/*
 * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Copyright @ 2015 Atlassian Pty Ltd
 *
 * Licensed 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 net.java.sip.communicator.impl.globaldisplaydetails;

import java.util.*;

import net.java.sip.communicator.service.globaldisplaydetails.*;
import net.java.sip.communicator.service.gui.*;
import net.java.sip.communicator.service.protocol.*;
import net.java.sip.communicator.service.protocol.globalstatus.*;
import net.java.sip.communicator.util.*;

import org.jitsi.service.configuration.*;
import org.jitsi.service.resources.*;
import org.osgi.framework.*;

/**
 *
 * @author Yana Stamcheva
 */
public class GlobalDisplayDetailsActivator
    implements  BundleActivator,
                ServiceListener
{
    /**
     * The bundle context.
     */
    private static BundleContext bundleContext;

    /**
     * The service giving access to image and string application resources.
     */
    private static ResourceManagementService resourcesService;

    /**
     * The service giving access to the configuration resources.
     */
    private static ConfigurationService configService;

    /**
     * The alert UI service.
     */
    private static AlertUIService alertUIService;

    /**
     * The UI service.
     */
    private static UIService uiService;

    /**
     * The display details implementation.
     */
    static GlobalDisplayDetailsImpl displayDetailsImpl;

    static GlobalStatusServiceImpl globalStatusService;

    /**
     * Initialize and start file service
     *
     * @param bc the <tt>BundleContext</tt>
     * @throws Exception if initializing and starting file service fails
     */
    public void start(BundleContext bc)
        throws Exception
    {
        bundleContext = bc;

        displayDetailsImpl = new GlobalDisplayDetailsImpl();
        globalStatusService = new GlobalStatusServiceImpl();

        bundleContext.addServiceListener(this);

        handleAlreadyRegisteredProviders();

        bundleContext.registerService(
                GlobalDisplayDetailsService.class.getName(),
                displayDetailsImpl,
                null);

        bundleContext.registerService(
                GlobalStatusService.class.getName(),
                globalStatusService,
                null);
    }

    /**
     * Searches and processes already registered providers.
     */
    private void handleAlreadyRegisteredProviders()
    {
        Collection<ServiceReference<ProtocolProviderService>> ppsRefs
            = ServiceUtils.getServiceReferences(
                    bundleContext,
                    ProtocolProviderService.class);

        if(ppsRefs.isEmpty())
            return;

        for (ServiceReference<ProtocolProviderService> ppsRef : ppsRefs)
        {
            ProtocolProviderService pps = bundleContext.getService(ppsRef);

            handleProviderAdded(pps);
        }
    }

    /**
     * Used to attach the listeners to existing or
     * just registered protocol provider.
     *
     * @param pps ProtocolProviderService
     */
    private void handleProviderAdded(ProtocolProviderService pps)
    {
        pps.addRegistrationStateChangeListener(displayDetailsImpl);
        globalStatusService.handleProviderAdded(pps);
    }

    /**
     * Stops this bundle.
     *
     * @param bundleContext the <tt>BundleContext</tt>
     * @throws Exception if the stop operation goes wrong
     */
    public void stop(BundleContext bundleContext)
        throws Exception
    {
    }

    /**
     * Returns the <tt>ResourceManagementService</tt>, through which we will
     * access all resources.
     *
     * @return the <tt>ResourceManagementService</tt>, through which we will
     * access all resources.
     */
    public static ResourceManagementService getResources()
    {
        if (resourcesService == null)
        {
            resourcesService
                = ServiceUtils.getService(
                        bundleContext,
                        ResourceManagementService.class);
        }
        return resourcesService;
    }

    /**
     * Returns the <tt>ConfigurationService</tt> obtained from the bundle
     * context.
     * @return the <tt>ConfigurationService</tt> obtained from the bundle
     * context
     */
    public static ConfigurationService getConfigurationService()
    {
        if(configService == null)
        {
            configService
                = ServiceUtils.getService(
                        bundleContext,
                        ConfigurationService.class);
        }
        return configService;
    }

    /**
     * Returns the <tt>AlertUIService</tt> obtained from the bundle
     * context.
     * @return the <tt>AlertUIService</tt> obtained from the bundle
     * context
     */
    public static AlertUIService getAlertUIService()
    {
        if(alertUIService == null)
        {
            alertUIService
                = ServiceUtils.getService(
                        bundleContext,
                        AlertUIService.class);
        }
        return alertUIService;
    }

    /**
     * Returns the <tt>UIService</tt> obtained from the bundle
     * context.
     * @return the <tt>UIService</tt> obtained from the bundle
     * context
     */
    public static UIService getUIService()
    {
        if(uiService == null)
        {
            uiService
                = ServiceUtils.getService(
                        bundleContext,
                        UIService.class);
        }
        return uiService;
    }

    /**
     * Implements the <tt>ServiceListener</tt> method. Verifies whether the
     * passed event concerns a <tt>ProtocolProviderService</tt> and adds or
     * removes a registration listener.
     *
     * @param event The <tt>ServiceEvent</tt> object.
     */
    public void serviceChanged(ServiceEvent event)
    {
        ServiceReference<?> serviceRef = event.getServiceReference();

        // if the event is caused by a bundle being stopped, we don't want to
        // know
        if (serviceRef.getBundle().getState() == Bundle.STOPPING)
        {
            return;
        }

        Object service = UtilActivator.bundleContext.getService(serviceRef);

        // we don't care if the source service is not a protocol provider
        if (!(service instanceof ProtocolProviderService))
        {
            return;
        }

        ProtocolProviderService pps = (ProtocolProviderService) service;

        switch (event.getType())
        {
        case ServiceEvent.REGISTERED:
            this.handleProviderAdded(pps);
            break;
        case ServiceEvent.UNREGISTERING:
            pps.removeRegistrationStateChangeListener(displayDetailsImpl);
            globalStatusService.handleProviderRemoved(pps);
            break;
        }
    }
}