insert history lines with redraw (#1769)

This delays the call to insert_history_lines until a redraw is
happening. Crucially, the new lines are inserted _after the viewport is
resized_. This results in fewer stray blank lines below the viewport
when modals (e.g. user approval) are closed.

codex-rs/tui/src/app.rs

@@ -17,6 +17,7 @@ use crossterm::event::KeyEvent;
 use crossterm::event::KeyEventKind;
 use ratatui::layout::Offset;
 use ratatui::prelude::Backend;
+use ratatui::text::Line;
 use std::path::PathBuf;
 use std::sync::Arc;
 use std::sync::atomic::AtomicBool;
@@ -55,6 +56,8 @@ pub(crate) struct App<'a> {
     /// True when a redraw has been scheduled but not yet executed.
     pending_redraw: Arc<AtomicBool>,
 
+    pending_history_lines: Vec<Line<'static>>,
+
     /// Stored parameters needed to instantiate the ChatWidget later, e.g.,
     /// after dismissing the Git-repo warning.
     chat_args: Option<ChatWidgetArgs>,
@@ -152,6 +155,7 @@ impl App<'_> {
         let file_search = FileSearchManager::new(config.cwd.clone(), app_event_tx.clone());
         Self {
             app_event_tx,
+            pending_history_lines: Vec::new(),
             app_event_rx,
             app_state,
             config,
@@ -197,7 +201,7 @@ impl App<'_> {
         while let Ok(event) = self.app_event_rx.recv() {
             match event {
                 AppEvent::InsertHistory(lines) => {
-                    crate::insert_history::insert_history_lines(terminal, lines);
+                    self.pending_history_lines.extend(lines);
                     self.app_event_tx.send(AppEvent::RequestRedraw);
                 }
                 AppEvent::RequestRedraw => {
@@ -409,6 +413,13 @@ impl App<'_> {
             terminal.clear()?;
             terminal.set_viewport_area(area);
         }
+        if !self.pending_history_lines.is_empty() {
+            crate::insert_history::insert_history_lines(
+                terminal,
+                self.pending_history_lines.clone(),
+            );
+            self.pending_history_lines.clear();
+        }
         match &mut self.app_state {
             AppState::Chat { widget } => {
                 terminal.draw(|frame| frame.render_widget_ref(&**widget, frame.area()))?;