// Copyright 2022 EMQ Technologies Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package protobuf

import (
	"fmt"
	"github.com/jhump/protoreflect/desc"
	"github.com/jhump/protoreflect/desc/protoparse"
	"strings"
)

type Converter struct {
	descriptor *desc.MessageDescriptor
	fc         *FieldConverter
}

var protoParser *protoparse.Parser

func init() {
	//etcDir, err := conf.GetConfLoc()
	//if err != nil {
	//	panic(err)
	//}
	protoParser = &protoparse.Parser{}
}

func NewConverter(schemaId string, fileName string) (*Converter, error) {
	des := strings.Split(schemaId, ".")
	if len(des) != 2 {
		return nil, fmt.Errorf("invalid schema id %s for protobuf, the format must be protoName.mesageName", schemaId)
	}
	if fds, err := protoParser.ParseFiles(fileName); err != nil {
		return nil, fmt.Errorf("parse schema file %s failed: %s", fileName, err)
	} else {
		messageDescriptor := fds[0].FindMessage(des[1])
		if messageDescriptor == nil {
			return nil, fmt.Errorf("message type %s not found in schema file %s", des[1], fileName)
		}
		return &Converter{
			descriptor: messageDescriptor,
			fc:         GetFieldConverter(),
		}, nil
	}
}

func (c *Converter) Encode(d interface{}) ([]byte, error) {
	switch m := d.(type) {
	case map[string]interface{}:
		msg, err := c.fc.encodeMap(c.descriptor, m)
		if err != nil {
			return nil, err
		}
		return msg.Marshal()
	default:
		return nil, fmt.Errorf("unsupported type %v, must be a map", d)
	}
}

func (c *Converter) Decode(b []byte) (interface{}, error) {
	//TODO implement me
	panic("implement me")
}