#!/usr/bin/env python3
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#

import argparse
import enum
import logging
import sys
import time
from gi.repository import GObject

from tuhi.dbusserver import TuhiDBusServer
from tuhi.ble import BlueZDeviceManager
from tuhi.wacom import WacomDevice
from tuhi.config import TuhiConfig

logging.basicConfig(format='%(levelname)s: %(name)s: %(message)s',
                    level=logging.INFO)
logger = logging.getLogger('tuhi')

WACOM_COMPANY_ID = 0x4755


class TuhiDevice(GObject.Object):
    '''
    Glue object to combine the backend bluez DBus object (that talks to the
    real device) with the frontend DBusServer object that exports the device
    over Tuhi's DBus interface
    '''

    class BatteryState(enum.Enum):
        UNKNOWN = 0
        CHARGING = 1
        DISCHARGING = 2

    __gsignals__ = {
        # Signal sent when an error occurs on the device itself.
        # Argument is a Wacom*Exception
        'device-error':
            (GObject.SIGNAL_RUN_FIRST, None, (GObject.TYPE_PYOBJECT,)),
    }

    BATTERY_UPDATE_MIN_INTERVAL = 300

    def __init__(self, bluez_device, config, uuid=None, paired=True):
        GObject.Object.__init__(self)
        self.config = config
        self._wacom_device = None
        # We need either uuid or paired as false
        assert uuid is not None or paired is False
        self.paired = paired
        self._uuid = uuid
        self._battery_state = TuhiDevice.BatteryState.UNKNOWN
        self._battery_percent = 0
        self._last_battery_update_time = 0
        self._battery_timer_source = None

        bluez_device.connect('connected', self._on_bluez_device_connected)
        bluez_device.connect('disconnected', self._on_bluez_device_disconnected)
        self._bluez_device = bluez_device

        self._tuhi_dbus_device = None

    @GObject.Property
    def paired(self):
        return self._paired

    @paired.setter
    def paired(self, paired):
        self._paired = paired

    @property
    def name(self):
        return self._bluez_device.name

    @property
    def address(self):
        return self._bluez_device.address

    @property
    def dbus_device(self):
        return self._tuhi_dbus_device

    @dbus_device.setter
    def dbus_device(self, device):
        assert self._tuhi_dbus_device is None
        self._tuhi_dbus_device = device
        self._tuhi_dbus_device.connect('pair-requested', self._on_pair_requested)
        self._tuhi_dbus_device.connect('notify::listening', self._on_listening_updated)

        drawings = self.config.load_drawings(self.address)
        if drawings:
            logger.debug(f'{self.address}: loaded {len(drawings)} drawings from disk')
        for d in drawings:
            self._tuhi_dbus_device.add_drawing(d)

    @GObject.Property
    def listening(self):
        return self._tuhi_dbus_device.listening

    @GObject.Property
    def battery_percent(self):
        return self._battery_percent

    @battery_percent.setter
    def battery_percent(self, value):
        self._battery_percent = value

    @GObject.Property
    def battery_state(self):
        return self._battery_state

    @battery_state.setter
    def battery_state(self, value):
        self._battery_state = value

    def connect_device(self):
        self._bluez_device.connect_device()

    def _on_bluez_device_connected(self, bluez_device):
        logger.debug(f'{bluez_device.address}: connected')
        if self._wacom_device is None:
            self._wacom_device = WacomDevice(bluez_device, self._uuid)
            self._wacom_device.connect('drawing', self._on_drawing_received)
            self._wacom_device.connect('done', self._on_fetching_finished, bluez_device)
            self._wacom_device.connect('button-press-required', self._on_button_press_required)
            self._wacom_device.connect('notify::uuid', self._on_uuid_updated, bluez_device)
            self._wacom_device.connect('battery-status', self._on_battery_status, bluez_device)

        self._wacom_device.start(not self.paired)
        self.pairing_mode = False

    def _on_bluez_device_disconnected(self, bluez_device):
        logger.debug(f'{bluez_device.address}: disconnected')

    def _on_pair_requested(self, dbus_device):
        if self.paired:
            return

        self.connect_device()

    def _on_drawing_received(self, device, drawing):
        logger.debug('Drawing received')
        self._tuhi_dbus_device.add_drawing(drawing)
        self.config.store_drawing(self.address, drawing)

    def _on_fetching_finished(self, device, exception, bluez_device):
        bluez_device.disconnect_device()
        if exception is not None:
            logger.info(exception)
            self.emit('device-error', exception)

    def _on_button_press_required(self, device):
        self._tuhi_dbus_device.notify_button_press_required()

    def _on_uuid_updated(self, wacom_device, pspec, bluez_device):
        self.config.new_device(bluez_device.address, wacom_device.uuid)
        self.paired = True

    def _on_listening_updated(self, dbus_device, pspec):
        self.notify('listening')

    def _on_battery_status(self, wacom_device, percent, is_charging, bluez_device):
        if is_charging:
            self.battery_state = TuhiDevice.BatteryState.CHARGING
        else:
            self.battery_state = TuhiDevice.BatteryState.DISCHARGING
        self.battery_percent = percent

