/*******************************************************************************
 * Copyright (c) 2016 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.equinox.internal.ds;

import java.util.List;
import org.eclipse.osgi.service.environment.EnvironmentInfo;
import org.osgi.framework.*;
import org.osgi.framework.namespace.BundleNamespace;
import org.osgi.framework.startlevel.BundleStartLevel;
import org.osgi.framework.wiring.BundleWire;
import org.osgi.framework.wiring.BundleWiring;

public class Activator implements BundleActivator {

	public void start(BundleContext context) throws Exception {
		ServiceReference<EnvironmentInfo> envInfoRef = context.getServiceReference(EnvironmentInfo.class);
		EnvironmentInfo envInfo = null;
		if (envInfoRef != null) {
			envInfo = context.getService(envInfoRef);
		}
		if (envInfo != null) {
			envInfo.setProperty("equinox.use.ds", "true"); //$NON-NLS-1$//$NON-NLS-2$
			context.ungetService(envInfoRef);
		} else {
			System.setProperty("equinox.use.ds", "true"); //$NON-NLS-1$ //$NON-NLS-2$
		}

		BundleWiring wiring = context.getBundle().adapt(BundleWiring.class);
		List<BundleWire> required = wiring.getRequiredWires(BundleNamespace.BUNDLE_NAMESPACE);
		if (required.isEmpty()) {
			throw new IllegalStateException("No org.apache.felix.scr bundle found!"); //$NON-NLS-1$
		}
		Bundle scr = required.get(0).getProvider().getBundle();
		if (!"org.apache.felix.scr".equals(scr.getSymbolicName())) { //$NON-NLS-1$
			throw new IllegalStateException("Required wrong bundle: " + scr); //$NON-NLS-1$
		}
		BundleStartLevel equinoxSDstartLevel = context.getBundle().adapt(BundleStartLevel.class);
		BundleStartLevel scrStartLevel = scr.adapt(BundleStartLevel.class);
		scrStartLevel.setStartLevel(equinoxSDstartLevel.getStartLevel());
		scr.start();
	}

	public void stop(BundleContext context) throws Exception {
		// do nothing; just keep scr persistently started
	}

}