fix: keep onboarding footer visible

Author: wangtsiao

crates/tui/src/inline_onboarding_tests.rs

@@ -26,18 +26,26 @@ use crate::tui::frame_requester::FrameRequester;
 fn onboarding_widget_with_available_model(
     model: Model,
     cwd: PathBuf,
+) -> (ChatWidget, mpsc::UnboundedReceiver<AppEvent>) {
+    onboarding_widget_with_models(vec![model.clone()], Some(model), cwd)
+}
+
+fn onboarding_widget_with_models(
+    models: Vec<Model>,
+    initial_model: Option<Model>,
+    cwd: PathBuf,
 ) -> (ChatWidget, mpsc::UnboundedReceiver<AppEvent>) {
     let (app_event_tx, app_event_rx) = mpsc::unbounded_channel();
     let widget = ChatWidget::new_with_app_event(ChatWidgetInit {
         frame_requester: FrameRequester::test_dummy(),
         app_event_tx: AppEventSender::new(app_event_tx),
-        initial_session: TuiSessionState::new(cwd, Some(model.clone())),
+        initial_session: TuiSessionState::new(cwd, initial_model),
         initial_reasoning_effort_selection: None,
         initial_permission_preset: devo_protocol::PermissionPreset::Default,
         initial_user_message: None,
         enhanced_keys_supported: true,
         is_first_run: false,
-        available_models: vec![model],
+        available_models: models,
         saved_models: Vec::new(),
         show_model_onboarding: true,
         exit_after_onboarding: false,
@@ -113,9 +121,42 @@ fn first_run_onboarding_starts_with_logo_and_hides_composer() {
 
     let rows = rendered_rows(&widget, 100, 24).join("\n");
     assert!(rows.contains("Choose model profile"));
+    assert!(rows.contains("Enter select  ·  Esc cancel"));
     assert!(!rows.contains("Complete onboarding to start chatting"));
     assert!(!rows.contains("SHIFT+TAB switch"));
     assert!(widget.desired_height(100) < u16::MAX);
+
+    let rows = rendered_rows(&widget, 100, widget.desired_height(100)).join("\n");
+    assert!(rows.contains("Enter select  ·  Esc cancel"));
+}
+
+#[test]
+fn model_selection_footer_stays_visible_in_short_viewport() {
+    let cwd = std::env::current_dir().expect("current directory is available");
+    let models = (0..12)
+        .map(|idx| Model {
+            slug: format!("model-{idx:02}"),
+            display_name: format!("Model {idx:02} Display Name"),
+            ..Model::default()
+        })
+        .collect::<Vec<_>>();
+    let initial_model = models.first().cloned();
+    let (mut widget, _app_event_rx) = onboarding_widget_with_models(models, initial_model, cwd);
+
+    for _ in 0..10 {
+        widget.handle_key_event(press_key(KeyCode::Down));
+    }
+
+    let rows = rendered_rows(&widget, 80, 8).join("\n");
+    assert!(
+        rows.contains("model-10"),
+        "expected selected model in:\n{rows}"
+    );
+    assert!(
+        rows.contains("Enter select  ·  Esc cancel"),
+        "expected fixed onboarding footer in:\n{rows}"
+    );
+    assert!(!rows.contains("Complete onboarding to start chatting"));
 }
 
 #[test]

crates/tui/src/onboarding_viewport.rs

@@ -44,6 +44,45 @@ pub(crate) fn render_lines_with_anchor(
     render_scrolled_paragraph(paragraph, total_rows, scroll_offset, area, buf);
 }
 
+pub(crate) fn render_lines_with_fixed_footer(
+    body_lines: Vec<Line<'static>>,
+    footer_lines: Vec<Line<'static>>,
+    anchor: Option<ViewportAnchor>,
+    area: Rect,
+    buf: &mut Buffer,
+) {
+    if area.width == 0 || area.height == 0 {
+        return;
+    }
+
+    let footer_paragraph =
+        Paragraph::new(Text::from(footer_lines.clone())).wrap(Wrap { trim: false });
+    let footer_rows = footer_paragraph.line_count(area.width);
+    let footer_height = u16::try_from(footer_rows)
+        .unwrap_or(u16::MAX)
+        .min(area.height);
+    let body_height = area.height.saturating_sub(footer_height);
+
+    if body_height > 0 {
+        render_lines_with_anchor(
+            body_lines,
+            anchor,
+            Rect {
+                height: body_height,
+                ..area
+            },
+            buf,
+        );
+    }
+
+    let footer_area = Rect {
+        y: area.y.saturating_add(body_height),
+        height: footer_height,
+        ..area
+    };
+    render_footer_paragraph(footer_paragraph, footer_rows, footer_area, buf);
+}
+
 fn scroll_offset_for_anchor(
     lines: &[Line<'static>],
     anchor: ViewportAnchor,
@@ -84,6 +123,26 @@ fn wrapped_row_count(lines: &[Line<'static>], width: u16) -> usize {
         .line_count(width)
 }
 
