/*
Copyright 2020 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"

	librbd "github.com/ceph/go-ceph/rbd"
	"github.com/container-storage-interface/spec/lib/go/csi"
	"google.golang.org/protobuf/types/known/timestamppb"

	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"
)

// createRBDClone creates a clone of the parentVol by creating a
// snapshot of the parentVol and cloning the snapshot to the cloneRbdVol.
// If deleteSnap is true, the snapshot is deleted after the clone is created.
func createRBDClone(
	ctx context.Context,
	parentVol, cloneRbdVol *rbdVolume,
	snap *rbdSnapshot,
	deleteSnap bool,
) error {
	// create snapshot
	err := parentVol.createSnapshot(ctx, snap)
	if err != nil {
		log.ErrorLog(ctx, "failed to create snapshot %s: %v", snap, err)

		return err
	}

	snap.RbdImageName = parentVol.RbdImageName
	// create clone image and delete snapshot
	err = cloneRbdVol.cloneRbdImageFromSnapshot(ctx, snap, parentVol)
	if err != nil {
		log.ErrorLog(
			ctx,
			"failed to clone rbd image %s from snapshot %s: %v",
			cloneRbdVol.RbdImageName,
			snap.RbdSnapName,
			err)
		err = fmt.Errorf(
			"failed to clone rbd image %s from snapshot %s: %w",
			cloneRbdVol.RbdImageName,
			snap.RbdSnapName,
			err)
	}
	if !deleteSnap {
		return nil
	}

	errSnap := parentVol.deleteSnapshot(ctx, snap)
	if errSnap != nil {
		log.ErrorLog(ctx, "failed to delete snapshot: %v", errSnap)
		delErr := cloneRbdVol.Delete(ctx)
		if delErr != nil {
			log.ErrorLog(ctx, "failed to delete rbd image: %s with error: %v", cloneRbdVol, delErr)
		}

		return err
	}

	return nil
}

// cleanUpSnapshot removes the RBD-snapshot (rbdSnap) from the RBD-image
// (parentVol) and deletes the RBD-image rbdVol.
func cleanUpSnapshot(
	ctx context.Context,
	parentVol *rbdVolume,
	rbdSnap *rbdSnapshot,
	rbdVol *rbdVolume,
) error {
	err := parentVol.deleteSnapshot(ctx, rbdSnap)
	if err != nil {
		if !errors.Is(err, rbderrors.ErrImageNotFound) && !errors.Is(err, rbderrors.ErrSnapNotFound) {
			log.ErrorLog(ctx, "failed to delete snapshot %q: %v", rbdSnap, err)

			return err
		}
	}

	if rbdVol != nil {
		err := rbdVol.Delete(ctx)
		if err != nil {
			if !errors.Is(err, rbderrors.ErrImageNotFound) {
				log.ErrorLog(ctx, "failed to delete rbd image %q with error: %v", rbdVol, err)

				return err
			}
		}
	}

	return nil
}

func (rv *rbdVolume) toSnapshot() *rbdSnapshot {
	return &rbdSnapshot{
		rbdImage: rbdImage{
			ClusterID:      rv.ClusterID,
			VolID:          rv.VolID,
			VolSize:        rv.VolSize,
			Monitors:       rv.Monitors,
			Pool:           rv.Pool,
			JournalPool:    rv.JournalPool,
			RadosNamespace: rv.RadosNamespace,
			RbdImageName:   rv.RbdImageName,
			ImageID:        rv.ImageID,
			CreatedAt:      rv.CreatedAt,
			// copyEncryptionConfig cannot be used here because the volume and the
			// snapshot will have the same volumeID which cases the panic in
			// copyEncryptionConfig function.
			blockEncryption: rv.blockEncryption,
			fileEncryption:  rv.fileEncryption,
		},
	}
}

func (rbdSnap *rbdSnapshot) toVolume() *rbdVolume {
	return &rbdVolume{
		rbdImage: rbdImage{
			ClusterID:      rbdSnap.ClusterID,
			VolID:          rbdSnap.VolID,
			Monitors:       rbdSnap.Monitors,
			Pool:           rbdSnap.Pool,
			JournalPool:    rbdSnap.JournalPool,
			RadosNamespace: rbdSnap.RadosNamespace,
			RbdImageName:   rbdSnap.RbdSnapName,
			ImageID:        rbdSnap.ImageID,
			CreatedAt:      rbdSnap.CreatedAt,
			// copyEncryptionConfig cannot be used here because the volume and the
			// snapshot will have the same volumeID which cases the panic in
			// copyEncryptionConfig function.
			blockEncryption: rbdSnap.blockEncryption,
			fileEncryption:  rbdSnap.fileEncryption,
		},
	}
}

func (rbdSnap *rbdSnapshot) ToCSI(ctx context.Context) (*csi.Snapshot, error) {
	switch {
	case rbdSnap.VolID == "":
		return nil, fmt.Errorf("%q does not have a volume-id set", rbdSnap)
	case rbdSnap.SourceVolumeID == "":
		return nil, fmt.Errorf("%q does not have a source-volume-id set", rbdSnap)
	}

	created, err := rbdSnap.GetCreationTime(ctx)
	if err != nil {
		return nil, err
	}

	return &csi.Snapshot{
		SizeBytes:       rbdSnap.VolSize,
		SnapshotId:      rbdSnap.VolID,
		SourceVolumeId:  rbdSnap.SourceVolumeID,
		CreationTime:    timestamppb.New(*created),
		ReadyToUse:      true,
		GroupSnapshotId: rbdSnap.groupID,
	}, nil
}

