package shell

import (
	"bufio"
	"bytes"
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"math"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/filer"
	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/volume_server_pb"
	"github.com/seaweedfs/seaweedfs/weed/storage"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle_map"
	"github.com/seaweedfs/seaweedfs/weed/storage/types"
	"github.com/seaweedfs/seaweedfs/weed/util"
	util_http "github.com/seaweedfs/seaweedfs/weed/util/http"
	"golang.org/x/sync/errgroup"
)

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

const (
	readbufferSize = 16
)

type commandVolumeFsck struct {
	env                      *CommandEnv
	writer                   io.Writer
	bucketsPath              string
	collection               *string
	volumeIds                map[uint32]bool
	tempFolder               string
	verbose                  *bool
	forcePurging             *bool
	findMissingChunksInFiler *bool
	verifyNeedle             *bool
}

func (c *commandVolumeFsck) Name() string {
	return "volume.fsck"
}

func (c *commandVolumeFsck) Help() string {
	return `check all volumes to find entries not used by the filer. It is optional and resource intensive.

	Important assumption!!!
		the system is all used by one filer.

	This command works this way:
	1. collect all file ids from all volumes, as set A
	2. collect all file ids from the filer, as set B
	3. find out the set A subtract B

	If -findMissingChunksInFiler is enabled, this works
	in a reverse way:
	1. collect all file ids from all volumes, as set A
	2. collect all file ids from the filer, as set B
	3. find out the set B subtract A

`
}

func (c *commandVolumeFsck) HasTag(tag CommandTag) bool {
	return tag == ResourceHeavy
}

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

	fsckCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
	c.verbose = fsckCommand.Bool("v", false, "verbose mode")
	c.findMissingChunksInFiler = fsckCommand.Bool("findMissingChunksInFiler", false, "see \"help volume.fsck\"")
	c.collection = fsckCommand.String("collection", "", "the collection name")
	volumeIds := fsckCommand.String("volumeId", "", "comma separated the volume id")
	applyPurging := fsckCommand.Bool("reallyDeleteFromVolume", false, "<expert only!> after detection, delete missing data from volumes / delete missing file entries from filer. Currently this only works with default filerGroup.")
	c.forcePurging = fsckCommand.Bool("forcePurging", false, "delete missing data from volumes in one replica used together with applyPurging")
	purgeAbsent := fsckCommand.Bool("reallyDeleteFilerEntries", false, "<expert only!> delete missing file entries from filer if the corresponding volume is missing for any reason, please ensure all still existing/expected volumes are connected! used together with findMissingChunksInFiler")
	tempPath := fsckCommand.String("tempPath", path.Join(os.TempDir()), "path for temporary idx files")
	cutoffTimeAgo := fsckCommand.Duration("cutoffTimeAgo", 5*time.Minute, "only include entries  on volume servers before this cutoff time to check orphan chunks")
	modifyTimeAgo := fsckCommand.Duration("modifyTimeAgo", 0, "only include entries after this modify time to check orphan chunks")
	c.verifyNeedle = fsckCommand.Bool("verifyNeedles", false, "check needles status from volume server")

	if err = fsckCommand.Parse(args); err != nil {
		return nil
	}

	if err = commandEnv.confirmIsLocked(args); err != nil {
		return
	}
	c.volumeIds = make(map[uint32]bool)
	if *volumeIds != "" {
		for _, volumeIdStr := range strings.Split(*volumeIds, ",") {
			if volumeIdInt, err := strconv.ParseUint(volumeIdStr, 10, 32); err == nil {
				c.volumeIds[uint32(volumeIdInt)] = true
			} else {
				return fmt.Errorf("parse volumeId string %s to int: %v", volumeIdStr, err)
			}
		}
	}
	c.env = commandEnv
	c.writer = writer

	c.bucketsPath, err = readFilerBucketsPath(commandEnv)
	if err != nil {
		return fmt.Errorf("read filer buckets path: %v", err)
	}

	// create a temp folder
	c.tempFolder, err = os.MkdirTemp(*tempPath, "sw_fsck")
	if err != nil {
		return fmt.Errorf("failed to create temp folder: %v", err)
	}
	if *c.verbose {
		fmt.Fprintf(c.writer, "working directory: %s\n", c.tempFolder)
	}
	defer os.RemoveAll(c.tempFolder)

