shell: Allow moving groups between outputs

src/shell/layout/tiling/mod.rs

@@ -640,6 +640,7 @@ impl TilingLayout {
         seat: &Seat<State>,
         focus_stack: impl Iterator<Item = &'a CosmicMapped> + 'a,
         desc: NodeDesc,
+        direction: Option<Direction>,
     ) -> Option<KeyboardFocusTarget> {
         let this_handle = &desc.handle;
         let mut this_tree = this.queue.trees.back().unwrap().0.copy_clone();
@@ -678,7 +679,7 @@ impl TilingLayout {
                 }
 
                 mapped.set_tiled(true);
-                other.map(mapped.clone(), Some(focus_stack), None);
+                other.map(mapped.clone(), Some(focus_stack), direction);
                 return Some(KeyboardFocusTarget::Element(mapped));
             }
             None => {
@@ -702,7 +703,12 @@ impl TilingLayout {
                             })
                             .map(|(id, _)| id)
                             .unwrap_or(other_tree.root_node_id().unwrap().clone());
-                        let orientation = {
+                        let orientation = if let Some(direction) = direction {
+                            match direction {
+                                Direction::Left | Direction::Right => Orientation::Vertical,
+                                Direction::Up | Direction::Down => Orientation::Horizontal,
+                            }
+                        } else {
                             let window_size = other_tree
                                 .get(&focused_node)
                                 .unwrap()
@@ -718,6 +724,15 @@ impl TilingLayout {
                         let id = other_tree.insert(node, InsertBehavior::AsRoot).unwrap();
                         TilingLayout::new_group(&mut other_tree, &focused_node, &id, orientation)
                             .unwrap();
+                        other_tree
+                            .make_nth_sibling(
+                                &id,
+                                match direction {
+                                    Some(Direction::Right) | Some(Direction::Down) => 0,
+                                    _ => 1,
+                                },
+                            )
+                            .unwrap();
                         id
                     }
                 };
@@ -3762,6 +3777,14 @@ impl TilingLayout {
         })
     }
 
+    pub fn element_for_node(&self, node: &NodeId) -> Option<&CosmicMapped> {
+        let tree = &self.queue.trees.back().unwrap().0;
+        tree.get(node).ok().and_then(|node| match node.data() {
+            Data::Mapped { mapped, .. } => Some(mapped),
+            _ => None,
+        })
+    }
+
     pub fn has_node(&self, node: &NodeId) -> bool {
         let tree = &self.queue.trees.back().unwrap().0;
         tree.root_node_id()

src/shell/mod.rs

@@ -2518,23 +2518,79 @@ impl Shell {
             .ok_or(InvalidWorkspaceIndex)?;
 
         let from_workspace = self.workspaces.active_mut(from_output);
-        let maybe_window = from_workspace.focus_stack.get(seat).last().cloned();
-
-        let Some(mapped) = maybe_window else {
-            return Ok(None);
-        };
-
+        let last_focused_window = from_workspace.focus_stack.get(seat).last().cloned();
         let from = from_workspace.handle;
 
-        Ok(self.move_window(
-            Some(seat),
-            &mapped,
-            &from,
-            &to,
-            follow,
-            direction,
-            workspace_state,
-        ))
+        match seat.get_keyboard().unwrap().current_focus() {
+            Some(KeyboardFocusTarget::Group(WindowGroup {
+                node, focus_stack, ..
+            })) => {
+                let new_pos = if follow {
+                    seat.set_active_output(&to_output);
+                    self.workspaces
+                        .idx_for_handle(&to_output, &to)
+                        .and_then(|to_idx| {
+                            self.activate(
+                                &to_output,
+                                to_idx,
+                                WorkspaceDelta::new_shortcut(),
+                                workspace_state,
+                            )
+                            .unwrap()
+                        })
+                } else {
+                    None
+                };
+
+                let spaces = self.workspaces.spaces_mut();
+                let (mut from_w, mut other_w) = spaces.partition::<Vec<_>, _>(|w| w.handle == from);
+                if let Some(from_workspace) = from_w.get_mut(0) {
+                    if let Some(to_workspace) = other_w.iter_mut().find(|w| w.handle == to) {
+                        {
+                            let mut stack = to_workspace.focus_stack.get_mut(&seat);
+                            for elem in focus_stack.iter().flat_map(|node_id| {
+                                from_workspace.tiling_layer.element_for_node(node_id)
+                            }) {
+                                stack.append(elem);
+                            }
+                        }
+                        let res = TilingLayout::move_tree(
+                            &mut from_workspace.tiling_layer,
+                            &mut to_workspace.tiling_layer,
+                            &to,
+                            seat,
+                            to_workspace.focus_stack.get(&seat).iter(),
+                            NodeDesc {
+                                handle: from,
+                                node,
+                                stack_window: None,
+                            },
+                            direction,
+                        );
+                        from_workspace.refresh_focus_stack();
+                        to_workspace.refresh_focus_stack();
+                        return Ok(res.zip(new_pos));
+                    }
+                }
+
+                Ok(None)
+            }
+            _ => {
+                if let Some(mapped) = last_focused_window {
+                    Ok(self.move_window(
+                        Some(seat),
+                        &mapped,
+                        &from,
+                        &to,
+                        follow,
+                        direction,
+                        workspace_state,
+                    ))
+                } else {
+                    Ok(None)
+                }
+            }
+        }
     }
 
     pub fn update_reactive_popups(&self, mapped: &CosmicMapped) {