#
#
#

from __future__ import absolute_import, division, print_function, unicode_literals

from logging import getLogger, INFO as _INFO
_log = getLogger(__name__)
del getLogger


from solaar.i18n import _
from . import configuration
from logitech_receiver import (
				Receiver,
				listener as _listener,
				status as _status,
				notifications as _notifications
			)

#
#
#

from collections import namedtuple
_GHOST_DEVICE = namedtuple('_GHOST_DEVICE', ['receiver', 'number', 'name', 'kind', 'status', 'online'])
_GHOST_DEVICE.__bool__ = lambda self: False
_GHOST_DEVICE.__nonzero__ = _GHOST_DEVICE.__bool__
del namedtuple

def _ghost(device):
	return _GHOST_DEVICE(
					receiver=device.receiver,
					number=device.number,
					name=device.name,
					kind=device.kind,
					status=None,
					online=False)

#
#
#

# how often to poll devices that haven't updated their statuses on their own
# (through notifications)
# _POLL_TICK = 5 * 60  # seconds


class ReceiverListener(_listener.EventsListener):
	"""Keeps the status of a Receiver.
	"""
	def __init__(self, receiver, status_changed_callback):
		super(ReceiverListener, self).__init__(receiver, self._notifications_handler)
		# no reason to enable polling yet
		# self.tick_period = _POLL_TICK
		# self._last_tick = 0

		assert status_changed_callback
		self.status_changed_callback = status_changed_callback
		_status.attach_to(receiver, self._status_changed)

	def has_started(self):
		if _log.isEnabledFor(_INFO):
			_log.info("%s: notifications listener has started (%s)", self.receiver, self.receiver.handle)
		notification_flags = self.receiver.enable_notifications()
		self.receiver.status[_status.KEYS.NOTIFICATION_FLAGS] = notification_flags
		self.receiver.notify_devices()
		self._status_changed(self.receiver)  #, _status.ALERT.NOTIFICATION)

	def has_stopped(self):
		r, self.receiver = self.receiver, None
		assert r is not None
		if _log.isEnabledFor(_INFO):
			_log.info("%s: notifications listener has stopped", r)

		# because udev is not notifying us about device removal,
		# make sure to clean up in _all_listeners
		_all_listeners.pop(r.path, None)

		r.status = _("The receiver was unplugged.")
		if r:
			try:
				r.close()
			except:
				_log.exception("closing receiver %s" % r.path)
		self.status_changed_callback(r)  #, _status.ALERT.NOTIFICATION)

	# def tick(self, timestamp):
	# 	if not self.tick_period:
	# 		raise Exception("tick() should not be called without a tick_period: %s", self)
	#
	# 	# not necessary anymore, we're now using udev monitor to watch for receiver status
	# 	# if self._last_tick > 0 and timestamp - self._last_tick > _POLL_TICK * 2:
	# 	# 	# if we missed a couple of polls, most likely the computer went into
	# 	# 	# sleep, and we have to reinitialize the receiver again
	# 	# 	_log.warn("%s: possible sleep detected, closing this listener", self.receiver)
	# 	# 	self.stop()
	# 	# 	return
	#
	# 	self._last_tick = timestamp
	#
	# 	try:
	# 		# read these in case they haven't been read already
	# 		# self.receiver.serial, self.receiver.firmware
	# 		if self.receiver.status.lock_open:
	# 			# don't mess with stuff while pairing
	# 			return
	#
	# 		self.receiver.status.poll(timestamp)
	#
	# 		# Iterating directly through the reciver would unnecessarily probe
	# 		# all possible devices, even unpaired ones.
	# 		# Checking for each device number in turn makes sure only already
	# 		# known devices are polled.
	# 		# This is okay because we should have already known about them all
	# 		# long before the first poll() happents, through notifications.
	# 		for number in range(1, 6):
	# 			if number in self.receiver:
	# 				dev = self.receiver[number]
	# 				if dev and dev.status is not None:
	# 					dev.status.poll(timestamp)
	# 	except Exception as e:
	# 		_log.exception("polling", e)

	def _status_changed(self, device, alert=_status.ALERT.NONE, reason=None):
		assert device is not None
		if _log.isEnabledFor(_INFO):
			if device.kind is None:
				_log.info("status_changed %s: %s, %s (%X) %s", device,
							'present' if bool(device) else 'removed',
							device.status, alert, reason or '')
			else:
				_log.info("status_changed %s: %s %s, %s (%X) %s", device,
							'paired' if bool(device) else 'unpaired',
							'online' if device.online else 'offline',
							device.status, alert, reason or '')

