import serial
import threading
from time import sleep

class SelfHealingSerial():
    """A wrapper class for pyserial's Serial class

    This reimplements the basic Serial functions but wraps them in _reestablish_and_retry.
    This attempts a reconnect if the arduino is unplugged or otherwise unavailable.

    Also this has defaults that work with the Adafruit M0 LoRa feather.
    """
    def __init__(self, path: str = '/dev/ttyACM0', baudrate: int = 115200, timeout: int = 2):
        self._path = path
        self._baudrate = baudrate
        self._timeout = timeout
        self._connection = None
        self._waiting_response = False

    def _establish_connection(self):
        """Connects to the feather
        """
        self._connection = serial.Serial(self._path, self._baudrate, timeout=self._timeout)

    def _reestablish_and_retry(func):
        """If disconnect, keep trying every second

        We know if there's a disconnect when the attempted function fails.
        """
        def wrapper(self: "SelfHealingSerial", *args, **kwargs):
            while True:
                try:
                    if not self._connection:
                        self._establish_connection()
                    return func(self, *args, **kwargs)
                except (IOError, serial.serialutil.SerialException):
                    print("Connection failed.")
                    sleep(1)
                    print("Reestablishing connection.")
                    self._connection = False
        return wrapper

    @_reestablish_and_retry
    def read_all(self):
        """Read all data from the serial port
        """
        return self._connection.read_all()

    @_reestablish_and_retry
    def write(self, bytestring: bytes):
        """Write to the serial port
        """
        self._waiting_response = True
        return self._connection.write(bytestring)

def print_serial(serial_obj: SelfHealingSerial):
    """Check for new serial output and print it to the terminal
    """
    while True:
        line = serial_obj.read_all()
        if line:
            serial_obj._waiting_response = False
            print("\n" + line.decode() + "\n>>>", end="")

def write_serial(serial_obj: SelfHealingSerial):
    """If we're not waiting for a response, write data to the serial port, then wait for a response.
    """
    while True:
        if not serial_obj._waiting_response:
            send_string = input("")
            if send_string and send_string != '\n' and send_string != '\r\n':
                serial_obj.write(send_string.encode('utf-8'))
        else:
            sleep(1)

if __name__ == "__main__":
    connection: SelfHealingSerial = SelfHealingSerial('/dev/ttyACM0', 115200, timeout=1)
    listen_thread = threading.Thread(target=print_serial, args=(connection,))
    listen_thread.start()
    print(">>> ", end="")

    write_serial(connection)