add toggle focus between floating and tiled layers

Adds focus_floats(), toggle_focus_float_tiled(), and their IPC
bindings so users can bind a key to swap focus between the floating
and tiled layers.

src/config/handler.rs

@@ -2359,6 +2359,18 @@ impl ConfigProxyHandler {
         Ok(())
     }
 
+    fn handle_seat_focus_floats(&self, seat: Seat) -> Result<(), CphError> {
+        let seat = self.get_seat(seat)?;
+        seat.focus_floats();
+        Ok(())
+    }
+
+    fn handle_seat_toggle_focus_float_tiled(&self, seat: Seat) -> Result<(), CphError> {
+        let seat = self.get_seat(seat)?;
+        seat.toggle_focus_float_tiled();
+        Ok(())
+    }
+
     fn handle_set_middle_click_paste_enabled(&self, enabled: bool) {
         self.state.set_primary_selection_enabled(enabled);
     }
@@ -3310,6 +3322,13 @@ impl ConfigProxyHandler {
             ClientMessage::SeatFocusTiles { seat } => {
                 self.handle_seat_focus_tiles(seat).wrn("seat_focus_tiles")?
             }
+            ClientMessage::SeatFocusFloats { seat } => {
+                self.handle_seat_focus_floats(seat).wrn("seat_focus_floats")?
+            }
+            ClientMessage::SeatToggleFocusFloatTiled { seat } => {
+                self.handle_seat_toggle_focus_float_tiled(seat)
+                    .wrn("seat_toggle_focus_float_tiled")?
+            }
             ClientMessage::SetMiddleClickPasteEnabled { enabled } => {
                 self.handle_set_middle_click_paste_enabled(enabled)
             }

src/ifs/wl_seat.rs

@@ -1163,6 +1163,36 @@ impl WlSeatGlobal {
         );
     }
 
+    pub fn toggle_focus_float_tiled(self: &Rc<Self>) {
+        let current = self.keyboard_node.get();
+        match current.node_layer().layer() {
+            NodeLayer::Tiled | NodeLayer::Fullscreen => self.focus_floats(),
+            _ => self.focus_tiles(),
+        }
+        self.maybe_schedule_warp_mouse_to_focus();
+    }
+
+    pub fn focus_floats(self: &Rc<Self>) {
+        let current = self.keyboard_node.get();
+        if current.node_layer().layer() == NodeLayer::Stacked {
+            return;
+        }
+        let Some(output) = current.node_output() else {
+            return;
+        };
+        let Some(ws) = output.workspace.get() else {
+            return;
+        };
+        if let Some(child) = ws
+            .stacked
+            .rev_iter()
+            .filter_map(|node| (*node).clone().node_into_float())
+            .find_map(|float| float.child.get())
+        {
+            child.node_do_focus(self, Direction::Unspecified);
+        }
+    }
+
     pub fn focus_tiles(self: &Rc<Self>) {
         let current = self.keyboard_node.get();
         if matches!(