package shell

import (
	"context"
	"flag"
	"fmt"
	"io"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/storage/types"

	"github.com/seaweedfs/seaweedfs/weed/pb"

	"google.golang.org/grpc"

	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/volume_server_pb"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"

	"github.com/seaweedfs/seaweedfs/weed/wdclient"
)

func init() {
	Commands = append(Commands, &commandVolumeTierUpload{})
}

type commandVolumeTierUpload struct {
}

func (c *commandVolumeTierUpload) Name() string {
	return "volume.tier.upload"
}

func (c *commandVolumeTierUpload) Help() string {
	return `upload the dat file of a volume to a remote tier

	volume.tier.upload [-collection=""] [-fullPercent=95] [-quietFor=1h]
	volume.tier.upload [-collection=""] -volumeId=<volume_id> -dest=<storage_backend> [-keepLocalDatFile]

	e.g.:
	volume.tier.upload -volumeId=7 -dest=s3
	volume.tier.upload -volumeId=7 -dest=s3.default

	The <storage_backend> is defined in master.toml.
	For example, "s3.default" in [storage.backend.s3.default]

	This command will move the dat file of a volume to a remote tier.

	SeaweedFS enables scalable and fast local access to lots of files, 
	and the cloud storage is slower by cost efficient. How to combine them together?

	Usually the data follows 80/20 rule: only 20% of data is frequently accessed.
	We can offload the old volumes to the cloud.

	With this, SeaweedFS can be both fast and scalable, and infinite storage space.
	Just add more local SeaweedFS volume servers to increase the throughput.

	The index file is still local, and the same O(1) disk read is applied to the remote file.

	Each replica keeps its own local index pointing at the same remote object,
	so the volume keeps its replica count for reads after tiering.

`
}

func (c *commandVolumeTierUpload) HasTag(CommandTag) bool {
	return false
}

func (c *commandVolumeTierUpload) Do(args []string, commandEnv *CommandEnv, writer io.Writer) (err error) {

	tierCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
	volumeId := tierCommand.Int("volumeId", 0, "the volume id")
	collection := tierCommand.String("collection", "", "the collection name")
	fullPercentage := tierCommand.Float64("fullPercent", 95, "the volume reaches the percentage of max volume size")
	quietPeriod := tierCommand.Duration("quietFor", 24*time.Hour, "select volumes without no writes for this period")
	dest := tierCommand.String("dest", "", "the target tier name")
	keepLocalDatFile := tierCommand.Bool("keepLocalDatFile", false, "whether keep local dat file")
	disk := tierCommand.String("disk", "", "[hdd|ssd|<tag>] hard drive or solid state drive or any tag")
	if err = tierCommand.Parse(args); err != nil {
		return nil
	}

	if err = commandEnv.confirmIsLocked(args); err != nil {
		return
	}

	vid := needle.VolumeId(*volumeId)

	// volumeId is provided
	if vid != 0 {
		return doVolumeTierUpload(commandEnv, writer, *collection, vid, *dest, *keepLocalDatFile)
	}

	var diskType *types.DiskType
	if disk != nil {
		_diskType := types.ToDiskType(*disk)
		diskType = &_diskType
	}

	// apply to all volumes in the collection
	// reusing collectVolumeIdsForEcEncode for now
	volumeIds, _, err := collectVolumeIdsForEcEncode(commandEnv, *collection, diskType, *fullPercentage, *quietPeriod, false)
	if err != nil {
		return err
	}
	fmt.Printf("tier upload volumes: %v\n", volumeIds)
	for _, vid := range volumeIds {
		if err = doVolumeTierUpload(commandEnv, writer, *collection, vid, *dest, *keepLocalDatFile); err != nil {
			return err
		}
	}

	return nil
}

func doVolumeTierUpload(commandEnv *CommandEnv, writer io.Writer, collection string, vid needle.VolumeId, dest string, keepLocalDatFile bool) (err error) {
	// find volume location
	topoInfo, _, err := collectTopologyInfo(commandEnv, 0)
	if err != nil {
		return fmt.Errorf("collect topology info: %v", err)
	}

	existingLocations := collectVolumeTierUploadLocations(topoInfo, vid, collection, writer)

	if len(existingLocations) == 0 {
		if collection == "" {
			return fmt.Errorf("volume %d not found", vid)
		}
		return fmt.Errorf("volume %d not found in collection %s", vid, collection)
	}

	err = markVolumeReplicasWritable(context.Background(), commandEnv.option.GrpcDialOption, vid, existingLocations, false, false)
	if err != nil {
		return fmt.Errorf("mark volume %d as readonly on %s: %v", vid, existingLocations[0].Url, err)
	}

