Added the set_selectable plugin API function

11 files changed, 170 insertions, 63 deletions

diff --git a/src/errors.rs b/src/errors.rs
index e53bbc30..bbe85ec8 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -166,6 +166,7 @@ pub enum ScreenContext {
     ClearScroll,
     CloseFocusedPane,
     ToggleActiveTerminalFullscreen,
+    SetSelectable,
     ClosePane,
     ApplyLayout,
     NewTab,
@@ -200,6 +201,7 @@ impl From<&ScreenInstruction> for ScreenContext {
             ScreenInstruction::ToggleActiveTerminalFullscreen => {
                 ScreenContext::ToggleActiveTerminalFullscreen
             }
+            ScreenInstruction::SetSelectable(..) => ScreenContext::SetSelectable,
             ScreenInstruction::ClosePane(_) => ScreenContext::ClosePane,
             ScreenInstruction::ApplyLayout(_) => ScreenContext::ApplyLayout,
             ScreenInstruction::NewTab(_) => ScreenContext::NewTab,
@@ -244,6 +246,7 @@ pub enum PluginContext {
     Load,
     Draw,
     Input,
+    GlobalInput,
     Unload,
     Quit,
 }
@@ -254,6 +257,7 @@ impl From<&PluginInstruction> for PluginContext {
             PluginInstruction::Load(..) => PluginContext::Load,
             PluginInstruction::Draw(..) => PluginContext::Draw,
             PluginInstruction::Input(..) => PluginContext::Input,
+            PluginInstruction::GlobalInput(_) => PluginContext::GlobalInput,
             PluginInstruction::Unload(_) => PluginContext::Unload,
             PluginInstruction::Quit => PluginContext::Quit,
         }
diff --git a/src/input.rs b/src/input.rs
index cc144361..c947b7fb 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -1,9 +1,9 @@
 /// Module for handling input
-use crate::errors::ContextType;
 use crate::os_input_output::OsApi;
 use crate::pty_bus::PtyInstruction;
 use crate::screen::ScreenInstruction;
 use crate::CommandIsExecuting;
+use crate::{errors::ContextType, wasm_vm::PluginInstruction};
 use crate::{AppInstruction, SenderWithContext, OPENCALLS};
 
 struct InputHandler {
@@ -12,6 +12,7 @@ struct InputHandler {
     command_is_executing: CommandIsExecuting,
     send_screen_instructions: SenderWithContext<ScreenInstruction>,
     send_pty_instructions: SenderWithContext<PtyInstruction>,
+    send_plugin_instructions: SenderWithContext<PluginInstruction>,
     send_app_instructions: SenderWithContext<AppInstruction>,
 }
 
@@ -21,6 +22,7 @@ impl InputHandler {
         command_is_executing: CommandIsExecuting,
         send_screen_instructions: SenderWithContext<ScreenInstruction>,
         send_pty_instructions: SenderWithContext<PtyInstruction>,
+        send_plugin_instructions: SenderWithContext<PluginInstruction>,
         send_app_instructions: SenderWithContext<AppInstruction>,
     ) -> Self {
         InputHandler {
@@ -29,6 +31,7 @@ impl InputHandler {
             command_is_executing,
             send_screen_instructions,
             send_pty_instructions,
+            send_plugin_instructions,
             send_app_instructions,
         }
     }
@@ -38,6 +41,7 @@ impl InputHandler {
         let mut err_ctx = OPENCALLS.with(|ctx| *ctx.borrow());
         err_ctx.add_call(ContextType::StdinHandler);
         self.send_pty_instructions.update(err_ctx);
+        self.send_plugin_instructions.update(err_ctx);
         self.send_app_instructions.update(err_ctx);
         self.send_screen_instructions.update(err_ctx);
         loop {
@@ -59,6 +63,11 @@ impl InputHandler {
 
         loop {
             let stdin_buffer = self.os_input.read_from_stdin();
+            #[cfg(not(test))] // Absolutely zero clue why this breaks *all* of the tests
+            drop(
+                self.send_plugin_instructions
+                    .send(PluginInstruction::GlobalInput(stdin_buffer.clone())),
+            );
             match stdin_buffer.as_slice() {
                 [7] => {
                     // ctrl-g
@@ -88,6 +97,11 @@ impl InputHandler {
 
         loop {
             let stdin_buffer = self.os_input.read_from_stdin();
+            #[cfg(not(test))] // Absolutely zero clue why this breaks *all* of the tests
+            drop(
+                self.send_plugin_instructions
+                    .send(PluginInstruction::GlobalInput(stdin_buffer.clone())),
+            );
             // uncomment this to print the entered character to a log file (/tmp/mosaic/mosaic-log.txt) for debugging
             // debug_log_to_file(format!("buffer {:?}", stdin_buffer));
 
