/*
Copyright 2021 The Ceph-CSI Authors.

Licensed 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 rbd

import (
	"context"
	"errors"
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"time"

	csicommon "github.com/ceph/ceph-csi/internal/csi-common"
	"github.com/ceph/ceph-csi/internal/rbd"
	corerbd "github.com/ceph/ceph-csi/internal/rbd"
	rbderrors "github.com/ceph/ceph-csi/internal/rbd/errors"
	"github.com/ceph/ceph-csi/internal/rbd/types"
	"github.com/ceph/ceph-csi/internal/util"
	"github.com/ceph/ceph-csi/internal/util/log"

	librbd "github.com/ceph/go-ceph/rbd"
	"github.com/ceph/go-ceph/rbd/admin"
	"github.com/csi-addons/spec/lib/go/replication"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/types/known/durationpb"
	"google.golang.org/protobuf/types/known/timestamppb"
)

// imageMirroringMode is used to indicate the mirroring mode for an RBD image.
type imageMirroringMode string

const (
	// imageMirrorModeSnapshot uses snapshots to propagate RBD images between
	// ceph clusters.
	imageMirrorModeSnapshot imageMirroringMode = "snapshot"
	// imageMirrorModeJournal uses journaling to propagate RBD images between
	// ceph clusters.
	imageMirrorModeJournal imageMirroringMode = "journal"

	// imageCreationTimeKey is the key to get/set the image creation timestamp
	// on the image metadata. The key is starting with `.rbd` so that it will
	// not get replicated to remote cluster.
	imageCreationTimeKey = ".rbd.image.creation_time"
)

const (
	// mirroringMode + key to get the imageMirroringMode from parameters.
	imageMirroringKey = "mirroringMode"
	// forceKey + key to get the force option from parameters.
	forceKey = "force"

	// schedulingIntervalKey to get the schedulingInterval from the
	// parameters.
	// Interval of time between scheduled snapshots. Typically in the form
	// <num><m,h,d>.
	schedulingIntervalKey = "schedulingInterval"

	// schedulingStartTimeKey to get the schedulingStartTime from the
	// parameters.
	// (optional) StartTime is the time the snapshot schedule
	// begins, can be specified using the ISO 8601 time format.
	schedulingStartTimeKey = "schedulingStartTime"

	// flattenModeKey to get the flattenMode from the parameters.
	// (optional) flattenMode decides how to handle images with parent.
	// (default) If set to "never", the image with parent will not be flattened.
	// If set to "force", the image with parent will be flattened.
	flattenModeKey = "flattenMode"
)

// ReplicationServer struct of rbd CSI driver with supported methods of Replication
// controller server spec.
type ReplicationServer struct {
	// added UnimplementedControllerServer as a member of
	// ControllerServer. if replication spec add more RPC services in the proto
	// file, then we don't need to add all RPC methods leading to forward
	// compatibility.
	*replication.UnimplementedControllerServer
	// Embed ControllerServer as it implements helper functions
	*corerbd.ControllerServer
	// driverInstance is the unique ID for this CSI-driver deployment.
	driverInstance string
}

// NewReplicationServer creates a new ReplicationServer which handles
// the Replication Service requests from the CSI-Addons specification.
func NewReplicationServer(instanceID string, c *corerbd.ControllerServer) *ReplicationServer {
	return &ReplicationServer{
		ControllerServer: c,
		driverInstance:   instanceID,
	}
}

func (rs *ReplicationServer) RegisterService(server grpc.ServiceRegistrar) {
	replication.RegisterControllerServer(server, rs)
}

// getForceOption extracts the force option from the GRPC request parameters.
// If not set, the default will be set to false.
func getForceOption(ctx context.Context, parameters map[string]string) (bool, error) {
	val, ok := parameters[forceKey]
	if !ok {
		log.WarningLog(ctx, "%s is not set in parameters, setting to default (%v)", forceKey, false)

		return false, nil
	}
	force, err := strconv.ParseBool(val)
	if err != nil {
		return false, status.Error(codes.Internal, err.Error())
	}

	return force, nil
}

// getFlattenMode gets flatten mode from the input GRPC request parameters.
// flattenMode is the key to check the mode in the parameters.
func getFlattenMode(ctx context.Context, parameters map[string]string) (types.FlattenMode, error) {
	val, ok := parameters[flattenModeKey]
	if !ok {
		log.DebugLog(ctx, "%q is not set in parameters, setting to default (%v)",
			flattenModeKey, types.FlattenModeNever)

		return types.FlattenModeNever, nil
	}

	mode := types.FlattenMode(val)
	switch mode {
	case types.FlattenModeForce, types.FlattenModeNever:
		return mode, nil
	}
	log.ErrorLog(ctx, "%q=%q is not supported", flattenModeKey, val)

	return mode, status.Errorf(codes.InvalidArgument, "%q=%q is not supported", flattenModeKey, val)
}

