kete: export the connected state of the bluez device to the tuhiketedevice

We need this in the live mode as the connection will be longer than
the usual retrieval of the data.

tools/kete.py

@@ -164,6 +164,17 @@ class _DBusSystemObject(_DBusObject):
 class BlueZDevice(_DBusSystemObject):
     def __init__(self, objpath):
         super().__init__('org.bluez', ORG_BLUEZ_DEVICE1, objpath)
+        self.proxy.connect('g-properties-changed', self._on_properties_changed)
+
+    @GObject.Property
+    def connected(self):
+        return self.proxy.get_cached_property('Connected').unpack()
+
+    def _on_properties_changed(self, obj, properties, invalidated_properties):
+        properties = properties.unpack()
+
+        if 'Connected' in properties:
+            self.notify('connected')
 
 
 class TuhiKeteDevice(_DBusObject):
@@ -174,6 +185,7 @@ class TuhiKeteDevice(_DBusObject):
         self.manager = manager
         self.is_registering = False
         self._bluez_device = BlueZDevice(self.property('BlueZDevice'))
+        self._bluez_device.connect('notify::connected', self._on_connected)
 
     @classmethod
     def is_device_address(cls, string):
@@ -205,6 +217,13 @@ class TuhiKeteDevice(_DBusObject):
     def battery_state(self):
         return self.property('BatteryState')
 
+    @GObject.Property
+    def connected(self):
+        return self._bluez_device.connected
+
+    def _on_connected(self, bluez_device, pspec):
+        self.notify('connected')
+
     def register(self):
         logger.debug(f'{self}: Register')
         # FIXME: Register() doesn't return anything useful yet, so we wait until