package weed_server

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

	"github.com/seaweedfs/seaweedfs/weed/cluster"
	"github.com/seaweedfs/seaweedfs/weed/filer"
	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
	"github.com/seaweedfs/seaweedfs/weed/util"
	"github.com/seaweedfs/seaweedfs/weed/util/constants"
	"google.golang.org/protobuf/proto"
)

func (fs *FilerServer) autoChunk(ctx context.Context, w http.ResponseWriter, r *http.Request, contentLength int64, so *operation.StorageOption) {

	// autoChunking can be set at the command-line level or as a query param. Query param overrides command-line
	query := r.URL.Query()

	chunkSize := fs.requestChunkSize(query)

	var reply *FilerPostResult
	var err error
	var md5bytes []byte
	if r.Method == http.MethodPost {
		if r.Header.Get("Content-Type") == "" && strings.HasSuffix(r.URL.Path, "/") {
			reply, err = fs.mkdir(ctx, w, r, so)
		} else {
			reply, md5bytes, err = fs.doPostAutoChunk(ctx, w, r, chunkSize, contentLength, so)
		}
	} else {
		reply, md5bytes, err = fs.doPutAutoChunk(ctx, w, r, chunkSize, contentLength, so)
	}
	if err != nil {
		errStr := err.Error()
		switch {
		case errStr == constants.ErrMsgOperationNotPermitted:
			writeJsonError(w, r, http.StatusForbidden, err)
		case strings.HasPrefix(errStr, "read input:") || errStr == io.ErrUnexpectedEOF.Error():
			writeJsonError(w, r, util.HttpStatusCancelled, err)
		case strings.HasSuffix(errStr, "is a file") || strings.HasSuffix(errStr, "already exists"):
			writeJsonError(w, r, http.StatusConflict, err)
		case errStr == constants.ErrMsgBadDigest,
			errStr == constants.ErrMsgAppendSaveInsideChunked,
			errStr == constants.ErrMsgAppendInlineMode,
			errStr == constants.ErrMsgOffsetWriteInline:
			writeJsonError(w, r, http.StatusBadRequest, err)
		default:
			writeJsonError(w, r, http.StatusInternalServerError, err)
		}
	} else if reply != nil {
		if len(md5bytes) > 0 {
			md5InBase64 := util.Base64Encode(md5bytes)
			w.Header().Set("Content-MD5", md5InBase64)
		}
		writeJsonQuiet(w, r, http.StatusCreated, reply)
	}
}

func (fs *FilerServer) doPostAutoChunk(ctx context.Context, w http.ResponseWriter, r *http.Request, chunkSize int32, contentLength int64, so *operation.StorageOption) (filerResult *FilerPostResult, md5bytes []byte, replyerr error) {
	multipartReader, multipartReaderErr := r.MultipartReader()
	if multipartReaderErr != nil {
		return nil, nil, multipartReaderErr
	}

	part1, part1Err := multipartReader.NextPart()
	if part1Err != nil {
		return nil, nil, part1Err
	}

	fileName := part1.FileName()
	if fileName != "" {
		fileName = path.Base(fileName)
	}
	contentType := part1.Header.Get("Content-Type")
	if contentType == "application/octet-stream" {
		contentType = ""
	}

	if err := fs.checkPermissions(ctx, r, fileName); err != nil {
		return nil, nil, err
	}

	if so.SaveInside {
		buf := bufPool.Get().(*bytes.Buffer)
		buf.Reset()
		if _, err := buf.ReadFrom(part1); err != nil {
			bufPool.Put(buf)
			return nil, nil, fmt.Errorf("read input: %w", err)
		}
		md5bytes = util.Md5(buf.Bytes())
		headerMd5 := r.Header.Get("Content-Md5")
		if headerMd5 != "" && !(util.Base64Encode(md5bytes) == headerMd5 || fmt.Sprintf("%x", md5bytes) == headerMd5) {
			bufPool.Put(buf)
			return nil, nil, errors.New(constants.ErrMsgBadDigest)
		}
		filerResult, replyerr, _ = fs.saveMetaData(ctx, r, fileName, contentType, so, chunkSize, md5bytes, nil, int64(buf.Len()), buf.Bytes())
		bufPool.Put(buf)
		return
	}

