rework message styling (#2877)

https://github.com/user-attachments/assets/cf07f62b-1895-44bb-b9c3-7a12032eb371

codex-rs/tui/src/bottom_pane/chat_composer.rs

@@ -27,6 +27,7 @@ use super::command_popup::CommandPopup;
 use super::file_search_popup::FileSearchPopup;
 use super::paste_burst::CharDecision;
 use super::paste_burst::PasteBurst;
+use crate::bottom_pane::paste_burst::FlushResult;
 use crate::slash_command::SlashCommand;
 use codex_protocol::custom_prompts::CustomPrompt;
 
@@ -223,7 +224,7 @@ impl ChatComposer {
             let placeholder = format!("[Pasted Content {char_count} chars]");
             self.textarea.insert_element(&placeholder);
             self.pending_pastes.push((placeholder, pasted));
-        } else if self.handle_paste_image_path(pasted.clone()) {
+        } else if char_count > 1 && self.handle_paste_image_path(pasted.clone()) {
             self.textarea.insert_str(" ");
         } else {
             self.textarea.insert_str(&pasted);
@@ -298,12 +299,7 @@ impl ChatComposer {
     }
 
     pub(crate) fn flush_paste_burst_if_due(&mut self) -> bool {
-        let now = Instant::now();
-        if let Some(pasted) = self.paste_burst.flush_if_due(now) {
-            let _ = self.handle_paste(pasted);
-            return true;
-        }
-        false
+        self.handle_paste_burst_flush(Instant::now())
     }
 
     pub(crate) fn is_in_paste_burst(&self) -> bool {
@@ -396,9 +392,11 @@ impl ChatComposer {
             KeyEvent {
                 code: KeyCode::Tab, ..
             } => {
+                // Ensure popup filtering/selection reflects the latest composer text
+                // before applying completion.
+                let first_line = self.textarea.text().lines().next().unwrap_or("");
+                popup.on_composer_text_change(first_line.to_string());
                 if let Some(sel) = popup.selected_item() {
-                    let first_line = self.textarea.text().lines().next().unwrap_or("");
-
                     match sel {
                         CommandItem::Builtin(cmd) => {
                             let starts_with_cmd = first_line
@@ -853,15 +851,36 @@ impl ChatComposer {
         }
     }
 
+    fn handle_paste_burst_flush(&mut self, now: Instant) -> bool {
+        match self.paste_burst.flush_if_due(now) {
+            FlushResult::Paste(pasted) => {
+                self.handle_paste(pasted);
+                true
+            }
+            FlushResult::Typed(ch) => {
+                // Mirror insert_str() behavior so popups stay in sync when a
+                // pending fast char flushes as normal typed input.
+                self.textarea.insert_str(ch.to_string().as_str());
+                // Keep popup sync consistent with key handling: prefer slash popup; only
+                // sync file popup when slash popup is NOT active.
+                self.sync_command_popup();
+                if matches!(self.active_popup, ActivePopup::Command(_)) {
+                    self.dismissed_file_popup_token = None;
+                } else {
+                    self.sync_file_search_popup();
+                }
+                true
+            }
+            FlushResult::None => false,
+        }
+    }
+
     /// Handle generic Input events that modify the textarea content.
     fn handle_input_basic(&mut self, input: KeyEvent) -> (InputResult, bool) {
         // If we have a buffered non-bracketed paste burst and enough time has
         // elapsed since the last char, flush it before handling a new input.
         let now = Instant::now();
-        if let Some(pasted) = self.paste_burst.flush_if_due(now) {
-            // Reuse normal paste path (handles large-paste placeholders).
-            self.handle_paste(pasted);
-        }
+        self.handle_paste_burst_flush(now);
 
         // If we're capturing a burst and receive Enter, accumulate it instead of inserting.
         if matches!(input.code, KeyCode::Enter)
@@ -1672,6 +1691,66 @@ mod tests {
         }
     }
 
+    #[test]
+    fn slash_popup_model_first_for_mo_ui() {
+        use insta::assert_snapshot;
+        use ratatui::Terminal;
+        use ratatui::backend::TestBackend;
+
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+
+        let mut composer = ChatComposer::new(
+            true,
+            sender,
+            false,
+            "Ask Codex to do anything".to_string(),
+            false,
+        );
+
+        // Type "/mo" humanlike so paste-burst doesn’t interfere.
+        type_chars_humanlike(&mut composer, &['/', 'm', 'o']);
+
+        let mut terminal = match Terminal::new(TestBackend::new(60, 4)) {
+            Ok(t) => t,
+            Err(e) => panic!("Failed to create terminal: {e}"),
+        };
+        terminal
+            .draw(|f| f.render_widget_ref(composer, f.area()))
+            .unwrap_or_else(|e| panic!("Failed to draw composer: {e}"));
+
+        // Visual snapshot should show the slash popup with /model as the first entry.
+        assert_snapshot!("slash_popup_mo", terminal.backend());
+    }
+
+    #[test]
+    fn slash_popup_model_first_for_mo_logic() {
+        use super::super::command_popup::CommandItem;
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+        let mut composer = ChatComposer::new(
+            true,
+            sender,
+            false,
+            "Ask Codex to do anything".to_string(),
+            false,
+        );
+        type_chars_humanlike(&mut composer, &['/', 'm', 'o']);
+
+        match &composer.active_popup {
+            ActivePopup::Command(popup) => match popup.selected_item() {
+                Some(CommandItem::Builtin(cmd)) => {
+                    assert_eq!(cmd.command(), "model")
+                }
+                Some(CommandItem::UserPrompt(_)) => {
+                    panic!("unexpected prompt selected for '/mo'")
+                }
+                None => panic!("no selected command for '/mo'"),
+            },
+            _ => panic!("slash popup not active after typing '/mo'"),
+        }
+    }
+
     // Test helper: simulate human typing with a brief delay and flush the paste-burst buffer
     fn type_chars_humanlike(composer: &mut ChatComposer, chars: &[char]) {
         use crossterm::event::KeyCode;