feat: add global last-pane navigation

refs #287

3 files changed, 87 insertions, 23 deletions

diff --git a/src/app/input/mod.rs b/src/app/input/mod.rs
index 0f0b3568..e145e628 100644
--- a/src/app/input/mod.rs
+++ b/src/app/input/mod.rs
@@ -367,7 +367,11 @@ impl AppState {
             follow_cwd,
         ));
 
-        if let Some(ws) = self.active.and_then(|i| self.workspaces.get_mut(i)) {
+        let previous_focus = self.current_pane_focus_target();
+        if let Some(ws_idx) = self.active {
+            let Some(ws) = self.workspaces.get_mut(ws_idx) else {
+                return;
+            };
             if let Ok(new_pane) = ws.split_focused(
                 direction,
                 new_rows,
@@ -381,7 +385,7 @@ impl AppState {
                 terminal_runtimes.insert(new_pane.terminal.id.clone(), new_pane.runtime);
                 self.terminals
                     .insert(new_pane.terminal.id.clone(), new_pane.terminal);
-                ws.layout.focus_pane(new_id);
+                self.record_pane_focus_change(previous_focus, ws_idx, new_id);
                 self.mark_session_dirty();
                 self.mode = Mode::Terminal;
             }
diff --git a/src/app/input/mouse.rs b/src/app/input/mouse.rs
index 8adfa55b..6db1a4a9 100644
--- a/src/app/input/mouse.rs
+++ b/src/app/input/mouse.rs
@@ -455,12 +455,10 @@ impl AppState {
                             return None;
                         }
 
-                        if let Some((ws_idx, tab_idx, pane_id)) =
+                        if let Some((ws_idx, _tab_idx, pane_id)) =
                             self.collapsed_agent_detail_target_at(mouse.row)
                         {
-                            self.switch_workspace(ws_idx);
-                            self.switch_tab(tab_idx);
-                            self.focus_pane(pane_id);
+                            self.focus_pane_in_workspace(ws_idx, pane_id);
                             self.mode = Mode::Terminal;
                         }
                         return None;
@@ -550,11 +548,10 @@ impl AppState {
                         return None;
                     }
 
-                    if let Some((ws_idx, tab_idx, pane_id)) = self.agent_detail_target_at(mouse.row)
+                    if let Some((ws_idx, _tab_idx, pane_id)) =
+                        self.agent_detail_target_at(mouse.row)
                     {
-                        self.switch_workspace(ws_idx);
-                        self.switch_tab(tab_idx);
-                        self.focus_pane(pane_id);
+                        self.focus_pane_in_workspace(ws_idx, pane_id);
                         self.mode = Mode::Terminal;
                         return None;
                     }
@@ -1027,12 +1024,10 @@ impl AppState {
             }
             Some(crate::ui::MobileSwitcherTarget::Agent {
                 ws_idx,
-                tab_idx,
+                tab_idx: _,
                 pane_id,
             }) => {
-                self.switch_workspace(ws_idx);
-                self.switch_tab(tab_idx);
-                self.focus_pane(pane_id);
+                self.focus_pane_in_workspace(ws_idx, pane_id);
                 self.mode = Mode::Terminal;
             }
             Some(crate::ui::MobileSwitcherTarget::Menu(action_idx)) => {
@@ -1264,11 +1259,8 @@ impl AppState {
     }
 
     pub(super) fn focus_pane(&mut self, pane_id: crate::layout::PaneId) {
-        if let Some(ws) = self.active.and_then(|i| self.workspaces.get_mut(i)) {
-            if ws.layout.focused() != pane_id {
-                ws.layout.focus_pane(pane_id);
-                self.mark_session_dirty();
-            }
+        if let Some(ws_idx) = self.active {
+            self.focus_pane_in_workspace(ws_idx, pane_id);
         }
     }
 
@@ -1290,13 +1282,11 @@ impl AppState {
         else {
             return;
         };
-        let Some(tab_idx) = self.workspaces[ws_idx].find_tab_index_for_pane(target.pane_id) else {
+        let Some(_tab_idx) = self.workspaces[ws_idx].find_tab_index_for_pane(target.pane_id) else {
             return;
         };
 
-        self.switch_workspace(ws_idx);
-        self.switch_tab(tab_idx);
-        self.focus_pane(target.pane_id);
+        self.focus_pane_in_workspace(ws_idx, target.pane_id);
         self.toast = None;
         self.mode = Mode::Terminal;
     }
@@ -1738,6 +1728,14 @@ mod tests {
         assert_eq!(app.state.workspaces[1].focused_pane_id(), Some(target_pane));
         assert!(app.state.toast.is_none());
         assert_eq!(app.state.mode, Mode::Terminal);
+
+        app.state.last_pane();
+
+        assert_eq!(app.state.active, Some(0));
+        assert_eq!(
+            app.state.workspaces[0].focused_pane_id(),
+            Some(app.state.workspaces[0].tabs[0].root_pane)
+        );
     }
 
