/**
 *  Copyright (C) 2010 Cloud.com, Inc.  All rights reserved.
 *
 * This software is licensed under the GNU General Public License v3 or later.
 *
 * It is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or any later version.
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
package com.cloud.ha;

import java.util.List;
import java.util.Map;

import javax.ejb.Local;
import javax.naming.ConfigurationException;

import org.apache.log4j.Logger;

import com.cloud.agent.AgentManager;
import com.cloud.agent.api.Answer;
import com.cloud.agent.api.FenceAnswer;
import com.cloud.agent.api.FenceCommand;
import com.cloud.exception.AgentUnavailableException;
import com.cloud.exception.OperationTimedoutException;
import com.cloud.host.HostVO;
import com.cloud.host.Status;
import com.cloud.host.dao.HostDao;
import com.cloud.hypervisor.Hypervisor.HypervisorType;
import com.cloud.utils.component.Inject;
import com.cloud.vm.VMInstanceVO;

@Local(value=FenceBuilder.class)
public class XenServerFencer implements FenceBuilder {
    private static final Logger s_logger = Logger.getLogger(XenServerFencer.class);
    String _name;

    @Inject HostDao _hostDao;
    @Inject AgentManager _agentMgr;

    @Override
    public Boolean fenceOff(VMInstanceVO vm, HostVO host) {
        if (host.getHypervisorType() != HypervisorType.XenServer) {
            s_logger.debug("Don't know how to fence non XenServer hosts " + host.getHypervisorType());
            return null;
        }

        List<HostVO> hosts = _hostDao.listByCluster(host.getClusterId());
        FenceCommand fence = new FenceCommand(vm, host);

        for (HostVO h : hosts) {
            if (h.getHypervisorType() == HypervisorType.XenServer) {
            	if( h.getStatus() != Status.Up ) {
            		continue;
            	}
            	if( h.getId() == host.getId() ) {
            		continue;
            	}
                FenceAnswer answer;
                try {
                    Answer ans = _agentMgr.send(h.getId(), fence);
                    if (!(ans instanceof FenceAnswer)) {
                        s_logger.debug("Answer is not fenceanswer.  Result = " + ans.getResult() + "; Details = " + ans.getDetails());
                        continue;
                    }
                    answer = (FenceAnswer) ans;
                } catch (AgentUnavailableException e) {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("Moving on to the next host because " + h.toString() + " is unavailable");
                    }
                    continue;
                } catch (OperationTimedoutException e) {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("Moving on to the next host because " + h.toString() + " is unavailable");
                    }
                    continue;
                }
                if (answer != null && answer.getResult()) {
                    return true;
                }
            }
        }

        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Unable to fence off " + vm.toString() + " on " + host.toString());
        }

        return false;
    }

    public XenServerFencer() {
        super();
    }

    @Override
    public boolean configure(String name, Map<String, Object> params) throws ConfigurationException {
        _name = name;
        return true;
    }

    @Override
    public String getName() {
        return _name;
    }

    @Override
    public boolean start() {
        return true;
    }

    @Override
    public boolean stop() {
        return true;
    }

}