feat(tui): improve popup layout and rendering for model selector and theme browser

- Add robust size calculations with configurable width bounds and height clamping.
- Guard against zero‑size areas and empty model/theme lists.
- Render popups centered with dynamic positioning, preventing negative Y coordinates.
- Introduce multi‑line list items, badges, and metadata display for models.
- Add ellipsis helper for long descriptions and separate title/metadata generation.
- Refactor theme selector to show current theme, built‑in/custom indicators, and a centered footer.
- Update highlight styles and selection handling for both popups.

crates/owlen-tui/src/ui.rs

@@ -2655,81 +2655,183 @@ fn model_has_feature(model: &ModelInfo, keywords: &[&str]) -> bool {
 
 fn render_model_selector(frame: &mut Frame<'_>, app: &ChatApp) {
     let theme = app.theme();
-    let area = centered_rect(60, 60, frame.area());
+    let area = frame.area();
-    frame.render_widget(Clear, area);
+    if area.width == 0 || area.height == 0 {
+        return;
+    }
 
-    let items: Vec<ListItem> = app
+    let selector_items = app.model_selector_items();
-        .model_selector_items()
+    if selector_items.is_empty() {
-        .iter()
+        return;
-        .map(|item| match item.kind() {
+    }
+
+    let max_width: u16 = 80;
+    let min_width: u16 = 50;
+    let mut width = area.width.min(max_width);
+    if area.width >= min_width {
+        width = width.max(min_width);
+    }
+    width = width.max(1);
+
+    let mut height = (selector_items.len().clamp(1, 10) as u16) * 3 + 6;
+    height = height.clamp(6, area.height);
+
+    let x = area.x + (area.width.saturating_sub(width)) / 2;
+    let mut y = area.y + (area.height.saturating_sub(height)) / 3;
+    if y < area.y {
+        y = area.y;
+    }
+
+    let popup_area = Rect::new(x, y, width, height);
+    frame.render_widget(Clear, popup_area);
+
+    let title_line = Line::from(vec![
+        Span::styled(
+            " Model Selector ",
+            Style::default().fg(theme.info).add_modifier(Modifier::BOLD),
+        ),
+        Span::styled(
+            format!("· Provider: {}", app.selected_provider),
+            Style::default()
+                .fg(theme.placeholder)
+                .add_modifier(Modifier::DIM),
+        ),
+    ]);
+
+    let block = Block::default()
+        .title(title_line)
+        .borders(Borders::ALL)
+        .border_style(Style::default().fg(theme.info))
+        .style(Style::default().bg(theme.background).fg(theme.text));
+
+    let inner = block.inner(popup_area);
+    frame.render_widget(block, popup_area);
+    if inner.width == 0 || inner.height == 0 {
+        return;
+    }
+
+    let layout = Layout::default()
+        .direction(Direction::Vertical)
+        .constraints([Constraint::Min(4), Constraint::Length(2)])
+        .split(inner);
+
+    let active_model_id = app.selected_model();
+
+    let mut items: Vec<ListItem> = Vec::new();
+    for item in selector_items.iter() {
+        match item.kind() {
             ModelSelectorItemKind::Header { provider, expanded } => {
                 let marker = if *expanded { "▼" } else { "▶" };
-                let label = format!("{} {}", marker, provider);
+                let lines = vec![Line::from(vec![
-                ListItem::new(Span::styled(
+                    Span::styled(
-                    label,
+                        marker,
-                    Style::default()
+                        Style::default()
-                        .fg(theme.focused_panel_border)
+                            .fg(theme.placeholder)
-                        .add_modifier(Modifier::BOLD),
+                            .add_modifier(Modifier::BOLD),
-                ))
+                    ),
+                    Span::raw(" "),
+                    Span::styled(
+                        provider.clone(),
+                        Style::default()
+                            .fg(theme.mode_command)
+                            .add_modifier(Modifier::BOLD),
+                    ),
+                ])];
+                items.push(ListItem::new(lines).style(Style::default().bg(theme.background)));
             }
             ModelSelectorItemKind::Model { model_index, .. } => {
+                let mut lines = Vec::new();
                 if let Some(model) = app.model_info_by_index(*model_index) {
                     let badges = model_badge_icons(model);
                     let detail = app.cached_model_detail(&model.id);
-                    let label = build_model_selector_label(model, detail, &badges);
+                    let (title, metadata) = build_model_selector_label(
-                    ListItem::new(Span::styled(
+                        model,
-                        label,
+                        detail,
-                        Style::default()
+                        &badges,
-                            .fg(theme.user_message_role)
+                        model.id == active_model_id,
-                            .add_modifier(Modifier::BOLD),
+                    );
-                    ))
+                    lines.push(Line::from(Span::styled(
+                        title,
+                        Style::default().fg(theme.text),
+                    )));
+                    if let Some(meta) = metadata {
+                        lines.push(Line::from(Span::styled(
+                            meta,
+                            Style::default()
+                                .fg(theme.placeholder)
+                                .add_modifier(Modifier::DIM),
+                        )));
+                    }
                 } else {
-                    ListItem::new(Span::styled(
+                    lines.push(Line::from(Span::styled(
                         "  <model unavailable>",
                         Style::default().fg(theme.error),
-                    ))
+                    )));
                 }
+                items.push(ListItem::new(lines).style(Style::default().bg(theme.background)));
             }
-            ModelSelectorItemKind::Empty { provider } => ListItem::new(Span::styled(
+            ModelSelectorItemKind::Empty { provider } => {
-                format!("  (no models configured for {provider})"),
+                let lines = vec![Line::from(Span::styled(
-                Style::default()
+                    format!("  (no models configured for {provider})"),
-                    .fg(theme.unfocused_panel_border)
-                    .add_modifier(Modifier::ITALIC),
-            )),
-        })
-        .collect();
-
-    let list = List::new(items)
-        .block(
-            Block::default()
-                .title(Span::styled(
-                    "Select Model — 🔧 tools • 🧠 thinking • 👁️ vision • 🎧 audio",
                     Style::default()
-                        .fg(theme.focused_panel_border)
+                        .fg(theme.placeholder)
-                        .add_modifier(Modifier::BOLD),
+                        .add_modifier(Modifier::DIM | Modifier::ITALIC),
-                ))
+                ))];
-                .borders(Borders::ALL)
+                items.push(ListItem::new(lines).style(Style::default().bg(theme.background)));
-                .style(Style::default().bg(theme.background).fg(theme.text)),
+            }
-        )
+        }
-        .highlight_style(
+    }
-            Style::default()
+
-                .fg(theme.focused_panel_border)
+    let highlight_style = Style::default()
-                .add_modifier(Modifier::BOLD),
+        .bg(theme.selection_bg)
-        )
+        .fg(theme.selection_fg)
-        .highlight_symbol("▶ ");
+        .add_modifier(Modifier::BOLD);
 