// getMirroringMode gets the mirroring mode from the input GRPC request parameters.
// mirroringMode is the key to check the mode in the parameters.
func getMirroringMode(ctx context.Context, parameters map[string]string) (librbd.ImageMirrorMode, error) {
	val, ok := parameters[imageMirroringKey]
	if !ok {
		log.WarningLog(
			ctx,
			"%s is not set in parameters, setting to mirroringMode to default (%s)",
			imageMirroringKey,
			imageMirrorModeSnapshot)

		return librbd.ImageMirrorModeSnapshot, nil
	}

	var mirroringMode librbd.ImageMirrorMode
	switch imageMirroringMode(val) {
	case imageMirrorModeSnapshot:
		mirroringMode = librbd.ImageMirrorModeSnapshot
	case imageMirrorModeJournal:
		mirroringMode = librbd.ImageMirrorModeJournal
	default:
		return mirroringMode, status.Errorf(codes.InvalidArgument, "%s %s not supported", imageMirroringKey, val)
	}

	return mirroringMode, nil
}

// validateSchedulingDetails gets the mirroring mode and scheduling details from the
// input GRPC request parameters and validates the scheduling is only supported
// for snapshot mirroring mode.
func validateSchedulingDetails(ctx context.Context, parameters map[string]string) error {
	var err error

	val := parameters[imageMirroringKey]

	switch imageMirroringMode(val) {
	case imageMirrorModeJournal:
		// journal mirror mode does not require scheduling parameters
		if _, ok := parameters[schedulingIntervalKey]; ok {
			log.WarningLog(ctx, "%s parameter cannot be used with %s mirror mode, ignoring it",
				schedulingIntervalKey, string(imageMirrorModeJournal))
		}
		if _, ok := parameters[schedulingStartTimeKey]; ok {
			log.WarningLog(ctx, "%s parameter cannot be used with %s mirror mode, ignoring it",
				schedulingStartTimeKey, string(imageMirrorModeJournal))
		}

		return nil
	case imageMirrorModeSnapshot:
	// If mirroring mode is not set in parameters, we are defaulting mirroring
	// mode to snapshot. Discard empty mirroring mode from validation as it is
	// an optional parameter.
	case "":
	default:
		return status.Error(codes.InvalidArgument, "scheduling is only supported for snapshot mode")
	}

	// validate mandatory interval field
	interval, ok := parameters[schedulingIntervalKey]
	if ok && interval == "" {
		return status.Error(codes.InvalidArgument, "scheduling interval cannot be empty")
	}
	adminStartTime := admin.StartTime(parameters[schedulingStartTimeKey])
	if !ok {
		// startTime is alone not supported it has to be present with interval
		if adminStartTime != "" {
			return status.Errorf(codes.InvalidArgument,
				"%q parameter is supported only with %q",
				schedulingStartTimeKey,
				schedulingIntervalKey)
		}
	}
	if interval != "" {
		err = validateSchedulingInterval(interval)
		if err != nil {
			return status.Error(codes.InvalidArgument, err.Error())
		}
	}

	return nil
}

// getSchedulingDetails returns scheduling interval and scheduling startTime.
func getSchedulingDetails(parameters map[string]string) (admin.Interval, admin.StartTime) {
	return admin.Interval(parameters[schedulingIntervalKey]),
		admin.StartTime(parameters[schedulingStartTimeKey])
}

