/*
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 core

import (
	"context"
	"errors"
	"time"

	cerrors "github.com/ceph/ceph-csi/internal/cephfs/errors"
	"github.com/ceph/ceph-csi/internal/util"
	"github.com/ceph/ceph-csi/internal/util/log"

	"github.com/ceph/go-ceph/cephfs/admin"
	"github.com/ceph/go-ceph/rados"
	"github.com/golang/protobuf/ptypes/timestamp"
)

// SnapshotClient is the interface that holds the signature of snapshot methods
// that interacts with CephFS snapshot API's.
type SnapshotClient interface {
	// CreateSnapshot creates a snapshot of the subvolume.
	CreateSnapshot(ctx context.Context) error
	// DeleteSnapshot deletes the snapshot of the subvolume.
	DeleteSnapshot(ctx context.Context) error
	// GetSnapshotInfo returns the snapshot info of the subvolume.
	GetSnapshotInfo(ctx context.Context) (SnapshotInfo, error)
	// CloneSnapshot clones the snapshot of the subvolume.
	CloneSnapshot(ctx context.Context, cloneVolOptions *SubVolume) error
	// SetAllSnapshotMetadata set all the metadata from arg parameters on
	// subvolume snapshot.
	SetAllSnapshotMetadata(parameters map[string]string) error
	// UnsetAllSnapshotMetadata unset all the metadata from arg keys on
	// subvolume snapshot.
	UnsetAllSnapshotMetadata(keys []string) error
	// ListSnapshotMetadata lists all the metadata on subvolume snapshot.
	ListSnapshotMetadata() (map[string]string, error)
}

// snapshotClient is the implementation of SnapshotClient interface.
type snapshotClient struct {
	*Snapshot                              // Embedded snapshot struct.
	clusterID      string                  // Cluster ID.
	clusterName    string                  // Cluster Name.
	enableMetadata bool                    // Set metadata on volume
	conn           *util.ClusterConnection // Cluster connection.
}

// Snapshot represents a subvolume snapshot and its cluster information.
type Snapshot struct {
	SnapshotID string // subvolume snapshot id.
	*SubVolume        // parent subvolume information.
}

// NewSnapshot creates a new snapshot client.
func NewSnapshot(
	conn *util.ClusterConnection,
	snapshotID,
	clusterID,
	clusterName string,
	setMetadata bool,
	vol *SubVolume,
) SnapshotClient {
	return &snapshotClient{
		Snapshot: &Snapshot{
			SnapshotID: snapshotID,
			SubVolume:  vol,
		},
		clusterID:      clusterID,
		clusterName:    clusterName,
		enableMetadata: setMetadata,
		conn:           conn,
	}
}

// CreateSnapshot creates a snapshot of the subvolume.
func (s *snapshotClient) CreateSnapshot(ctx context.Context) error {
	fsa, err := s.conn.GetFSAdmin()
	if err != nil {
		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)

		return err
	}

	err = fsa.CreateSubVolumeSnapshot(s.FsName, s.SubvolumeGroup, s.VolID, s.SnapshotID)
	if err != nil {
		log.ErrorLog(ctx, "failed to create subvolume snapshot %s %s in fs %s: %s",
			s.SnapshotID, s.VolID, s.FsName, err)

		return err
	}

	return nil
}

// DeleteSnapshot deletes the snapshot of the subvolume.
func (s *snapshotClient) DeleteSnapshot(ctx context.Context) error {
	fsa, err := s.conn.GetFSAdmin()
	if err != nil {
		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)

		return err
	}

	err = fsa.ForceRemoveSubVolumeSnapshot(s.FsName, s.SubvolumeGroup, s.VolID, s.SnapshotID)
	if err != nil {
		log.ErrorLog(ctx, "failed to delete subvolume snapshot %s %s in fs %s: %s",
			s.SnapshotID, s.VolID, s.FsName, err)

		return err
	}

	return nil
}

type SnapshotInfo struct {
	CreatedAt        time.Time
	CreationTime     *timestamp.Timestamp
	HasPendingClones string
}

// GetSnapshotInfo returns the snapshot info of the subvolume.
func (s *snapshotClient) GetSnapshotInfo(ctx context.Context) (SnapshotInfo, error) {
	snap := SnapshotInfo{}
	fsa, err := s.conn.GetFSAdmin()
	if err != nil {
		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)

		return snap, err
	}

	info, err := fsa.SubVolumeSnapshotInfo(s.FsName, s.SubvolumeGroup, s.VolID, s.SnapshotID)
	if err != nil {
		if errors.Is(err, rados.ErrNotFound) {
			return snap, cerrors.ErrSnapNotFound
		}
		log.ErrorLog(
			ctx,
			"failed to get subvolume snapshot info %s %s in fs %s with error %s",
			s.VolID,
			s.SnapshotID,
			s.FsName,
			err)

		return snap, err
	}
	snap.CreatedAt = info.CreatedAt.Time
	snap.HasPendingClones = info.HasPendingClones

	return snap, nil
}

// CloneSnapshot clones the snapshot of the subvolume.
func (s *snapshotClient) CloneSnapshot(
	ctx context.Context,
	cloneSubVol *SubVolume,
) error {
	fsa, err := s.conn.GetFSAdmin()
	if err != nil {
		log.ErrorLog(ctx, "could not get FSAdmin: %s", err)

		return err
	}
	co := &admin.CloneOptions{
		TargetGroup: cloneSubVol.SubvolumeGroup,
	}
	if cloneSubVol.Pool != "" {
		co.PoolLayout = cloneSubVol.Pool
	}

	log.DebugLog(ctx, "cloning the subvolume snapshot %s/%s/%s/%s to %s/%s/%s",
		s.FsName,
		s.SubvolumeGroup,
		s.VolID,
		s.SnapshotID,
		s.FsName,
		cloneSubVol.SubvolumeGroup,
		cloneSubVol.VolID,
	)

	err = fsa.CloneSubVolumeSnapshot(s.FsName, s.SubvolumeGroup, s.VolID, s.SnapshotID, cloneSubVol.VolID, co)
	if err != nil {
		log.ErrorLog(
			ctx,
			"failed to clone subvolume snapshot %s %s into %s in fs %s with error: %s",
			s.VolID,
			s.SnapshotID,
			cloneSubVol.VolID,
			s.FsName,
			err)
		if errors.Is(err, rados.ErrNotFound) {
			return cerrors.ErrVolumeNotFound
		}

		return err
	}

	return nil
}
