//
// Licensed to the Apache Software Foundation (ASF) under one
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// 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
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package com.cloud.hypervisor.kvm.resource.wrapper;

import com.cloud.agent.api.Answer;
import com.cloud.agent.api.PrepareForMigrationAnswer;
import com.cloud.agent.api.PrepareForMigrationCommand;
import com.cloud.agent.api.to.DiskTO;
import com.cloud.agent.api.to.NicTO;
import com.cloud.agent.api.to.VirtualMachineTO;
import com.cloud.exception.InternalErrorException;
import com.cloud.hypervisor.kvm.resource.LibvirtComputingResource;
import com.cloud.hypervisor.kvm.storage.KVMStoragePoolManager;
import com.cloud.resource.CommandWrapper;
import com.cloud.resource.ResourceWrapper;
import com.cloud.storage.Volume;
import org.apache.log4j.Logger;
import org.libvirt.Connect;
import org.libvirt.LibvirtException;

import java.net.URISyntaxException;

@ResourceWrapper(handles =  PrepareForMigrationCommand.class)
public final class LibvirtPrepareForMigrationCommandWrapper extends CommandWrapper<PrepareForMigrationCommand, Answer, LibvirtComputingResource> {

    private static final Logger s_logger = Logger.getLogger(LibvirtPrepareForMigrationCommandWrapper.class);

    @Override
    public Answer execute(final PrepareForMigrationCommand command, final LibvirtComputingResource libvirtComputingResource) {
        final VirtualMachineTO vm = command.getVirtualMachine();

        if (command.isRollback()) {
            return handleRollback(command, libvirtComputingResource);
        }

        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Preparing host for migrating " + vm);
        }

        final NicTO[] nics = vm.getNics();

        boolean skipDisconnect = false;

        final KVMStoragePoolManager storagePoolMgr = libvirtComputingResource.getStoragePoolMgr();
        try {
            final LibvirtUtilitiesHelper libvirtUtilitiesHelper = libvirtComputingResource.getLibvirtUtilitiesHelper();

            final Connect conn = libvirtUtilitiesHelper.getConnectionByVmName(vm.getName());
            for (final NicTO nic : nics) {
                libvirtComputingResource.getVifDriver(nic.getType(), nic.getName()).plug(nic, null, "", null);
            }

            /* setup disks, e.g for iso */
            final DiskTO[] volumes = vm.getDisks();
            for (final DiskTO volume : volumes) {
                if (volume.getType() == Volume.Type.ISO) {
                    libvirtComputingResource.getVolumePath(conn, volume);
                }
            }

            skipDisconnect = true;

            if (!storagePoolMgr.connectPhysicalDisksViaVmSpec(vm)) {
                return new PrepareForMigrationAnswer(command, "failed to connect physical disks to host");
            }

            return new PrepareForMigrationAnswer(command);
        } catch (final LibvirtException e) {
            return new PrepareForMigrationAnswer(command, e.toString());
        } catch (final InternalErrorException e) {
            return new PrepareForMigrationAnswer(command, e.toString());
        } catch (final URISyntaxException e) {
            return new PrepareForMigrationAnswer(command, e.toString());
        } finally {
            if (!skipDisconnect) {
                storagePoolMgr.disconnectPhysicalDisksViaVmSpec(vm);
            }
        }
    }

    private Answer handleRollback(PrepareForMigrationCommand command, LibvirtComputingResource libvirtComputingResource) {
        KVMStoragePoolManager storagePoolMgr = libvirtComputingResource.getStoragePoolMgr();
        VirtualMachineTO vmTO = command.getVirtualMachine();

        if (!storagePoolMgr.disconnectPhysicalDisksViaVmSpec(vmTO)) {
            return new PrepareForMigrationAnswer(command, "failed to disconnect physical disks from host");
        }

        return new PrepareForMigrationAnswer(command);
    }
}