package filesys

import (
	"context"
	"path/filepath"

	"github.com/chrislusf/seaweedfs/weed/glog"
	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/fuse"
)

func getxattr(entry *filer_pb.Entry, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {

	if entry == nil {
		return fuse.ErrNoXattr
	}
	if entry.Extended == nil {
		return fuse.ErrNoXattr
	}
	data, found := entry.Extended[req.Name]
	if !found {
		return fuse.ErrNoXattr
	}
	if req.Position < uint32(len(data)) {
		size := req.Size
		if req.Position+size >= uint32(len(data)) {
			size = uint32(len(data)) - req.Position
		}
		if size == 0 {
			resp.Xattr = data[req.Position:]
		} else {
			resp.Xattr = data[req.Position : req.Position+size]
		}
	}

	return nil

}

func setxattr(entry *filer_pb.Entry, req *fuse.SetxattrRequest) error {

	if entry == nil {
		return fuse.EIO
	}

	if entry.Extended == nil {
		entry.Extended = make(map[string][]byte)
	}
	data, _ := entry.Extended[req.Name]

	newData := make([]byte, int(req.Position)+len(req.Xattr))

	copy(newData, data)

	copy(newData[int(req.Position):], req.Xattr)

	entry.Extended[req.Name] = newData

	return nil

}

func removexattr(entry *filer_pb.Entry, req *fuse.RemovexattrRequest) error {

	if entry == nil {
		return fuse.ErrNoXattr
	}

	if entry.Extended == nil {
		return fuse.ErrNoXattr
	}

	_, found := entry.Extended[req.Name]

	if !found {
		return fuse.ErrNoXattr
	}

	delete(entry.Extended, req.Name)

	return nil

}

func listxattr(entry *filer_pb.Entry, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error {

	if entry == nil {
		return fuse.EIO
	}

	for k := range entry.Extended {
		resp.Append(k)
	}

	size := req.Size
	if req.Position+size >= uint32(len(resp.Xattr)) {
		size = uint32(len(resp.Xattr)) - req.Position
	}

	if size == 0 {
		resp.Xattr = resp.Xattr[req.Position:]
	} else {
		resp.Xattr = resp.Xattr[req.Position : req.Position+size]
	}

	return nil

}

func (wfs *WFS) maybeLoadEntry(ctx context.Context, dir, name string) (entry *filer_pb.Entry, err error) {

	fullpath := filepath.Join(dir, name)
	item := wfs.listDirectoryEntriesCache.Get(fullpath)
	if item != nil && !item.Expired() {
		entry = item.Value().(*filer_pb.Entry)
		return
	}
	glog.V(3).Infof("read entry cache miss %s", fullpath)

	err = wfs.WithFilerClient(ctx, func(client filer_pb.SeaweedFilerClient) error {

		request := &filer_pb.LookupDirectoryEntryRequest{
			Name:      name,
			Directory: dir,
		}

		resp, err := client.LookupDirectoryEntry(ctx, request)
		if err != nil {
			glog.V(3).Infof("file attr read file %v: %v", request, err)
			return fuse.ENOENT
		}

		entry = resp.Entry
		if entry != nil {
			wfs.listDirectoryEntriesCache.Set(fullpath, entry, wfs.option.EntryCacheTtl)
		}

		return nil
	})

	return
}