	fileChunks, md5Hash, chunkOffset, err, smallContent := fs.uploadRequestToChunks(ctx, w, r, part1, chunkSize, fileName, contentType, contentLength, so)
	if err != nil {
		return nil, nil, err
	}

	md5bytes = md5Hash.Sum(nil)
	headerMd5 := r.Header.Get("Content-Md5")
	if headerMd5 != "" && !(util.Base64Encode(md5bytes) == headerMd5 || fmt.Sprintf("%x", md5bytes) == headerMd5) {
		fs.filer.DeleteUncommittedChunks(ctx, fileChunks)
		return nil, nil, errors.New(constants.ErrMsgBadDigest)
	}
	var uncommittedChunks []*filer_pb.FileChunk
	filerResult, replyerr, uncommittedChunks = fs.saveMetaData(ctx, r, fileName, contentType, so, chunkSize, md5bytes, fileChunks, chunkOffset, smallContent)
	if replyerr != nil {
		fs.filer.DeleteUncommittedChunks(ctx, uncommittedChunks)
	}

	return
}

func (fs *FilerServer) doPutAutoChunk(ctx context.Context, w http.ResponseWriter, r *http.Request, chunkSize int32, contentLength int64, so *operation.StorageOption) (filerResult *FilerPostResult, md5bytes []byte, replyerr error) {

	fileName := path.Base(r.URL.Path)
	contentType := r.Header.Get("Content-Type")
	if contentType == "application/octet-stream" {
		contentType = ""
	}

	if err := fs.checkPermissions(ctx, r, fileName); err != nil {
		return nil, nil, err
	}

	fileChunks, md5Hash, chunkOffset, err, smallContent := fs.uploadRequestToChunks(ctx, w, r, r.Body, chunkSize, fileName, contentType, contentLength, so)

	if err != nil {
		return nil, nil, err
	}

	md5bytes = md5Hash.Sum(nil)
	headerMd5 := r.Header.Get("Content-Md5")
	if headerMd5 != "" && !(util.Base64Encode(md5bytes) == headerMd5 || fmt.Sprintf("%x", md5bytes) == headerMd5) {
		fs.filer.DeleteUncommittedChunks(ctx, fileChunks)
		return nil, nil, errors.New(constants.ErrMsgBadDigest)
	}
	var uncommittedChunks []*filer_pb.FileChunk
	filerResult, replyerr, uncommittedChunks = fs.saveMetaData(ctx, r, fileName, contentType, so, chunkSize, md5bytes, fileChunks, chunkOffset, smallContent)
	if replyerr != nil {
		fs.filer.DeleteUncommittedChunks(ctx, uncommittedChunks)
	}

	return
}

func isAppend(r *http.Request) bool {
	return r.URL.Query().Get("op") == "append"
}

func skipCheckParentDirEntry(r *http.Request) bool {
	return r.URL.Query().Get("skipCheckParentDir") == "true"
}

// requestChunkSize resolves the auto-chunking size from the maxMB query param
// or the server default, clamped so the int32 chunk size cannot overflow into
// a non-positive value that would drop the upload's contents.
func (fs *FilerServer) requestChunkSize(query url.Values) int32 {
	parsedMaxMB, _ := strconv.ParseInt(query.Get("maxMB"), 10, 32)
	maxMB := parsedMaxMB
	if maxMB <= 0 {
		maxMB = int64(fs.option.MaxMB)
	}
	const maxChunkSizeMB = math.MaxInt32 / (1024 * 1024) // 2047
	if maxMB > maxChunkSizeMB {
		maxMB = maxChunkSizeMB
	}
	return int32(maxMB) * 1024 * 1024
}

