/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.cloudstack.storage.motion;

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

import javax.inject.Inject;

import com.cloud.agent.api.to.DiskTO;
import com.cloud.storage.Storage;
import org.apache.cloudstack.engine.subsystem.api.storage.ClusterScope;
import org.apache.cloudstack.engine.subsystem.api.storage.CopyCommandResult;
import org.apache.cloudstack.engine.subsystem.api.storage.DataMotionStrategy;
import org.apache.cloudstack.engine.subsystem.api.storage.DataObject;
import org.apache.cloudstack.engine.subsystem.api.storage.DataStore;
import org.apache.cloudstack.engine.subsystem.api.storage.DataStoreManager;
import org.apache.cloudstack.engine.subsystem.api.storage.EndPoint;
import org.apache.cloudstack.engine.subsystem.api.storage.EndPointSelector;
import org.apache.cloudstack.engine.subsystem.api.storage.HostScope;
import org.apache.cloudstack.engine.subsystem.api.storage.ObjectInDataStoreStateMachine.Event;
import org.apache.cloudstack.engine.subsystem.api.storage.Scope;
import org.apache.cloudstack.engine.subsystem.api.storage.SnapshotInfo;
import org.apache.cloudstack.engine.subsystem.api.storage.StorageAction;
import org.apache.cloudstack.engine.subsystem.api.storage.StorageCacheManager;
import org.apache.cloudstack.engine.subsystem.api.storage.StrategyPriority;
import org.apache.cloudstack.engine.subsystem.api.storage.VolumeInfo;
import org.apache.cloudstack.engine.subsystem.api.storage.ZoneScope;
import org.apache.cloudstack.framework.async.AsyncCompletionCallback;
import org.apache.cloudstack.framework.config.dao.ConfigurationDao;
import org.apache.cloudstack.storage.RemoteHostEndPoint;
import org.apache.cloudstack.storage.command.CopyCommand;
import org.apache.cloudstack.storage.datastore.db.VolumeDataStoreDao;
import org.apache.cloudstack.storage.datastore.db.VolumeDataStoreVO;
import org.apache.cloudstack.storage.image.datastore.ImageStoreEntity;
import org.apache.cloudstack.storage.to.PrimaryDataStoreTO;
import org.apache.log4j.Logger;
import org.springframework.stereotype.Component;

import com.cloud.agent.api.Answer;
import com.cloud.agent.api.storage.MigrateVolumeAnswer;
import com.cloud.agent.api.storage.MigrateVolumeCommand;
import com.cloud.agent.api.to.DataObjectType;
import com.cloud.agent.api.to.DataStoreTO;
import com.cloud.agent.api.to.DataTO;
import com.cloud.agent.api.to.NfsTO;
import com.cloud.agent.api.to.VirtualMachineTO;
import com.cloud.configuration.Config;
import com.cloud.host.Host;
import com.cloud.hypervisor.Hypervisor;
import com.cloud.storage.DataStoreRole;
import com.cloud.storage.Snapshot.Type;
import com.cloud.storage.SnapshotVO;
import com.cloud.storage.StorageManager;
import com.cloud.storage.Storage.StoragePoolType;
import com.cloud.storage.StoragePool;
import com.cloud.storage.VolumeVO;
import com.cloud.storage.dao.SnapshotDao;
import com.cloud.storage.dao.VolumeDao;
import com.cloud.utils.NumbersUtil;
import com.cloud.utils.db.DB;
import com.cloud.utils.exception.CloudRuntimeException;
import com.cloud.vm.VirtualMachineManager;

@Component
public class AncientDataMotionStrategy implements DataMotionStrategy {
    private static final Logger s_logger = Logger.getLogger(AncientDataMotionStrategy.class);
    private static final String NO_REMOTE_ENDPOINT_SSVM = "No remote endpoint to send command, check if host or ssvm is down?";
    private static final String NO_REMOTE_ENDPOINT_WITH_ENCRYPTION = "No remote endpoint to send command, unable to find a valid endpoint. Requires encryption support: %s";