// Delete removes the snapshot from the RBD image and then
// the RBD image itself. If the backing RBD snapshot and image is removed
// successfully, the reservation for the snapshot is removed from the journal.
//
// NOTE: As the function manipulates omaps, it should be called with a lock against the request name
// held, to prevent parallel operations from modifying the state of the omaps for this request name.
func (rbdSnap *rbdSnapshot) Delete(ctx context.Context) error {
	rbdVol := rbdSnap.toVolume()

	err := rbdVol.Connect(rbdSnap.conn.Creds)
	if err != nil {
		return err
	}
	defer rbdVol.Destroy(ctx)

	rbdVol.ImageID = rbdSnap.ImageID
	// update parent name to delete the snapshot
	rbdSnap.RbdImageName = rbdVol.RbdImageName
	err = cleanUpSnapshot(ctx, rbdVol, rbdSnap, rbdVol)
	if err != nil {
		log.ErrorLog(ctx, "failed to cleanup image %s and snapshot %s: %v", rbdVol, rbdSnap, err)

		return err
	}

	err = undoSnapReservation(ctx, rbdSnap, rbdSnap.conn.Creds)
	if err != nil {
		log.ErrorLog(ctx, "failed to remove reservation for snapname (%s) with backing snap (%s) on image (%s) (%s)",
			rbdSnap.RequestName, rbdSnap.RbdSnapName, rbdSnap.RbdImageName, err)

		return err
	}

	return nil
}

func undoSnapshotCloning(
	ctx context.Context,
	parentVol *rbdVolume,
	rbdSnap *rbdSnapshot,
	cloneVol *rbdVolume,
	cr *util.Credentials,
) error {
	err := cleanUpSnapshot(ctx, parentVol, rbdSnap, cloneVol)
	if err != nil {
		log.ErrorLog(ctx, "failed to clean up  %s or %s: %v", cloneVol, rbdSnap, err)

		return err
	}
	err = undoSnapReservation(ctx, rbdSnap, cr)

	return err
}

// NewSnapshotByID creates a new rbdSnapshot from the rbdVolume.
//
// Parameters:
// - name of the new rbd-image backing the snapshot
// - id of the rbd-snapshot to clone
//
// FIXME: When resolving the Snapshot, the RbdImageName will be set to the name
// of the parent image. This is can cause issues when not accounting for that
// and the Snapshot is deleted; instead of deleting the snapshot image, the
// parent image is removed.
//
//nolint:gocyclo,cyclop // TODO: reduce complexity.
func (rv *rbdVolume) NewSnapshotByID(
	ctx context.Context,
	cr *util.Credentials,
	name string,
	id uint64,
) (types.Snapshot, error) {
	snap := rv.toSnapshot()
	snap.RequestName = name

	srcVolID, err := rv.GetID(ctx)
	if err != nil {
		return nil, err
	}

	snap.SourceVolumeID = srcVolID

	// reserveSnap sets snap.{RbdSnapName,ReservedID,VolID}
	err = reserveSnap(ctx, snap, rv, cr)
	if err != nil {
		return nil, fmt.Errorf("failed to create a reservation in the journal for snapshot image %q: %w", snap, err)
	}
	defer func() {
		if err != nil {
			undoErr := undoSnapReservation(ctx, snap, cr)
			if undoErr != nil {
				log.WarningLog(ctx, "failed undoing reservation of snapshot %q: %v", name, undoErr)
			}
		}
	}()

	// A new snapshot image will be created, and needs to have a unique
	// name.
	// FIXME: the journal contains rv.RbdImageName as SourceName. When
	// resolving the snapshot image, snap.RbdImageName will be set to the
	// original RbdImageName/SourceName (incorrect). This is fixed-up in
	// rbdManager.GetSnapshotByID(), this needs to be done cleaner.
	snap.RbdImageName = snap.RbdSnapName

	err = rv.Connect(cr)
	if err != nil {
		return nil, err
	}

	err = rv.openIoctx()
	if err != nil {
		return nil, err
	}

	// set the features for the clone image.
	f := []string{librbd.FeatureNameLayering, librbd.FeatureNameDeepFlatten}
	rv.ImageFeatureSet = librbd.FeatureSetFromNames(f)

	options, err := rv.constructImageOptions(ctx)
	if err != nil {
		return nil, err
	}
	defer options.Destroy()

	err = options.SetUint64(librbd.ImageOptionCloneFormat, 2)
	if err != nil {
		return nil, err
	}