func (fs *FilerServer) checkPermissions(ctx context.Context, r *http.Request, fileName string) error {
	fullPath := fs.fixFilePath(ctx, r, fileName)
	enforced, err := fs.wormEnforcedForEntry(ctx, fullPath)
	if err != nil {
		return err
	} else if enforced {
		// you cannot change a worm file
		return errors.New(constants.ErrMsgOperationNotPermitted)
	}

	return nil
}

func (fs *FilerServer) wormEnforcedForEntry(ctx context.Context, fullPath string) (bool, error) {
	rule := fs.filer.FilerConf.MatchStorageRule(fullPath)
	if !rule.GetWorm() {
		return false, nil
	}

	entry, err := fs.filer.FindEntry(ctx, util.FullPath(fullPath))
	if err != nil {
		if errors.Is(err, filer_pb.ErrNotFound) {
			return false, nil
		}

		return false, err
	}

	// worm is not enforced
	if entry.WORMEnforcedAtTsNs == 0 {
		return false, nil
	}

	// worm will never expire
	if rule.WormRetentionTimeSeconds == 0 {
		return true, nil
	}

	enforcedAt := time.Unix(0, entry.WORMEnforcedAtTsNs)

	// worm is expired
	if time.Now().Sub(enforcedAt).Seconds() >= float64(rule.WormRetentionTimeSeconds) {
		return false, nil
	}

	return true, nil
}

func (fs *FilerServer) fixFilePath(ctx context.Context, r *http.Request, fileName string) string {
	// fix the path
	fullPath := r.URL.Path
	if strings.HasSuffix(fullPath, "/") {
		if fileName != "" {
			fullPath += fileName
		}
	} else {
		if fileName != "" {
			if possibleDirEntry, findDirErr := fs.filer.FindEntry(ctx, util.FullPath(fullPath)); findDirErr == nil {
				if possibleDirEntry.IsDirectory() {
					fullPath += "/" + fileName
				}
			}
		}
	}

	return fullPath
}

func (fs *FilerServer) saveMetaData(ctx context.Context, r *http.Request, fileName string, contentType string, so *operation.StorageOption, chunkSize int32, md5bytes []byte, fileChunks []*filer_pb.FileChunk, chunkOffset int64, content []byte) (filerResult *FilerPostResult, replyerr error, uncommittedChunks []*filer_pb.FileChunk) {
	uncommittedChunks = fileChunks

	// detect file mode
	modeStr := r.URL.Query().Get("mode")
	if modeStr == "" {
		modeStr = "0660"
	}
	mode, err := strconv.ParseUint(modeStr, 8, 32)
	if err != nil {
		glog.ErrorfCtx(ctx, "Invalid mode format: %s, use 0660 by default", modeStr)
		mode = 0660
	}

	// fix the path
	path := fs.fixFilePath(ctx, r, fileName)

	var entry *filer.Entry
	var newChunks []*filer_pb.FileChunk
	var mergedChunks []*filer_pb.FileChunk