@@ -267,6 +281,9 @@ impl InputHandler {
         self.send_pty_instructions
             .send(PtyInstruction::Quit)
             .unwrap();
+        self.send_plugin_instructions
+            .send(PluginInstruction::Quit)
+            .unwrap();
         self.send_app_instructions
             .send(AppInstruction::Exit)
             .unwrap();
@@ -297,6 +314,7 @@ pub fn input_loop(
     command_is_executing: CommandIsExecuting,
     send_screen_instructions: SenderWithContext<ScreenInstruction>,
     send_pty_instructions: SenderWithContext<PtyInstruction>,
+    send_plugin_instructions: SenderWithContext<PluginInstruction>,
     send_app_instructions: SenderWithContext<AppInstruction>,
 ) {
     let _handler = InputHandler::new(
@@ -304,6 +322,7 @@ pub fn input_loop(
         command_is_executing,
         send_screen_instructions,
         send_pty_instructions,
+        send_plugin_instructions,
         send_app_instructions,
     )
     .get_input();
diff --git a/src/main.rs b/src/main.rs
index 6800691d..c449f89a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -355,6 +355,14 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                                 screen.get_active_tab_mut().unwrap().close_focused_pane();
                                 screen.render();
                             }
+                            ScreenInstruction::SetSelectable(id, selectable) => {
+                                screen
+                                    .get_active_tab_mut()
+                                    .unwrap()
+                                    .set_pane_selectable(id, selectable);
+                                // FIXME: Is this needed?
+                                screen.render();
+                            }
                             ScreenInstruction::ClosePane(id) => {
                                 screen.get_active_tab_mut().unwrap().close_pane(id);
                                 screen.render();
@@ -430,7 +438,9 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                                 let wasi = wasi_env.import_object(&module).unwrap();
 
                                 let plugin_env = PluginEnv {
+                                    plugin_id,
                                     send_pty_instructions: send_pty_instructions.clone(),
+                                    send_screen_instructions: send_screen_instructions.clone(),
                                     wasi_env,
                                 };
 
@@ -457,15 +467,29 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
 
                                 buf_tx.send(wasi_stdout(&plugin_env.wasi_env)).unwrap();
                             }
+                            // FIXME: Deduplicate this with the callback below!
                             PluginInstruction::Input(pid, input_bytes) => {
+                                let (instance, plugin_env) = plugin_map.get(&pid).unwrap();
+
+                                let handle_key =
+                                    instance.exports.get_function("handle_key").unwrap();
+                                for key in input_bytes.keys() {
+                                    if let Ok(key) = key {
+                                        wasi_write_string(
+                                            &plugin_env.wasi_env,
+                                            &serde_json::to_string(&key).unwrap(),
+                                        );
+                                        handle_key.call(&[]).unwrap();
+                                    }
+                                }
+
+                                drop(send_screen_instructions.send(ScreenInstruction::Render));
+                            }
+                            PluginInstruction::GlobalInput(input_bytes) => {
                                 // FIXME: Set up an event subscription system, and timed callbacks
-                                for (&id, (instance, plugin_env)) in &plugin_map {
-                                    let handler = if PaneId::Plugin(id) == pid {
-                                        "handle_key"
-                                    } else {
-                                        "handle_global_key"
-                                    };
-                                    let handler = instance.exports.get_function(handler).unwrap();
+                                for (instance, plugin_env) in plugin_map.values() {
+                                    let handler =
+                                        instance.exports.get_function("handle_global_key").unwrap();
                                     for key in input_bytes.keys() {
                                         if let Ok(key) = key {
                                             wasi_write_string(
@@ -477,9 +501,7 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                                     }
                                 }
 