	// indicator to remove the snapshot after a failure
	removeSnap := true
	var snapImage *librbd.Snapshot

	log.DebugLog(ctx, "going to clone snapshot image %q from image %q with snapshot ID %d", snap, rv, id)

	err = librbd.CloneImageByID(rv.ioctx, rv.RbdImageName, id, rv.ioctx, snap.RbdImageName, options)
	if err != nil && !errors.Is(err, librbd.ErrExist) {
		log.ErrorLog(ctx, "failed to clone snapshot %q with id %d: %v", snap, id, err)

		return nil, fmt.Errorf("failed to clone %q with snapshot id %d as new image %q: %w", rv.RbdImageName, id, snap, err)
	}
	defer func() {
		if !removeSnap {
			// success, no need to remove the snapshot image
			return
		}

		if snapImage != nil {
			err = snapImage.Remove()
			if err != nil {
				log.ErrorLog(ctx, "failed to remove snapshot of image %q after failure: %v", snap, err)
			}
		}

		err = librbd.RemoveImage(rv.ioctx, snap.RbdImageName)
		if err != nil {
			log.ErrorLog(ctx, "failed to remove snapshot image %q after failure: %v", snap, err)
		}
	}()

	// update the snapshot image in the journal, after the image info is updated
	j, err := snapJournal.Connect(snap.Monitors, snap.RadosNamespace, cr)
	if err != nil {
		return nil, fmt.Errorf("snapshot image %q failed to connect to journal: %w", snap, err)
	}
	defer j.Destroy()

	err = snap.Connect(cr)
	if err != nil {
		return nil, fmt.Errorf("failed to connect snapshot image %q: %w", snap, err)
	}
	defer snap.Destroy(ctx)

	image, err := snap.open()
	if err != nil {
		return nil, fmt.Errorf("failed to open snapshot image %q: %w", snap, err)
	}
	defer func() {
		cErr := image.Close()
		if cErr != nil {
			log.WarningLog(ctx, "resource leak, failed to close image: %v", cErr)
		}
	}()

	snapImage, err = image.CreateSnapshot(snap.RbdSnapName)
	if err != nil && !errors.Is(err, librbd.ErrExist) {
		return nil, fmt.Errorf("failed to create snapshot on image %q: %w", snap, err)
	}

	err = snap.repairImageID(ctx, j, true)
	if err != nil {
		return nil, fmt.Errorf("failed to repair image id for snapshot image %q: %w", snap, err)
	}

	// all ok, don't remove the snapshot image in a defer statement
	removeSnap = false

	return snap, nil
}

func (rbdSnap *rbdSnapshot) SetVolumeGroup(ctx context.Context, cr *util.Credentials, groupID string) error {
	vi := util.CSIIdentifier{}
	err := vi.DecomposeCSIID(rbdSnap.VolID)
	if err != nil {
		return err
	}

	j, err := snapJournal.Connect(rbdSnap.Monitors, rbdSnap.RadosNamespace, cr)
	if err != nil {
		return fmt.Errorf("snapshot %q failed to connect to journal: %w", rbdSnap, err)
	}
	defer j.Destroy()

	err = j.StoreGroupID(ctx, rbdSnap.Pool, vi.ObjectUUID, groupID)
	if err != nil {
		return fmt.Errorf("failed to set volume group ID for snapshot %q: %w", rbdSnap, err)
	}

	rbdSnap.groupID = groupID

	return nil
}

// GetSize returns the size of the snapshot in bytes.
func (rbdSnap *rbdSnapshot) GetSize() int64 {
	return rbdSnap.VolSize
}

// rbdSnapFromSnapshot converts a types.Snapshot to a *rbdSnapshot.
// It returns an error if the snapshot is nil or not of type *rbdSnapshot.
func rbdSnapFromSnapshot(snap types.Snapshot) (*rbdSnapshot, error) {
	if snap == nil {
		return nil, errors.New("nil snapshot provided")
	}

	rbdSnap, ok := snap.(*rbdSnapshot)
	if !ok {
		return nil, errors.New("snapshot object is not of type rbdSnapshot")
	}

	return rbdSnap, nil
}

// getRBDSnapID returns the associated rbd snapshot ID.
func (rbdSnap *rbdSnapshot) getRBDSnapID(ctx context.Context) (uint64, error) {
	vol := rbdSnap.toVolume()
	vol.conn = rbdSnap.conn.Copy()
	defer vol.Destroy(ctx)

	image, err := vol.open()
	if err != nil {
		return 0, err
	}
	defer func() {
		cErr := image.Close()
		if cErr != nil {
			log.WarningLog(ctx, "resource leak, failed to close image: %v", cErr)
		}
	}()

	parentInfo, err := image.GetParent()
	if err != nil {
		return 0, err
	}

	return parentInfo.Snap.ID, nil
}
