/**
 *  Copyright (c) 2011, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 *  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 org.wso2.carbon.ntask.core.internal;

import org.apache.axis2.engine.ListenerManager;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.osgi.framework.BundleContext;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.ServiceReference;
import org.osgi.service.component.ComponentContext;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Deactivate;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.annotations.ReferenceCardinality;
import org.osgi.service.component.annotations.ReferencePolicy;
import org.quartz.Scheduler;
import org.quartz.impl.StdSchedulerFactory;
import org.wso2.carbon.core.ServerStartupObserver;
import org.wso2.carbon.ntask.core.TaskStartupHandler;
import org.wso2.carbon.ntask.core.impl.QuartzCachedThreadPool;
import org.wso2.carbon.ntask.core.impl.TaskAxis2ConfigurationContextObserver;
import org.wso2.carbon.ntask.core.service.TaskService;
import org.wso2.carbon.ntask.core.service.impl.TaskServiceImpl;
import org.wso2.carbon.registry.core.service.RegistryService;
import org.wso2.carbon.securevault.SecretCallbackHandlerService;
import org.wso2.carbon.user.core.service.RealmService;
import org.wso2.carbon.utils.Axis2ConfigurationContextObserver;
import org.wso2.carbon.utils.CarbonUtils;
import org.wso2.carbon.utils.ConfigurationContextService;

import java.io.File;
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * This class represents the Tasks declarative service component.
 */
@Component(
        name = "tasks.component",
        immediate = true)
public class TasksDSComponent {

    private static final String QUARTZ_PROPERTIES_FILE_NAME = "quartz.properties";

    private final Log log = LogFactory.getLog(TasksDSComponent.class);

    private static RegistryService registryService;

    private static RealmService realmService;

    private static Scheduler scheduler;

    private static ConfigurationContextService configCtxService;

    private static SecretCallbackHandlerService secretCallbackHandlerService;

    private static TaskService taskService;

    private static ExecutorService executor = Executors.newCachedThreadPool();

    @Activate
    protected void activate(ComponentContext ctx) {

        try {
            if (executor.isShutdown()) {
                executor = Executors.newCachedThreadPool();
            }
            String quartzConfigFilePath = CarbonUtils.getCarbonConfigDirPath() + File.separator + "etc" + File
                    .separator + QUARTZ_PROPERTIES_FILE_NAME;
            StdSchedulerFactory fac;
            if (new File(quartzConfigFilePath).exists()) {
                fac = new StdSchedulerFactory(quartzConfigFilePath);
            } else {
                fac = new StdSchedulerFactory(this.getStandardQuartzProps());
            }
            TasksDSComponent.scheduler = fac.getScheduler();
            TasksDSComponent.getScheduler().start();
            if (getTaskService() == null) {
                taskService = new TaskServiceImpl();
            }
            BundleContext bundleContext = ctx.getBundleContext();
            bundleContext.registerService(ServerStartupObserver.class.getName(), new TaskStartupHandler(taskService),
                    null);
            bundleContext.registerService(TaskService.class.getName(), getTaskService(), null);
            bundleContext.registerService(Axis2ConfigurationContextObserver.class.getName(), new
                    TaskAxis2ConfigurationContextObserver(getTaskService()), null);
            taskService.runAfterRegistrationActions();
        } catch (Throwable e) {
            log.error("Error in intializing Tasks component: " + e.getMessage(), e);
        }
    }

    private Properties getStandardQuartzProps() {

        Properties result = new Properties();
        result.put("org.quartz.scheduler.skipUpdateCheck", "true");
        result.put("org.quartz.threadPool.class", QuartzCachedThreadPool.class.getName());
        return result;
    }

    public static void executeTask(Runnable runnable) {

        executor.submit(runnable);
    }

    @Deactivate
    protected void deactivate(ComponentContext ctx) {

        if (TasksDSComponent.getScheduler() != null) {
            try {
                TasksDSComponent.getScheduler().shutdown();
            } catch (Exception e) {
                log.error(e);
            }
        }
        executor.shutdown();
        taskService = null;
    }

    public static TaskService getTaskService() {

        return taskService;
    }

    public static Scheduler getScheduler() {

        return scheduler;
    }

    @Reference(
            name = "registry.service",
            service = org.wso2.carbon.registry.core.service.RegistryService.class,
            cardinality = ReferenceCardinality.OPTIONAL,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsetRegistryService")
    protected void setRegistryService(RegistryService registryService) {

        TasksDSComponent.registryService = registryService;
    }

    protected void unsetRegistryService(RegistryService registryService) {

        TasksDSComponent.registryService = null;
    }

    public static RegistryService getRegistryService() {

        return TasksDSComponent.registryService;
    }

    @Reference(
            name = "user.realmservice.default",
            service = org.wso2.carbon.user.core.service.RealmService.class,
            cardinality = ReferenceCardinality.OPTIONAL,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsetRealmService")
    protected void setRealmService(RealmService realmService) {

        TasksDSComponent.realmService = realmService;
    }

    protected void unsetRealmService(RealmService realmService) {

        TasksDSComponent.realmService = null;
    }

    public static RealmService getRealmService() {

        return TasksDSComponent.realmService;
    }

    @Reference(
            name = "config.context.service",
            service = org.wso2.carbon.utils.ConfigurationContextService.class,
            cardinality = ReferenceCardinality.MANDATORY,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsetConfigurationContextService")
    protected void setConfigurationContextService(ConfigurationContextService configCtxService) {

        TasksDSComponent.configCtxService = configCtxService;
    }

    protected void unsetConfigurationContextService(ConfigurationContextService configCtxService) {

        TasksDSComponent.configCtxService = null;
    }

    public static ConfigurationContextService getConfigurationContextService() {

        return TasksDSComponent.configCtxService;
    }

    public static SecretCallbackHandlerService getSecretCallbackHandlerService() {

        return TasksDSComponent.secretCallbackHandlerService;
    }

    @Reference(
            name = "secret.callback.handler.service",
            service = org.wso2.carbon.securevault.SecretCallbackHandlerService.class,
            cardinality = ReferenceCardinality.MANDATORY,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsetSecretCallbackHandlerService")
    protected void setSecretCallbackHandlerService(SecretCallbackHandlerService secretCallbackHandlerService) {

        TasksDSComponent.secretCallbackHandlerService = secretCallbackHandlerService;
    }

    protected void unsetSecretCallbackHandlerService(SecretCallbackHandlerService secretCallbackHandlerService) {

        TasksDSComponent.secretCallbackHandlerService = null;
    }

    @Reference(
            name = "listener.manager.service",
            service = org.apache.axis2.engine.ListenerManager.class,
            cardinality = ReferenceCardinality.MANDATORY,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsetListenerManager")
    protected void setListenerManager(ListenerManager lm) {
        /* we don't really need this, the listener manager service is acquired
         * to make sure, as a workaround, that the task component is initialized
         * after the axis2 clustering agent is initialized */
    }

    protected void unsetListenerManager(ListenerManager lm) {
        /* empty */
    }
}
