import serial
import struct
from usb_pb2 import UsbPackageType
from serial.tools import list_ports


def make_header(typeid: UsbPackageType, length: int) -> bytearray: 
    struct_format = '<HHB'  # '<' for little-endian, 'H' for uint16_t, 'B' for uint8_t
    # Calculate the check byte as the sum of length and type
    typeidint = int(typeid) 
    check = (length & 0xFF) + ((length >> 8) & 0xFF) + (typeidint & 0xFF) + ((typeidint >> 8) & 0xFF)
    packed_data = struct.pack(struct_format, length, typeid, check)
    return packed_data

def send_package(typeid : UsbPackageType, data: bytearray, serial: serial.Serial):
    head = make_header(typeid, len(data))
    package = head + data
    serial.write(package)


def setup_connection() -> serial.Serial: 
    stm_port = None
    for port in list_ports.comports():
        print(port)
        if "STM32 Virtual ComPort" in port.description:
            stm_port = port.device
            break

    if stm_port is None:
        print("STM32 Virtual ComPort not found")
        exit(-1)
    else:
        # Open the serial port
        ser = serial.Serial(stm_port,baudrate=5000000)
        return ser