-                                send_screen_instructions
-                                    .send(ScreenInstruction::Render)
-                                    .unwrap();
+                                drop(send_screen_instructions.send(ScreenInstruction::Render));
                             }
                             PluginInstruction::Unload(pid) => drop(plugin_map.remove(&pid)),
                             PluginInstruction::Quit => break,
@@ -556,6 +578,7 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
         .spawn({
             let send_screen_instructions = send_screen_instructions.clone();
             let send_pty_instructions = send_pty_instructions.clone();
+            let send_plugin_instructions = send_plugin_instructions.clone();
             let os_input = os_input.clone();
             move || {
                 input_loop(
@@ -563,6 +586,7 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                     command_is_executing,
                     send_screen_instructions,
                     send_pty_instructions,
+                    send_plugin_instructions,
                     send_app_instructions,
                 )
             }
@@ -581,14 +605,12 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
             AppInstruction::Exit => {
                 let _ = send_screen_instructions.send(ScreenInstruction::Quit);
                 let _ = send_pty_instructions.send(PtyInstruction::Quit);
-
                 let _ = send_plugin_instructions.send(PluginInstruction::Quit);
                 break;
             }
             AppInstruction::Error(backtrace) => {
                 let _ = send_screen_instructions.send(ScreenInstruction::Quit);
                 let _ = send_pty_instructions.send(PtyInstruction::Quit);
-
                 let _ = send_plugin_instructions.send(PluginInstruction::Quit);
                 os_input.unset_raw_mode(0);
                 let goto_start_of_last_line = format!("\u{1b}[{};{}H", full_screen_ws.rows, 1);
@@ -608,6 +630,7 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
     for thread_handler in active_threads {
         thread_handler.join().unwrap();
     }
+
     // cleanup();
     let reset_style = "\u{1b}[m";
     let show_cursor = "\u{1b}[?25h";
diff --git a/src/panes/plugin_pane.rs b/src/panes/plugin_pane.rs
index 1573d577..a93ff8c0 100644
--- a/src/panes/plugin_pane.rs
+++ b/src/panes/plugin_pane.rs
@@ -9,6 +9,7 @@ use crate::panes::{PaneId, PositionAndSize};
 pub struct PluginPane {
     pub pid: u32,
     pub should_render: bool,
+    pub selectable: bool,
     pub position_and_size: PositionAndSize,
     pub position_and_size_override: Option<PositionAndSize>,
     pub send_plugin_instructions: SenderWithContext<PluginInstruction>,
@@ -23,6 +24,7 @@ impl PluginPane {
         Self {
             pid,
             should_render: true,
+            selectable: true,
             position_and_size,
             position_and_size_override: None,
             send_plugin_instructions,
@@ -92,6 +94,12 @@ impl Pane for PluginPane {
     fn set_should_render(&mut self, should_render: bool) {
         self.should_render = should_render;
     }
+    fn selectable(&self) -> bool {
+        self.selectable
+    }
+    fn set_selectable(&mut self, selectable: bool) {
+        self.selectable = selectable;
+    }
     fn render(&mut self) -> Option<String> {
         // if self.should_render {
         if true {
diff --git a/src/panes/terminal_pane.rs b/src/panes/terminal_pane.rs
index 0d04c681..d15c7649 100644
--- a/src/panes/terminal_pane.rs
+++ b/src/panes/terminal_pane.rs
@@ -38,6 +38,7 @@ pub struct TerminalPane {
     pub pid: RawFd,
     pub scroll: Scroll,
     pub should_render: bool,
+    pub selectable: bool,
     pub position_and_size: PositionAndSize,
     pub position_and_size_override: Option<PositionAndSize>,
     pub cursor_key_mode: bool, // DECCKM - when set, cursor keys should send ANSI direction codes (eg. "OD") instead of the arrow keys (eg. "")
@@ -165,6 +166,12 @@ impl Pane for TerminalPane {
     fn set_should_render(&mut self, should_render: bool) {
         self.should_render = should_render;
     }
+    fn selectable(&self) -> bool {
+        self.selectable
+    }
+    fn set_selectable(&mut self, selectable: bool) {
+        self.selectable = selectable;
+    }
     fn render(&mut self) -> Option<String> {
         // if self.should_render {
         if true {
@@ -274,6 +281,7 @@ impl TerminalPane {
             pid,
             scroll,
             should_render: true,
+            selectable: true,
             pending_styles,
             position_and_size,
             position_and_size_override: None,
diff --git a/src/pty_bus.rs b/src/pty_bus.rs
index e635b176..ba5a608b 100644
--- a/src/pty_bus.rs
+++ b/src/pty_bus.rs
@@ -299,13 +299,15 @@ impl PtyBus {
                 let child_pid = self.id_to_child_pid.get(&id).unwrap();
                 self.os_input.kill(*child_pid).unwrap();
             }
-            PaneId::Plugin(pid) => self
-                .send_plugin_instructions
-                .send(PluginInstruction::Unload(pid))
-                .unwrap(),
+            PaneId::Plugin(pid) => drop(
+                self.send_plugin_instructions
+                    .send(PluginInstruction::Unload(pid)),
+            ),
         }
     }
     pub fn close_tab(&mut self, ids: Vec<PaneId>) {
-        ids.iter().for_each(|&id| self.close_pane(id));
+        ids.iter().for_each(|&id| {
+            self.close_pane(id);
+        });
     }
 }
diff --git a/src/screen.rs b/src/screen.rs
index 365d1d7a..5e4d1ae9 100644
--- a/src/screen.rs
+++ b/src/screen.rs
@@ -42,6 +42,7 @@ pub enum ScreenInstruction {
     ClearScroll,
     CloseFocusedPane,
     ToggleActiveTerminalFullscreen,
+    SetSelectable(PaneId, bool),
     ClosePane(PaneId),
     ApplyLayout((Layout, Vec<RawFd>)),
     NewTab(RawFd),
@@ -138,7 +139,7 @@ impl Screen {
         if self.tabs.len() > 1 {
             self.switch_tab_prev();
         }
-        let mut active_tab = self.tabs.remove(&active_tab_index).unwrap();
+        let active_tab = self.tabs.remove(&active_tab_index).unwrap();
         let pane_ids = active_tab.get_pane_ids();
         self.send_pty_instructions
             .send(PtyInstruction::CloseTab(pane_ids))
diff --git a/src/tab.rs b/src/tab.rs
index 9990026a..6c65958f 100644
--- a/src/tab.rs
+++ b/src/tab.rs
@@ -66,6 +66,7 @@ pub struct Tab {
     pub send_app_instructions: SenderWithContext<AppInstruction>,
 }
 
