ui: improved notifications behaviour

Up until now, clicking on a system notification caused several
behaviours depending on the Desktop Environment:
 - On Gnome it executed opensnitch_ui.desktop, which as of today kills
   the running opensnitch-ui process, and relaunches it.
 - On other DEs the notifications was just dismissed.

To improve the first behaviour, the Hint "desktop-entry" has been removed.
Now clicking on a notification on Gnome will bring the main window to the
front if it's opened.

On the other hand a new button has been added to the notifications, to
open the main window if it's not opened, or bring it to the front
otherwise.

ui/opensnitch/notifications.py

@@ -35,7 +35,13 @@ class DesktopNotifications():
     URGENCY_NORMAL = 1
     URGENCY_CRITICAL = 2
 
+    # must be a string
+    ACTION_ID_OPEN = "action-open"
+    ACTION_ID_ALLOW = "action-allow"
+    ACTION_ID_DENY = "action-deny"
+
     def __init__(self):
+        self.ACTION_OPEN = QC.translate("popups", "Open")
         self.ACTION_ALLOW = QC.translate("popups", "Allow")
         self.ACTION_DENY = QC.translate("popups", "Deny")
         self.IS_LIBNOTIFY_AVAILABLE = True
@@ -85,7 +91,7 @@ class DesktopNotifications():
         """
         return self.DOES_SUPPORT_ACTIONS
 
-    def show(self, title, body, icon="dialog-information", urgency=URGENCY_NORMAL):
+    def show(self, title, body, icon="dialog-information", urgency=URGENCY_NORMAL, callback=None):
         try:
             ntf = self.ntf2.Notification(title, body, icon)
 
@@ -99,8 +105,12 @@ class DesktopNotifications():
 
             ntf.set_urgency(urgency)
             ntf.set_category(self.CATEGORY_NETWORK)
-            # used to display our app icon an name.
+            # used to display our app icon and name.
-            ntf.set_hint(self.HINT_DESKTOP_ENTRY, "opensnitch_ui")
+            # Note: setting this Hint causes some DEs to call opensnitch_ui.desktop file,
+            # that as of today, kills and relaunches the current opensnitch-ui process.
+            #ntf.set_hint(self.HINT_DESKTOP_ENTRY, "opensnitch_ui")
+            if self.DOES_SUPPORT_ACTIONS and callback != None:
+                ntf.add_action(self.ACTION_ID_OPEN, self.ACTION_OPEN, callback)
             ntf.show()
         except Exception as e:
             print("[notifications] show() exception:", e)
@@ -124,8 +134,8 @@ class DesktopNotifications():
         ntf.timeout = timeout * 1000
         if self.DOES_SUPPORT_ACTIONS:
             ntf.set_urgency(self.ntf2.URGENCY_CRITICAL)
-            ntf.add_action("allow", self.ACTION_ALLOW, callback, connection)
+            ntf.add_action(self.ACTION_ID_ALLOW, self.ACTION_ALLOW, callback, connection)
-            ntf.add_action("deny", self.ACTION_DENY, callback, connection)
+            ntf.add_action(self.ACTION_ID_DENY, self.ACTION_DENY, callback, connection)
             #ntf.add_action("open-gui", QC.translate("popups", "View"), callback, connection)
         ntf.set_category(self.CATEGORY_NETWORK)
         ntf.set_hint(self.HINT_DESKTOP_ENTRY, "opensnitch_ui")

ui/opensnitch/service.py

@@ -330,6 +330,12 @@ class UIService(ui_pb2_grpc.UIServicer, QtWidgets.QGraphicsObject):
 
     @QtCore.pyqtSlot(str, str, int, int)
     def _show_systray_message(self, title, body, icon, urgency):
+        def callback_open_clicked(notifObject, action):
+            if action == DesktopNotifications.ACTION_ID_OPEN:
+                self._stats_dialog.show()
+                #self._stats_dialog.raise()
+                self._stats_dialog.activateWindow()
+
         if self._desktop_notifications.are_enabled():
             timeout = self._cfg.getInt(Config.DEFAULT_TIMEOUT_KEY, 15)
 
@@ -338,7 +344,8 @@ class UIService(ui_pb2_grpc.UIServicer, QtWidgets.QGraphicsObject):
                     self._desktop_notifications.show(
                         title,
                         body,
-                        os.path.join(self._path, "res/icon-white.svg")
+                        os.path.join(self._path, "res/icon-white.svg"),
+                        callback=callback_open_clicked
                     )
                 except:
                     self._tray.showMessage(title, body, icon, timeout * 1000)