import urwid
import sys
import serial


class COMScreen(urwid.raw_display.Screen):

    def __init__(self, input=sys.stdin, output=sys.stdout):
        super().__init__(input, output)

    def write(self, data):
        self._log("WRITE: "   " ".join(data)   "\n")
        super().write(data.encode())

    def _getch(self, timeout):
        c = super()._getch(timeout)
        self._log("CHAR: "   str(c))
        return c

    def _log(self, stuff):
        print(stuff)


ser = serial.Serial("/dev/ttyUSB0", baudrate=9600,
                    bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
                    xonxoff=False, rtscts=False)

txt = urwid.Text(u"Hello World")
fill = urwid.Filler(txt, 'top')

with open('/dev/ttyUSB0', 'rb') as inf, open('/dev/ttyUSB0', 'wb') as outf:
    loop = urwid.MainLoop(fill, screen=COMScreen(input=inf, output=outf))
    loop.run()