	isAppend := isAppend(r)
	isOffsetWrite := len(fileChunks) > 0 && fileChunks[0].Offset > 0
	var existingEntry *filer.Entry
	var existingSnapshot *filer_pb.Entry
	var distributedLock *cluster.LiveLock
	// when it is an append
	if isAppend || isOffsetWrite {
		if fs.filer.Dlm != nil && len(fs.filer.Dlm.LockRing.GetSnapshot()) > 1 {
			lockClient := cluster.NewLockClient(fs.grpcDialOption, fs.option.Host)
			distributedLock = lockClient.NewBlockingLongLivedLock(path, string(fs.option.Host), 0)
			if distributedLock == nil {
				replyerr = fmt.Errorf("failed to acquire lock for %s; retry the request", path)
				return
			}
			defer distributedLock.Stop()
		}
		if fs.entryLockTable != nil {
			pathLock := fs.entryLockTable.AcquireLock("appendEntry", util.FullPath(path), util.ExclusiveLock)
			defer fs.entryLockTable.ReleaseLock(util.FullPath(path), pathLock)
		}
		var findErr error
		existingEntry, findErr = fs.filer.FindEntry(ctx, util.FullPath(path))
		if findErr != nil && !errors.Is(findErr, filer_pb.ErrNotFound) {
			glog.V(0).InfofCtx(ctx, "failing to find %s: %v", path, findErr)
			replyerr = fmt.Errorf("find entry %q: %w", path, findErr)
			return
		}
		if existingEntry != nil {
			existingSnapshot = existingEntry.ToProtoEntry()
			entry = cloneEntryForAppend(existingEntry)
		}
	}

	inlineAppendHandled := false
	inlineAppendConverted := false
	if entry != nil {
		inlineCandidate := len(entry.Content) > 0 ||
			(isAppend && entry.FileSize == 0 && entry.Remote == nil && len(entry.HardLinkId) == 0 && len(entry.GetChunks()) == 0)
		if isAppend && content != nil && !inlineCandidate {
			if so.SaveInside {
				replyerr = errors.New(constants.ErrMsgAppendSaveInsideChunked)
				return
			}
			replyerr = fmt.Errorf("inline file changed while preparing append; retry the request")
			return
		}

		if inlineCandidate {
			if isOffsetWrite {
				// TODO: support inline offset writes separately from append semantics.
				replyerr = errors.New(constants.ErrMsgOffsetWriteInline)
				return
			}
			if !isAppend || so.SaveInside || entry.Remote != nil || len(entry.HardLinkId) != 0 || len(entry.GetChunks()) != 0 {
				replyerr = errors.New(constants.ErrMsgAppendInlineMode)
				return
			}
			if entry.FileSize > uint64(len(entry.Content)) {
				replyerr = fmt.Errorf("inline file %q has inconsistent size: metadata=%d content=%d", path, entry.FileSize, len(entry.Content))
				return
			}

			entry.Mtime = time.Now()
			entry.Md5 = nil
			oldContentSize := int64(len(entry.Content))