    @Inject
    EndPointSelector selector;
    @Inject
    ConfigurationDao configDao;
    @Inject
    VolumeDao volDao;
    @Inject
    DataStoreManager dataStoreMgr;
    @Inject
    StorageCacheManager cacheMgr;
    @Inject
    VolumeDataStoreDao volumeDataStoreDao;

    @Inject
    StorageManager storageManager;
    @Inject
    SnapshotDao snapshotDao;

    @Override
    public StrategyPriority canHandle(DataObject srcData, DataObject destData) {
        return StrategyPriority.DEFAULT;
    }

    @Override
    public StrategyPriority canHandle(Map<VolumeInfo, DataStore> volumeMap, Host srcHost, Host destHost) {
        return StrategyPriority.CANT_HANDLE;
    }

    protected boolean needCacheStorage(DataObject srcData, DataObject destData) {
        DataTO srcTO = srcData.getTO();
        DataStoreTO srcStoreTO = srcTO.getDataStore();

        if (srcStoreTO instanceof NfsTO || srcStoreTO.getRole() == DataStoreRole.ImageCache) {
            return false;
        }
        DataTO destTO = destData.getTO();
        DataStoreTO destStoreTO = destTO.getDataStore();

        if (destStoreTO instanceof NfsTO || destStoreTO.getRole() == DataStoreRole.ImageCache) {
            return false;
        }
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("needCacheStorage true, dest at " + destTO.getPath() + " dest role " + destStoreTO.getRole().toString() + srcTO.getPath() + " src role " +
                srcStoreTO.getRole().toString());
        }
        return true;
    }

    private Scope getZoneScope(Scope destScope) {
        ZoneScope zoneScope = null;
        if (destScope instanceof ClusterScope) {
            ClusterScope clusterScope = (ClusterScope)destScope;
            zoneScope = new ZoneScope(clusterScope.getZoneId());
        } else if (destScope instanceof HostScope) {
            HostScope hostScope = (HostScope)destScope;
            zoneScope = new ZoneScope(hostScope.getZoneId());
        } else {
            zoneScope = (ZoneScope)destScope;
        }
        return zoneScope;
    }

    private Scope pickCacheScopeForCopy(DataObject srcData, DataObject destData) {
        Scope srcScope = srcData.getDataStore().getScope();
        Scope destScope = destData.getDataStore().getScope();

        Scope selectedScope = null;
        if (srcScope.getScopeId() != null) {
            selectedScope = getZoneScope(srcScope);
        } else if (destScope.getScopeId() != null) {
            selectedScope = getZoneScope(destScope);
        } else {
            s_logger.warn("Cannot find a zone-wide scope for movement that needs a cache storage");
        }
        return selectedScope;
    }

    protected Answer copyObject(DataObject srcData, DataObject destData, Host destHost) {
        int primaryStorageDownloadWait = StorageManager.PRIMARY_STORAGE_DOWNLOAD_WAIT.value();
        Answer answer = null;
        DataObject cacheData = null;
        DataObject srcForCopy = srcData;
        try {
            if (needCacheStorage(srcData, destData)) {
                Scope destScope = pickCacheScopeForCopy(srcData, destData);
                srcForCopy = cacheData = cacheMgr.createCacheObject(srcData, destScope);
            }