	// collect all volume id locations
	dataNodeVolumeIdToVInfo, err := c.collectVolumeIds()
	if err != nil {
		return fmt.Errorf("failed to collect all volume locations: %v", err)
	}

	if err != nil {
		return fmt.Errorf("read filer buckets path: %v", err)
	}

	var collectCutoffFromAtNs int64 = 0
	if cutoffTimeAgo.Seconds() != 0 {
		collectCutoffFromAtNs = time.Now().Add(-*cutoffTimeAgo).UnixNano()
	}
	var collectModifyFromAtNs int64 = 0
	if modifyTimeAgo.Seconds() != 0 {
		collectModifyFromAtNs = time.Now().Add(-*modifyTimeAgo).UnixNano()
	}
	// collect each volume file ids
	eg, gCtx := errgroup.WithContext(context.Background())
	_ = gCtx
	for _dataNodeId, _volumeIdToVInfo := range dataNodeVolumeIdToVInfo {
		dataNodeId, volumeIdToVInfo := _dataNodeId, _volumeIdToVInfo
		eg.Go(func() error {
			for volumeId, vinfo := range volumeIdToVInfo {
				if len(c.volumeIds) > 0 {
					if _, ok := c.volumeIds[volumeId]; !ok {
						delete(volumeIdToVInfo, volumeId)
						continue
					}
				}
				if *c.collection != "" && vinfo.collection != *c.collection {
					delete(volumeIdToVInfo, volumeId)
					continue
				}
				err = c.collectOneVolumeFileIds(dataNodeId, volumeId, vinfo)
				if err != nil {
					return fmt.Errorf("failed to collect file ids from volume %d on %s: %v", volumeId, vinfo.server, err)
				}
			}
			if *c.verbose {
				fmt.Fprintf(c.writer, "dn %+v filtred %d volumes and locations.\n", dataNodeId, len(dataNodeVolumeIdToVInfo[dataNodeId]))
			}
			return nil
		})
	}
	err = eg.Wait()
	if err != nil {
		fmt.Fprintf(c.writer, "got error: %v", err)
		return err
	}

	if *c.findMissingChunksInFiler {
		// collect all filer file ids and paths

		if err = c.collectFilerFileIdAndPaths(dataNodeVolumeIdToVInfo, *purgeAbsent, collectModifyFromAtNs, collectCutoffFromAtNs); err != nil {
			return fmt.Errorf("collectFilerFileIdAndPaths: %v", err)
		}
		for dataNodeId, volumeIdToVInfo := range dataNodeVolumeIdToVInfo {
			// for each volume, check filer file ids
			if err = c.findFilerChunksMissingInVolumeServers(volumeIdToVInfo, dataNodeId, *applyPurging); err != nil {
				return fmt.Errorf("findFilerChunksMissingInVolumeServers: %v", err)
			}
		}
	} else {
		// collect all filer file ids
		if err = c.collectFilerFileIdAndPaths(dataNodeVolumeIdToVInfo, false, 0, 0); err != nil {
			return fmt.Errorf("failed to collect file ids from filer: %v", err)
		}
		// volume file ids subtract filer file ids
		if err = c.findExtraChunksInVolumeServers(dataNodeVolumeIdToVInfo, *applyPurging, uint64(collectModifyFromAtNs), uint64(collectCutoffFromAtNs)); err != nil {
			return fmt.Errorf("findExtraChunksInVolumeServers: %v", err)
		}
	}

	return nil
}

func (c *commandVolumeFsck) collectFilerFileIdAndPaths(dataNodeVolumeIdToVInfo map[string]map[uint32]VInfo, purgeAbsent bool, collectModifyFromAtNs int64, cutoffFromAtNs int64) error {
	if *c.verbose {
		fmt.Fprintf(c.writer, "checking each file from filer path %s...\n", c.getCollectFilerFilePath())
	}

	files := make(map[uint32]*os.File)
	for _, volumeIdToServer := range dataNodeVolumeIdToVInfo {
		for vid := range volumeIdToServer {
			if _, ok := files[vid]; ok {
				continue
			}
			dst, openErr := os.OpenFile(getFilerFileIdFile(c.tempFolder, vid), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
			if openErr != nil {
				return fmt.Errorf("failed to create file %s: %v", getFilerFileIdFile(c.tempFolder, vid), openErr)
			}
			files[vid] = dst
		}
	}
	defer func() {
		for _, f := range files {
			f.Close()
		}
	}()