// validateSchedulingInterval return the interval as it is if its ending with
// `m|h|d` or else it will return error.
func validateSchedulingInterval(interval string) error {
	re := regexp.MustCompile(`^\d+[mhd]$`)
	if re.MatchString(interval) {
		return nil
	}

	return errors.New("interval specified without d, h, m suffix")
}

// EnableVolumeReplication extracts the RBD volume information from the
// volumeID, If the image is present it will enable the mirroring based on the
// user provided information.
func (rs *ReplicationServer) EnableVolumeReplication(ctx context.Context,
	req *replication.EnableVolumeReplicationRequest,
) (*replication.EnableVolumeReplicationResponse, error) {
	volumeID := csicommon.GetIDFromReplication(req)
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "empty volume ID in request")
	}
	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	err = validateSchedulingDetails(ctx, req.GetParameters())
	if err != nil {
		return nil, err
	}

	if acquired := rs.VolumeLocks.TryAcquire(volumeID); !acquired {
		log.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)

		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer rs.VolumeLocks.Release(volumeID)

	mgr := rbd.NewManager(rs.driverInstance, req.GetParameters(), req.GetSecrets())
	defer mgr.Destroy(ctx)

	rbdVol, err := mgr.GetVolumeByID(ctx, volumeID)
	if err != nil {
		return nil, getGRPCError(err)
	}
	mirror, err := rbdVol.ToMirror()
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	// extract the mirroring mode
	mirroringMode, err := getMirroringMode(ctx, req.GetParameters())
	if err != nil {
		return nil, err
	}
	// extract the flatten mode
	flattenMode, err := getFlattenMode(ctx, req.GetParameters())
	if err != nil {
		return nil, err
	}

	info, err := mirror.GetMirroringInfo(ctx)
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Internal, err.Error())
	}
	log.UsefulLog(ctx, "mirror state is %s", info.GetState())
	if info.GetState() != librbd.MirrorImageEnabled.String() {
		err = rbdVol.HandleParentImageExistence(ctx, flattenMode)
		if err != nil {
			log.ErrorLog(ctx, err.Error())

			return nil, getGRPCError(err)
		}
		err = mirror.EnableMirroring(ctx, mirroringMode)
		if err != nil {
			log.ErrorLog(ctx, err.Error())

			return nil, status.Error(codes.Internal, err.Error())
		}
	}

	return &replication.EnableVolumeReplicationResponse{}, nil
}

// DisableVolumeReplication extracts the RBD volume information from the
// volumeID, If the image is present and the mirroring is enabled on the RBD
// image it will disable the mirroring.
func (rs *ReplicationServer) DisableVolumeReplication(ctx context.Context,
	req *replication.DisableVolumeReplicationRequest,
) (*replication.DisableVolumeReplicationResponse, error) {
	volumeID := csicommon.GetIDFromReplication(req)
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "empty volume ID in request")
	}
	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	if acquired := rs.VolumeLocks.TryAcquire(volumeID); !acquired {
		log.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)

		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer rs.VolumeLocks.Release(volumeID)

	mgr := rbd.NewManager(rs.driverInstance, req.GetParameters(), req.GetSecrets())
	defer mgr.Destroy(ctx)

	rbdVol, err := mgr.GetVolumeByID(ctx, volumeID)
	if err != nil {
		return nil, getGRPCError(err)
	}
	mirror, err := rbdVol.ToMirror()
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	// extract the force option
	force, err := getForceOption(ctx, req.GetParameters())
	if err != nil {
		return nil, err
	}

	info, err := mirror.GetMirroringInfo(ctx)
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Internal, err.Error())
	}
	log.UsefulLog(ctx, "mirror state is %s", info.GetState())
	switch info.GetState() {
	// image is already in disabled state
	case librbd.MirrorImageDisabled.String():
	// image mirroring is still disabling
	case librbd.MirrorImageDisabling.String():
		return nil, status.Errorf(codes.Aborted, "%s is in disabling state", volumeID)
	case librbd.MirrorImageEnabled.String():
		err = corerbd.DisableVolumeReplication(mirror, ctx, info.IsPrimary(), force)
		if err != nil {
			return nil, getGRPCError(err)
		}

		return &replication.DisableVolumeReplicationResponse{}, nil
	default:
		return nil, status.Errorf(codes.InvalidArgument, "image is in %s Mode", info.GetState())
	}

	return &replication.DisableVolumeReplicationResponse{}, nil
}

// PromoteVolume extracts the RBD volume information from the volumeID, If the
// image is present, mirroring is enabled and the image is in demoted state it
// will promote the volume as primary.
// If the image is already primary it will return success.
func (rs *ReplicationServer) PromoteVolume(ctx context.Context,
	req *replication.PromoteVolumeRequest,
) (*replication.PromoteVolumeResponse, error) {
	volumeID := csicommon.GetIDFromReplication(req)
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "empty volume ID in request")
	}
	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	if acquired := rs.VolumeLocks.TryAcquire(volumeID); !acquired {
		log.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)

