/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.felix.coordination.impl;

import java.util.Hashtable;

import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;

import org.apache.felix.jmx.service.coordination.CoordinatorMBean;
import org.apache.felix.service.coordination.Coordinator;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;
import org.osgi.framework.ServiceFactory;
import org.osgi.framework.ServiceReference;
import org.osgi.framework.ServiceRegistration;
import org.osgi.util.tracker.ServiceTracker;

@SuppressWarnings("deprecation")
public class Activator implements BundleActivator {

    private CoordinationMgr mgr;

    private ServiceTracker mbeanServerTracker;

    private ServiceRegistration coordinatorService;

    public void start(BundleContext context) {
        mgr = new CoordinationMgr();

        try {
            mbeanServerTracker = new MBeanServerTracker(context, mgr);
            mbeanServerTracker.open();
        } catch (MalformedObjectNameException e) {
            // TODO log
        }

        ServiceFactory factory = new CoordinatorFactory(mgr);
        Hashtable<String, String> props = new Hashtable<String, String>();
        props.put(Constants.SERVICE_DESCRIPTION,
            "Coordinator Service Implementation");
        props.put(Constants.SERVICE_VENDOR, "The Apache Software Foundation");
        coordinatorService = context.registerService(
            Coordinator.class.getName(), factory, props);
    }

    public void stop(BundleContext context) {
        if (coordinatorService != null) {
            coordinatorService.unregister();
            coordinatorService = null;
        }

        if (mbeanServerTracker != null) {
            mbeanServerTracker.close();
            mbeanServerTracker = null;
        }

        mgr.cleanUp();
    }

    static final class CoordinatorFactory implements ServiceFactory {

        private final CoordinationMgr mgr;

        CoordinatorFactory(final CoordinationMgr mgr) {
            this.mgr = mgr;
        }

        public Object getService(Bundle bundle, ServiceRegistration registration) {
            return new CoordinatorImpl(bundle, mgr);
        }

        public void ungetService(Bundle bundle,
                ServiceRegistration registration, Object service) {
            // nothing to do
        }

    }

    static final class MBeanServerTracker extends ServiceTracker {

        private final CoordinationMgr mgr;

        private final ObjectName objectName;

        MBeanServerTracker(final BundleContext context,
                final CoordinationMgr mgr) throws MalformedObjectNameException {
            super(context, MBeanServer.class.getName(), null);
            this.mgr = mgr;
            this.objectName = new ObjectName(CoordinatorMBean.OBJECTNAME);
        }

        @Override
        public Object addingService(ServiceReference reference) {
            MBeanServer server = (MBeanServer) super.addingService(reference);

            try {
                server.registerMBean(mgr, objectName);
            } catch (Exception e) {
                // TODO: log
            }

            return server;
        }

        @Override
        public void removedService(ServiceReference reference, Object service) {
            try {
                ((MBeanServer) service).unregisterMBean(objectName);
            } catch (Exception e) {
                // TODO: log
            }

            super.removedService(reference, service);
        }
    }
}