package needle

import (
	"fmt"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/storage/backend"
	. "github.com/seaweedfs/seaweedfs/weed/storage/types"
	"github.com/seaweedfs/seaweedfs/weed/util"
)

func (n *Needle) Append(w backend.BackendStorageFile, version Version) (offset uint64, size Size, actualSize int64, err error) {

	switch version {
	case Version1:
		return writeNeedleV1(w, n)
	case Version2:
		return writeNeedleV2(w, n)
	case Version3:
		return writeNeedleV3(w, n)
	default:
		err = fmt.Errorf("unsupported version: %d", version)
		return
	}
}

func WriteNeedleBlob(w backend.BackendStorageFile, dataSlice []byte, size Size, appendAtNs uint64, version Version) (offset uint64, err error) {

	if end, _, e := w.GetStat(); e == nil {
		defer func(w backend.BackendStorageFile, off int64) {
			if err != nil {
				if te := w.Truncate(end); te != nil {
					glog.V(0).Infof("Failed to truncate %s back to %d with error: %v", w.Name(), end, te)
				}
			}
		}(w, end)
		offset = uint64(end)
	} else {
		err = fmt.Errorf("Cannot Read Current Volume Position: %v", e)
		return
	}

	if version == Version3 {
		tsOffset := NeedleHeaderSize + size + NeedleChecksumSize
		util.Uint64toBytes(dataSlice[tsOffset:tsOffset+TimestampSize], appendAtNs)
	}

	if err == nil {
		_, err = w.WriteAt(dataSlice, int64(offset))
	}

	return

}