	return doTraverseBfsAndSaving(c.env, c.writer, c.getCollectFilerFilePath(), false,
		func(entry *filer_pb.FullEntry, outputChan chan interface{}) (err error) {
			if *c.verbose && entry.Entry.IsDirectory {
				fmt.Fprintf(c.writer, "checking directory %s\n", util.NewFullPath(entry.Dir, entry.Entry.Name))
			}
			dataChunks, manifestChunks, resolveErr := filer.ResolveChunkManifest(filer.LookupFn(c.env), entry.Entry.GetChunks(), 0, math.MaxInt64)
			if resolveErr != nil {
				return fmt.Errorf("failed to ResolveChunkManifest: %+v", resolveErr)
			}
			dataChunks = append(dataChunks, manifestChunks...)
			for _, chunk := range dataChunks {
				if cutoffFromAtNs != 0 && chunk.ModifiedTsNs > cutoffFromAtNs {
					continue
				}
				if collectModifyFromAtNs != 0 && chunk.ModifiedTsNs < collectModifyFromAtNs {
					continue
				}
				outputChan <- &Item{
					vid:     chunk.Fid.VolumeId,
					fileKey: chunk.Fid.FileKey,
					cookie:  chunk.Fid.Cookie,
					path:    util.NewFullPath(entry.Dir, entry.Entry.Name),
				}
			}
			return nil
		},
		func(outputChan chan interface{}) {
			buffer := make([]byte, readbufferSize)
			for item := range outputChan {
				i := item.(*Item)
				if f, ok := files[i.vid]; ok {
					util.Uint64toBytes(buffer, i.fileKey)
					util.Uint32toBytes(buffer[8:], i.cookie)
					util.Uint32toBytes(buffer[12:], uint32(len(i.path)))
					f.Write(buffer)
					f.Write([]byte(i.path))
				} else if *c.findMissingChunksInFiler && len(c.volumeIds) == 0 {
					fmt.Fprintf(c.writer, "%d,%x%08x %s volume not found\n", i.vid, i.fileKey, i.cookie, i.path)
					if purgeAbsent {
						fmt.Printf("deleting path %s after volume not found", i.path)
						c.httpDelete(i.path)
					}
				}
			}
		})
}

func (c *commandVolumeFsck) findFilerChunksMissingInVolumeServers(volumeIdToVInfo map[uint32]VInfo, dataNodeId string, applyPurging bool) error {

	for volumeId, vinfo := range volumeIdToVInfo {
		checkErr := c.oneVolumeFileIdsCheckOneVolume(dataNodeId, volumeId, applyPurging)
		if checkErr != nil {
			return fmt.Errorf("failed to collect file ids from volume %d on %s: %v", volumeId, vinfo.server, checkErr)
		}
	}
	return nil
}

func (c *commandVolumeFsck) findExtraChunksInVolumeServers(dataNodeVolumeIdToVInfo map[string]map[uint32]VInfo, applyPurging bool, modifyFrom, cutoffFrom uint64) error {

	var totalInUseCount, totalOrphanChunkCount, totalOrphanDataSize uint64
	volumeIdOrphanFileIds := make(map[uint32]map[string]bool)
	isSeveralReplicas := make(map[uint32]bool)
	isEcVolumeReplicas := make(map[uint32]bool)
	isReadOnlyReplicas := make(map[uint32]bool)
	serverReplicas := make(map[uint32][]pb.ServerAddress)
	for dataNodeId, volumeIdToVInfo := range dataNodeVolumeIdToVInfo {
		for volumeId, vinfo := range volumeIdToVInfo {
			inUseCount, orphanFileIds, orphanDataSize, checkErr := c.oneVolumeFileIdsSubtractFilerFileIds(dataNodeId, volumeId, &vinfo, modifyFrom, cutoffFrom)
			if checkErr != nil {
				return fmt.Errorf("failed to collect file ids from volume %d on %s: %v", volumeId, vinfo.server, checkErr)
			}
			isSeveralReplicas[volumeId] = false
			if _, found := volumeIdOrphanFileIds[volumeId]; !found {
				volumeIdOrphanFileIds[volumeId] = make(map[string]bool)
			} else {
				isSeveralReplicas[volumeId] = true
			}
			for _, fid := range orphanFileIds {
				if isSeveralReplicas[volumeId] {
					if _, found := volumeIdOrphanFileIds[volumeId][fid]; !found {
						continue
					}
				}
				volumeIdOrphanFileIds[volumeId][fid] = isSeveralReplicas[volumeId]
			}