		if device.kind is None:
			assert device == self.receiver
			# the status of the receiver changed
			self.status_changed_callback(device, alert, reason)
			return

		assert device.receiver == self.receiver
		if not device:
			# Device was unpaired, and isn't valid anymore.
			# We replace it with a ghost so that the UI has something to work
			# with while cleaning up.
			_log.warn("device %s was unpaired, ghosting", device)
			device = _ghost(device)

		self.status_changed_callback(device, alert, reason)

		if not device:
			# the device was just unpaired, need to update the
			# status of the receiver as well
			self.status_changed_callback(self.receiver)

	def _notifications_handler(self, n):
		assert self.receiver
		# if _log.isEnabledFor(_DEBUG):
		# 	_log.debug("%s: handling %s", self.receiver, n)
		if n.devnumber == 0xFF:
			# a receiver notification
			_notifications.process(self.receiver, n)
			return

		# a device notification
		assert n.devnumber > 0 and n.devnumber <= self.receiver.max_devices
		already_known = n.devnumber in self.receiver
		if not already_known and n.sub_id == 0x41:
			dev = self.receiver.register_new_device(n.devnumber, n)
		else:
			dev = self.receiver[n.devnumber]

		if not dev:
			_log.warn("%s: received %s for invalid device %d: %r", self.receiver, n, n.devnumber, dev)
			return

		if not already_known:
			if _log.isEnabledFor(_INFO):
				_log.info("%s triggered new device %s (%s)", n, dev, dev.kind)
			# If there are saved configs, bring the device's settings up-to-date.
			# They will be applied when the device is marked as online.
			configuration.attach_to(dev)
			_status.attach_to(dev, self._status_changed)
			# the receiver changed status as well
			self._status_changed(self.receiver)

		assert dev
		assert dev.status is not None
		_notifications.process(dev, n)
		if self.receiver.status.lock_open and not already_known:
			# this should be the first notification after a device was paired
			assert n.sub_id == 0x41 and n.address == 0x04
			if _log.isEnabledFor(_INFO):
				_log.info("%s: pairing detected new device", self.receiver)
			self.receiver.status.new_device = dev
		elif dev:
			if dev.online is None:
				dev.ping()

	def __str__(self):
		return '<ReceiverListener(%s,%s)>' % (self.receiver.path, self.receiver.handle)
	__unicode__ = __str__

#
#
#

# all known receiver listeners
# listeners that stop on their own may remain here
_all_listeners = {}


def _start(device_info):
	assert _status_callback
	receiver = Receiver.open(device_info)
	if receiver:
		rl = ReceiverListener(receiver, _status_callback)
		rl.start()
		_all_listeners[device_info.path] = rl
		return rl

	_log.warn("failed to open %s", device_info)


def start_all():
	# just in case this it called twice in a row...
	stop_all()

	if _log.isEnabledFor(_INFO):
		_log.info("starting receiver listening threads")
	for device_info in _base.receivers():
		_process_receiver_event('add', device_info)


def stop_all():
	listeners = list(_all_listeners.values())
	_all_listeners.clear()

	if listeners:
		if _log.isEnabledFor(_INFO):
			_log.info("stopping receiver listening threads %s", listeners)

		for l in listeners:
			l.stop()

	configuration.save()

	if listeners:
		for l in listeners:
			l.join()


# stop/start all receiver threads on suspend/resume events, if possible
from . import upower
upower.watch(start_all, stop_all)


from logitech_receiver import base as _base
_status_callback = None
_error_callback = None

def setup_scanner(status_changed_callback, error_callback):
	global _status_callback, _error_callback
	assert _status_callback is None, 'scanner was already set-up'

	_status_callback = status_changed_callback
	_error_callback = error_callback

	_base.notify_on_receivers_glib(_process_receiver_event)


# receiver add/remove events will start/stop listener threads
def _process_receiver_event(action, device_info):
	assert action is not None
	assert device_info is not None
	assert _error_callback

	if _log.isEnabledFor(_INFO):
		_log.info("receiver event %s %s", action, device_info)

	# whatever the action, stop any previous receivers at this path
	l = _all_listeners.pop(device_info.path, None)
	if l is not None:
		assert isinstance(l, ReceiverListener)
		l.stop()

	if action == 'add':
		# a new receiver device was detected
		try:
			_start(device_info)
		except OSError:
			# permission error, ignore this path for now
			_error_callback('permissions', device_info.path)