			switch {
			case content != nil:
				if int64(len(content)) != chunkOffset || len(fileChunks) != 0 {
					replyerr = fmt.Errorf("invalid buffered inline append: size=%d offset=%d chunks=%d", len(content), chunkOffset, len(fileChunks))
					return
				}
				combinedSize := oldContentSize + int64(len(content))
				if len(content) == 0 || (fs.option.SaveToFilerLimit > 0 && combinedSize < fs.option.SaveToFilerLimit) {
					combinedContent := make([]byte, 0, combinedSize)
					combinedContent = append(combinedContent, entry.Content...)
					combinedContent = append(combinedContent, content...)
					entry.Content = combinedContent
					entry.Chunks = nil
					entry.FileSize = uint64(combinedSize)
					entry.Md5 = util.Md5(combinedContent)
					newChunks = nil
					inlineAppendHandled = true
				} else {
					// The file grew after the upload path chose inline buffering. Promote
					// the complete current file and this append as one chunk stream.
					combinedContent := make([]byte, 0, combinedSize)
					combinedContent = append(combinedContent, entry.Content...)
					combinedContent = append(combinedContent, content...)
					fileChunks, _, chunkOffset, replyerr, _ = fs.uploadReaderToChunks(ctx, r, bytes.NewReader(combinedContent), 0, chunkSize, fileName, contentType, true, so)
					if replyerr != nil {
						return
					}
					if chunkOffset != combinedSize {
						uncommittedChunks = fileChunks
						replyerr = fmt.Errorf("promoted inline append size mismatch: uploaded=%d expected=%d", chunkOffset, combinedSize)
						return
					}
					entry.Content = nil
					entry.FileSize = uint64(chunkOffset)
					newChunks = fileChunks
					uncommittedChunks = fileChunks
					inlineAppendHandled = true
					inlineAppendConverted = true
				}
			case len(fileChunks) > 0:
				prefixChunks, _, prefixOffset, uploadErr, _ := fs.uploadReaderToChunks(ctx, r, bytes.NewReader(entry.Content), 0, chunkSize, fileName, contentType, true, so)
				if uploadErr != nil {
					replyerr = uploadErr
					return
				}
				uncommittedChunks = append(append([]*filer_pb.FileChunk(nil), fileChunks...), prefixChunks...)
				if prefixOffset != oldContentSize {
					replyerr = fmt.Errorf("converted inline content size mismatch: uploaded=%d expected=%d", prefixOffset, oldContentSize)
					return
				}
				for _, chunk := range fileChunks {
					chunk.Offset += oldContentSize
				}
				newChunks = append(append([]*filer_pb.FileChunk(nil), prefixChunks...), fileChunks...)
				entry.Content = nil
				entry.FileSize = uint64(oldContentSize) + uint64(chunkOffset)
				inlineAppendHandled = true
				inlineAppendConverted = true
				uncommittedChunks = newChunks
			case chunkOffset == 0:
				// An empty append must not migrate an inline file, even if the
				// current threshold is disabled or lower than the file's size.
				entry.FileSize = uint64(oldContentSize)
				entry.Md5 = util.Md5(entry.Content)
				newChunks = nil
				inlineAppendHandled = true
			default:
				replyerr = fmt.Errorf("inline append has no content or uploaded chunks")
				return
			}
		}

		if !inlineAppendHandled {
			entry.Mtime = time.Now()
			entry.Md5 = nil
			// New request chunks start at offset zero; append them after the
			// existing chunk-backed file.
			if isAppend {
				for _, chunk := range fileChunks {
					chunk.Offset += int64(entry.FileSize)
				}
				entry.FileSize += uint64(chunkOffset)
			}
			newChunks = append(append([]*filer_pb.FileChunk(nil), entry.GetChunks()...), fileChunks...)
		}

	} else {
		if isAppend && !so.SaveInside && content != nil {
			replyerr = fmt.Errorf("inline append target disappeared while uploading; retry the request")
			return
		}
		glog.V(4).InfolnCtx(ctx, "saving", path)
		newChunks = fileChunks
		entry = &filer.Entry{
			FullPath: util.FullPath(path),
			Attr: filer.Attr{
				Mtime:    time.Now(),
				Crtime:   time.Now(),
				Mode:     os.FileMode(mode),
				Uid:      OS_UID,
				Gid:      OS_GID,
				TtlSec:   so.TtlSeconds,
				Mime:     contentType,
				Md5:      md5bytes,
				FileSize: uint64(chunkOffset),
			},
			Content: content,
		}
	}

	// maybe concatenate small chunks into one whole chunk
	mergedChunks, replyerr = fs.maybeMergeChunks(ctx, so, newChunks)
	if replyerr != nil {
		glog.V(0).InfofCtx(ctx, "merge chunks %s: %v", r.RequestURI, replyerr)
		mergedChunks = newChunks
	}
	if inlineAppendConverted {
		uncommittedChunks = mergedChunks
	}

	// maybe compact entry chunks
	mergedChunks, replyerr = filer.MaybeManifestize(fs.saveAsChunk(ctx, so), fs.filer.DeleteChunksNotRecursive, mergedChunks)
	if replyerr != nil {
		glog.V(0).InfofCtx(ctx, "manifestize %s: %v", r.RequestURI, replyerr)
		if inlineAppendConverted {
			uncommittedChunks = mergedChunks
		}
		return
	}
	if inlineAppendConverted {
		uncommittedChunks = mergedChunks
	}
	entry.Chunks = mergedChunks
	if isOffsetWrite {
		entry.Md5 = nil
		entry.FileSize = entry.Size()
	}

	filerResult = &FilerPostResult{
		Name: fileName,
		Size: int64(entry.FileSize),
	}