+fn render_footer_paragraph(
+    paragraph: Paragraph<'_>,
+    total_rows: usize,
+    area: Rect,
+    buf: &mut Buffer,
+) {
+    if area.height == 0 {
+        return;
+    }
+
+    let visible_rows = area.height as usize;
+    if total_rows <= visible_rows {
+        paragraph.render(area, buf);
+        return;
+    }
+
+    let scroll_offset = total_rows.saturating_sub(visible_rows);
+    render_scrolled_paragraph(paragraph, total_rows, scroll_offset, area, buf);
+}
+
 fn render_scrolled_paragraph(
     paragraph: Paragraph<'_>,
     total_rows: usize,

crates/tui/src/onboarding_widget.rs

@@ -42,6 +42,7 @@ use crate::bottom_pane::scroll_state::ScrollState;
 use crate::exec_cell::spinner;
 use crate::onboarding_viewport::ViewportAnchor;
 use crate::onboarding_viewport::render_lines_with_anchor;
+use crate::onboarding_viewport::render_lines_with_fixed_footer;
 use crate::render::renderable::Renderable;
 use crate::tui::frame_requester::FrameRequester;
 
@@ -796,6 +797,7 @@ impl OnboardingWidget {
         }
         let current = state.selected_idx.unwrap_or(0);
         state.selected_idx = Some(if current == 0 { len - 1 } else { current - 1 });
+        state.ensure_visible(len, MAX_POPUP_ROWS.min(len));
     }
 
     fn model_move_down(state: &mut ScrollState, filtered_indices: &[usize]) {
@@ -805,6 +807,7 @@ impl OnboardingWidget {
         }
         let current = state.selected_idx.unwrap_or(0);
         state.selected_idx = Some((current + 1) % len);
+        state.ensure_visible(len, MAX_POPUP_ROWS.min(len));
     }
 
     fn model_apply_filter(
@@ -832,6 +835,7 @@ impl OnboardingWidget {
         } else {
             Some(0)
         };
+        state.scroll_top = 0;
     }
 
     fn custom_model_name_handle_key(&mut self, key: KeyEvent) {
@@ -2070,15 +2074,9 @@ impl OnboardingWidget {
 
         let max_visible = MAX_POPUP_ROWS.min(filtered_indices.len().max(1));
         let scroll_offset = state
-            .selected_idx
-            .map(|sel| {
-                if sel >= max_visible.saturating_sub(2) {
-                    sel.saturating_sub(max_visible.saturating_sub(3))
-                } else {
-                    0
-                }
-            })
-            .unwrap_or(0);
+            .scroll_top
+            .min(filtered_indices.len().saturating_sub(max_visible));
+        let mut anchor = None;
 
         for (vis_idx, &actual_idx) in filtered_indices
             .iter()
@@ -2088,20 +2086,25 @@ impl OnboardingWidget {
         {
             if let Some(item) = items.get(actual_idx) {
                 let is_selected = state.selected_idx == Some(vis_idx);
+                let start = lines.len();
                 let description = if item.display_name == item.slug {
                     None
                 } else {
                     Some(item.display_name.clone())
                 };
                 Self::render_option_row(&mut lines, item.slug.clone(), description, is_selected);
+                if is_selected {
+                    anchor = Some(ViewportAnchor {
+                        start,
+                        end: lines.len(),
+                    });
+                }
             }
         }
 
-        Self::render_footer(&mut lines, "Enter select", "Esc cancel");
-
-        Paragraph::new(lines)
-            .wrap(Wrap { trim: false })
-            .render(content_area, buf);
+        let mut footer_lines = Vec::new();
+        Self::render_footer(&mut footer_lines, "Enter select", "Esc cancel");
+        render_lines_with_fixed_footer(lines, footer_lines, anchor, content_area, buf);
     }
 
     fn render_custom_model_name(input: &str, cursor_pos: usize, area: Rect, buf: &mut Buffer) {
@@ -2421,10 +2424,24 @@ impl Renderable for OnboardingWidget {
     fn desired_height(&self, _width: u16) -> u16 {
         match &self.state {
             OnboardingState::ModelSelection {
-                filtered_indices, ..
+                items,
+                state,
+                filtered_indices,
+                ..
             } => {
-                let items = MAX_POPUP_ROWS.min(filtered_indices.len().max(1)) as u16;
-                items + 8
+                let max_visible = MAX_POPUP_ROWS.min(filtered_indices.len().max(1));
+                let scroll_offset = state
+                    .scroll_top
+                    .min(filtered_indices.len().saturating_sub(max_visible));
+                let option_rows = filtered_indices
+                    .iter()
+                    .skip(scroll_offset)
+                    .take(max_visible)
+                    .filter_map(|idx| items.get(*idx))
+                    .map(|item| if item.display_name == item.slug { 1 } else { 2 })
+                    .sum::<u16>()
+                    .max(1);
+                option_rows + 9
             }
             OnboardingState::CustomModelName { .. } => 8,
             OnboardingState::ProviderSelection { items, .. } => items.len() as u16 * 2 + 6,