s3

type AWSAPI interface {
	GetObject(ctx context.Context, in *awss3.GetObjectInput, optFns ...func(*awss3.Options)) (*awss3.GetObjectOutput, error)
	PutObject(ctx context.Context, in *awss3.PutObjectInput, optFns ...func(*awss3.Options)) (*awss3.PutObjectOutput, error)
	HeadObject(ctx context.Context, in *awss3.HeadObjectInput, optFns ...func(*awss3.Options)) (*awss3.HeadObjectOutput, error)
	DeleteObject(ctx context.Context, in *awss3.DeleteObjectInput, optFns ...func(*awss3.Options)) (*awss3.DeleteObjectOutput, error)
	ListObjectsV2(ctx context.Context, in *awss3.ListObjectsV2Input, optFns ...func(*awss3.Options)) (*awss3.ListObjectsV2Output, error)
	CreateMultipartUpload(
		ctx context.Context, in *awss3.CreateMultipartUploadInput, optFns ...func(*awss3.Options),
	) (*awss3.CreateMultipartUploadOutput, error)
	UploadPart(ctx context.Context, in *awss3.UploadPartInput, optFns ...func(*awss3.Options)) (*awss3.UploadPartOutput, error)
	CompleteMultipartUpload(
		ctx context.Context, in *awss3.CompleteMultipartUploadInput, optFns ...func(*awss3.Options),
	) (*awss3.CompleteMultipartUploadOutput, error)
	AbortMultipartUpload(
		ctx context.Context, in *awss3.AbortMultipartUploadInput, optFns ...func(*awss3.Options),
	) (*awss3.AbortMultipartUploadOutput, error)
}

type Backend struct {
	// contains filtered or unexported fields
}

type MultipartObjectStore interface {
	// CreateMultipartUpload starts an upload for key and returns its id. Nothing is visible under
	// key until CompleteMultipartUpload.
	CreateMultipartUpload(ctx context.Context, key string) (uploadID string, err error)

	// UploadPart stores data as the upload's partNum-th part (1-based) and returns its ETag.
	// Uploading the same part number again replaces it, so a retry by part number is safe.
	UploadPart(ctx context.Context, key, uploadID string, partNum int32, data []byte) (etag string, err error)

	// CompleteMultipartUpload publishes the parts, in etags order, as the object under key.
	CompleteMultipartUpload(ctx context.Context, key, uploadID string, etags []string) error

	// AbortMultipartUpload discards the upload and its parts. It is idempotent.
	AbortMultipartUpload(ctx context.Context, key, uploadID string) error
}

type ObjectStore interface {
	// GetObject returns the object bytes, or an error wrapping [ErrObjectNotFound] if absent.
	GetObject(ctx context.Context, key string) ([]byte, error)

	// PutObject stores data under key, overwriting any existing object.
	PutObject(ctx context.Context, key string, data []byte) error

	// PutObjectIfAbsent stores data under key only if it does not exist, returning whether it
	// was created (the conditional write — S3 If-None-Match: *).
	PutObjectIfAbsent(ctx context.Context, key string, data []byte) (bool, error)

	// PutObjectIfVersion stores data under key only if the object's current ETag is etag, and
	// returns the ETag the object then has. An empty etag demands that the object not exist
	// (If-None-Match: *); a non-empty one is S3's If-Match. ok is false — with a nil error —
	// when the condition did not hold, including an If-Match against an absent key, which S3
	// answers 404 rather than 412.
	PutObjectIfVersion(ctx context.Context, key string, data []byte, etag string) (newETag string, ok bool, err error)

	// GetObjectVersion returns the object bytes and its ETag, or an error wrapping
	// [ErrObjectNotFound] if absent.
	GetObjectVersion(ctx context.Context, key string) ([]byte, string, error)

	// HeadObject reports whether key exists.
	HeadObject(ctx context.Context, key string) (bool, error)

	// DeleteObject removes key. It is idempotent (no error if the key is absent), mirroring
	// S3 DeleteObject.
	DeleteObject(ctx context.Context, key string) error

	// ListObjects returns every key under prefix (the implementation paginates internally).
	// Order is unspecified; the [Backend] sorts.
	ListObjects(ctx context.Context, prefix string) ([]string, error)
}

type Option func(*config)

type RangeObjectStore interface {
	// GetObjectRange returns the object's [off, off+n) bytes, clamped to its end. Absent keys error
	// like [ObjectStore.GetObject].
	GetObjectRange(ctx context.Context, key string, off, n int64) ([]byte, error)
}