     #[test]
diff --git a/src/app/input/navigate.rs b/src/app/input/navigate.rs
index 108fed8b..3b8435df 100644
--- a/src/app/input/navigate.rs
+++ b/src/app/input/navigate.rs
@@ -285,6 +285,7 @@ impl App {
         let Some(ws_idx) = self.state.active else {
             return Err(std::io::Error::other("no active workspace"));
         };
+        let previous_focus_target = self.state.current_pane_focus_target();
         let (rows, cols) = self.state.estimate_pane_size();
         let new_rows = rows.max(4);
         let new_cols = cols.max(10);
@@ -323,6 +324,13 @@ impl App {
         self.state
             .terminals
             .insert(new_pane.terminal.id.clone(), new_pane.terminal);
+        let new_focus_target = crate::app::state::PaneFocusTarget {
+            workspace_id: ws.id.clone(),
+            pane_id: new_pane_id,
+        };
+        if previous_focus_target.as_ref() != Some(&new_focus_target) {
+            self.state.previous_pane_focus = previous_focus_target;
+        }
         ws.active_tab_mut()
             .expect("workspace must have an active tab")
             .layout
@@ -499,6 +507,7 @@ pub(crate) enum NavigateAction {
     ToggleSidebar,
     CyclePaneNext,
     CyclePanePrevious,
+    LastPane,
     Help,
     Settings,
     ReloadConfig,
@@ -589,6 +598,7 @@ fn action_for_key(
         (&kb.focus_pane_down, NavigateAction::FocusPaneDown),
         (&kb.focus_pane_up, NavigateAction::FocusPaneUp),
         (&kb.focus_pane_right, NavigateAction::FocusPaneRight),
+        (&kb.last_pane, NavigateAction::LastPane),
         (&kb.cycle_pane_next, NavigateAction::CyclePaneNext),
         (&kb.cycle_pane_previous, NavigateAction::CyclePanePrevious),
         (&kb.split_vertical, NavigateAction::SplitVertical),
@@ -794,6 +804,10 @@ pub(super) fn execute_navigate_action_in_context(
             state.cycle_pane(true);
             leave_navigate_mode(state);
         }
+        NavigateAction::LastPane => {
+            state.last_pane();
+            leave_navigate_mode(state);
+        }
         NavigateAction::Help => super::modal::open_keybind_help(state),
         NavigateAction::Settings => super::settings::open_settings(state),
         NavigateAction::ReloadConfig => {
@@ -1454,6 +1468,40 @@ navigate_pane_right = "ctrl+l"
     }
 
     #[test]
+    fn terminal_direct_last_pane_shortcut_maps_to_navigation_action() {
+        let mut state = state_with_workspaces(&["test"]);
+        state.keybinds.last_pane = crate::config::ActionKeybinds::direct("alt+l");
+
+        let action = terminal_direct_navigation_action(
+            &state,
+            TerminalKey::new(KeyCode::Char('l'), KeyModifiers::ALT),
+        );
+
+        assert_eq!(action, Some(NavigateAction::LastPane));
+    }
+
+    #[test]
+    fn prefix_tab_override_can_map_to_last_pane() {
+        let config: Config = toml::from_str(
+            r#"
+[keys]
+last_pane = "prefix+tab"
+"#,
+        )
+        .unwrap();
+        let mut state = state_with_workspaces(&["test"]);
+        state.keybinds = config.keybinds();
+
+        let pane_action = action_for_key(
+            &state,
+            TerminalKey::new(KeyCode::Tab, KeyModifiers::empty()),
+            BindingDispatch::Prefix,
+        );
+
+        assert_eq!(pane_action, Some(NavigateAction::LastPane));
+    }
+
+    #[test]
     fn terminal_direct_indexed_tab_shortcut_maps_to_navigation_action() {
         let mut state = state_with_workspaces(&["test"]);
         let config: Config = toml::from_str("[keys]\nswitch_tab = \"ctrl+3\"\n").unwrap();
@@ -1747,6 +1795,7 @@ navigate_pane_right = "ctrl+l"
             app.render_dirty.clone(),
         )
         .expect("workspace should spawn");
+        let root_pane = workspace.tabs[0].root_pane;
         app.state.workspaces = vec![workspace];
         app.terminal_runtimes.insert(terminal.id.clone(), runtime);
         app.state.terminals.insert(terminal.id.clone(), terminal);
@@ -1774,6 +1823,19 @@ navigate_pane_right = "ctrl+l"
         assert_eq!(app.state.workspaces[0].tabs[0].layout.pane_count(), 2);
         assert_eq!(app.terminal_runtimes.len(), 2);
         assert!(app.state.workspaces[0].tabs[0].zoomed);
+        let overlay_pane = app.state.workspaces[0].focused_pane_id().unwrap();
+        assert_ne!(overlay_pane, root_pane);
+
+        app.state.last_pane();
+
+        assert_eq!(app.state.workspaces[0].focused_pane_id(), Some(root_pane));
+
+        app.state.last_pane();
+
+        assert_eq!(
+            app.state.workspaces[0].focused_pane_id(),
+            Some(overlay_pane)
+        );
 
         let _ = wait_for_file(&output_path);
         let deadline = std::time::Instant::now() + Duration::from_secs(2);