"""One thread owns the USB handle; the GTK main loop never waits for USB."""
from .i18n import tr
import queue
import threading
from gi.repository import GLib
from .controller import Controller
from .transport import DeviceError, Hidraw, discover


class Worker(threading.Thread):
    def __init__(self, callback, *, device_path=None, demo=False):
        super().__init__(name='btd700-usb', daemon=True)
        self.callback = callback
        self.device_path = device_path
        self.demo = demo
        self.commands = queue.Queue()
        self.stopping = threading.Event()
        self.controller = None
        self.transport = None

    def submit(self, method, args, kwargs):
        self.commands.put((method, args, kwargs))

    def stop(self):
        self.stopping.set()
        self.commands.put(None)

    def run(self):
        try:
            while not self.stopping.is_set():
                try:
                    action = self.commands.get(timeout=2)
                except queue.Empty:
                    action = None
                if self.stopping.is_set():
                    break
                error = ''
                try:
                    if self.controller is None:
                        if self.demo:
                            from .demo import DemoTransport
                            self.transport = DemoTransport()
                        else:
                            devices = discover()
                            if self.device_path:
                                devices = [d for d in devices if d.path == self.device_path]
                            if not devices:
                                raise DeviceError(tr('Kein BTD 700 gefunden. Bitte den Dongle einstecken.'))
                            if len(devices) > 1:
                                raise DeviceError(tr('Mehrere BTD 700 gefunden. Mit --device /dev/hidrawN auswählen.'))
                            self.transport = Hidraw(devices[0])
                        self.controller = Controller(self.transport)
                    if action:
                        method, args, kwargs = action
                        try:
                            getattr(self.controller, method)(*args, **kwargs)
                        except (ValueError, DeviceError, TimeoutError) as exc:
                            error = str(exc)
                    status = self.controller.snapshot()
                    GLib.idle_add(self.callback, status, error, bool(action))
                except Exception as exc:
                    if self.transport:
                        self.transport.close()
                    self.transport = self.controller = None
                    GLib.idle_add(self.callback, None, error or str(exc), bool(action))
        finally:
            if self.transport:
                self.transport.close()