            CopyCommand cmd = new CopyCommand(srcForCopy.getTO(), addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(destData.getTO()), primaryStorageDownloadWait,
                    VirtualMachineManager.ExecuteInSequence.value());
            EndPoint ep = destHost != null ? RemoteHostEndPoint.getHypervisorHostEndPoint(destHost) : selector.select(srcForCopy, destData);
            if (ep == null) {
                s_logger.error(NO_REMOTE_ENDPOINT_SSVM);
                answer = new Answer(cmd, false, NO_REMOTE_ENDPOINT_SSVM);
            } else {
                answer = ep.sendMessage(cmd);
            }

            if (cacheData != null) {
                final Long cacheId = cacheData.getId();
                final String cacheType = cacheData.getType().toString();
                final String cacheUuid = cacheData.getUuid().toString();

                if (srcData.getType() == DataObjectType.VOLUME &&
                    (destData.getType() == DataObjectType.VOLUME ||
                     destData.getType() == DataObjectType.TEMPLATE)) {
                    // volume transfer from primary to secondary. Volume transfer between primary pools are already handled by copyVolumeBetweenPools
                    // Delete cache in order to certainly transfer a latest image.
                    s_logger.debug("Delete " + cacheType + " cache(id: " + cacheId +
                                   ", uuid: " + cacheUuid + ")");
                    cacheMgr.deleteCacheObject(srcForCopy);
                } else {
                    // for template, we want to leave it on cache for performance reason
                    if ((answer == null || !answer.getResult()) && srcForCopy.getRefCount() < 2) {
                        // cache object created by this copy, not already there
                        s_logger.warn("Copy may not be handled correctly by agent(id: " + (ep != null ? ep.getId() : "\"unspecified\"") + ")." +
                                      " Delete " + cacheType + " cache(id: " + cacheId +
                                      ", uuid: " + cacheUuid + ")");
                        cacheMgr.deleteCacheObject(srcForCopy);
                    } else {
                        s_logger.debug("Decrease reference count of " + cacheType +
                                       " cache(id: " + cacheId + ", uuid: " + cacheUuid + ")");
                        cacheMgr.releaseCacheObject(srcForCopy);
                    }
                }
            }
            return answer;
        } catch (Exception e) {
            s_logger.debug("copy object failed: ", e);
            if (cacheData != null) {
                cacheMgr.deleteCacheObject(cacheData);
            }
            throw new CloudRuntimeException(e.toString());
        }
    }

    /**
     * Adds {@code 'vmware.create.full.clone'} value for a given primary storage, whose HV is VMware, on datastore's {@code fullCloneFlag} field
     * @param dataTO Dest data store TO
     * @return dataTO including fullCloneFlag, if provided
     */
    protected DataTO addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(DataTO dataTO) {
        if (dataTO != null && dataTO.getHypervisorType().equals(Hypervisor.HypervisorType.VMware)){
            DataStoreTO dataStoreTO = dataTO.getDataStore();
            if (dataStoreTO != null && dataStoreTO instanceof PrimaryDataStoreTO){
                PrimaryDataStoreTO primaryDataStoreTO = (PrimaryDataStoreTO) dataStoreTO;
                primaryDataStoreTO.setFullCloneFlag(StorageManager.VmwareCreateCloneFull.valueIn(primaryDataStoreTO.getId()));
                StoragePool pool = storageManager.getStoragePool(primaryDataStoreTO.getId());
                primaryDataStoreTO.setDiskProvisioningStrictnessFlag(storageManager.DiskProvisioningStrictness.valueIn(pool.getDataCenterId()));
            }
        }
        return dataTO;
    }


    protected Answer copyObject(DataObject srcData, DataObject destData) {
        return copyObject(srcData, destData, null);
    }

    protected DataObject cacheSnapshotChain(SnapshotInfo snapshot, Scope scope) {
        DataObject leafData = null;
        DataStore store = cacheMgr.getCacheStorage(snapshot, scope);
        while (snapshot != null) {
            DataObject cacheData = cacheMgr.createCacheObject(snapshot, store);
            if (leafData == null) {
                leafData = cacheData;
            }
            snapshot = snapshot.getParent();
        }
        return leafData;
    }


    protected void deleteSnapshotCacheChain(SnapshotInfo snapshot) {
        while (snapshot != null) {
            cacheMgr.deleteCacheObject(snapshot);
            snapshot = snapshot.getParent();
        }
    }

    protected void releaseSnapshotCacheChain(SnapshotInfo snapshot) {
        while (snapshot != null) {
            cacheMgr.releaseCacheObject(snapshot);
            snapshot = snapshot.getParent();
        }
    }

    protected Answer copyVolumeFromSnapshot(DataObject snapObj, DataObject volObj) {
        SnapshotInfo snapshot = (SnapshotInfo)snapObj;
        StoragePool pool = (StoragePool)volObj.getDataStore();

