add(overlay): add overlay (#875)

* add overlay instructions to the `render` function

  this is a continuation of #871

zellij-server/src/screen.rs

@@ -12,7 +12,7 @@ use crate::{
     pty::{ClientOrTabIndex, PtyInstruction, VteBytes},
     tab::{Output, Tab},
     thread_bus::Bus,
-    ui::overlay::{Overlay, OverlayWindow},
+    ui::overlay::{Overlay, OverlayWindow, Overlayable},
     wasm_vm::PluginInstruction,
     ClientId, ServerInstruction,
 };
@@ -179,7 +179,7 @@ pub(crate) struct Screen {
     /// The full size of this [`Screen`].
     size: Size,
     /// The overlay that is drawn on top of [`Pane`]'s', [`Tab`]'s and the [`Screen`]
-    _overlay: OverlayWindow,
+    overlay: OverlayWindow,
     /// The indices of this [`Screen`]'s active [`Tab`]s.
     active_tab_indices: BTreeMap<ClientId, usize>,
     tab_history: BTreeMap<ClientId, Vec<usize>>,
@@ -204,7 +204,7 @@ impl Screen {
             colors: client_attributes.palette,
             active_tab_indices: BTreeMap::new(),
             tabs: BTreeMap::new(),
-            _overlay: OverlayWindow::default(),
+            overlay: OverlayWindow::default(),
             tab_history: BTreeMap::new(),
             mode_info,
             draw_pane_frames,
@@ -359,9 +359,12 @@ impl Screen {
     pub fn render(&mut self) {
         let mut output = Output::default();
         let mut tabs_to_close = vec![];
+        let size = self.size;
+        let overlay = self.overlay.clone();
         for (tab_index, tab) in self.tabs.iter_mut() {
             if tab.has_active_panes() {
-                tab.render(&mut output);
+                let vte_overlay = overlay.generate_overlay(size);
+                tab.render(&mut output, Some(vte_overlay));
             } else {
                 tabs_to_close.push(*tab_index);
             }
@@ -405,6 +408,11 @@ impl Screen {
         }
     }
 
+    /// Returns a mutable reference to this [`Screen`]'s active [`Overlays`].
+    pub fn get_active_overlays_mut(&mut self) -> &mut Vec<Overlay> {
+        &mut self.overlay.overlay_stack
+    }
+
     /// Returns a mutable reference to this [`Screen`]'s indexed [`Tab`].
     pub fn get_indexed_tab_mut(&mut self, tab_index: usize) -> Option<&mut Tab> {
         self.get_tabs_mut().get_mut(&tab_index)
@@ -1100,10 +1108,45 @@ pub(crate) fn screen_thread_main(
 
                 screen.render();
             }
-            ScreenInstruction::AddOverlay(_, _) => {}
-            ScreenInstruction::RemoveOverlay(_) => {}
-            ScreenInstruction::ConfirmPrompt(_) => {}
-            ScreenInstruction::DenyPrompt(_) => {}
+            ScreenInstruction::AddOverlay(overlay, _client_id) => {
+                screen.get_active_overlays_mut().pop();
+                screen.get_active_overlays_mut().push(overlay);
+                screen
+                    .bus
+                    .senders
+                    .send_to_server(ServerInstruction::UnblockInputThread)
+                    .unwrap();
+            }
+            ScreenInstruction::RemoveOverlay(_client_id) => {
+                screen.get_active_overlays_mut().pop();
+                screen.render();
+                screen
+                    .bus
+                    .senders
+                    .send_to_server(ServerInstruction::UnblockInputThread)
+                    .unwrap();
+            }
+            ScreenInstruction::ConfirmPrompt(_client_id) => {
+                let overlay = screen.get_active_overlays_mut().pop();
+                let instruction = overlay.map(|o| o.prompt_confirm()).flatten();
+                if let Some(instruction) = instruction {
+                    screen.bus.senders.send_to_server(*instruction).unwrap();
+                }
+                screen
+                    .bus
+                    .senders
+                    .send_to_server(ServerInstruction::UnblockInputThread)
+                    .unwrap();
+            }
+            ScreenInstruction::DenyPrompt(_client_id) => {
+                screen.get_active_overlays_mut().pop();
+                screen.render();
+                screen
+                    .bus
+                    .senders
+                    .send_to_server(ServerInstruction::UnblockInputThread)
+                    .unwrap();
+            }
         }
     }
 }

zellij-server/src/tab.rs

@@ -872,7 +872,7 @@ impl Tab {
             resize_pty!(pane, self.os_api);
         }
     }
-    pub fn render(&mut self, output: &mut Output) {
+    pub fn render(&mut self, output: &mut Output, overlay: Option<String>) {
         if self.connected_clients.is_empty() || self.active_panes.is_empty() {
             return;
         }
@@ -923,6 +923,12 @@ impl Tab {
                         }
                     }
                 }
+
+                // FIXME: Once clients can be distinguished
+                if let Some(overlay_vte) = &overlay {
+                    output.push_str_to_all_clients(overlay_vte);
+                }
+
                 if let Some(vte_output) = pane.render() {
                     // FIXME: Use Termion for cursor and style clearing?
                     output.push_str_to_all_clients(&format!(