	// Save standard HTTP headers as extended attributes
	// Note: S3 API now writes directly to volume servers and saves metadata via gRPC
	// This handler is for non-S3 clients (WebDAV, SFTP, mount, curl, etc.)
	if entry.Extended == nil {
		entry.Extended = make(map[string][]byte)
	}
	for k, v := range r.Header {
		if len(v) > 0 && len(v[0]) > 0 {
			if k == filer.ExtRemoteRenameSourceKey {
				continue // set by the filer only: it picks the remote key reads serve
			}
			if strings.HasPrefix(k, needle.PairNamePrefix) || k == "Cache-Control" || k == "Expires" || k == "Content-Disposition" {
				entry.Extended[k] = []byte(v[0])
			}
			if k == "Response-Content-Disposition" {
				entry.Extended["Content-Disposition"] = []byte(v[0])
			}
		}
	}

	if isAppend || isOffsetWrite {
		if distributedLock != nil && !distributedLock.IsLocked() {
			replyerr = fmt.Errorf("lost distributed lock for %s; retry the request", path)
			return
		}
		freshEntry, freshErr := fs.filer.FindEntry(ctx, util.FullPath(path))
		if freshErr != nil && !errors.Is(freshErr, filer_pb.ErrNotFound) {
			replyerr = fmt.Errorf("failed to recheck entry %q before write: %w", path, freshErr)
			return
		}
		sameEntry := freshEntry == nil && existingSnapshot == nil ||
			freshEntry != nil && existingSnapshot != nil &&
				proto.Equal(existingSnapshot, freshEntry.ToProtoEntry())
		if !sameEntry {
			replyerr = fmt.Errorf("entry %s changed during append; retry the request", path)
			return
		}
	}

	dbErr := fs.filer.CreateEntry(context.WithoutCancel(ctx), entry, nil, false, false, nil, skipCheckParentDirEntry(r), so.MaxFileNameLength)
	if dbErr != nil {
		replyerr = dbErr
		filerResult.Error = dbErr.Error()
		glog.V(0).InfofCtx(ctx, "failing to write %s to filer server : %v", path, dbErr)
		if inlineAppendConverted {
			uncommittedChunks = fs.inlineAppendChunksNotReferenced(ctx, util.FullPath(path), mergedChunks)
		}
	} else {
		uncommittedChunks = nil
	}
	return
}

func cloneEntryForAppend(entry *filer.Entry) *filer.Entry {
	cloned := entry.ShallowClone()
	cloned.Attr.Md5 = append([]byte(nil), entry.Md5...)
	cloned.Attr.GroupNames = append([]string(nil), entry.GroupNames...)
	cloned.Chunks = append([]*filer_pb.FileChunk(nil), entry.GetChunks()...)
	cloned.Content = append([]byte(nil), entry.Content...)
	cloned.WORMEnforcedAtTsNs = entry.WORMEnforcedAtTsNs
	if entry.Extended != nil {
		cloned.Extended = make(map[string][]byte, len(entry.Extended))
		for key, value := range entry.Extended {
			cloned.Extended[key] = append([]byte(nil), value...)
		}
	}
	return cloned
}

func (fs *FilerServer) inlineAppendChunksNotReferenced(ctx context.Context, path util.FullPath, chunks []*filer_pb.FileChunk) []*filer_pb.FileChunk {
	verifyCtx, cancel := context.WithTimeout(context.WithoutCancel(ctx), 5*time.Second)
	defer cancel()

	entry, err := fs.filer.FindEntry(verifyCtx, path)
	if err != nil && !errors.Is(err, filer_pb.ErrNotFound) {
		glog.V(0).InfofCtx(verifyCtx, "cannot verify inline append chunks for %s after metadata write failure: %v; retaining them", path, err)
		return nil
	}