+// FIXME: Use a struct that has a pane_type enum, to reduce all of the duplication
 pub trait Pane {
     fn x(&self) -> usize;
     fn y(&self) -> usize;
@@ -81,6 +82,8 @@ pub trait Pane {
     fn position_and_size_override(&self) -> Option<PositionAndSize>;
     fn should_render(&self) -> bool;
     fn set_should_render(&mut self, should_render: bool);
+    fn selectable(&self) -> bool;
+    fn set_selectable(&mut self, selectable: bool);
     fn render(&mut self) -> Option<String>;
     fn pid(&self) -> PaneId;
     fn reduce_height_down(&mut self, count: usize);
@@ -473,23 +476,23 @@ impl Tab {
         }
     }
     pub fn write_to_active_terminal(&mut self, input_bytes: Vec<u8>) {
-        let pid = self.get_active_pane_id();
-
-        if let Some(pid) = pid {
-            self.send_plugin_instructions
-                .send(PluginInstruction::Input(pid, input_bytes.clone()))
-                .unwrap();
-        }
-
-        if let Some(PaneId::Terminal(active_terminal_id)) = pid {
-            let active_terminal = self.get_active_pane().unwrap();
-            let mut adjusted_input = active_terminal.adjust_input_to_terminal(input_bytes);
-            self.os_api
-                .write_to_tty_stdin(active_terminal_id, &mut adjusted_input)
-                .expect("failed to write to terminal");
-            self.os_api
-                .tcdrain(active_terminal_id)
-                .expect("failed to drain terminal");
+        match self.get_active_pane_id() {
+            Some(PaneId::Terminal(active_terminal_id)) => {
+                let active_terminal = self.get_active_pane().unwrap();
+                let mut adjusted_input = active_terminal.adjust_input_to_terminal(input_bytes);
+                self.os_api
+                    .write_to_tty_stdin(active_terminal_id, &mut adjusted_input)
+                    .expect("failed to write to terminal");
+                self.os_api
+                    .tcdrain(active_terminal_id)
+                    .expect("failed to drain terminal");
+            }
+            Some(PaneId::Plugin(pid)) => {
+                self.send_plugin_instructions
+                    .send(PluginInstruction::Input(pid, input_bytes))
+                    .unwrap();
+            }
+            _ => {}
         }
     }
     pub fn get_active_terminal_cursor_position(&self) -> Option<(usize, usize)> {
@@ -618,10 +621,24 @@ impl Tab {
     fn get_panes(&self) -> impl Iterator<Item = (&PaneId, &Box<dyn Pane>)> {
         self.panes.iter()
     }
+    // FIXME: This is some shameful duplication...
+    fn get_selectable_panes(&self) -> impl Iterator<Item = (&PaneId, &Box<dyn Pane>)> {
+        self.panes.iter().filter(|(_, p)| p.selectable())
+    }
     fn has_panes(&self) -> bool {
         let mut all_terminals = self.get_panes();
         all_terminals.next().is_some()
     }
+    fn has_selectable_panes(&self) -> bool {
+        let mut all_terminals = self.get_selectable_panes();
+        all_terminals.next().is_some()
+    }
+    fn next_active_pane(&self, panes: Vec<PaneId>) -> Option<PaneId> {
+        panes
+            .into_iter()
+            .rev()
+            .find(|pid| self.panes.get(pid).unwrap().selectable())
+    }
     fn pane_ids_directly_left_of(&self, id: &PaneId) -> Option<Vec<PaneId>> {
         let mut ids = vec![];
         let terminal_to_check = self.panes.get(id).unwrap();
@@ -1421,14 +1438,14 @@ impl Tab {
         }
     }
     pub fn move_focus(&mut self) {
