feat(panes): `FocusLastPane` action (#4241)

* feat(panes): focus last pane (#4142)

* add tests

* add client id parameter to `add_floating_pane`

* add action for floating panes

* add tests for floating panes

* add keybinds to configs

* rebase fixes

* simplify focus logic when adding stacked pane

* formatting fix

* formatting fix 2

* fix: make sure expanding pane always focuses it for all clients in stack

* add pr

* fix rebase

---------

Co-authored-by: Aram Drevekenin <aram@poor.dev>

12 files changed, 41 insertions, 2 deletions

diff --git a/zellij-utils/src/cli.rs b/zellij-utils/src/cli.rs
index 5b169170..a00c4d05 100644
--- a/zellij-utils/src/cli.rs
+++ b/zellij-utils/src/cli.rs
@@ -765,6 +765,8 @@ pub enum CliAction {
         /// The pane_id of the pane, eg. terminal_1, plugin_2 or 3
         pane_id: String,
     },
+    /// Change focus to the last focused frame
+    FocusLastPane,
     /// Move the focused pane in the specified direction. [right|left|up|down]
     MoveFocus {
         direction: Direction,
diff --git a/zellij-utils/src/client_server_contract/common_types.proto b/zellij-utils/src/client_server_contract/common_types.proto
index 1dfc3994..718cc279 100644
--- a/zellij-utils/src/client_server_contract/common_types.proto
+++ b/zellij-utils/src/client_server_contract/common_types.proto
@@ -278,6 +278,7 @@ message Action {
     SetLightThemeAction set_light_theme = 138;
     ToggleThemeAction toggle_theme = 139;
     ToggleMobileModeAction toggle_mobile_mode = 140;
+    FocusLastPaneAction focus_last_pane = 141;
   }
 }
 