        String basicErrMsg = "Failed to create volume from " + snapshot.getName() + " on pool " + pool;
        DataStore store = snapObj.getDataStore();
        DataStoreTO storTO = store.getTO();
        DataObject srcData = snapObj;
        try {
            if (!(storTO instanceof NfsTO)) {
                // cache snapshot to zone-wide staging store for the volume to be created
                srcData = cacheSnapshotChain(snapshot, new ZoneScope(pool.getDataCenterId()));
            }

            String value = configDao.getValue(Config.CreateVolumeFromSnapshotWait.toString());
            int _createVolumeFromSnapshotWait = NumbersUtil.parseInt(value, Integer.parseInt(Config.CreateVolumeFromSnapshotWait.getDefaultValue()));

            EndPoint ep = null;
            if (srcData.getDataStore().getRole() == DataStoreRole.Primary) {
                ep = selector.select(volObj);
            } else {
                ep = selector.select(srcData, volObj);
            }

            CopyCommand cmd = new CopyCommand(srcData.getTO(), addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(volObj.getTO()), _createVolumeFromSnapshotWait, VirtualMachineManager.ExecuteInSequence.value());

            Answer answer = null;
            if (ep == null) {
                s_logger.error(NO_REMOTE_ENDPOINT_SSVM);
                answer = new Answer(cmd, false, NO_REMOTE_ENDPOINT_SSVM);
            } else {
                answer = ep.sendMessage(cmd);
            }

            return answer;
        } catch (Exception e) {
            s_logger.error(basicErrMsg, e);
            throw new CloudRuntimeException(basicErrMsg);
        } finally {
            if (!(storTO instanceof NfsTO)) {
                // still keep snapshot on cache which may be migrated from previous secondary storage
                releaseSnapshotCacheChain((SnapshotInfo)srcData);
            }
        }
    }

    protected Answer cloneVolume(DataObject template, DataObject volume) {
        CopyCommand cmd = new CopyCommand(template.getTO(), addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(volume.getTO()), 0, VirtualMachineManager.ExecuteInSequence.value());
        try {
            EndPoint ep = selector.select(volume, anyVolumeRequiresEncryption(volume));
            Answer answer = null;
            if (ep == null) {
                s_logger.error(NO_REMOTE_ENDPOINT_SSVM);
                answer = new Answer(cmd, false, NO_REMOTE_ENDPOINT_SSVM);
            } else {
                answer = ep.sendMessage(cmd);
            }
            return answer;
        } catch (Exception e) {
            s_logger.debug("Failed to send to storage pool", e);
            throw new CloudRuntimeException("Failed to send to storage pool", e);
        }
    }

    private void deleteVolumeOnSecondaryStore(DataObject objectInStore) {
        ImageStoreEntity store = (ImageStoreEntity) objectInStore.getDataStore();
        store.delete(objectInStore);
        List<VolumeDataStoreVO> volumesOnStore =  volumeDataStoreDao.listByVolume(objectInStore.getId(), store.getId());
        for (VolumeDataStoreVO volume : volumesOnStore) {
            volumeDataStoreDao.remove(volume.getId());
        }
    }

    protected Answer copyVolumeBetweenPools(DataObject srcData, DataObject destData) {
        String value = configDao.getValue(Config.CopyVolumeWait.key());
        int _copyvolumewait = NumbersUtil.parseInt(value, Integer.parseInt(Config.CopyVolumeWait.getDefaultValue()));

