// Returns the name of the VM on which this code is running.
// This is done by searching for the name of virtual machine by current IP.
// Prerequisite: this code assumes VMWare vmtools or open-vm-tools to be installed in the VM.
func readInstanceID(cfg *VSphereConfig) (string, error) {
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return "", err
	}

	if len(addrs) == 0 {
		return "", fmt.Errorf("unable to retrieve Instance ID")
	}

	// Create context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create vSphere client
	c, err := vsphereLogin(cfg, ctx)
	if err != nil {
		return "", err
	}
	defer c.Logout(ctx)

	// Create a new finder
	f := find.NewFinder(c.Client, true)

	// Fetch and set data center
	dc, err := f.Datacenter(ctx, cfg.Global.Datacenter)
	if err != nil {
		return "", err
	}
	f.SetDatacenter(dc)

	s := object.NewSearchIndex(c.Client)

	var svm object.Reference
	for _, v := range addrs {
		ip, _, err := net.ParseCIDR(v.String())
		if err != nil {
			return "", fmt.Errorf("unable to parse cidr from ip")
		}

		// Finds a virtual machine or host by IP address.
		svm, err = s.FindByIp(ctx, dc, ip.String(), true)
		if err == nil && svm != nil {
			break
		}
	}
	if svm == nil {
		return "", fmt.Errorf("unable to retrieve vm reference from vSphere")
	}

	var vm mo.VirtualMachine
	err = s.Properties(ctx, svm.Reference(), []string{"name"}, &vm)
	if err != nil {
		return "", err
	}
	return vm.Name, nil
}

func (flag *SearchFlag) search() (object.Reference, error) {
	ctx := context.TODO()
	var ref object.Reference
	var err error

	c, err := flag.Client()
	if err != nil {
		return nil, err
	}

	dc, err := flag.Datacenter()
	if err != nil {
		return nil, err
	}

	switch {
	case flag.byDatastorePath != "":
		ref, err = flag.searchByDatastorePath(c, dc)
	case flag.byDNSName != "":
		ref, err = flag.searchByDNSName(c, dc)
	case flag.byInventoryPath != "":
		ref, err = flag.searchByInventoryPath(c, dc)
	case flag.byIP != "":
		ref, err = flag.searchByIP(c, dc)
	case flag.byUUID != "":
		ref, err = flag.searchByUUID(c, dc)
	default:
		err = errors.New("no search flag specified")
	}

	if err != nil {
		return nil, err
	}

	if ref == nil {
		return nil, fmt.Errorf("no such %s", flag.entity)
	}

	// set the InventoryPath field
	finder, err := flag.Finder()
	if err != nil {
		return nil, err
	}
	ref, err = finder.ObjectReference(ctx, ref.Reference())
	if err != nil {
		return nil, err
	}

	return ref, nil
}

// Returns the name of the VM and its Cluster on which this code is running.
// This is done by searching for the name of virtual machine by current IP.
// Prerequisite: this code assumes VMWare vmtools or open-vm-tools to be installed in the VM.
func readInstance(cfg *VSphereConfig) (string, string, error) {
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return "", "", err
	}

	if len(addrs) == 0 {
		return "", "", fmt.Errorf("unable to retrieve Instance ID")
	}

	// Create context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create vSphere client
	c, err := vsphereLogin(cfg, ctx)
	if err != nil {
		return "", "", err
	}
	defer c.Logout(ctx)

	// Create a new finder
	f := find.NewFinder(c.Client, true)

	// Fetch and set data center
	dc, err := f.Datacenter(ctx, cfg.Global.Datacenter)
	if err != nil {
		return "", "", err
	}
	f.SetDatacenter(dc)

	s := object.NewSearchIndex(c.Client)

	var svm object.Reference
	for _, v := range addrs {
		ip, _, err := net.ParseCIDR(v.String())
		if err != nil {
			return "", "", fmt.Errorf("unable to parse cidr from ip")
		}

		// Finds a virtual machine or host by IP address.
		svm, err = s.FindByIp(ctx, dc, ip.String(), true)
		if err == nil && svm != nil {
			break
		}
	}
	if svm == nil {
		return "", "", fmt.Errorf("unable to retrieve vm reference from vSphere")
	}

	var vm mo.VirtualMachine
	err = s.Properties(ctx, svm.Reference(), []string{"name", "resourcePool"}, &vm)
	if err != nil {
		return "", "", err
	}

	var cluster string
	if vm.ResourcePool != nil {
		// Extract the Cluster Name if VM belongs to a ResourcePool
		var rp mo.ResourcePool
		err = s.Properties(ctx, *vm.ResourcePool, []string{"parent"}, &rp)
		if err == nil {
			var ccr mo.ClusterComputeResource
			err = s.Properties(ctx, *rp.Parent, []string{"name"}, &ccr)
			if err == nil {
				cluster = ccr.Name
			} else {
				glog.Warningf("VM %s, does not belong to a vSphere Cluster, will not have FailureDomain label", vm.Name)
			}
		} else {
			glog.Warningf("VM %s, does not belong to a vSphere Cluster, will not have FailureDomain label", vm.Name)
		}
	}
	return vm.Name, cluster, nil
}