package mount

import (
	"context"
	"fmt"
	"syscall"
	"time"

	"github.com/seaweedfs/go-fuse/v2/fuse"
	"google.golang.org/protobuf/proto"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/util"
)

func (wfs *WFS) saveEntry(path util.FullPath, entry *filer_pb.Entry) (code fuse.Status) {

	parentDir, _ := path.DirAndName()

	wfs.mapPbIdFromLocalToFiler(entry)
	defer wfs.mapPbIdFromFilerToLocal(entry)

	request := &filer_pb.UpdateEntryRequest{
		Directory:  parentDir,
		Entry:      entry,
		Signatures: []int32{wfs.signature},
	}

	glog.V(1).Infof("save entry: %v", request)

	var resp *filer_pb.UpdateEntryResponse
	err := retryMetadataFlushIf(context.Background(), func() error {
		var callErr error
		resp, callErr = wfs.streamUpdateEntry(context.Background(), request)
		return callErr
	}, isRetryableFilerError, func(nextAttempt, totalAttempts int, backoff time.Duration, err error) {
		glog.Warningf("saveEntry %s: retrying UpdateEntry (attempt %d/%d) after %v: %v",
			path, nextAttempt, totalAttempts, backoff, err)
	})

	if err != nil {
		// Wrap with %w so grpcErrorToFuseStatus can still unwrap the gRPC status
		// (e.g. codes.Canceled → ETIMEDOUT). Using %v would stringify the error and
		// status.FromError would fall through to the default EIO.
		err = fmt.Errorf("UpdateEntry dir %s: %w", path, err)
		fuseStatus := grpcErrorToFuseStatus(err)
		if fuseStatus == fuse.EIO {
			glog.Errorf("saveEntry failed for %s: %v (returning EIO)", path, err)
		} else {
			glog.V(1).Infof("saveEntry failed for %s: %v (returning %v)", path, err, fuseStatus)
		}
		return fuseStatus
	}

	// The mutation is acknowledged; bring any open handle for this path up
	// to the acknowledged state — a handle opened while this save was in
	// flight holds an older entry, and advancing its version alone would
	// fence out the events carrying what it lacks. A no-change update
	// returns no event but still carries the log position it confirmed.
	ackVersion := ackVersionTsNs(resp)
	if inode, found := wfs.inodeToPath.GetInode(path); found {
		if fh, fhFound := wfs.fhMap.FindFileHandle(inode); fhFound {
			ackedEntry := proto.Clone(entry).(*filer_pb.Entry)
			wfs.mapPbIdFromFilerToLocal(ackedEntry)
			fh.installAckedEntry(ackedEntry, ackVersion, resp.GetLogSignature())
		}
	}

	event := resp.GetMetadataEvent()
	if event == nil {
		event = metadataUpdateEvent(parentDir, entry)
		if event != nil {
			event.TsNs = ackVersion
		}
	}
	if applyErr := wfs.applyLocalMetadataEvent(context.Background(), event); applyErr != nil {
		glog.Warningf("saveEntry %s: best-effort metadata apply failed: %v", path, applyErr)
		wfs.inodeToPath.InvalidateChildrenCache(util.FullPath(parentDir))
	}

	return fuse.OK
}

func (wfs *WFS) mapPbIdFromFilerToLocal(entry *filer_pb.Entry) {
	if entry.Attributes == nil {
		return
	}
	entry.Attributes.Uid, entry.Attributes.Gid = wfs.option.UidGidMapper.FilerToLocal(entry.Attributes.Uid, entry.Attributes.Gid)
}
func (wfs *WFS) mapPbIdFromLocalToFiler(entry *filer_pb.Entry) {
	if entry.Attributes == nil {
		return
	}
	entry.Attributes.Uid, entry.Attributes.Gid = wfs.option.UidGidMapper.LocalToFiler(entry.Attributes.Uid, entry.Attributes.Gid)
}

// sanitizeFuseName scrubs a name arriving from the kernel before it is placed
// in a proto string field. Linux (and macOS) pass raw bytes for filenames;
// apps like GNOME Trash produce partial files whose names contain binary
// payloads. Proto3 `string` fields require valid UTF-8, so an unsanitized
// name causes gRPC to fail the whole AssignVolume / CreateEntry / DeleteEntry
// RPC with "grpc: error while marshaling: string field contains invalid
// UTF-8", which surfaces to userspace as EIO. Sanitizing at every FUSE
// boundary keeps filer RPCs marshalable and prevents a single ill-named file
// from poisoning the shared gRPC channel for every other in-flight request.
//
// Delegates to util.SanitizeUTF8Name so the replacement character is chosen
// in exactly one place across the codebase.
func sanitizeFuseName(name string) string {
	return util.SanitizeUTF8Name(name)
}

func checkName(name string) (string, fuse.Status) {
	name = sanitizeFuseName(name)
	// The Linux FUSE kernel module enforces NAME_MAX=255 at the VFS layer.
	// Return ENAMETOOLONG early to avoid creating entries that cannot be
	// looked up via normal syscalls (stat, chmod, etc.).
	if len(name) > 255 {
		return name, fuse.Status(syscall.ENAMETOOLONG)
	}
	return name, fuse.OK
}