		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer rs.VolumeLocks.Release(volumeID)

	mgr := rbd.NewManager(rs.driverInstance, req.GetParameters(), req.GetSecrets())
	defer mgr.Destroy(ctx)

	rbdVol, err := mgr.GetVolumeByID(ctx, volumeID)
	if err != nil {
		return nil, getGRPCError(err)
	}
	mirror, err := rbdVol.ToMirror()
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	info, err := mirror.GetMirroringInfo(ctx)
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Internal, err.Error())
	}
	log.UsefulLog(ctx, "mirror state is %s, primary: %s", info.GetState(), info.IsPrimary())

	if info.GetState() != librbd.MirrorImageEnabled.String() {
		return nil, status.Errorf(
			codes.InvalidArgument,
			"mirroring is not enabled on %s, image is in %s Mode",
			volumeID,
			info.GetState())
	}

	// promote secondary to primary
	if !info.IsPrimary() {
		if req.GetForce() {
			// workaround for https://github.com/ceph/ceph-csi/issues/2736
			// TODO: remove this workaround when the issue is fixed
			err = mirror.ForcePromote(ctx, cr)
		} else {
			err = mirror.Promote(ctx, req.GetForce())
		}
		if err != nil {
			log.ErrorLog(ctx, err.Error())
			// In case of the DR the image on the primary site cannot be
			// demoted as the cluster is down, during failover the image need
			// to be force promoted. RBD returns `Device or resource busy`
			// error message if the image cannot be promoted for above reason.
			// Return FailedPrecondition so that replication operator can send
			// request to force promote the image.
			if strings.Contains(err.Error(), "Device or resource busy") {
				return nil, status.Error(codes.FailedPrecondition, err.Error())
			}

			return nil, status.Error(codes.Internal, err.Error())
		}
	}

	interval, startTime := getSchedulingDetails(req.GetParameters())
	if interval != admin.NoInterval {
		err = mirror.AddSnapshotScheduling(interval, startTime)
		if err != nil {
			return nil, err
		}
		log.DebugLog(
			ctx,
			"Added scheduling at interval %s, start time %s for volume %s",
			interval,
			startTime,
			rbdVol)
	}

	return &replication.PromoteVolumeResponse{}, nil
}

// DemoteVolume extracts the RBD volume information from the
// volumeID, If the image is present, mirroring is enabled and the
// image is in promoted state it will demote the volume as secondary.
// If the image is already secondary it will return success.
func (rs *ReplicationServer) DemoteVolume(ctx context.Context,
	req *replication.DemoteVolumeRequest,
) (*replication.DemoteVolumeResponse, error) {
	volumeID := csicommon.GetIDFromReplication(req)
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "empty volume ID in request")
	}
	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	if acquired := rs.VolumeLocks.TryAcquire(volumeID); !acquired {
		log.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)

		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer rs.VolumeLocks.Release(volumeID)

	mgr := rbd.NewManager(rs.driverInstance, req.GetParameters(), req.GetSecrets())
	defer mgr.Destroy(ctx)

	rbdVol, err := mgr.GetVolumeByID(ctx, volumeID)
	if err != nil {
		return nil, getGRPCError(err)
	}
	mirror, err := rbdVol.ToMirror()
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	creationTime, err := rbdVol.GetCreationTime(ctx)
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Internal, err.Error())
	}

	info, err := mirror.GetMirroringInfo(ctx)
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Internal, err.Error())
	}
	log.UsefulLog(ctx, "mirror state is %s, primary: %s", info.GetState(), info.IsPrimary())

	if info.GetState() != librbd.MirrorImageEnabled.String() {
		return nil, status.Errorf(
			codes.InvalidArgument,
			"mirroring is not enabled on %s, image is in %s Mode",
			volumeID,
			info.GetState())
	}

