# Module to choose and open a serial port
# Written as a telemetry tool by:
# The UoN Robot Wars Project, 2018

def selectserial():

    """Cross-platform function to find appropriate serial ports, query the user if necessary, and open one of them"""

    import platform
    import serial
    import os

    import easygui

    import logging

    
    devpatterns = ['ttyACM', 'ttyUSB', 'rfcomm']
    targetdevs = []
    if platform.system()=='Windows':
        com_ports = ['COM%s' % (i + 1) for i in range(256)]
        for port in com_ports:
            try:
                s = serial.Serial(port)
                s.close()
                targetdevs.append(port)
            except (OSError, serial.SerialException):
                pass
        os='Windows'    #may be useful
    else:
        alldevs = os.listdir("/dev/")
        targetdevs = []
        for dev in alldevs:
            for pattern in devpatterns:
                if pattern in dev:
                    targetdevs.append("/dev/" + dev)
        os='Other'     #may be useful

    if len(targetdevs) == 0:

        return "Sorry, no serial devices found."

    elif len(targetdevs) > 1:

        logging.info("Found multiple serial devices: ")

        for i, dev in enumerate(targetdevs):

            logging.info("  " + str(i) + ": " + dev)

        message = "Please choose a serial port to recieve data through:"
        title = "Found multiple serial ports!"
        serialport = easygui.choicebox(message, title, targetdevs)

        if serialport == None:

            logging.info("User cancelled selection dialogue")
            return None

    else:

        logging.info("Only found one likely serial device: " + targetdevs[0])

        serialport = targetdevs[0]
        

    try:
        datafeed = serial.Serial(
        port=serialport,
        baudrate = 9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS,
        timeout=1
        )

        logging.info("Sucessfully opened " + serialport + " as data source!")

        return datafeed
    except Exception as e:

        logging.critical(str(e))
        return None