	// copy the .dat file to remote tier
	err = uploadDatToRemoteTier(commandEnv.option.GrpcDialOption, writer, vid, collection, existingLocations[0].ServerAddress(), dest, keepLocalDatFile)
	if err != nil {
		return fmt.Errorf("copy dat file for volume %d on %s to %s: %v", vid, existingLocations[0].Url, dest, err)
	}

	if keepLocalDatFile {
		return nil
	}
	// Re-copy the uploaded replica's .idx/.vif onto the other replicas instead
	// of deleting them: the remote object key lives only in the .vif, so losing
	// the single server holding it would orphan the volume.
	for i, location := range existingLocations {
		if i == 0 {
			continue
		}
		fmt.Fprintf(writer, "replicate remote volume %d metadata from %s to %s\n", vid, existingLocations[0].Url, location.Url)
		err = replicateVolumeToServer(context.Background(), commandEnv.option.GrpcDialOption, writer, vid, existingLocations[0].ServerAddress(), location.ServerAddress(), "", 0)
		if err != nil {
			return fmt.Errorf("replicate volume %d from %s to %s: %v", vid, existingLocations[0].Url, location.Url, err)
		}
	}

	return nil
}

// collectVolumeTierUploadLocations lists the replica locations of a volume,
// putting an already-tiered replica first so a rerun after a partial failure
// reuses its remote object instead of uploading a second copy.
func collectVolumeTierUploadLocations(topoInfo *master_pb.TopologyInfo, vid needle.VolumeId, collection string, writer io.Writer) []wdclient.Location {
	var tiered, local []wdclient.Location
	eachDataNode(topoInfo, func(dc DataCenterId, rack RackId, dn *master_pb.DataNodeInfo) {
		for _, disk := range dn.DiskInfos {
			for _, vi := range disk.VolumeInfos {
				if needle.VolumeId(vi.Id) == vid && (collection == "" || vi.Collection == collection) {
					fmt.Fprintf(writer, "find volume %d from Url:%s, GrpcPort:%d, DC:%s\n", vid, dn.Id, dn.GrpcPort, string(dc))
					loc := wdclient.Location{
						Url:        dn.Id,
						PublicUrl:  dn.Id,
						GrpcPort:   int(dn.GrpcPort),
						DataCenter: string(dc),
					}
					if vi.RemoteStorageName != "" {
						tiered = append(tiered, loc)
					} else {
						local = append(local, loc)
					}
				}
			}
		}
	})
	return append(tiered, local...)
}

func uploadDatToRemoteTier(grpcDialOption grpc.DialOption, writer io.Writer, volumeId needle.VolumeId, collection string, sourceVolumeServer pb.ServerAddress, dest string, keepLocalDatFile bool) error {

	err := operation.WithVolumeServerClient(true, sourceVolumeServer, grpcDialOption, func(volumeServerClient volume_server_pb.VolumeServerClient) error {
		stream, copyErr := volumeServerClient.VolumeTierMoveDatToRemote(context.Background(), &volume_server_pb.VolumeTierMoveDatToRemoteRequest{
			VolumeId:               uint32(volumeId),
			Collection:             collection,
			DestinationBackendName: dest,
			KeepLocalDatFile:       keepLocalDatFile,
		})

		if stream == nil {
			if copyErr == nil {
				// when the volume is already uploaded, VolumeTierMoveDatToRemote will return nil stream and nil error
				// so we should directly return in this caseAdd commentMore actions
				fmt.Fprintf(writer, "volume %v already uploaded", volumeId)
				return nil
			} else {
				return copyErr
			}
		}
		var lastProcessed int64
		for {
			resp, recvErr := stream.Recv()
			if recvErr != nil {
				if recvErr == io.EOF {
					break
				} else {
					return recvErr
				}
			}

			processingSpeed := float64(resp.Processed-lastProcessed) / 1024.0 / 1024.0

			fmt.Fprintf(writer, "copied %.2f%%, %d bytes, %.2fMB/s\n", resp.ProcessedPercentage, resp.Processed, processingSpeed)

			lastProcessed = resp.Processed
		}

		return copyErr
	})

	return err

}
