conqp.rcon/rcon/gui.py

"""GTK based GUI."""

from argparse import ArgumentParser, Namespace
from json import dump, load
from logging import DEBUG, INFO, basicConfig, getLogger
from os import getenv, name
from pathlib import Path
from socket import timeout
from typing import Iterable, NamedTuple

from gi import require_version
require_version('Gtk', '3.0')
# pylint: disable=C0413
from gi.repository import Gtk

from rcon.config import LOG_FORMAT
from rcon.exceptions import RequestIdMismatch, WrongPassword
from rcon.proto import Client


__all__ = ['main']


if name == 'posix':
    CACHE_DIR = Path.home().joinpath('.cache')
elif name == 'nt':
    CACHE_DIR = Path(getenv('TEMP') or getenv('TMP'))
else:
    raise NotImplementedError('Unsupported operating system.')


CACHE_FILE = CACHE_DIR.joinpath('rcongui.json')
LOGGER = getLogger('rcongui')


def get_args() -> Namespace:
    """Parses the command line arguments."""

    parser = ArgumentParser(description='A minimalistic, GTK-based RCON GUI.')
    parser.add_argument('-d', '--debug', action='store_true',
                        help='print additional debug information')
    parser.add_argument('-t', '--timeout', type=float, metavar='seconds',
                        help='connection timeout in seconds')
    return parser.parse_args()


class RCONParams(NamedTuple):
    """Represents the RCON parameters."""

    host: str
    port: int
    passwd: str
    command: Iterable[str]


class GUI(Gtk.Window):  # pylint: disable=R0902
    """A GTK based GUI for RCON."""

    def __init__(self, args: Namespace):
        """Initializes the GUI."""
        super().__init__(title='RCON GUI')
        self.args = args

        self.set_position(Gtk.WindowPosition.CENTER)

        self.grid = Gtk.Grid()
        self.add(self.grid)

        self.host = Gtk.Entry()
        self.host.set_placeholder_text('Host')
        self.grid.attach(self.host, 0, 0, 1, 1)

        self.port = Gtk.Entry()
        self.port.set_placeholder_text('Port')
        self.grid.attach(self.port, 1, 0, 1, 1)

        self.passwd = Gtk.Entry()
        self.passwd.set_placeholder_text('Password')
        self.passwd.set_visibility(False)
        self.grid.attach(self.passwd, 2, 0, 1, 1)

        self.command = Gtk.Entry()
        self.command.set_placeholder_text('Command')
        self.grid.attach(self.command, 0, 1, 2, 1)

        self.button = Gtk.Button(label='Run')
        self.button.connect('clicked', self.on_button_clicked)
        self.grid.attach(self.button, 2, 1, 1, 1)

        self.result = Gtk.TextView()
        self.result.set_wrap_mode(Gtk.WrapMode.WORD)
        self.grid.attach(self.result, 0, 2, 2, 1)

        self.savepw = Gtk.CheckButton(label='Save password')
        self.grid.attach(self.savepw, 2, 2, 1, 1)

        self.load_gui_settings()

    @property
    def result_text(self) -> str:
        """Returns the result text."""
        if (buf := self.result.get_buffer()) is not None:
            start = buf.get_iter_at_line(0)
            end = buf.get_iter_at_line(buf.get_line_count())
            return buf.get_text(start, end, True)

        return ''

    @result_text.setter
    def result_text(self, text: str):
        """Sets the result text."""
        if (buf := self.result.get_buffer()) is not None:
            buf.set_text(text)

    @property
    def gui_settings(self) -> dict:
        """Returns the GUI settings as a dict."""
        json = {
            'host': self.host.get_text(),
            'port': self.port.get_text(),
            'command': self.command.get_text(),
            'result': self.result_text,
            'savepw': (savepw := self.savepw.get_active())
        }

        if savepw:
            json['passwd'] = self.passwd.get_text()

        return json

    @gui_settings.setter
    def gui_settings(self, json: dict):
        """Sets the GUI settings."""
        self.host.set_text(json.get('host', ''))
        self.port.set_text(json.get('port', ''))
        self.passwd.set_text(json.get('passwd', ''))
        self.command.set_text(json.get('command', ''))
        self.result_text = json.get('result', '')
        self.savepw.set_active(json.get('savepw', False))

    def load_gui_settings(self) -> dict:
        """Loads the GUI settings from the cache file."""
        try:
            with CACHE_FILE.open('r') as cache:
                self.gui_settings = load(cache)
        except FileNotFoundError:
            LOGGER.warning('Cache file not found: %s', CACHE_FILE)
        except PermissionError:
            LOGGER.error('Insufficient permissions to read: %s', CACHE_FILE)
        except ValueError:
            LOGGER.error('Cache file contains garbage: %s', CACHE_FILE)

    def save_gui_settings(self):
        """Saves the GUI settings to the cache file."""
        try:
            with CACHE_FILE.open('w') as cache:
                dump(self.gui_settings, cache)
        except PermissionError:
            LOGGER.error('Insufficient permissions to read: %s', CACHE_FILE)

    def show_error(self, message: str):
        """Shows an error message."""
        message_dialog = Gtk.MessageDialog(
            transient_for=self,
            message_type=Gtk.MessageType.ERROR,
            buttons=Gtk.ButtonsType.OK,
            text=message)
        message_dialog.run()
        message_dialog.destroy()

    def get_rcon_params(self) -> RCONParams:
        """Returns all settings as a dict."""
        if not (host := self.host.get_text().strip()):
            raise ValueError('No host specified.')

        if not (port := self.port.get_text().strip()):
            raise ValueError('No port specified.')

        try:
            port = int(port)
        except ValueError:
            raise ValueError('Invalid port specified.') from None

        if not 0 <= port <= 65535:
            raise ValueError('Invalid port specified.')

        if not (command := self.command.get_text().strip()):
            raise ValueError('No command entered.')

        command = tuple(filter(None, command.split()))
        return RCONParams(host, port, self.passwd.get_text(), command)

    def run_rcon(self) -> str:
        """Returns the current RCON settings."""
        params = self.get_rcon_params()

        with Client(params.host, params.port, timeout=self.args.timeout,
                    passwd=params.passwd) as client:
            return client.run(*params.command)

    def on_button_clicked(self, _):
        """Runs the client."""
        try:
            result = self.run_rcon()
        except ValueError as error:
            self.show_error(str(error))
        except ConnectionRefusedError:
            self.show_error('Connection refused.')
        except (TimeoutError, timeout):
            self.show_error('Connection timed out.')
        except WrongPassword:
            self.show_error('Wrong password.')
        except RequestIdMismatch as mismatch:
            self.show_error(
                'Request ID mismatch.\n'
                f'Expected {mismatch.sent}, but got {mismatch.received}.')
        else:
            self.result_text = result

    def terminate(self, *args, **kwargs):
        """Saves the settings and terminates the application."""
        self.save_gui_settings()
        Gtk.main_quit(*args, **kwargs)


def main() -> None:
    """Starts the GUI."""

    args = get_args()
    basicConfig(format=LOG_FORMAT, level=DEBUG if args.debug else INFO)
    win = GUI(args)
    win.connect('destroy', win.terminate)
    win.show_all()
    Gtk.main()