package bin

import (
	"bytes"
	"fmt"
	"io"
	"net"

	"google.golang.org/protobuf/proto"
)

func WriteMessage(conn net.Conn, m proto.Message) error {
	data, err := proto.Marshal(m)
	if err != nil {
		return fmt.Errorf("proto.Marshal: %w", err)
	}
	var (
		length = len(data)
		w      = bytes.NewBuffer(nil)
	)
	w.Write([]byte{
		byte(length),
		byte(length >> 8),
	})
	w.Write(data)
	if _, err := conn.Write(w.Bytes()); err != nil {
		return fmt.Errorf("conn.Write: %w", err)
	}
	return nil
}

func ReadMessage(conn net.Conn, m proto.Message) error {
	buf := make([]byte, 2)
	if _, err := io.ReadFull(conn, buf); err != nil {
		return fmt.Errorf("io.ReadFull: %w", err)
	}
	length := int(buf[0]) | (int(buf[1]) << 8)
	buf = make([]byte, length)
	if _, err := io.ReadFull(conn, buf); err != nil {
		return fmt.Errorf("io.ReadFull: %w", err)
	}
	if err := proto.Unmarshal(buf, m); err != nil {
		return fmt.Errorf("proto.Unmarshal: %w", err)
	}
	return nil
}