        # If we don't get battery updates for a while, switch the state
        # to unknown
        if self._battery_timer_source is not None:
            GObject.source_remove(self._battery_timer_source)
        self._battery_timer_source = \
            GObject.timeout_add_seconds(self.BATTERY_UPDATE_MIN_INTERVAL,
                                        self._on_battery_timeout)
        self._last_battery_update_time = time.time()

    def _on_battery_timeout(self):
        if self._last_battery_update_time < time.time() - self.BATTERY_UPDATE_MIN_INTERVAL:
            self.battery_state = TuhiDevice.BatteryState.UNKNOWN
        self._battery_timer_source = None  # gets auto-destroyed
        return False


class Tuhi(GObject.Object):
    __gsignals__ = {
        'device-added':
            (GObject.SIGNAL_RUN_FIRST, None, (GObject.TYPE_PYOBJECT,)),
        'device-connected':
            (GObject.SIGNAL_RUN_FIRST, None, (GObject.TYPE_PYOBJECT,)),
    }

    def __init__(self):
        GObject.Object.__init__(self)
        self.server = TuhiDBusServer()
        self.server.connect('bus-name-acquired', self._on_tuhi_bus_name_acquired)
        self.server.connect('bus-name-lost', self._on_tuhi_bus_name_lost)
        self.server.connect('search-start-requested', self._on_start_search_requested)
        self.server.connect('search-stop-requested', self._on_stop_search_requested)
        self.bluez = BlueZDeviceManager()
        self.bluez.connect('device-added', self._on_bluez_device_updated)
        self.bluez.connect('device-updated', self._on_bluez_device_updated)
        self.bluez.connect('discovery-started', self._on_bluez_discovery_started)
        self.bluez.connect('discovery-stopped', self._on_bluez_discovery_stopped)

        self.config = TuhiConfig()

        self.devices = {}

        self._search_stop_handler = None
        self.mainloop = GObject.MainLoop()

    def _on_tuhi_bus_name_acquired(self, dbus_server):
        self.bluez.connect_to_bluez()

    def _on_tuhi_bus_name_lost(self, dbus_server):
        self.mainloop.quit()

    def _on_start_search_requested(self, dbus_server, stop_handler):
        self._search_stop_handler = stop_handler
        self.bluez.start_discovery()

    def _on_stop_search_requested(self, dbus_server):
        # If you request to stop, you get a successful stop and we ignore
        # anything the server does underneath
        self._search_stop_handler(0)
        self._search_stop_handler = None
        self.bluez.stop_discovery()
        self._search_device_handler = None

    @classmethod
    def _is_pairing_device(cls, bluez_device):
        if bluez_device.vendor_id != WACOM_COMPANY_ID:
            return False

        manufacturer_data = bluez_device.get_manufacturer_data(WACOM_COMPANY_ID)
        return manufacturer_data is not None and len(manufacturer_data) == 4

    def _on_bluez_discovery_started(self, manager):
        # Something else may turn discovery mode on, we don't care about
        # it then
        if not self._search_stop_handler:
            return

    def _on_bluez_discovery_stopped(self, manager):
        if self._search_stop_handler is not None:
            self._search_stop_handler(0)

        # restart discovery if some users are already in the listening mode
        self._on_listening_updated(None, None)

    def _on_bluez_device_updated(self, manager, bluez_device, event=True):
        uuid = None

        # check if the device is already known by us
        try:
            config = self.config.devices[bluez_device.address]
            uuid = config['uuid']
        except KeyError:
            pass

        if uuid is None and bluez_device.vendor_id != WACOM_COMPANY_ID:
            return

        # if event is set, the device has been 'hotplugged' in the bluez stack
        # so ManufacturerData is reliable. Else, consider the device not in
        # the pairing mode
        pairing_device = False
        if event:
            pairing_device = Tuhi._is_pairing_device(bluez_device)

        if not pairing_device:
            if uuid is None:
                logger.info(f'{bluez_device.address}: device without config, must be paired first')
                return
            logger.debug(f'{bluez_device.address}: UUID {uuid}')

        # create the device if unknown from us
        if bluez_device.address not in self.devices:
                d = TuhiDevice(bluez_device, self.config, uuid=uuid, paired=not pairing_device)
                d.dbus_device = self.server.create_device(d)
                d.connect('notify::listening', self._on_listening_updated)
                self.devices[bluez_device.address] = d

        d = self.devices[bluez_device.address]

        if pairing_device:
            d.paired = False
            logger.debug(f'{bluez_device.objpath}: call Pair() on device')
        elif d.listening:
            d.connect_device()

    def _on_listening_updated(self, tuhi_dbus_device, pspec):
        listen = False
        for dev in self.devices.values():
            if dev.listening:
                listen = True
                break

        if listen:
            self.bluez.start_discovery()
        else:
            self.bluez.stop_discovery()

    def run(self):
        self.mainloop.run()


def main(args=sys.argv):
    desc = 'Daemon to extract the pen stroke data from Wacom SmartPad devices'
    parser = argparse.ArgumentParser(description=desc)
    parser.add_argument('-v', '--verbose',
                        help='Show some debugging informations',
                        action='store_true',
                        default=False)

    ns = parser.parse_args(args[1:])
    if ns.verbose:
        logger.setLevel(logging.DEBUG)

    try:
        Tuhi().run()
    except KeyboardInterrupt:
        pass
    finally:
        pass