.getActivePage() != null) {
				return new SlaveSelectionService(window.getActivePage());
			}
			return new SlaveSelectionService((ISelectionService) parent);
		}

		if (IProgressService.class.equals(serviceInterface)) {
			if (site instanceof PartSite) {
				return ((PartSite) site).getSiteProgressService();
			}
		}
		if (IPartService.class.equals(serviceInterface)) {
			return new SlavePartService((IPartService) parent);
		}
		if (IPageService.class.equals(serviceInterface)) {
			return new SlavePageService((IPageService) parent);
		}

		return null;
	}
}