/*
 * Copyright (c) 2014 Cisco Systems, Inc. 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
 */
package org.opendaylight.controller.sal.rest.doc;

import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

import org.opendaylight.controller.sal.core.api.Broker;
import org.opendaylight.controller.sal.core.api.Provider;
import org.opendaylight.controller.sal.core.api.model.SchemaService;
import org.opendaylight.controller.sal.core.api.mount.MountProvisionService;
import org.opendaylight.controller.sal.core.api.mount.MountProvisionService.MountProvisionListener;
import org.opendaylight.controller.sal.rest.doc.impl.ApiDocGenerator;
import org.opendaylight.controller.sal.rest.doc.mountpoints.MountPointSwagger;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DocProvider implements BundleActivator, ServiceTrackerCustomizer<Broker, Broker>,
        Provider, AutoCloseable {

    private final Logger _logger = LoggerFactory.getLogger(DocProvider.class);

    private ServiceTracker<Broker, Broker> brokerServiceTracker;
    private BundleContext bundleContext;
    private Broker.ProviderSession session;

    private final List<AutoCloseable> toClose = new LinkedList<>();

    @Override
    public void close() throws Exception {
        stop(bundleContext);
    }

    @Override
    public void onSessionInitiated(Broker.ProviderSession providerSession) {
        SchemaService schemaService = providerSession.getService(SchemaService.class);
        ApiDocGenerator.getInstance().setSchemaService(schemaService);

        MountProvisionService mountService = providerSession
                .getService(MountProvisionService.class);
        ListenerRegistration<MountProvisionListener> registration = mountService
                .registerProvisionListener(MountPointSwagger.getInstance());
        MountPointSwagger.getInstance().setGlobalSchema(schemaService);
        synchronized (toClose) {
            toClose.add(registration);
        }
        MountPointSwagger.getInstance().setMountService(mountService);

        _logger.debug("Restconf API Explorer started");
    }

    @Override
    public Collection<ProviderFunctionality> getProviderFunctionality() {
        return Collections.emptySet();
    }

    @Override
    public void start(BundleContext context) throws Exception {
        bundleContext = context;
        brokerServiceTracker = new ServiceTracker(context, Broker.class, this);
        brokerServiceTracker.open();
    }

    @Override
    public void stop(BundleContext context) throws Exception {
        if (brokerServiceTracker != null)
            brokerServiceTracker.close();

        if (session != null)
            session.close();

        synchronized (toClose) {
            for (AutoCloseable close : toClose) {
                close.close();
            }
        }
    }

    @Override
    public Broker addingService(ServiceReference<Broker> reference) {
        Broker broker = bundleContext.getService(reference);
        session = broker.registerProvider(this, bundleContext);
        return broker;
    }

    @Override
    public void modifiedService(ServiceReference<Broker> reference, Broker service) {
        if (session != null)
            session.close();

        Broker broker = bundleContext.getService(reference);
        session = broker.registerProvider(this, bundleContext);
    }

    @Override
    public void removedService(ServiceReference<Broker> reference, Broker service) {
        bundleContext.ungetService(reference);
    }
}