Add i3 focus tracking and harden X11 handoff

tests/test_compositor_state_adapter_regressions.py

@@ -11,6 +11,7 @@ import cthulhu as cthulhu_package
 
 from cthulhu import cthulhu_state
 from cthulhu import compositor_state_adapter
+from cthulhu import compositor_state_i3
 from cthulhu import compositor_state_types
 from cthulhu import compositor_state_wayland
 
@@ -74,7 +75,7 @@ class CompositorStateAdapterRegressionTests(unittest.TestCase):
         self.assertTrue(callable(selectedBackend.activate_calls[0]))
         self.assertEqual(adapter.get_snapshot().backend_name, "selected")
 
-    def test_default_workspace_backends_include_wayland_then_null_backend(self) -> None:
+    def test_default_workspace_backends_include_i3_wayland_then_null_backend(self) -> None:
         adapter = compositor_state_adapter.CompositorStateAdapter()
 
         backend_types = [type(backend) for backend in adapter._workspaceBackends]
@@ -82,11 +83,68 @@ class CompositorStateAdapterRegressionTests(unittest.TestCase):
         self.assertEqual(
             backend_types,
             [
+                compositor_state_i3.I3WorkspaceBackend,
                 compositor_state_wayland.WaylandSharedProtocolsBackend,
                 compositor_state_wayland.NullWorkspaceBackend,
             ],
         )
 
+    def test_workspace_payload_records_i3_foreground_context(self) -> None:
+        backend = FakeWorkspaceBackend(True, "i3-ipc")
+        adapter = compositor_state_adapter.CompositorStateAdapter(workspace_backends=[backend])
+
+        adapter.activate()
+        backend.activate_calls[-1](
+            compositor_state_types.WORKSPACE_STATE_CHANGED,
+            {"8"},
+            "i3-window-focus",
+            {
+                "focused_window_id": 0x200000C,
+                "focused_window_title": "9 devel",
+                "focused_workspace_empty": False,
+            },
+        )
+
+        snapshot = adapter.get_snapshot()
+        self.assertEqual(snapshot.active_workspace_ids, frozenset({"8"}))
+        self.assertEqual(snapshot.focused_window_id, 0x200000C)
+        self.assertEqual(snapshot.focused_window_title, "9 devel")
+        self.assertFalse(snapshot.focused_workspace_empty)
+
+    def test_confirmed_empty_workspace_clears_stale_accessible_context(self) -> None:
+        backend = FakeWorkspaceBackend(True, "i3-ipc")
+        adapter = compositor_state_adapter.CompositorStateAdapter(workspace_backends=[backend])
+        adapter.activate()
+        adapter._snapshot = compositor_state_types.DesktopContextSnapshot(
+            session_type="x11",
+            backend_name="i3-ipc",
+            active_window_token="42:Browser",
+            locus_of_focus_token="42:Web content",
+            active_window_pid=42,
+            locus_of_focus_pid=42,
+            active_window_name="Browser",
+            locus_of_focus_name="Web content",
+        )
+
+        backend.activate_calls[-1](
+            compositor_state_types.WORKSPACE_STATE_CHANGED,
+            {"9"},
+            "i3-workspace-focus",
+            {
+                "focused_window_id": None,
+                "focused_window_title": "",
+                "focused_workspace_empty": True,
+            },
+        )
+
+        snapshot = adapter.get_snapshot()
+        self.assertEqual(snapshot.active_window_token, "")
+        self.assertEqual(snapshot.locus_of_focus_token, "")
+        self.assertEqual(snapshot.active_window_pid, -1)
+        self.assertEqual(snapshot.locus_of_focus_pid, -1)
+        self.assertEqual(snapshot.active_window_name, "")
+        self.assertEqual(snapshot.locus_of_focus_name, "")
+
     def test_wayland_backend_is_unavailable_without_wayland_session(self) -> None:
         backend = compositor_state_wayland.WaylandSharedProtocolsBackend()