// object storage it will have the following parameters as constants.
//
//	maxPartsCount - 10000
//	maxMultipartPutObjectSize - 5TiB
func optimalPartSize(objectSize int64) (partSize int64, err error) {
	// object size is '-1' set it to 5TiB.
	if objectSize == -1 {
		objectSize = maxMultipartPutObjectSize
	}

	// object size is larger than supported maximum.

type WarmBackendGetOpts struct {
	startOffset int64
	length      int64
}

// WarmBackend provides interface to be implemented by remote tier backends
type WarmBackend interface {
	Put(ctx context.Context, object string, r io.Reader, length int64) (remoteVersionID, error)
	PutWithMeta(ctx context.Context, object string, r io.Reader, length int64, meta map[string]string) (remoteVersionID, error)

// ShardFileSize - returns final erasure size from original size.
func (e ErasureInfo) ShardFileSize(totalLength int64) int64 {
	if totalLength == 0 {
		return 0
	}
	if totalLength == -1 {
		return -1
	}
	numShards := totalLength / e.BlockSize
	lastBlockSize := totalLength % e.BlockSize
	lastShardSize := ceilFrac(lastBlockSize, int64(e.DataBlocks))
	return numShards*e.ShardSize() + lastShardSize
}

}

// commonTime returns a maximally occurring time from a list of time.
func commonTimeAndOccurrence(times []time.Time, group time.Duration) (maxTime time.Time, maxima int) {
	timeOccurrenceMap := make(map[int64]int, len(times))
	groupNano := group.Nanoseconds()
	// Ignore the uuid sentinel and count the rest.
	for _, t := range times {
		if t.Equal(timeSentinel) || t.IsZero() {
			continue
		}
		nano := t.UnixNano()

	destObj := object
	if s3.Prefix != "" {
		destObj = fmt.Sprintf("%s/%s", s3.Prefix, object)
	}
	return destObj
}

func (s3 *warmBackendS3) PutWithMeta(ctx context.Context, object string, r io.Reader, length int64, meta map[string]string) (remoteVersionID, error) {
	res, err := s3.client.PutObject(ctx, s3.Bucket, s3.getDest(object), r, length, minio.PutObjectOptions{
		SendContentMd5: true,
		StorageClass:   s3.StorageClass,

	destObj := object
	if az.Prefix != "" {
		destObj = fmt.Sprintf("%s/%s", az.Prefix, object)
	}
	return destObj
}

func (az *warmBackendAzure) PutWithMeta(ctx context.Context, object string, r io.Reader, length int64, meta map[string]string) (remoteVersionID, error) {
	azMeta := map[string]*string{}
	for k, v := range meta {
		azMeta[k] = to.Ptr(v)
	}

	destObj := object
	if gcs.Prefix != "" {
		destObj = fmt.Sprintf("%s/%s", gcs.Prefix, object)
	}
	return destObj
}

func (gcs *warmBackendGCS) PutWithMeta(ctx context.Context, key string, data io.Reader, length int64, meta map[string]string) (remoteVersionID, error) {
	object := gcs.client.Bucket(gcs.Bucket).Object(gcs.getDest(key))
	w := object.NewWriter(ctx)
	if gcs.StorageClass != "" {
		w.ObjectAttrs.StorageClass = gcs.StorageClass
	}

// buffer becomes too large, ReadFrom will panic with [ErrTooLarge].
func (b *Buffer) ReadFrom(r io.Reader) (n int64, err error) {
	b.lastRead = opInvalid
	for {
		i := b.grow(MinRead)
		b.buf = b.buf[:i]
		m, e := r.Read(b.buf[i:cap(b.buf)])
		if m < 0 {
			panic(errNegativeRead)
		}

		b.buf = b.buf[:i+m]
		n += int64(m)
		if e == io.EOF {
			return n, nil // e is EOF, so return nil explicitly
		}
		if e != nil {

	fmt.Fprint(w, "Hello, ")
	fmt.Fprint(w, "world!")
	w.Flush() // Don't forget to flush!
	// Output: Hello, world!
}

func ExampleWriter_AvailableBuffer() {
	w := bufio.NewWriter(os.Stdout)
	for _, i := range []int64{1, 2, 3, 4} {
		b := w.AvailableBuffer()
		b = strconv.AppendInt(b, i, 10)
		b = append(b, ' ')
		w.Write(b)
	}
	w.Flush()
	// Output: 1 2 3 4
}

	w.buf = append(w.buf, p...)
	w.writeBytes += len(p)
	return len(p), nil
}

func (w *readFromWriter) ReadFrom(r io.Reader) (int64, error) {
	b, err := io.ReadAll(r)
	w.buf = append(w.buf, b...)
	w.readFromBytes += len(b)
	return int64(len(b)), err
}

// Test that calling (*Writer).ReadFrom with a partially-filled buffer
// fills the buffer before switching over to ReadFrom.