package blob

import (
	"context"
	"io"

	"github.com/pkg/errors"
)

type SeekBlobArgs struct {
	ReaderID ReaderID
	Offset   int64
	Whence   int
}

type SeekBlobReply struct {
	Read int64
	EOF  bool
}

func (s *Service) SeekBlob(ctx context.Context, args *SeekBlobArgs, reply *SeekBlobReply) error {
	reader, err := s.getOpenedReader(args.ReaderID)
	if err != nil {
		return errors.WithStack(err)
	}

	read, err := reader.Seek(args.Offset, args.Whence)
	if err != nil && !errors.Is(err, io.EOF) {
		return errors.WithStack(err)
	}

	*reply = SeekBlobReply{
		Read: read,
		EOF:  errors.Is(err, io.EOF),
	}

	return nil
}