package blob

import (
	"context"
	"io"

	"github.com/pkg/errors"
)

type ReadBlobArgs struct {
	ReaderID ReaderID
	Length   int
}

type ReadBlobReply struct {
	Data []byte
	Read int
	EOF  bool
}

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

	buff := make([]byte, args.Length)

	read, err := reader.Read(buff)
	if err != nil && !errors.Is(err, io.EOF) {
		return errors.WithStack(err)
	}

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

	return nil
}