"""Tool used to reset a Arduino Leonardo board."""
from os import O_NDELAY, O_NOCTTY, O_RDWR, open as os_open, close as os_close
import sys
from termios import (
    B1200,
    TCSANOW,
    TIOCM_DTR,
    TIOCM_RTS,
    TIOCMBIC,
    TIOCMBIS,
    tcgetattr,
    tcsetattr
)
from fcntl import ioctl
from argparse import ArgumentParser
from dataclasses import dataclass
from pathlib import Path
from struct import pack
from time import sleep


@dataclass
class ParsedArguments:
    """Parsed command-line arguments."""
    serial_port: Path


class TTYAttributes:
    """TTY attributes."""

    def __init__(self, tty_fd: int):
        """Initializes the TTY attributes."""
        self.__tty_fd = tty_fd
        self.__attrs = tcgetattr(tty_fd)

    @property
    def ispeed(self):
        """The ispeed."""
        return self.__attrs[4]

    @ispeed.setter
    def ispeed(self, ispeed: int):
        self.__attrs[4] = ispeed

    @property
    def ospeed(self):
        """The ospeed."""
        return self.__attrs[5]

    @ospeed.setter
    def ospeed(self, ospeed: int):
        self.__attrs[5] = ospeed

    def set(self):
        """Sets the TTY attributes."""
        tcsetattr(self.__tty_fd, TCSANOW, self.__attrs)


RESET_BAUD_RATE = B1200

DESCRIPTION = "Tool used to reset a Arduino Leonardo board."


def main():
    """Main."""
    parser = ArgumentParser(allow_abbrev=False, description=DESCRIPTION)

    parser.add_argument(
        "serial_port",
        type=Path,
        help="The serial port for a Arduino Leonardo board"
    )

    arguments = parser.parse_args(namespace=ParsedArguments)

    is_serial_port_char_device = arguments.serial_port.is_char_device()

    # Verify that the serial port exists
    if not arguments.serial_port.is_file() and not is_serial_port_char_device:
        print("Error: The serial port file doesn't exist")
        sys.exit(1)

    # Verify that the serial port is a character device
    if not is_serial_port_char_device:
        print("Error: The serial port file is not a character device")
        sys.exit(1)

    serial_port_fd = os_open(
        str(arguments.serial_port),
        O_RDWR | O_NOCTTY | O_NDELAY
    )

    tty_attributes = TTYAttributes(serial_port_fd)

    tty_attributes.ispeed = RESET_BAUD_RATE
    tty_attributes.ospeed = RESET_BAUD_RATE

    tty_attributes.set()

    ioctl(serial_port_fd, TIOCMBIS, pack("I", TIOCM_RTS))
    ioctl(serial_port_fd, TIOCMBIC, pack("I", TIOCM_DTR))

    os_close(serial_port_fd)

    sleep(1.98)


if __name__ == "__main__":
    main()