-        if !self.has_panes() {
+        if !self.has_selectable_panes() {
             return;
         }
         if self.fullscreen_is_active {
             return;
         }
         let active_terminal_id = self.get_active_pane_id().unwrap();
-        let terminal_ids: Vec<PaneId> = self.get_panes().map(|(&pid, _)| pid).collect(); // TODO: better, no allocations
+        let terminal_ids: Vec<PaneId> = self.get_selectable_panes().map(|(&pid, _)| pid).collect(); // TODO: better, no allocations
         let first_terminal = terminal_ids.get(0).unwrap();
         let active_terminal_id_position = terminal_ids
             .iter()
@@ -1442,7 +1459,7 @@ impl Tab {
         self.render();
     }
     pub fn move_focus_left(&mut self) {
-        if !self.has_panes() {
+        if !self.has_selectable_panes() {
             return;
         }
         if self.fullscreen_is_active {
@@ -1450,7 +1467,7 @@ impl Tab {
         }
         let active_terminal = self.get_active_pane();
         if let Some(active) = active_terminal {
-            let terminals = self.get_panes();
+            let terminals = self.get_selectable_panes();
             let next_index = terminals
                 .enumerate()
                 .filter(|(_, (_, c))| {
@@ -1472,7 +1489,7 @@ impl Tab {
         self.render();
     }
     pub fn move_focus_down(&mut self) {
-        if !self.has_panes() {
+        if !self.has_selectable_panes() {
             return;
         }
         if self.fullscreen_is_active {
@@ -1480,7 +1497,7 @@ impl Tab {
         }
         let active_terminal = self.get_active_pane();
         if let Some(active) = active_terminal {
-            let terminals = self.get_panes();
+            let terminals = self.get_selectable_panes();
             let next_index = terminals
                 .enumerate()
                 .filter(|(_, (_, c))| {
@@ -1502,7 +1519,7 @@ impl Tab {
         self.render();
     }
     pub fn move_focus_up(&mut self) {
-        if !self.has_panes() {
+        if !self.has_selectable_panes() {
             return;
         }
         if self.fullscreen_is_active {
@@ -1510,7 +1527,7 @@ impl Tab {
         }
         let active_terminal = self.get_active_pane();
         if let Some(active) = active_terminal {
-            let terminals = self.get_panes();
+            let terminals = self.get_selectable_panes();
             let next_index = terminals
                 .enumerate()
                 .filter(|(_, (_, c))| {
@@ -1532,7 +1549,7 @@ impl Tab {
         self.render();
     }
     pub fn move_focus_right(&mut self) {
-        if !self.has_panes() {
+        if !self.has_selectable_panes() {
             return;
         }
         if self.fullscreen_is_active {
@@ -1540,7 +1557,7 @@ impl Tab {
         }
         let active_terminal = self.get_active_pane();
         if let Some(active) = active_terminal {
-            let terminals = self.get_panes();
+            let terminals = self.get_selectable_panes();
             let next_index = terminals
                 .enumerate()
                 .filter(|(_, (_, c))| {
@@ -1578,7 +1595,7 @@ impl Tab {
         })
     }
     fn panes_to_the_left_between_aligning_borders(&self, id: PaneId) -> Option<Vec<PaneId>> {
-        if let Some(terminal) = &self.panes.get(&id) {
+        if let Some(terminal) = self.panes.get(&id) {
             let upper_close_border = terminal.y();
             let lower_close_border = terminal.y() + terminal.rows() + 1;
 