        Scope destScope = getZoneScope(destData.getDataStore().getScope());
        DataStore cacheStore = cacheMgr.getCacheStorage(destScope);
        boolean bypassSecondaryStorage = false;
        if (srcData instanceof VolumeInfo && ((VolumeInfo)srcData).isDirectDownload()) {
            bypassSecondaryStorage = true;
        }
        boolean encryptionRequired = anyVolumeRequiresEncryption(srcData, destData);

        if (cacheStore == null) {
            if (bypassSecondaryStorage) {
                CopyCommand cmd = new CopyCommand(srcData.getTO(), destData.getTO(), _copyvolumewait, VirtualMachineManager.ExecuteInSequence.value());
                EndPoint ep = selector.select(srcData, destData, encryptionRequired);
                Answer answer = null;
                if (ep == null) {
                    String errMsg = String.format(NO_REMOTE_ENDPOINT_WITH_ENCRYPTION, encryptionRequired);
                    s_logger.error(errMsg);
                    answer = new Answer(cmd, false, errMsg);
                } else {
                    answer = ep.sendMessage(cmd);
                }
                return answer;
            }
            // need to find a nfs or cifs image store, assuming that can't copy volume
            // directly to s3
            ImageStoreEntity imageStore = (ImageStoreEntity)dataStoreMgr.getImageStoreWithFreeCapacity(destScope.getScopeId());
            if (imageStore == null || !imageStore.getProtocol().equalsIgnoreCase("nfs") && !imageStore.getProtocol().equalsIgnoreCase("cifs")) {
                String errMsg = "can't find a nfs (or cifs) image store to satisfy the need for a staging store";
                Answer answer = new Answer(null, false, errMsg);
                return answer;
            }

            DataObject objOnImageStore = imageStore.create(srcData);
            Answer answer = null;
            try {
                objOnImageStore.processEvent(Event.CreateOnlyRequested);
                answer = copyObject(srcData, objOnImageStore);

                if (answer == null || !answer.getResult()) {
                    if (answer != null) {
                        s_logger.debug("copy to image store failed: " + answer.getDetails());
                    }
                    objOnImageStore.processEvent(Event.OperationFailed);
                    imageStore.delete(objOnImageStore);
                    return answer;
                }

                objOnImageStore.processEvent(Event.OperationSuccessed, answer);

                objOnImageStore.processEvent(Event.CopyingRequested);

                CopyCommand cmd = new CopyCommand(objOnImageStore.getTO(), addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(destData.getTO()), _copyvolumewait, VirtualMachineManager.ExecuteInSequence.value());
                EndPoint ep = selector.select(objOnImageStore, destData, encryptionRequired);
                if (ep == null) {
                    String errMsg = String.format(NO_REMOTE_ENDPOINT_WITH_ENCRYPTION, encryptionRequired);
                    s_logger.error(errMsg);
                    answer = new Answer(cmd, false, errMsg);
                } else {
                    answer = ep.sendMessage(cmd);
                }

                if (answer == null || !answer.getResult()) {
                    if (answer != null) {
                        s_logger.debug("copy to primary store failed: " + answer.getDetails());
                    }
                    objOnImageStore.processEvent(Event.OperationFailed);
                    imageStore.delete(objOnImageStore);
                    return answer;
                }
            } catch (Exception e) {
                if (imageStore.exists(objOnImageStore)) {
                    objOnImageStore.processEvent(Event.OperationFailed);
                    imageStore.delete(objOnImageStore);
                }
                s_logger.error("Failed to perform operation: "+ e.getLocalizedMessage());
                throw e;
            }

