major refactoring :/

packet.go

@@ -8,16 +8,18 @@ import (
 )
 
 const (
-	RemoteGetState      = uint16(0x01)
-	RemoteHandleMessage = uint16(0x02)
-	ResponseBody        = uint16(0x03)
+	RemoteGetState           = uint16(0x01)
+	RemoteHandleMessage      = uint16(0x02)
+	ResponseBody             = uint16(0x03)
+	RemoteGetStateReply      = uint16(0x04)
+	RemoteHandleMessageReply = uint16(0x05)
 )
 
 type CartPacket struct {
 	Version     uint16
 	MessageType uint16
-	Id          CartId
 	DataLength  uint16
+	Id          CartId
 }
 
 type Packet struct {
@@ -37,8 +39,8 @@ func SendCartPacket(conn io.Writer, id CartId, messageType uint16, datafn func(w
 	binary.Write(conn, binary.LittleEndian, CartPacket{
 		Version:     2,
 		MessageType: messageType,
-		Id:          id,
 		DataLength:  uint16(len(data)),
+		Id:          id,
 	})
 	_, err = conn.Write(data)
 	return err
@@ -86,19 +88,29 @@ func SendProxyResponse(conn io.Writer, data any) error {
 	})
 }
 
+func ReadPacket[V Packet | CartPacket](conn io.Reader, packet *V) error {
+	return binary.Read(conn, binary.LittleEndian, packet)
+}
+
+func GetPacketData(conn io.Reader, len int) ([]byte, error) {
+	data := make([]byte, len)
+	l, err := conn.Read(data)
+	if l != len {
+		return nil, fmt.Errorf("expected %d bytes, got %d", len, l)
+	}
+	return data, err
+}
+
 func ReceivePacket(conn io.Reader) (uint16, []byte, error) {
 	var packet Packet
-	err := binary.Read(conn, binary.LittleEndian, &packet)
+	err := ReadPacket(conn, &packet)
 	if err != nil {
 		return packet.MessageType, nil, err
 	}
-	data := make([]byte, packet.DataLength)
-	l, err := conn.Read(data)
+
+	data, err := GetPacketData(conn, int(packet.DataLength))
 	if err != nil {
 		return packet.MessageType, nil, err
 	}
-	if l != int(packet.DataLength) {
-		return packet.MessageType, nil, fmt.Errorf("expected %d bytes, got %d", packet.DataLength, l)
-	}
 	return packet.MessageType, data, nil
 }