			totalInUseCount += inUseCount
			totalOrphanChunkCount += uint64(len(orphanFileIds))
			totalOrphanDataSize += orphanDataSize

			if *c.verbose {
				for _, fid := range orphanFileIds {
					fmt.Fprintf(c.writer, "%s:%s\n", vinfo.collection, fid)
				}
			}
			isEcVolumeReplicas[volumeId] = vinfo.isEcVolume
			if isReadOnly, found := isReadOnlyReplicas[volumeId]; !(found && isReadOnly) {
				isReadOnlyReplicas[volumeId] = vinfo.isReadOnly
			}
			serverReplicas[volumeId] = append(serverReplicas[volumeId], vinfo.server)
		}

		for volumeId, orphanReplicaFileIds := range volumeIdOrphanFileIds {
			if !(applyPurging && len(orphanReplicaFileIds) > 0) {
				continue
			}
			orphanFileIds := []string{}
			for fid, foundInAllReplicas := range orphanReplicaFileIds {
				if !isSeveralReplicas[volumeId] || *c.forcePurging || (isSeveralReplicas[volumeId] && foundInAllReplicas) {
					orphanFileIds = append(orphanFileIds, fid)
				}
			}
			if !(len(orphanFileIds) > 0) {
				continue
			}
			if *c.verbose {
				fmt.Fprintf(c.writer, "purging process for volume %d.\n", volumeId)
			}

			if isEcVolumeReplicas[volumeId] {
				fmt.Fprintf(c.writer, "skip purging for Erasure Coded volume %d.\n", volumeId)
				continue
			}
			for _, server := range serverReplicas[volumeId] {
				needleVID := needle.VolumeId(volumeId)

				if isReadOnlyReplicas[volumeId] {
					err := markVolumeWritable(c.env.option.GrpcDialOption, needleVID, server, true, false)
					if err != nil {
						return fmt.Errorf("mark volume %d read/write: %v", volumeId, err)
					}
					fmt.Fprintf(c.writer, "temporarily marked %d on server %v writable for forced purge\n", volumeId, server)
					defer markVolumeWritable(c.env.option.GrpcDialOption, needleVID, server, false, false)

					fmt.Fprintf(c.writer, "marked %d on server %v writable for forced purge\n", volumeId, server)
				}

				if *c.verbose {
					fmt.Fprintf(c.writer, "purging files from volume %d\n", volumeId)
				}

				if err := c.purgeFileIdsForOneVolume(volumeId, orphanFileIds); err != nil {
					return fmt.Errorf("purging volume %d: %v", volumeId, err)
				}
			}
		}
	}

	if !applyPurging {
		pct := float64(totalOrphanChunkCount*100) / (float64(totalOrphanChunkCount + totalInUseCount))
		fmt.Fprintf(c.writer, "\nTotal\t\tentries:%d\torphan:%d\t%.2f%%\t%dB\n",
			totalOrphanChunkCount+totalInUseCount, totalOrphanChunkCount, pct, totalOrphanDataSize)

		fmt.Fprintf(c.writer, "This could be normal if multiple filers or no filers are used.\n")
	}

	if totalOrphanChunkCount == 0 {
		fmt.Fprintf(c.writer, "no orphan data\n")
	}

	return nil
}

func (c *commandVolumeFsck) collectOneVolumeFileIds(dataNodeId string, volumeId uint32, vinfo VInfo) error {

	if *c.verbose {
		fmt.Fprintf(c.writer, "collecting volume %d file ids from %s ...\n", volumeId, vinfo.server)
	}

	return operation.WithVolumeServerClient(false, vinfo.server, c.env.option.GrpcDialOption,
		func(volumeServerClient volume_server_pb.VolumeServerClient) error {
			ext := ".idx"
			if vinfo.isEcVolume {
				ext = ".ecx"
			}

