package grpcall

import (
	"encoding/json"
	"fmt"
	"io"

	"github.com/golang/protobuf/jsonpb"
	"github.com/golang/protobuf/proto"
)

type RequestData func(msg proto.Message) error

type RequestParser interface {
	Next(msg proto.Message) error
}

type JsonRequestParser struct {
	dec         *json.Decoder
	unmarshaler jsonpb.Unmarshaler
}

func (this JsonRequestParser) Next(msg proto.Message) error {
	if err := this.unmarshaler.UnmarshalNext(this.dec, msg); err != nil {
		if err == io.EOF {
			return err
		}

		return fmt.Errorf("unmarshal request json data error, %s", err)
	}
	return nil
}

func NewJsonRequestParser(resolver jsonpb.AnyResolver, in io.Reader) RequestParser {
	return &JsonRequestParser{
		dec:         json.NewDecoder(in),
		unmarshaler: jsonpb.Unmarshaler{AnyResolver: resolver},
	}
}