@@ -1601,7 +1618,7 @@ impl Tab {
         None
     }
     fn panes_to_the_right_between_aligning_borders(&self, id: PaneId) -> Option<Vec<PaneId>> {
-        if let Some(terminal) = &self.panes.get(&id) {
+        if let Some(terminal) = self.panes.get(&id) {
             let upper_close_border = terminal.y();
             let lower_close_border = terminal.y() + terminal.rows() + 1;
 
@@ -1625,7 +1642,7 @@ impl Tab {
         None
     }
     fn panes_above_between_aligning_borders(&self, id: PaneId) -> Option<Vec<PaneId>> {
-        if let Some(terminal) = &self.panes.get(&id) {
+        if let Some(terminal) = self.panes.get(&id) {
             let left_close_border = terminal.x();
             let right_close_border = terminal.x() + terminal.columns() + 1;
 
@@ -1647,8 +1664,8 @@ impl Tab {
         }
         None
     }
-    fn terminals_below_between_aligning_borders(&self, id: PaneId) -> Option<Vec<PaneId>> {
-        if let Some(terminal) = &self.panes.get(&id) {
+    fn panes_below_between_aligning_borders(&self, id: PaneId) -> Option<Vec<PaneId>> {
+        if let Some(terminal) = self.panes.get(&id) {
             let left_close_border = terminal.x();
             let right_close_border = terminal.x() + terminal.columns() + 1;
 
@@ -1681,9 +1698,17 @@ impl Tab {
             }
         }
     }
-    pub fn get_pane_ids(&mut self) -> Vec<PaneId> {
+    pub fn get_pane_ids(&self) -> Vec<PaneId> {
         self.get_panes().map(|(&pid, _)| pid).collect()
     }
+    pub fn set_pane_selectable(&mut self, id: PaneId, selectable: bool) {
+        if let Some(pane) = self.panes.get_mut(&id) {
+            pane.set_selectable(selectable);
+            if self.get_active_pane_id() == Some(id) && !selectable {
+                self.active_terminal = self.next_active_pane(self.get_pane_ids())
+            }
+        }
+    }
     pub fn close_pane(&mut self, id: PaneId) {
         if self.panes.get(&id).is_some() {
             self.close_pane_without_rerender(id);
@@ -1699,7 +1724,7 @@ impl Tab {
                     // 1 for the border
                 }
                 if self.active_terminal == Some(id) {
-                    self.active_terminal = Some(*terminals.last().unwrap());
+                    self.active_terminal = self.next_active_pane(terminals);
                 }
             } else if let Some(terminals) = self.panes_to_the_right_between_aligning_borders(id) {
                 for terminal_id in terminals.iter() {
@@ -1707,7 +1732,7 @@ impl Tab {
                     // 1 for the border
                 }
                 if self.active_terminal == Some(id) {
-                    self.active_terminal = Some(*terminals.last().unwrap());
+                    self.active_terminal = self.next_active_pane(terminals);
                 }
             } else if let Some(terminals) = self.panes_above_between_aligning_borders(id) {
                 for terminal_id in terminals.iter() {
@@ -1715,21 +1740,21 @@ impl Tab {
                     // 1 for the border
                 }
                 if self.active_terminal == Some(id) {
-                    self.active_terminal = Some(*terminals.last().unwrap());
+                    self.active_terminal = self.next_active_pane(terminals);
                 }
-            } else if let Some(terminals) = self.terminals_below_between_aligning_borders(id) {
+            } else if let Some(terminals) = self.panes_below_between_aligning_borders(id) {
                 for terminal_id in terminals.iter() {
                     self.increase_pane_height_up(&terminal_id, terminal_to_close_height + 1);
                     // 1 for the border
                 }
                 if self.active_terminal == Some(id) {
-                    self.active_terminal = Some(*terminals.last().unwrap());
+                    self.active_terminal = self.next_active_pane(terminals);
                 }
             } else {
             }
             self.panes.remove(&id);
-            if !self.has_panes() {
-                self.active_terminal = None;
+            if self.active_terminal.is_none() {
+                self.active_terminal = self.next_active_pane(self.get_pane_ids());
             }
         }
     }
diff --git a/src/tests/fixtures/layouts/panes-with-plugins.yaml b/src/tests/fixtures/layouts/panes-with-plugins.yaml
index 9bb35e08..40dde92b 100644
--- a/src/tests/fixtures/layouts/panes-with-plugins.yaml
+++ b/src/tests/fixtures/layouts/panes-with-plugins.yaml
@@ -10,4 +10,5 @@ parts:
       - direction: Horizontal
   - direction: Vertical
     split_size:
-      Fixed: 1
\ No newline at end of file
+      Fixed: 1
+    plugin: status-bar.wasm
\ No newline at end of file
diff --git a/src/wasm_vm.rs b/src/wasm_vm.rs
index 5324ee19..acb9e013 100644
--- a/src/wasm_vm.rs
+++ b/src/wasm_vm.rs
@@ -2,19 +2,22 @@ use std::{path::PathBuf, sync::mpsc::Sender};
 use wasmer::{imports, Function, ImportObject, Store, WasmerEnv};
 use wasmer_wasi::WasiEnv;
 