			copyFileClient, err := volumeServerClient.CopyFile(context.Background(), &volume_server_pb.CopyFileRequest{
				VolumeId:                 volumeId,
				Ext:                      ext,
				CompactionRevision:       math.MaxUint32,
				StopOffset:               math.MaxInt64,
				Collection:               vinfo.collection,
				IsEcVolume:               vinfo.isEcVolume,
				IgnoreSourceFileNotFound: false,
			})
			if err != nil {
				return fmt.Errorf("failed to start copying volume %d%s: %v", volumeId, ext, err)
			}

			var buf bytes.Buffer
			for {
				resp, err := copyFileClient.Recv()
				if errors.Is(err, io.EOF) {
					break
				}
				if err != nil {
					return err
				}
				buf.Write(resp.FileContent)
			}
			idxFilename := getVolumeFileIdFile(c.tempFolder, dataNodeId, volumeId)
			err = writeToFile(buf.Bytes(), idxFilename)
			if err != nil {
				return fmt.Errorf("failed to copy %d%s from %s: %v", volumeId, ext, vinfo.server, err)
			}

			return nil
		})

}

type Item struct {
	vid     uint32
	fileKey uint64
	cookie  uint32
	path    util.FullPath
}

func (c *commandVolumeFsck) readFilerFileIdFile(volumeId uint32, fn func(needleId types.NeedleId, itemPath util.FullPath)) error {
	fp, err := os.Open(getFilerFileIdFile(c.tempFolder, volumeId))
	if err != nil {
		return err
	}
	defer fp.Close()

	br := bufio.NewReader(fp)
	buffer := make([]byte, readbufferSize)
	var readSize int
	var readErr error
	item := &Item{vid: volumeId}
	for {
		readSize, readErr = io.ReadFull(br, buffer)
		if errors.Is(readErr, io.EOF) {
			break
		}
		if readErr != nil {
			return readErr
		}
		if readSize != readbufferSize {
			return fmt.Errorf("readSize mismatch")
		}
		item.fileKey = util.BytesToUint64(buffer[:8])
		item.cookie = util.BytesToUint32(buffer[8:12])
		pathSize := util.BytesToUint32(buffer[12:16])
		pathBytes := make([]byte, int(pathSize))
		n, err := io.ReadFull(br, pathBytes)
		if err != nil {
			fmt.Fprintf(c.writer, "%d,%x%08x in unexpected error: %v\n", volumeId, item.fileKey, item.cookie, err)
		}
		if n != int(pathSize) {
			fmt.Fprintf(c.writer, "%d,%x%08x %d unexpected file name size %d\n", volumeId, item.fileKey, item.cookie, pathSize, n)
		}
		item.path = util.FullPath(pathBytes)
		needleId := types.NeedleId(item.fileKey)
		fn(needleId, item.path)
	}
	return nil
}

func (c *commandVolumeFsck) oneVolumeFileIdsCheckOneVolume(dataNodeId string, volumeId uint32, applyPurging bool) (err error) {
	if *c.verbose {
		fmt.Fprintf(c.writer, "find missing file chunks in dataNodeId %s volume %d ...\n", dataNodeId, volumeId)
	}

	db := needle_map.NewMemDb()
	defer db.Close()

	if err = db.LoadFromIdx(getVolumeFileIdFile(c.tempFolder, dataNodeId, volumeId)); err != nil {
		return
	}
	if err = c.readFilerFileIdFile(volumeId, func(needleId types.NeedleId, itemPath util.FullPath) {
		if _, found := db.Get(needleId); !found {
			fmt.Fprintf(c.writer, "%s\n", itemPath)
			if applyPurging {
				c.httpDelete(itemPath)
			}
		}
	}); err != nil {
		return
	}
	return nil
}

func (c *commandVolumeFsck) httpDelete(path util.FullPath) {
	req, err := http.NewRequest(http.MethodDelete, "", nil)

	req.URL = &url.URL{
		Scheme: "http",
		Host:   c.env.option.FilerAddress.ToHttpAddress(),
		Path:   string(path),
	}
	if *c.verbose {
		fmt.Fprintf(c.writer, "full HTTP delete request to be sent: %v\n", req)
	}
	if err != nil {
		fmt.Fprintf(c.writer, "HTTP delete request error: %v\n", err)
	}

	resp, err := util_http.GetGlobalHttpClient().Do(req)
	if err != nil {
		fmt.Fprintf(c.writer, "DELETE fetch error: %v\n", err)
	}
	defer resp.Body.Close()

