package blob

import (
	"context"
	"io"

	"forge.cadoles.com/arcad/edge/pkg/storage"
	"github.com/pkg/errors"
)

type NewBlobWriterArgs struct {
	BlobID   storage.BlobID
	BucketID BucketID
}

type NewBlobWriterReply struct {
	WriterID WriterID
}

func (s *Service) NewBlobWriter(ctx context.Context, args *NewBlobWriterArgs, reply *NewBlobWriterReply) error {
	bucket, err := s.getOpenedBucket(args.BucketID)
	if err != nil {
		return errors.WithStack(err)
	}

	writerID, err := NewWriterID()
	if err != nil {
		return errors.WithStack(err)
	}

	writer, err := bucket.NewWriter(ctx, args.BlobID)
	if err != nil {
		return errors.WithStack(err)
	}

	s.writers.Store(writerID, writer)

	*reply = NewBlobWriterReply{
		WriterID: writerID,
	}

	return nil
}

func (s *Service) getOpenedWriter(id WriterID) (io.WriteCloser, error) {
	raw, exists := s.writers.Load(id)
	if !exists {
		return nil, errors.Errorf("could not find writer '%s'", id)
	}

	writer, ok := raw.(io.WriteCloser)
	if !ok {
		return nil, errors.Errorf("unexpected type '%T' for writer", raw)
	}

	return writer, nil
}