	// demote image to secondary
	if info.IsPrimary() {
		// If volume is demoted first, ControllerUnpublishVolume will fail to remove metadata
		// since the image will be Read-only.
		// Ensure volume is unpublished before demotion.
		if err := checkVolumeUnpublished(ctx, rs.Driver.GetNodeID(), rbdVol); err != nil {
			return nil, status.Errorf(codes.FailedPrecondition, "volume cannot be demoted: %v", err)
		}
		// store the image creation time for resync
		_, err = rbdVol.GetMetadata(imageCreationTimeKey)
		if err != nil && errors.Is(err, librbd.ErrNotFound) {
			log.DebugLog(ctx, "setting image creation time %s for %s", creationTime, rbdVol)
			err = rbdVol.SetMetadata(imageCreationTimeKey, timestampToString(creationTime))
		}
		if err != nil {
			log.ErrorLog(ctx, err.Error())

			return nil, status.Error(codes.Internal, err.Error())
		}

		err = mirror.Demote(ctx)
		if err != nil {
			log.ErrorLog(ctx, err.Error())

			return nil, status.Error(codes.Internal, err.Error())
		}
	}

	return &replication.DemoteVolumeResponse{}, nil
}

// checkRemoteSiteStatus checks the state of the remote cluster.
// It returns true if the state of the remote cluster is up and unknown.
func checkRemoteSiteStatus(ctx context.Context, mirrorStatus []types.SiteStatus) bool {
	ready := true
	found := false
	for _, s := range mirrorStatus {
		log.UsefulLog(
			ctx,
			"peer site mirrorUUID=%q, daemon up=%t, mirroring state=%q, description=%q and lastUpdate=%d",
			s.GetMirrorUUID(),
			s.IsUP(),
			s.GetState(),
			s.GetDescription(),
			s.GetLastUpdate())
		if s.GetMirrorUUID() != "" {
			found = true
			// If ready is already "false" do not flip it based on another remote peer status
			if ready && (s.GetState() != librbd.MirrorImageStatusStateUnknown.String() || !s.IsUP()) {
				ready = false
			}
		}
	}

	// Return readiness only if at least one remote peer status was processed
	return found && ready
}

// ResyncVolume extracts the RBD volume information from the volumeID, If the
// image is present, mirroring is enabled and the image is in demoted state.
// If yes it will resync the image to correct the split-brain.
//
//nolint:gocyclo,cyclop // TODO: reduce complexity
func (rs *ReplicationServer) ResyncVolume(ctx context.Context,
	req *replication.ResyncVolumeRequest,
) (*replication.ResyncVolumeResponse, error) {
	volumeID := csicommon.GetIDFromReplication(req)
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "empty volume ID in request")
	}
	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	if acquired := rs.VolumeLocks.TryAcquire(volumeID); !acquired {
		log.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)

		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer rs.VolumeLocks.Release(volumeID)
	mgr := rbd.NewManager(rs.driverInstance, req.GetParameters(), req.GetSecrets())
	defer mgr.Destroy(ctx)

	rbdVol, err := mgr.GetVolumeByID(ctx, volumeID)
	if err != nil {
		return nil, getGRPCError(err)
	}
	mirror, err := rbdVol.ToMirror()
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	info, err := mirror.GetMirroringInfo(ctx)
	if err != nil {
		// in case of Resync the image will get deleted and gets recreated and
		// it takes time for this operation.
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Aborted, err.Error())
	}

	if info.GetState() != librbd.MirrorImageEnabled.String() {
		return nil, status.Error(codes.InvalidArgument, "image mirroring is not enabled")
	}

	// return error if the image is still primary
	if info.IsPrimary() {
		return nil, status.Error(codes.InvalidArgument, "image is in primary state")
	}

	sts, err := mirror.GetGlobalMirroringStatus(ctx)
	if err != nil {
		// the image gets recreated after issuing resync
		if errors.Is(err, rbderrors.ErrImageNotFound) {
			// caller retries till RBD syncs an initial version of the image to
			// report its status in the resync call. Ideally, this line will not
			// be executed as the error would get returned due to getMirroringInfo
			// failing to find an image above.
			return nil, status.Error(codes.Aborted, err.Error())
		}
		log.ErrorLog(ctx, err.Error())

		return nil, status.Error(codes.Internal, err.Error())
	}
	ready := false

	localStatus, err := sts.GetLocalSiteStatus()
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return nil, fmt.Errorf("failed to get local status: %w", err)
	}

	log.UsefulLog(
		ctx,
		"local status: daemon up=%t, image mirroring state=%q, description=%q and lastUpdate=%s",
		localStatus.IsUP(),
		localStatus.GetState(),
		localStatus.GetDescription(),
		localStatus.GetLastUpdate())