	_, err = io.ReadAll(resp.Body)
	if err != nil {
		fmt.Fprintf(c.writer, "DELETE response error: %v\n", err)
	}

	if *c.verbose {
		fmt.Fprintln(c.writer, "delete response Status : ", resp.Status)
		fmt.Fprintln(c.writer, "delete response Headers : ", resp.Header)
	}
}

func (c *commandVolumeFsck) oneVolumeFileIdsSubtractFilerFileIds(dataNodeId string, volumeId uint32, vinfo *VInfo, modifyFrom, cutoffFrom uint64) (inUseCount uint64, orphanFileIds []string, orphanDataSize uint64, err error) {

	volumeFileIdDb := needle_map.NewMemDb()
	defer volumeFileIdDb.Close()

	if err = volumeFileIdDb.LoadFromIdx(getVolumeFileIdFile(c.tempFolder, dataNodeId, volumeId)); err != nil {
		err = fmt.Errorf("failed to LoadFromIdx %+v", err)
		return
	}

	if err = c.readFilerFileIdFile(volumeId, func(filerNeedleId types.NeedleId, itemPath util.FullPath) {
		inUseCount++
		if *c.verifyNeedle {
			if needleValue, ok := volumeFileIdDb.Get(filerNeedleId); ok && !needleValue.Size.IsDeleted() {
				if _, err := readNeedleStatus(c.env.option.GrpcDialOption, vinfo.server, volumeId, *needleValue); err != nil {
					// files may be deleted during copying filesIds
					if !strings.Contains(err.Error(), storage.ErrorDeleted.Error()) {
						fmt.Fprintf(c.writer, "failed to read %d:%s needle status of file %s: %+v\n",
							volumeId, filerNeedleId.String(), itemPath, err)
						if *c.forcePurging {
							return
						}
					}
				}
			}
		}

		if err = volumeFileIdDb.Delete(filerNeedleId); err != nil && *c.verbose {
			fmt.Fprintf(c.writer, "failed to nm.delete %s(%+v): %+v", itemPath, filerNeedleId, err)
		}
	}); err != nil {
		err = fmt.Errorf("failed to readFilerFileIdFile %+v", err)
		return
	}

	var orphanFileCount uint64
	if err = volumeFileIdDb.AscendingVisit(func(n needle_map.NeedleValue) error {
		if n.Size.IsDeleted() {
			return nil
		}
		if cutoffFrom > 0 || modifyFrom > 0 {
			return operation.WithVolumeServerClient(false, vinfo.server, c.env.option.GrpcDialOption,
				func(volumeServerClient volume_server_pb.VolumeServerClient) error {
					resp, err := volumeServerClient.ReadNeedleMeta(context.Background(), &volume_server_pb.ReadNeedleMetaRequest{
						VolumeId: volumeId,
						NeedleId: types.NeedleIdToUint64(n.Key),
						Offset:   n.Offset.ToActualOffset(),
						Size:     int32(n.Size),
					})
					if err != nil {
						return fmt.Errorf("read needle meta with id %d from volume %d: %v", n.Key, volumeId, err)
					}
					if (modifyFrom == 0 || modifyFrom <= resp.AppendAtNs) && (cutoffFrom == 0 || resp.AppendAtNs <= cutoffFrom) {
						orphanFileIds = append(orphanFileIds, n.Key.FileId(volumeId))
						orphanFileCount++
						orphanDataSize += uint64(n.Size)
					}
					return nil
				})
		} else {
			orphanFileIds = append(orphanFileIds, n.Key.FileId(volumeId))
			orphanFileCount++
			orphanDataSize += uint64(n.Size)
		}
		return nil
	}); err != nil {
		err = fmt.Errorf("failed to AscendingVisit %+v", err)
		return
	}

