package jsonpb

import (
	"bytes"
	"encoding/json"
	"reflect"

	"github.com/gogo/protobuf/proto"

	"github.com/golang/protobuf/jsonpb"

	"github.com/go-kratos/kratos/v2/encoding"
)

// Name is the name registered for the json codec.
const Name = "jsonpb"

var jsonpbMarshaler *jsonpb.Marshaler

func init() {
	jsonpbMarshaler = &jsonpb.Marshaler{
		EnumsAsInts:  true,
		EmitDefaults: true,
		OrigName:     true,
	}
	encoding.RegisterCodec(codec{})
}

// codec is a Codec implementation with json.
type codec struct{}

func (codec) Marshal(v interface{}) ([]byte, error) {
	if _, ok := v.(proto.Message); ok {
		var buf bytes.Buffer
		err := jsonpbMarshaler.Marshal(&buf, v.(proto.Message))
		if err != nil {
			return nil, err
		}
		return buf.Bytes(), nil
	}
	return json.Marshal(v)
}

func (codec) Unmarshal(data []byte, v interface{}) error {
	rv := reflect.ValueOf(v)
	for rv.Kind() == reflect.Ptr {
		if rv.IsNil() && rv.CanInterface() {
			rv.Set(reflect.New(rv.Type().Elem()))
			v = rv.Interface()
		}
		rv = rv.Elem()
	}
	return json.Unmarshal(data, v)
}

func (codec) Name() string {
	return Name
}