            objOnImageStore.processEvent(Event.OperationSuccessed);
            deleteVolumeOnSecondaryStore(objOnImageStore);
            return answer;
        } else {
            DataObject cacheData = cacheMgr.createCacheObject(srcData, destScope);
            CopyCommand cmd = new CopyCommand(cacheData.getTO(), destData.getTO(), _copyvolumewait, VirtualMachineManager.ExecuteInSequence.value());
            EndPoint ep = selector.select(cacheData, destData, encryptionRequired);
            Answer answer = null;
            if (ep == null) {
                String errMsg = String.format(NO_REMOTE_ENDPOINT_WITH_ENCRYPTION, encryptionRequired);
                s_logger.error(errMsg);
                answer = new Answer(cmd, false, errMsg);
            } else {
                answer = ep.sendMessage(cmd);
            }
            // delete volume on cache store
            if (cacheData != null) {
                cacheMgr.deleteCacheObject(cacheData);
            }
            return answer;
        }

    }

    protected Answer migrateVolumeToPool(DataObject srcData, DataObject destData) {
        String value = configDao.getValue(Config.MigrateWait.key());
        int waitInterval = NumbersUtil.parseInt(value, Integer.parseInt(Config.MigrateWait.getDefaultValue()));

        VolumeInfo volume = (VolumeInfo)srcData;
        StoragePool srcPool = (StoragePool)dataStoreMgr.getDataStore(srcData.getDataStore().getId(), DataStoreRole.Primary);
        StoragePool destPool = (StoragePool)dataStoreMgr.getDataStore(destData.getDataStore().getId(), DataStoreRole.Primary);
        MigrateVolumeCommand command = new MigrateVolumeCommand(volume.getId(), volume.getPath(), destPool, volume.getAttachedVmName(), volume.getVolumeType(), waitInterval, volume.getChainInfo());
        if (srcPool.getParent() != 0) {
            command.setContextParam(DiskTO.PROTOCOL_TYPE, Storage.StoragePoolType.DatastoreCluster.toString());
        }

        boolean encryptionRequired = anyVolumeRequiresEncryption(srcData, destData);

        EndPoint ep = selector.select(srcData, StorageAction.MIGRATEVOLUME);
        Answer answer = null;
        if (ep == null) {
            String errMsg = String.format(NO_REMOTE_ENDPOINT_WITH_ENCRYPTION, encryptionRequired);
            s_logger.error(errMsg);
            answer = new Answer(command, false, errMsg);
        } else {
            answer = ep.sendMessage(command);
        }

        if (answer == null || !answer.getResult()) {
            throw new CloudRuntimeException("Failed to migrate volume " + volume + " to storage pool " + destPool);
        } else {
            // Update the volume details after migration.
            VolumeVO volumeVo = volDao.findById(volume.getId());
            Long oldPoolId = volume.getPoolId();
            volumeVo.setPath(((MigrateVolumeAnswer)answer).getVolumePath());
            String chainInfo = ((MigrateVolumeAnswer)answer).getVolumeChainInfo();
            if (chainInfo != null) {
                volumeVo.setChainInfo(chainInfo);
            }
            volumeVo.setPodId(destPool.getPodId());
            volumeVo.setPoolId(destPool.getId());
            volumeVo.setLastPoolId(oldPoolId);
            // For SMB, pool credentials are also stored in the uri query string.  We trim the query string
            // part  here to make sure the credentials do not get stored in the db unencrypted.
            String folder = destPool.getPath();
            if (destPool.getPoolType() == StoragePoolType.SMB && folder != null && folder.contains("?")) {
                folder = folder.substring(0, folder.indexOf("?"));
            }
            volumeVo.setFolder(folder);
            volDao.update(volume.getId(), volumeVo);
        }