	if orphanFileCount > 0 {
		pct := float64(orphanFileCount*100) / (float64(orphanFileCount + inUseCount))
		fmt.Fprintf(c.writer, "dataNode:%s\tvolume:%d\tentries:%d\torphan:%d\t%.2f%%\t%dB\n",
			dataNodeId, volumeId, orphanFileCount+inUseCount, orphanFileCount, pct, orphanDataSize)
	}

	return

}

type VInfo struct {
	server     pb.ServerAddress
	collection string
	isEcVolume bool
	isReadOnly bool
}

func (c *commandVolumeFsck) collectVolumeIds() (volumeIdToServer map[string]map[uint32]VInfo, err error) {

	if *c.verbose {
		fmt.Fprintf(c.writer, "collecting volume id and locations from master ...\n")
	}

	volumeIdToServer = make(map[string]map[uint32]VInfo)
	// collect topology information
	topologyInfo, _, err := collectTopologyInfo(c.env, 0)
	if err != nil {
		return
	}

	eachDataNode(topologyInfo, func(dc string, rack RackId, t *master_pb.DataNodeInfo) {
		var volumeCount, ecShardCount int
		dataNodeId := t.GetId()
		for _, diskInfo := range t.DiskInfos {
			if _, ok := volumeIdToServer[dataNodeId]; !ok {
				volumeIdToServer[dataNodeId] = make(map[uint32]VInfo)
			}
			for _, vi := range diskInfo.VolumeInfos {
				volumeIdToServer[dataNodeId][vi.Id] = VInfo{
					server:     pb.NewServerAddressFromDataNode(t),
					collection: vi.Collection,
					isEcVolume: false,
					isReadOnly: vi.ReadOnly,
				}
				volumeCount += 1
			}
			for _, ecShardInfo := range diskInfo.EcShardInfos {
				volumeIdToServer[dataNodeId][ecShardInfo.Id] = VInfo{
					server:     pb.NewServerAddressFromDataNode(t),
					collection: ecShardInfo.Collection,
					isEcVolume: true,
					isReadOnly: true,
				}
				ecShardCount += 1
			}
		}
		if *c.verbose {
			fmt.Fprintf(c.writer, "dn %+v collected %d volumes and %d ec shards.\n", dataNodeId, volumeCount, ecShardCount)
		}
	})
	return
}

func (c *commandVolumeFsck) purgeFileIdsForOneVolume(volumeId uint32, fileIds []string) (err error) {
	fmt.Fprintf(c.writer, "purging orphan data for volume %d...\n", volumeId)
	locations, found := c.env.MasterClient.GetLocations(volumeId)
	if !found {
		return fmt.Errorf("failed to find volume %d locations", volumeId)
	}

	resultChan := make(chan []*volume_server_pb.DeleteResult, len(locations))
	var wg sync.WaitGroup
	for _, location := range locations {
		wg.Add(1)
		go func(server pb.ServerAddress, fidList []string) {
			defer wg.Done()

			if deleteResults, deleteErr := operation.DeleteFileIdsAtOneVolumeServer(server, c.env.option.GrpcDialOption, fidList, false); deleteErr != nil {
				err = deleteErr
			} else if deleteResults != nil {
				resultChan <- deleteResults
			}

		}(location.ServerAddress(), fileIds)
	}
	wg.Wait()
	close(resultChan)

	for results := range resultChan {
		for _, result := range results {
			if result.Error != "" {
				fmt.Fprintf(c.writer, "purge error: %s\n", result.Error)
			}
		}
	}

	return
}

func (c *commandVolumeFsck) getCollectFilerFilePath() string {
	if *c.collection != "" {
		return fmt.Sprintf("%s/%s", c.bucketsPath, *c.collection)
	}
	return "/"
}

func getVolumeFileIdFile(tempFolder string, dataNodeid string, vid uint32) string {
	return filepath.Join(tempFolder, fmt.Sprintf("%s_%d.idx", dataNodeid, vid))
}

func getFilerFileIdFile(tempFolder string, vid uint32) string {
	return filepath.Join(tempFolder, fmt.Sprintf("%d.fid", vid))
}

func writeToFile(bytes []byte, fileName string) error {
	flags := os.O_WRONLY | os.O_CREATE | os.O_TRUNC
	dst, err := os.OpenFile(fileName, flags, 0644)
	if err != nil {
		return nil
	}
	defer dst.Close()

	dst.Write(bytes)
	return nil
}