	referenced := make(map[string]struct{})
	if entry != nil {
		for _, chunk := range entry.GetChunks() {
			referenced[chunk.GetFileIdString()] = struct{}{}
		}
	}

	var unreferenced []*filer_pb.FileChunk
	for _, chunk := range chunks {
		if _, found := referenced[chunk.GetFileIdString()]; !found {
			unreferenced = append(unreferenced, chunk)
		}
	}
	return unreferenced
}

func (fs *FilerServer) saveAsChunk(ctx context.Context, so *operation.StorageOption) filer.SaveDataAsChunkFunctionType {

	return func(reader io.Reader, name string, offset int64, tsNs int64, expectedDataSize uint64) (*filer_pb.FileChunk, error) {
		var fileId string
		var uploadResult *operation.UploadResult

		err := util.Retry("saveAsChunk", func() error {
			// assign one file id for one chunk
			assignedFileId, urlLocation, auth, assignErr := fs.assignNewFileInfo(ctx, so, expectedDataSize)
			if assignErr != nil {
				return assignErr
			}

			fileId = assignedFileId

			// upload the chunk to the volume server
			uploadOption := &operation.UploadOption{
				UploadUrl:         urlLocation,
				Filename:          name,
				Cipher:            fs.option.Cipher,
				IsInputCompressed: false,
				MimeType:          "",
				PairMap:           nil,
				Jwt:               auth,
			}

			uploader, uploaderErr := operation.NewUploader()
			if uploaderErr != nil {
				return uploaderErr
			}

			var uploadErr error
			uploadCtx := context.WithoutCancel(ctx)
			uploadResult, uploadErr, _ = uploader.Upload(uploadCtx, reader, uploadOption)
			if uploadErr != nil {
				return uploadErr
			}
			return nil
		})
		if err != nil {
			return nil, err
		}

		return uploadResult.ToPbFileChunk(fileId, offset, tsNs), nil
	}
}

func (fs *FilerServer) mkdir(ctx context.Context, w http.ResponseWriter, r *http.Request, so *operation.StorageOption) (filerResult *FilerPostResult, replyerr error) {

	// detect file mode
	modeStr := r.URL.Query().Get("mode")
	if modeStr == "" {
		modeStr = "0660"
	}
	mode, err := strconv.ParseUint(modeStr, 8, 32)
	if err != nil {
		glog.ErrorfCtx(ctx, "Invalid mode format: %s, use 0660 by default", modeStr)
		mode = 0660
	}

	// fix the path
	path := r.URL.Path
	if strings.HasSuffix(path, "/") {
		path = path[:len(path)-1]
	}

	existingEntry, err := fs.filer.FindEntry(ctx, util.FullPath(path))
	if err == nil && existingEntry != nil {
		replyerr = fmt.Errorf("dir %s already exists", path)
		return
	}

	glog.V(4).InfolnCtx(ctx, "mkdir", path)
	entry := &filer.Entry{
		FullPath: util.FullPath(path),
		Attr: filer.Attr{
			Mtime:  time.Now(),
			Crtime: time.Now(),
			Mode:   os.FileMode(mode) | os.ModeDir,
			Uid:    OS_UID,
			Gid:    OS_GID,
			TtlSec: so.TtlSeconds,
		},
	}

	filerResult = &FilerPostResult{
		Name: util.FullPath(path).Name(),
	}

	if dbErr := fs.filer.CreateEntry(context.WithoutCancel(ctx), entry, nil, false, false, nil, false, so.MaxFileNameLength); dbErr != nil {
		replyerr = dbErr
		filerResult.Error = dbErr.Error()
		glog.V(0).InfofCtx(ctx, "failing to create dir %s on filer server : %v", path, dbErr)
	}
	return filerResult, replyerr
}