@@ -287,6 +288,7 @@ message Action {
 message QuitAction {}
 message FocusNextPaneAction {}
 message FocusPreviousPaneAction {}
+message FocusLastPaneAction {}
 message SwitchFocusAction {}
 message MovePaneBackwardsAction {}
 message ClearScreenAction {}
diff --git a/zellij-utils/src/data.rs b/zellij-utils/src/data.rs
index 16ff560e..c11f777f 100644
--- a/zellij-utils/src/data.rs
+++ b/zellij-utils/src/data.rs
@@ -3384,6 +3384,7 @@ pub enum PluginCommand {
     ResizeWithDirection(ResizeStrategy),
     FocusNextPane,
     FocusPreviousPane,
+    FocusLastPane,
     MoveFocus(Direction),
     MoveFocusOrTab(Direction),
     Detach,
diff --git a/zellij-utils/src/errors.rs b/zellij-utils/src/errors.rs
index 8e4bc66c..c9e8e25f 100644
--- a/zellij-utils/src/errors.rs
+++ b/zellij-utils/src/errors.rs
@@ -246,6 +246,7 @@ pub enum ScreenContext {
     SwitchFocus,
     FocusNextPane,
     FocusPreviousPane,
+    FocusLastPane,
     FocusPaneAt,
     MoveFocusLeft,
     MoveFocusLeftOrPreviousTab,
diff --git a/zellij-utils/src/input/actions.rs b/zellij-utils/src/input/actions.rs
index cf5fc448..40158b8b 100644
--- a/zellij-utils/src/input/actions.rs
+++ b/zellij-utils/src/input/actions.rs
@@ -158,6 +158,8 @@ pub enum Action {
     /// Switch focus to next pane in specified direction.
     FocusNextPane,
     FocusPreviousPane,
+    /// Switch focus to the last focused pane.
+    FocusLastPane,
     /// Move the focus pane in specified direction.
     SwitchFocus,
     MoveFocus {
@@ -828,6 +830,7 @@ impl Action {
                     ))?;
                 Ok(vec![Action::FocusPaneByPaneId { pane_id }])
             },
+            CliAction::FocusLastPane => Ok(vec![Action::FocusLastPane]),
             CliAction::MoveFocus { direction } => Ok(vec![Action::MoveFocus { direction }]),
             CliAction::MoveFocusOrTab { direction } => {
                 Ok(vec![Action::MoveFocusOrTab { direction }])
diff --git a/zellij-utils/src/ipc/protobuf_conversion.rs b/zellij-utils/src/ipc/protobuf_conversion.rs
index d1bfb7d4..c4941676 100644
--- a/zellij-utils/src/ipc/protobuf_conversion.rs
+++ b/zellij-utils/src/ipc/protobuf_conversion.rs
@@ -915,6 +915,7 @@ impl From<crate::input::actions::Action>
             EditFileAction,
             EditScrollbackAction,
             EditScrollbackByPaneIdAction,
+            FocusLastPaneAction,
             FocusNextPaneAction,
             FocusPaneByPaneIdAction,
             FocusPluginPaneWithIdAction,
@@ -1090,6 +1091,9 @@ impl From<crate::input::actions::Action>
             crate::input::actions::Action::FocusPreviousPane => {
                 ActionType::FocusPreviousPane(FocusPreviousPaneAction {})
             },
+            crate::input::actions::Action::FocusLastPane => {
+                ActionType::FocusLastPane(FocusLastPaneAction {})
+            },
             crate::input::actions::Action::SwitchFocus => {
                 ActionType::SwitchFocus(SwitchFocusAction {})
             },
@@ -1961,6 +1965,7 @@ impl TryFrom<crate::client_server_contract::client_server_contract::Action>
             ActionType::FocusPreviousPane(_) => {
                 Ok(crate::input::actions::Action::FocusPreviousPane)
             },
+            ActionType::FocusLastPane(_) => Ok(crate::input::actions::Action::FocusLastPane),
             ActionType::SwitchFocus(_) => Ok(crate::input::actions::Action::SwitchFocus),
             ActionType::MoveFocus(move_focus_action) => {
                 Ok(crate::input::actions::Action::MoveFocus {
diff --git a/zellij-utils/src/kdl/mod.rs b/zellij-utils/src/kdl/mod.rs
index 0164ef92..14695f68 100644
--- a/zellij-utils/src/kdl/mod.rs
+++ b/zellij-utils/src/kdl/mod.rs
@@ -48,6 +48,7 @@ macro_rules! parse_kdl_action_arguments {
                 "Quit" => Ok(Action::Quit),
                 "FocusNextPane" => Ok(Action::FocusNextPane),
                 "FocusPreviousPane" => Ok(Action::FocusPreviousPane),
+                "FocusLastPane" => Ok(Action::FocusLastPane),
                 "SwitchFocus" => Ok(Action::SwitchFocus),
                 "EditScrollback" => Ok(Action::EditScrollback { ansi: false }),
                 "ScrollUp" => Ok(Action::ScrollUp),
@@ -660,6 +661,7 @@ impl Action {
             },
             Action::FocusNextPane => Some(KdlNode::new("FocusNextPane")),
             Action::FocusPreviousPane => Some(KdlNode::new("FocusPreviousPane")),
+            Action::FocusLastPane => Some(KdlNode::new("FocusLastPane")),
             Action::SwitchFocus => Some(KdlNode::new("SwitchFocus")),
             Action::MoveFocus { direction } => {
                 let mut node = KdlNode::new("MoveFocus");
@@ -1512,6 +1514,9 @@ impl TryFrom<(&KdlNode, &Options)> for Action {
             "FocusPreviousPane" => {
                 parse_kdl_action_arguments!(action_name, action_arguments, kdl_action)
             },
+            "FocusLastPane" => {
+                parse_kdl_action_arguments!(action_name, action_arguments, kdl_action)
+            },
             "SwitchFocus" => parse_kdl_action_arguments!(action_name, action_arguments, kdl_action),
             "EditScrollback" => {
                 let ansi = crate::kdl_get_bool_property_or_child_value!(kdl_action, "ansi")
@@ -6729,6 +6734,7 @@ fn keybinds_to_string_with_all_actions() {
                         config_key_2 "config_value_2";
                     };
                 }
+                bind "Ctrl Alt k" { FocusLastPane; }
             }
         }"#;
     let document: KdlDocument = fake_config.parse().unwrap();
diff --git a/zellij-utils/src/kdl/snapshots/zellij_utils__kdl__keybinds_to_string_with_all_actions.snap b/zellij-utils/src/kdl/snapshots/zellij_utils__kdl__keybinds_to_string_with_all_actions.snap
index 43e85faa..b0119a63 100644
--- a/zellij-utils/src/kdl/snapshots/zellij_utils__kdl__keybinds_to_string_with_all_actions.snap
+++ b/zellij-utils/src/kdl/snapshots/zellij_utils__kdl__keybinds_to_string_with_all_actions.snap
@@ -1,6 +1,5 @@
 ---
 source: zellij-utils/src/kdl/mod.rs
-assertion_line: 2731
 expression: serialized.to_string()
 ---
 keybinds clear-defaults=true {
@@ -47,6 +46,7 @@ keybinds clear-defaults=true {
         }
         bind "Alt j" { GoToPreviousTab; }
         bind "Ctrl k" { MovePane "right"; }
+        bind "Ctrl Alt k" { FocusLastPane; }
         bind "Alt k" { CloseTab; }
         bind "Ctrl l" { MovePaneBackwards; }
         bind "Alt l" { GoToTab 1; }
@@ -127,4 +127,3 @@ keybinds clear-defaults=true {
         bind "Alt z" { SearchInput 0; }
     }
 }
-
diff --git a/zellij-utils/src/plugin_api/action.proto b/zellij-utils/src/plugin_api/action.proto
index 7eedf393..68c859b8 100644
--- a/zellij-utils/src/plugin_api/action.proto
+++ b/zellij-utils/src/plugin_api/action.proto
@@ -493,6 +493,7 @@ enum ActionName {
     SetDarkTheme = 101;
     SetLightTheme = 102;
     ToggleTheme = 103;
+    FocusLastPane = 104;
 }
 