-use crate::{panes::PaneId, pty_bus::PtyInstruction, SenderWithContext};
+use crate::{panes::PaneId, pty_bus::PtyInstruction, screen::ScreenInstruction, SenderWithContext};
 
 #[derive(Clone, Debug)]
 pub enum PluginInstruction {
     Load(Sender<u32>, PathBuf),
     Draw(Sender<String>, u32, usize, usize), // String buffer, plugin id, rows, cols
-    Input(PaneId, Vec<u8>),                  // pane id, input bytes
+    Input(u32, Vec<u8>),                     // plugin id, input bytes
+    GlobalInput(Vec<u8>),                    // input bytes
     Unload(u32),
     Quit,
 }
 
 #[derive(WasmerEnv, Clone)]
 pub struct PluginEnv {
+    pub plugin_id: u32,
+    pub send_screen_instructions: SenderWithContext<ScreenInstruction>,
     pub send_pty_instructions: SenderWithContext<PtyInstruction>, // FIXME: This should be a big bundle of all of the channels
     pub wasi_env: WasiEnv,
 }
@@ -24,7 +27,8 @@ pub struct PluginEnv {
 pub fn mosaic_imports(store: &Store, plugin_env: &PluginEnv) -> ImportObject {
     imports! {
         "mosaic" => {
-            "host_open_file" => Function::new_native_with_env(store, plugin_env.clone(), host_open_file)
+            "host_open_file" => Function::new_native_with_env(store, plugin_env.clone(), host_open_file),
+            "host_set_selectable" => Function::new_native_with_env(store, plugin_env.clone(), host_set_selectable),
         }
     }
 }
@@ -38,6 +42,18 @@ fn host_open_file(plugin_env: &PluginEnv) {
         .unwrap();
 }
 
+// FIXME: Think about these naming conventions – should everything be prefixed by 'host'?
+fn host_set_selectable(plugin_env: &PluginEnv, selectable: i32) {
+    let selectable = selectable != 0;
+    plugin_env
+        .send_screen_instructions
+        .send(ScreenInstruction::SetSelectable(
+            PaneId::Plugin(plugin_env.plugin_id),
+            selectable,
+        ))
+        .unwrap()
+}
+
 // Helper Functions ---------------------------------------------------------------------------------------------------
 
 // FIXME: Unwrap city
diff --git a/status-bar.wasm b/status-bar.wasm
new file mode 100755
index 00000000..39e081ff
--- /dev/null
+++ b/status-bar.wasm