/**
 * Abiquo community edition
 * cloud management application for hybrid clouds
 * Copyright (C) 2008-2010 - Abiquo Holdings S.L.
 *
 * This application is free software; you can redistribute it and/or
 * modify it under the terms of the GNU LESSER GENERAL PUBLIC
 * LICENSE as published by the Free Software Foundation under
 * version 3 of the License
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * LESSER GENERAL PUBLIC LICENSE v.3 for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
package com.abiquo.api.eventing;

import java.util.Collection;
import java.util.List;

import org.hibernate.HibernateException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import com.abiquo.api.services.RemoteServiceService;
import com.abiquo.api.services.stub.VsmServiceStub;
import com.abiquo.api.tracer.TracerLogger;
import com.abiquo.model.enumerator.RemoteServiceType;
import com.abiquo.server.core.cloud.VirtualMachine;
import com.abiquo.server.core.cloud.VirtualMachineDAO;
import com.abiquo.server.core.cloud.VirtualMachineRep;
import com.abiquo.server.core.infrastructure.Datacenter;
import com.abiquo.server.core.infrastructure.InfrastructureRep;
import com.abiquo.server.core.infrastructure.RemoteService;
import com.abiquo.tracer.ComponentType;
import com.abiquo.tracer.EventType;
import com.abiquo.tracer.SeverityType;

/**
 * Implements Virtual System Monitor subscription initialization and checks.
 * 
 * @author daniel.estevez
 */
@Service("vsmSubscriber")
@Transactional(readOnly = true, propagation = Propagation.REQUIRED)
public class VSMSubscriberImpl implements VSMSubscriber
{

    /** The logger. */
    private static final Logger LOGGER = LoggerFactory.getLogger(VSMSubscriberImpl.class);

    // Uncomment this to enable only-at-the-beginning execution
    /**
     * private static boolean executed = false;
     */

    @Autowired
    protected TracerLogger tracer;

    @Autowired
    protected VirtualMachineDAO vMachineDAO;

    @Autowired
    protected VirtualMachineRep vMachineRep;

    @Autowired
    protected InfrastructureRep infraRep;

    @Autowired
    protected VsmServiceStub vsmStub;

    @Autowired
    private RemoteServiceService remoteServiceService;

    /**
     * Attempts an VSM subscription for each VA. If subscription succeeds the task is unsheduled.
     * Gets all VM Deployed and subscribes to VSM
     */
    @Override
    public void subscribe()
    {
        try
        {
            LOGGER.info("Refreshing Virtual System Monitor subscriptions");

            // Uncomment this to enable only-at-the-beginning execution
            /**
             * LOGGER.debug("VSMSubscriber.executed is now : " + VSMSubscriber.executed); if
             * (VSMSubscriber.executed) return;
             */

            // Get the Virtual appliance list
            // OPTIMIZED -> we recover all VMs by Datacenter? or PMachine?
            Collection<Datacenter> allDCs = infraRep.findAll();
            for (Datacenter datacenter : allDCs)
            {
                RemoteService remoteService =
                    remoteServiceService.getRemoteService(datacenter.getId(),
                        RemoteServiceType.VIRTUAL_SYSTEM_MONITOR);
                List<VirtualMachine> vMachines =
                    vMachineDAO.findVirtualMachinesByDatacenter(datacenter.getId());
                for (VirtualMachine vMachine : vMachines)
                {
                    if (vMachine.getState().existsInHypervisor())
                    {
                        LOGGER.info("Refreshing subscription for virtual machine '"
                            + vMachine.getName() + '"');
                        vsmStub.subscribe(remoteService, vMachine, Boolean.FALSE);
                    }
                }
            }

            // Uncomment this to enable only-at-the-beginning execution
            /**
             * // Task finished ok. It should be unscheduled LOGGER .info(
             * "VSMSubscriber.executed set to TRUERefreshing Virtual System Monitor subscriptions");
             * VSMSubscriber.executed = true;
             */

        }
        catch (HibernateException e)
        {
            LOGGER.error("An error was occurred when refreshing the VSM subscriptions caused by:",
                e);
            tracer.log(SeverityType.MAJOR, ComponentType.API, EventType.REMOTE_SERVICES_CHECK,
                "vsm.subscriber.error", e.getCause());

            // Uncomment this to enable only-at-the-beginning execution
            /**
             * VSMSubscriber.executed = false;
             */

        }
    }
}