	//  To recover from split brain (up+error) state the image need to be
	//  demoted and requested for resync on site-a and then the image on site-b
	//  should be demoted. The volume should be marked to ready=true when the
	//  image state on both the clusters are up+unknown because during the last
	//  snapshot syncing the data gets copied first and then image state on the
	//  site-a changes to up+unknown.

	// If the image state on both the sites are up+unknown consider that
	// complete data is synced as the last snapshot
	// gets exchanged between the clusters.
	if localStatus.GetState() == librbd.MirrorImageStatusStateUnknown.String() && localStatus.IsUP() {
		ready = checkRemoteSiteStatus(ctx, sts.GetAllSitesStatus())
	}

	creationTime, err := rbdVol.GetCreationTime(ctx)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "failed to get image info for %s: %s", rbdVol, err.Error())
	}

	// image creation time is stored in the image metadata. it looks like
	// `"seconds:1692879841 nanos:631526669"`
	// If the image gets resynced the local image creation time will be
	// lost, if the keys is not present in the image metadata then we can
	// assume that the image is already resynced.
	savedImageTime, err := rbdVol.GetMetadata(imageCreationTimeKey)
	if err != nil && !errors.Is(err, librbd.ErrNotFound) {
		return nil, status.Errorf(codes.Internal,
			"failed to get %s key from image metadata for %s: %s",
			imageCreationTimeKey,
			rbdVol,
			err.Error())
	}

	// If the savedImageTime is not empty,
	// then the image might be in need of resync.
	if savedImageTime != "" {
		st, sErr := timestampFromString(savedImageTime)
		if sErr != nil {
			return nil, status.Errorf(codes.Internal, "failed to parse image creation time: %s", sErr.Error())
		}
		log.DebugLog(ctx, "image %s, savedImageTime=%v, currentImageTime=%v", rbdVol, st, creationTime)

		// Fetch the last sync info from the local status in order
		// to determine if the image is syncing or not.
		syncInfo, sErr := localStatus.GetLastSyncInfo(ctx)
		if sErr != nil && !errors.Is(sErr, rbderrors.ErrLastSyncTimeNotFound) {
			return nil, status.Errorf(codes.Internal, "failed to get last sync info: %s", sErr.Error())
		}
		// consider the image to be not syncing if either
		// - the last sync time was not found
		// or
		// - the sync info indicates the image is not syncing
		isNotSyncing := errors.Is(sErr, rbderrors.ErrLastSyncTimeNotFound) || !syncInfo.IsSyncing()

		// image needs to be resynced if
		// - force option is set
		// - image creation time is equal to the saved image creation time
		// - image is not already in syncing state
		if req.GetForce() && st.Equal(*creationTime) && isNotSyncing {
			err = mirror.Resync(ctx)
			if err != nil {
				return nil, getGRPCError(err)
			}
		}
	}

	if !ready {
		err = checkVolumeResyncStatus(ctx, localStatus)
		if err != nil {
			return nil, status.Error(codes.Internal, err.Error())
		}
	}

	err = rbdVol.RepairResyncedImageID(ctx, ready)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "failed to resync Image ID: %s", err.Error())
	}

	resp := &replication.ResyncVolumeResponse{
		Ready: ready,
	}

	return resp, nil
}

// timestampToString converts the time.Time object to string.
func timestampToString(st *time.Time) string {
	return fmt.Sprintf("seconds:%d nanos:%d", st.Unix(), st.Nanosecond())
}

