package daemonconn

import (
	"encoding/json"
	"errors"
	"net"
)

type Message interface {
	TypeID() uint32
}

type DaemonConn struct {
	FrameReadWriter
}

func FromConn(conn net.Conn) DaemonConn {
	return DaemonConn{FrameReadWriter{conn}}
}

func (dc DaemonConn) ReadMessage() (Message, error) {
	frame, err := dc.FrameReadWriter.ReadFrame()
	if err != nil {
		return nil, err
	}

	var msg Message

	switch frame.Type() {
	case MessageTypeEchoRequest:
		msg, err = frameToMessage[EchoRequest](frame)
	case MessageTypeEchoResponse:
		msg, err = frameToMessage[EchoResponse](frame)
	default:
		err = errors.New("unknown frame type")
	}

	if err != nil {
		return nil, err
	}

	return msg, nil
}

func (dc DaemonConn) WriteMessage(msg Message) error {
	msgBytes, err := json.Marshal(msg)
	if err != nil {
		return err
	}

	f := frame{typeID: msg.TypeID(), valueBytes: msgBytes}
	err = dc.WriteFrame(f)
	if err != nil {
		return err
	}

	return nil
}

func frameToMessage[M Message](frame Frame) (Message, error) {
	var msg M

	err := json.Unmarshal(frame.Value(), &msg)
	if err != nil {
		return nil, err
	}

	return msg, nil
}