package dagpb

import (
	"io"

	ld "gitlab.dms3.io/ld/go-ld-prime"
	cidlink "gitlab.dms3.io/ld/go-ld-prime/linking/cid"
	"gitlab.dms3.io/ld/go-ld-prime/multicodec"
	"gitlab.dms3.io/ld/go-ld-prime/traversal"
)

var (
	_ ld.Decoder = Decode
	_ ld.Encoder = Encode
)

func init() {
	multicodec.RegisterDecoder(0x70, Decode)
	multicodec.RegisterEncoder(0x70, Encode)
}

// AddSupportToChooser takes an existing node prototype chooser and subs in
// PBNode for the dag-pb multicodec code.
func AddSupportToChooser(existing traversal.LinkTargetNodePrototypeChooser) traversal.LinkTargetNodePrototypeChooser {
	return func(lnk ld.Link, lnkCtx ld.LinkContext) (ld.NodePrototype, error) {
		if lnk, ok := lnk.(cidlink.Link); ok && lnk.Cid.Prefix().Codec == 0x70 {
			return Type.PBNode, nil
		}
		return existing(lnk, lnkCtx)
	}
}

// We switched to simpler API names after v1.0.0, so keep the old names around
// as deprecated forwarding funcs until a future v2+.
// TODO: consider deprecating Marshal/Unmarshal too, since it's a bit
// unnecessary to have two supported names for each API.

// Deprecated: use Decode instead.
func Decoder(na ld.NodeAssembler, r io.Reader) error { return Decode(na, r) }

// Deprecated: use Decode instead.
func Unmarshal(na ld.NodeAssembler, r io.Reader) error { return Decode(na, r) }

// Deprecated: use Encode instead.
func Encoder(inNode ld.Node, w io.Writer) error { return Encode(inNode, w) }

// Deprecated: use Encode instead.
func Marshal(inNode ld.Node, w io.Writer) error { return Encode(inNode, w) }