/**
 *  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.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.resource.ResourceManager;
import com.cloud.utils.component.Inject;
import com.cloud.vm.VMInstanceVO;

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

	@Inject HostDao _hostDao;
	@Inject AgentManager _agentMgr;
	@Inject ResourceManager _resourceMgr;
	@Override
	public boolean configure(String name, Map<String, Object> params)
			throws ConfigurationException {
		// TODO Auto-generated method stub
		  _name = name;
		 return true;
	}

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

	@Override
	public boolean start() {
		// TODO Auto-generated method stub
		return true;
	}

	@Override
	public boolean stop() {
		// TODO Auto-generated method stub
		return true;
	}

	  public KVMFencer() {
	        super();
	    }

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

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

		for (HostVO h : hosts) {
			if (h.getHypervisorType() == HypervisorType.KVM) {
				if( h.getStatus() != Status.Up ) {
					continue;
				}
				if( h.getId() == host.getId() ) {
					continue;
				}
				FenceAnswer answer;
				try {
					answer = (FenceAnswer)_agentMgr.send(h.getId(), fence);
				} 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;
	}
}