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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.cloudstack.affinity;

import java.util.List;
import java.util.Set;
import java.util.HashSet;
import java.util.ArrayList;

import javax.inject.Inject;

import com.cloud.vm.VMInstanceVO;
import org.apache.commons.collections.CollectionUtils;
import org.apache.log4j.Logger;

import org.apache.cloudstack.affinity.dao.AffinityGroupDao;
import org.apache.cloudstack.affinity.dao.AffinityGroupVMMapDao;

import com.cloud.deploy.DeployDestination;
import com.cloud.deploy.DeploymentPlan;
import com.cloud.deploy.DeploymentPlanner.ExcludeList;
import com.cloud.exception.AffinityConflictException;
import com.cloud.vm.VirtualMachine;
import com.cloud.vm.VirtualMachineProfile;
import com.cloud.vm.dao.VMInstanceDao;

public class HostAffinityProcessor extends AffinityProcessorBase implements AffinityGroupProcessor {

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

    @Inject
    protected VMInstanceDao _vmInstanceDao;
    @Inject
    protected AffinityGroupDao _affinityGroupDao;
    @Inject
    protected AffinityGroupVMMapDao _affinityGroupVMMapDao;

    @Override
    public void process(VirtualMachineProfile vmProfile, DeploymentPlan plan, ExcludeList avoid) throws AffinityConflictException {
        VirtualMachine vm = vmProfile.getVirtualMachine();
        List<AffinityGroupVMMapVO> vmGroupMappings = _affinityGroupVMMapDao.findByVmIdType(vm.getId(), getType());
        if (CollectionUtils.isNotEmpty(vmGroupMappings)) {
            for (AffinityGroupVMMapVO vmGroupMapping : vmGroupMappings) {
                processAffinityGroup(vmGroupMapping, plan, vm);
            }
        }
    }

    /**
     * Process Affinity Group for VM deployment
     */
    protected void processAffinityGroup(AffinityGroupVMMapVO vmGroupMapping, DeploymentPlan plan, VirtualMachine vm) {
        AffinityGroupVO group = _affinityGroupDao.findById(vmGroupMapping.getAffinityGroupId());
        s_logger.debug("Processing affinity group " + group.getName() + " for VM Id: " + vm.getId());

        List<Long> groupVMIds = _affinityGroupVMMapDao.listVmIdsByAffinityGroup(group.getId());
        groupVMIds.remove(vm.getId());

        List<Long> preferredHosts = getPreferredHostsFromGroupVMIds(groupVMIds);
        plan.setPreferredHosts(preferredHosts);
    }

    /**
     * Get host ids set from vm ids list
     */
    protected Set<Long> getHostIdSet(List<Long> vmIds) {
        Set<Long> hostIds = new HashSet<>();
        for (Long groupVMId : vmIds) {
            VMInstanceVO groupVM = _vmInstanceDao.findById(groupVMId);
            if (groupVM != null && groupVM.getHostId() != null) {
                hostIds.add(groupVM.getHostId());
            }
        }
        return hostIds;
    }

    /**
     * Get preferred host ids list from the affinity group VMs
     */
    protected List<Long> getPreferredHostsFromGroupVMIds(List<Long> vmIds) {
        return new ArrayList<>(getHostIdSet(vmIds));
    }

    @Override
    public boolean check(VirtualMachineProfile vmProfile, DeployDestination plannedDestination) throws AffinityConflictException {
        if (plannedDestination.getHost() == null) {
            return true;
        }
        long plannedHostId = plannedDestination.getHost().getId();
        VirtualMachine vm = vmProfile.getVirtualMachine();
        List<AffinityGroupVMMapVO> vmGroupMappings = _affinityGroupVMMapDao.findByVmIdType(vm.getId(), getType());

        if (CollectionUtils.isNotEmpty(vmGroupMappings)) {
            for (AffinityGroupVMMapVO vmGroupMapping : vmGroupMappings) {
                if (!checkAffinityGroup(vmGroupMapping, vm, plannedHostId)) {
                    return false;
                }
            }
        }

        return true;
    }

    /**
     * Check Affinity Group
     */
    protected boolean checkAffinityGroup(AffinityGroupVMMapVO vmGroupMapping, VirtualMachine vm, long plannedHostId) {
        List<Long> groupVMIds = _affinityGroupVMMapDao.listVmIdsByAffinityGroup(vmGroupMapping.getAffinityGroupId());
        groupVMIds.remove(vm.getId());

        Set<Long> hostIds = getHostIdSet(groupVMIds);
        return CollectionUtils.isEmpty(hostIds) || hostIds.contains(plannedHostId);
    }

}