        return answer;
    }

    // Note: destHost is currently only used if the copyObject method is invoked
    @Override
    public void copyAsync(DataObject srcData, DataObject destData, Host destHost, AsyncCompletionCallback<CopyCommandResult> callback) {
        Answer answer = null;
        String errMsg = null;
        try {
            s_logger.debug("copyAsync inspecting src type " + srcData.getType().toString() + " copyAsync inspecting dest type " + destData.getType().toString());
            if (srcData.getType() == DataObjectType.SNAPSHOT && destData.getType() == DataObjectType.VOLUME) {
                answer = copyVolumeFromSnapshot(srcData, destData);
            } else if (srcData.getType() == DataObjectType.SNAPSHOT && destData.getType() == DataObjectType.TEMPLATE) {
                answer = createTemplateFromSnapshot(srcData, destData);
            } else if (srcData.getType() == DataObjectType.TEMPLATE && destData.getType() == DataObjectType.VOLUME) {
                answer = cloneVolume(srcData, destData);
            } else if (destData.getType() == DataObjectType.VOLUME && srcData.getType() == DataObjectType.VOLUME &&
                srcData.getDataStore().getRole() == DataStoreRole.Primary && destData.getDataStore().getRole() == DataStoreRole.Primary) {
                if (srcData.getId() == destData.getId()) {
                    // The volume has to be migrated across storage pools.
                    answer = migrateVolumeToPool(srcData, destData);
                } else {
                    answer = copyVolumeBetweenPools(srcData, destData);
                }
            } else if (srcData.getType() == DataObjectType.SNAPSHOT && destData.getType() == DataObjectType.SNAPSHOT) {
                answer = copySnapshot(srcData, destData);
            } else {
                answer = copyObject(srcData, destData, destHost);
            }

            if (answer != null && !answer.getResult()) {
                errMsg = answer.getDetails();
            }
        } catch (Exception e) {
            s_logger.debug("copy failed", e);
            errMsg = e.toString();
        }
        CopyCommandResult result = new CopyCommandResult(null, answer);
        result.setResult(errMsg);
        callback.complete(result);
    }

    @DB
    protected Answer createTemplateFromSnapshot(DataObject srcData, DataObject destData) {

        String value = configDao.getValue(Config.CreatePrivateTemplateFromSnapshotWait.toString());
        int _createprivatetemplatefromsnapshotwait = NumbersUtil.parseInt(value, Integer.parseInt(Config.CreatePrivateTemplateFromSnapshotWait.getDefaultValue()));

        boolean needCache = false;
        if (needCacheStorage(srcData, destData)) {
            needCache = true;
            SnapshotInfo snapshot = (SnapshotInfo) srcData;
            srcData = cacheSnapshotChain(snapshot, snapshot.getDataStore().getScope());
        }

        EndPoint ep = null;
        if (srcData.getDataStore().getRole() == DataStoreRole.Primary) {
            ep = selector.select(destData);
        } else {
            ep = selector.select(srcData, destData);
        }

        CopyCommand cmd = new CopyCommand(srcData.getTO(), addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(destData.getTO()), _createprivatetemplatefromsnapshotwait, VirtualMachineManager.ExecuteInSequence.value());
        Answer answer = null;
        if (ep == null) {
            s_logger.error(NO_REMOTE_ENDPOINT_SSVM);
            answer = new Answer(cmd, false, NO_REMOTE_ENDPOINT_SSVM);
        } else {
            answer = ep.sendMessage(cmd);
        }

        // clean up snapshot copied to staging
        if (needCache && srcData != null) {
            cacheMgr.releaseCacheObject(srcData);  // reduce ref count, but keep it there on cache which is converted from previous secondary storage
        }
        return answer;
    }

    protected Answer copySnapshot(DataObject srcData, DataObject destData) {
        String value = configDao.getValue(Config.BackupSnapshotWait.toString());
        int _backupsnapshotwait = NumbersUtil.parseInt(value, Integer.parseInt(Config.BackupSnapshotWait.getDefaultValue()));