// timestampFromString parses the timestamp string and returns the time.Time
// object.
func timestampFromString(timestamp string) (time.Time, error) {
	st := time.Time{}
	parts := strings.Fields(timestamp)
	if len(parts) != 2 {
		return st, fmt.Errorf("failed to parse image creation time: %s", timestamp)
	}
	if len(strings.Split(parts[0], ":")) != 2 || len(strings.Split(parts[1], ":")) != 2 {
		return st, fmt.Errorf("failed to parse image creation time: %s", timestamp)
	}
	secondsStr := strings.Split(parts[0], ":")[1]
	nanosStr := strings.Split(parts[1], ":")[1]

	seconds, err := strconv.ParseInt(secondsStr, 10, 64)
	if err != nil {
		return st, fmt.Errorf("failed to parse image creation time seconds: %s", err.Error())
	}

	nanos, err := strconv.ParseInt(nanosStr, 10, 32)
	if err != nil {
		return st, fmt.Errorf("failed to parse image creation time nenos: %s", err.Error())
	}

	st = time.Unix(seconds, nanos)

	return st, nil
}

func getGRPCError(err error) error {
	if err == nil {
		return status.Error(codes.OK, codes.OK.String())
	}

	errorStatusMap := map[error]codes.Code{
		rbderrors.ErrImageNotFound:      codes.NotFound,
		util.ErrPoolNotFound:            codes.NotFound,
		rbderrors.ErrInvalidArgument:    codes.InvalidArgument,
		rbderrors.ErrFlattenInProgress:  codes.Aborted,
		rbderrors.ErrAborted:            codes.Aborted,
		rbderrors.ErrFailedPrecondition: codes.FailedPrecondition,
		rbderrors.ErrUnavailable:        codes.Unavailable,
	}

	for e, code := range errorStatusMap {
		if errors.Is(err, e) {
			return status.Error(code, err.Error())
		}
	}

	// Handle any other non nil error not listed in the map as internal error
	return status.Error(codes.Internal, err.Error())
}

// GetVolumeReplicationInfo extracts the RBD volume information from the volumeID, If the
// image is present, mirroring is enabled and the image is in primary state.
func (rs *ReplicationServer) GetVolumeReplicationInfo(ctx context.Context,
	req *replication.GetVolumeReplicationInfoRequest,
) (*replication.GetVolumeReplicationInfoResponse, error) {
	volumeID := csicommon.GetIDFromReplication(req)
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "empty volume ID in request")
	}
	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		log.ErrorLog(ctx, "failed to get user credentials: %v", err)

		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	if acquired := rs.VolumeLocks.TryAcquire(volumeID); !acquired {
		log.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)

		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer rs.VolumeLocks.Release(volumeID)
	mgr := rbd.NewManager(rs.driverInstance, nil, req.GetSecrets())
	defer mgr.Destroy(ctx)

	rbdVol, err := mgr.GetVolumeByID(ctx, volumeID)
	if err != nil {
		log.ErrorLog(ctx, "failed to get volume with id %q: %v", volumeID, err)

		switch {
		case errors.Is(err, rbderrors.ErrImageNotFound):
			err = status.Error(codes.NotFound, err.Error())
		case errors.Is(err, util.ErrPoolNotFound):
			err = status.Error(codes.NotFound, err.Error())
		default:
			err = status.Error(codes.Internal, err.Error())
		}

		return nil, err
	}
	mirror, err := rbdVol.ToMirror()
	if err != nil {
		log.ErrorLog(ctx, "failed to convert volume %q to mirror type: %v", rbdVol, err)

		return nil, status.Error(codes.Internal, err.Error())
	}

	info, err := mirror.GetMirroringInfo(ctx)
	if err != nil {
		log.ErrorLog(ctx, "failed to get info for mirror %q: %v", mirror, err)

		return nil, status.Error(codes.Aborted, err.Error())
	}

	if info.GetState() != librbd.MirrorImageEnabled.String() {
		return nil, status.Error(codes.InvalidArgument, "image mirroring is not enabled")
	}

	// return error if the image is not in primary state
	if !info.IsPrimary() {
		return nil, status.Error(codes.InvalidArgument, "image is not in primary state")
	}

	mirrorStatus, err := mirror.GetGlobalMirroringStatus(ctx)
	if err != nil {
		log.ErrorLog(ctx, "failed to get status for mirror %q: %v", mirror, err)

		if errors.Is(err, rbderrors.ErrImageNotFound) {
			return nil, status.Error(codes.Aborted, err.Error())
		}

		return nil, status.Error(codes.Internal, err.Error())
	}

	remoteStatus, err := mirrorStatus.GetRemoteSiteStatus(ctx)
	if err != nil {
		log.ErrorLog(ctx, "failed to get remote site status for mirror %q: %v", mirror, err)

