// Copyright 2012 Citrix Systems, Inc. Licensed under the
// Apache License, Version 2.0 (the "License"); you may not use this
// file except in compliance with the License.  Citrix Systems, Inc.
// reserves all rights not expressly granted by 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.
// 
// Automatically generated by addcopyright.py at 04/03/2012
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.resource.ResourceManager;
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;
    @Inject ResourceManager _resourceMgr;

    @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 = _resourceMgr.listAllHostsInCluster(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;
    }

}