        DataObject cacheData = null;
        SnapshotInfo snapshotInfo = (SnapshotInfo)srcData;
        Boolean snapshotFullBackup = snapshotInfo.getFullBackup();
        Boolean fullSnapshot = true;
        if (snapshotFullBackup != null) {
            fullSnapshot = snapshotFullBackup;
        }
        Map<String, String> options = new HashMap<String, String>();

        addCommandOptions(snapshotInfo, fullSnapshot, options);
        boolean encryptionRequired = anyVolumeRequiresEncryption(srcData, destData);

        Answer answer = null;
        try {
            if (needCacheStorage(srcData, destData)) {
                Scope selectedScope = pickCacheScopeForCopy(srcData, destData);
                cacheData = cacheMgr.getCacheObject(srcData, selectedScope);

                CopyCommand cmd = new CopyCommand(srcData.getTO(), addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(destData.getTO()), _backupsnapshotwait, VirtualMachineManager.ExecuteInSequence.value());
                cmd.setCacheTO(cacheData.getTO());
                cmd.setOptions(options);
                EndPoint ep = selector.select(srcData, destData, encryptionRequired);
                if (ep == null) {
                    s_logger.error(NO_REMOTE_ENDPOINT_SSVM);
                    answer = new Answer(cmd, false, NO_REMOTE_ENDPOINT_SSVM);
                } else {
                    answer = ep.sendMessage(cmd);
                }
            } else {
                addFullCloneAndDiskprovisiongStrictnessFlagOnVMwareDest(destData.getTO());
                CopyCommand cmd = new CopyCommand(srcData.getTO(), destData.getTO(), _backupsnapshotwait, VirtualMachineManager.ExecuteInSequence.value());
                cmd.setOptions(options);
                EndPoint ep = selector.select(srcData, destData, StorageAction.BACKUPSNAPSHOT, encryptionRequired);
                if (ep == null) {
                    s_logger.error(NO_REMOTE_ENDPOINT_SSVM);
                    answer = new Answer(cmd, false, NO_REMOTE_ENDPOINT_SSVM);
                } else {
                    answer = ep.sendMessage(cmd);
                }

            }
            // clean up cache entry
            if (cacheData != null) {
                cacheMgr.deleteCacheObject(cacheData);
            }
            return answer;
        } catch (Exception e) {
            s_logger.debug("copy snasphot failed: ", e);
            if (cacheData != null) {
                cacheMgr.deleteCacheObject(cacheData);
            }
            throw new CloudRuntimeException(e.toString());
        }

    }

    private void addCommandOptions(SnapshotInfo snapshotInfo, Boolean fullSnapshot, Map<String, String> options) {
        SnapshotVO snap = snapshotDao.findById(snapshotInfo.getSnapshotId());
        if (snap != null && Type.FROM_GROUP.name().equals(snap.getTypeDescription())) {
            options.put("typeDescription", snap.getTypeDescription());
        }
        options.put("fullSnapshot", fullSnapshot.toString());
        options.put(SnapshotInfo.BackupSnapshotAfterTakingSnapshot.key(), String.valueOf(SnapshotInfo.BackupSnapshotAfterTakingSnapshot.value()));
    }

    @Override
    public void copyAsync(Map<VolumeInfo, DataStore> volumeMap, VirtualMachineTO vmTo, Host srcHost, Host destHost, AsyncCompletionCallback<CopyCommandResult> callback) {
        CopyCommandResult result = new CopyCommandResult(null, null);
        result.setResult("Unsupported operation requested for copying data.");
        callback.complete(result);
    }

    /**
     * Does any object require encryption support?
     */
    private boolean anyVolumeRequiresEncryption(DataObject ... objects) {
        for (DataObject o : objects) {
            // this fails code smell for returning true twice, but it is more readable than combining all tests into one statement
            if (o instanceof VolumeInfo && ((VolumeInfo) o).getPassphraseId() != null) {
                return true;
            } else if (o instanceof SnapshotInfo && ((SnapshotInfo) o).getBaseVolume().getPassphraseId() != null) {
                return true;
            }
        }
        return false;
    }
}