		if errors.Is(err, librbd.ErrNotExist) {
			return nil, status.Errorf(codes.NotFound, "failed to get remote status: %v", err)
		}

		return nil, status.Errorf(codes.Internal, "failed to get remote status: %v", err)
	}

	lastSyncInfo, err := remoteStatus.GetLastSyncInfo(ctx)
	if err != nil {
		if errors.Is(err, rbderrors.ErrLastSyncTimeNotFound) {
			return nil, status.Errorf(codes.FailedPrecondition, "failed to get last sync info: %v", err)
		}

		return nil, status.Errorf(codes.Internal, "failed to get last sync info: %v", err)
	}

	resp := replication.GetVolumeReplicationInfoResponse{
		LastSyncTime:  timestamppb.New(lastSyncInfo.GetLastSyncTime()),
		LastSyncBytes: lastSyncInfo.GetLastSyncBytes(),
	}

	// lastDuration is optional, can be nil
	lastDuration := lastSyncInfo.GetLastSyncDuration()
	if lastDuration != nil {
		resp.LastSyncDuration = durationpb.New(*lastDuration)
	}

	replicationStatus, statusMessage := getCurrentReplicationStatus(ctx, mirrorStatus)

	resp.Status = replicationStatus
	resp.StatusMessage = statusMessage

	return &resp, nil
}

func checkVolumeResyncStatus(ctx context.Context, localStatus types.SiteStatus) error {
	// we are considering local snapshot timestamp to check if the resync is
	// started or not, if we dont see local_snapshot_timestamp in the
	// description of localStatus, we are returning error. if we see the local
	// snapshot timestamp in the description we return resyncing started.
	//
	// Note: without a local_snapshot_timestamp, GetLastSyncInfo() returns an error.
	_, err := localStatus.GetLastSyncInfo(ctx)
	if err != nil {
		return fmt.Errorf("failed to get last sync info: %w", err)
	}

	return nil
}

func getCurrentReplicationStatus(ctx context.Context, mirrorGlobalStatus types.GlobalStatus,
) (replication.GetVolumeReplicationInfoResponse_Status, string) {
	// get image local status
	localStatus, err := mirrorGlobalStatus.GetLocalSiteStatus()
	if err != nil {
		log.ErrorLog(ctx, err.Error())

		return replication.GetVolumeReplicationInfoResponse_UNKNOWN, "status not found"
	}

	// parse only the message from the description of the image/group status
	statusDesc := localStatus.GetDescription()
	desc := strings.SplitN(statusDesc, ",", 2)[0]

	// check if mirroring state is up/down
	isUp := localStatus.IsUP()

	if !isUp {
		return replication.GetVolumeReplicationInfoResponse_DEGRADED, desc
	}

	resp := replication.GetVolumeReplicationInfoResponse_UNKNOWN
	switch localStatus.GetState() {
	case librbd.MirrorImageStatusStateError.String():
		resp = replication.GetVolumeReplicationInfoResponse_ERROR
	// return HEALTHY only for primary and secondary state, i.e, stopped and replaying respectively
	case librbd.MirrorImageStatusStateReplaying.String(), librbd.MirrorImageStatusStateStopped.String():
		resp = replication.GetVolumeReplicationInfoResponse_HEALTHY
	default:
		log.DebugLog(
			ctx,
			"mirroring is in intermediary state, state=%v, description=%v",
			localStatus.GetState(), desc)
	}

	return resp, desc
}

// checkVolumeUnpublished verifies that the volume has been properly unpublished
// by checking that clientaddress and userId mapping metadata is not present.
func checkVolumeUnpublished(ctx context.Context, nodeId string, rv types.Volume) error {
	volumeId, err := rv.GetID(ctx)
	if err != nil {
		return err
	}

	clientMetadataKeys := []string{
		corerbd.GetClientAddressKey(volumeId, nodeId),
		corerbd.GetUserIDMappingKey(volumeId, nodeId),
	}

	for _, key := range clientMetadataKeys {
		_, err := rv.GetMetadata(key)
		if err != nil && !errors.Is(err, librbd.ErrNotFound) {
			return err
		}
		if !errors.Is(err, librbd.ErrNotFound) {
			return fmt.Errorf("metadata %q is still present on the image %q", key, rv)
		}
	}

	return nil
}
