"""Serial monitor."""
import argparse
import sys
import asyncio
import os

if os.name == "nt":  # NT-based operating systems (Windows)
    from serial.serialwin32 import Serial
elif os.name == "posix":
    from serial.serialposix import Serial
else:
    raise NotImplementedError(
        "Sorry no implementation for your platform ({}) available."
        .format(sys.platform)
    )


async def read(port: str, baud_rate: int):
    """Reads a serial port."""
    with Serial(port, baud_rate) as serial_port:
        while(serial_port.is_open):
            sys.stdout.buffer.write(serial_port.read())
            sys.stdout.flush()


async def main():
    """Monitors serial output."""
    parser = argparse.ArgumentParser(
        description="A tool for monitoring a Arduino")

    parser.add_argument(
        "port", help="A serial device port e.g. /dev/ttyACM0 or com3")
    parser.add_argument("baud_rate", help="The serial device baud rate")

    args = parser.parse_args()

    await read(args.port, args.baud_rate)

if __name__ == "__main__":
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        print("\nReceived keyboard interrupt. Exiting...")
        exit(0)