Activate already open apps instead of running a new copy of them

ulauncher/search/apps/AppSearchMode.py

@@ -1,6 +1,25 @@
+import json
+
+import dbus
+
 from ulauncher.api.shared.action.RenderResultListAction import RenderResultListAction
 from ulauncher.search.BaseSearchMode import BaseSearchMode
 from ulauncher.search.apps.AppDb import AppDb
+from ulauncher.search.apps.AppIconCache import AppIconCache
+from ulauncher.search.apps.AppResultItem import AppResultItem
+from ulauncher.api.shared.action.BaseAction import BaseAction
+
+
+class ActivateAppAction(BaseAction):
+
+    def __init__(self, activate_cb):
+        self.activate_cb = activate_cb
+
+    def keep_app_open(self):
+        return False
+
+    def run(self):
+        self.activate_cb()
 
 
 class AppSearchMode(BaseSearchMode):
@@ -12,6 +31,41 @@ def __init__(self, search_modes):
         self.search_modes = search_modes
         self.app_db = AppDb.get_instance()
 
+        self.app_icon_cache = AppIconCache.get_instance()
+
+        self.bus = dbus.SessionBus()
+
+        obj = self.bus.get_object(
+            'org.gnome.Shell', '/org/gnome/Shell')
+        eval_call = obj.get_dbus_method(
+            'Eval', dbus_interface='org.gnome.Shell')
+
+        self.get_active_windows = lambda: eval_call(r'''
+            Main.Shell.AppSystem.get_default().get_running().map(
+                app => {
+                    return {
+                        id: app.get_id(),
+                    };
+                }
+            )
+        ''')
+
+        self.activate_window = lambda app_id: eval_call(f'''
+            Main.activateWindow(
+                Main.Shell.AppSystem.get_default().lookup_app(
+                    {json.dumps(app_id)}
+                ).get_windows()[0]
+            )
+        ''')
+
+    def patch_on_enter(self, result_item):
+        def new_on_enter(query, old_on_enter=result_item.on_enter):
+            old_on_enter(query)
+            activate = lambda: self.activate_window(
+                result_item.record['desktop_file_short'])
+            return ActivateAppAction(activate)
+        return new_on_enter
+
     def is_enabled(self, query):
         """
         AppSearchMode is a default search mode and is always enabled
@@ -29,4 +83,13 @@ def handle_query(self, query):
             for mode in self.search_modes:
                 result_list.extend(mode.get_default_items())
 
+        status, active_apps = self.get_active_windows()
+        if status:
+            active_apps = {app['id'] for app in json.loads(active_apps)}
+
+            for r in result_list:
+                if isinstance(r, AppResultItem):
+                    if r.record['desktop_file_short'] in active_apps:
+                        r.on_enter = self.patch_on_enter(r)
+
         return RenderResultListAction(result_list)