 message Position {
diff --git a/zellij-utils/src/plugin_api/action.rs b/zellij-utils/src/plugin_api/action.rs
index 34b3adce..f4e35d84 100644
--- a/zellij-utils/src/plugin_api/action.rs
+++ b/zellij-utils/src/plugin_api/action.rs
@@ -168,6 +168,10 @@ impl TryFrom<ProtobufAction> for Action {
                 Some(_) => Err("FocusPreviousPane should not have a payload"),
                 None => Ok(Action::FocusPreviousPane),
             },
+            Some(ProtobufActionName::FocusLastPane) => match protobuf_action.optional_payload {
+                Some(_) => Err("FocusLastPane should not have a payload"),
+                None => Ok(Action::FocusLastPane),
+            },
             Some(ProtobufActionName::SwitchFocus) => match protobuf_action.optional_payload {
                 Some(_) => Err("SwitchFocus should not have a payload"),
                 None => Ok(Action::SwitchFocus),
@@ -1173,6 +1177,10 @@ impl TryFrom<Action> for ProtobufAction {
                 name: ProtobufActionName::FocusPreviousPane as i32,
                 optional_payload: None,
             }),
+            Action::FocusLastPane => Ok(ProtobufAction {
+                name: ProtobufActionName::FocusLastPane as i32,
+                optional_payload: None,
+            }),
             Action::SwitchFocus => Ok(ProtobufAction {
                 name: ProtobufActionName::SwitchFocus as i32,
                 optional_payload: None,
diff --git a/zellij-utils/src/plugin_api/plugin_command.proto b/zellij-utils/src/plugin_api/plugin_command.proto
index c65bcbfd..82f4d835 100644
--- a/zellij-utils/src/plugin_api/plugin_command.proto
+++ b/zellij-utils/src/plugin_api/plugin_command.proto
@@ -213,6 +213,7 @@ enum CommandName {
   NewTabUnfocused = 220;
   NewTiledPaneInTab = 221;
   ExitMobileMode = 222;
+  FocusLastPane = 223;
 }
 
 message PluginCommand {
diff --git a/zellij-utils/src/plugin_api/plugin_command.rs b/zellij-utils/src/plugin_api/plugin_command.rs
index 42b0774f..546c3586 100644
--- a/zellij-utils/src/plugin_api/plugin_command.rs
+++ b/zellij-utils/src/plugin_api/plugin_command.rs
@@ -980,6 +980,12 @@ impl TryFrom<ProtobufPluginCommand> for PluginCommand {
                 }
                 Ok(PluginCommand::FocusPreviousPane)
             },
+            Some(CommandName::FocusLastPane) => {
+                if protobuf_plugin_command.payload.is_some() {
+                    return Err("FocusLastPane should not have a payload");
+                }
+                Ok(PluginCommand::FocusLastPane)
+            },
             Some(CommandName::MoveFocus) => match protobuf_plugin_command.payload {
                 Some(Payload::MoveFocusPayload(move_payload)) => match move_payload.direction {
                     Some(direction) => Ok(PluginCommand::MoveFocus(direction.try_into()?)),
@@ -3005,6 +3011,10 @@ impl TryFrom<PluginCommand> for ProtobufPluginCommand {
                 name: CommandName::FocusPreviousPane as i32,
                 payload: None,
             }),
+            PluginCommand::FocusLastPane => Ok(ProtobufPluginCommand {
+                name: CommandName::FocusLastPane as i32,
+                payload: None,
+            }),
             PluginCommand::MoveFocus(direction) => Ok(ProtobufPluginCommand {
                 name: CommandName::MoveFocus as i32,
                 payload: Some(Payload::MoveFocusPayload(MovePayload {