     let mut state = ListState::default();
     state.select(app.selected_model_item());
-    frame.render_stateful_widget(list, area, &mut state);
+
+    let list = List::new(items)
+        .highlight_style(highlight_style)
+        .highlight_symbol("  ")
+        .style(Style::default().bg(theme.background).fg(theme.text));
+
+    frame.render_stateful_widget(list, layout[0], &mut state);
+
+    let footer = Paragraph::new(Line::from(Span::styled(
+        "Enter: select · Space: toggle provider · ←/→ collapse/expand · Esc: cancel",
+        Style::default().fg(theme.placeholder),
+    )))
+    .alignment(Alignment::Center)
+    .style(Style::default().bg(theme.background).fg(theme.placeholder));
+    frame.render_widget(footer, layout[1]);
 }
 
 fn build_model_selector_label(
     model: &ModelInfo,
     detail: Option<&DetailedModelInfo>,
     badges: &[&'static str],
-) -> String {
+    is_current: bool,
-    let mut parts = vec![model.id.clone()];
+) -> (String, Option<String>) {
+    let mut display_name = if model.name.trim().is_empty() {
+        model.id.clone()
+    } else {
+        model.name.clone()
+    };
 
+    if !display_name.eq_ignore_ascii_case(&model.id) {
+        display_name.push_str(&format!(" · {}", model.id));
+    }
+
+    let mut title = format!("  {}", display_name);
+    if !badges.is_empty() {
+        title.push(' ');
+        title.push_str(&badges.join(" "));
+    }
+    if is_current {
+        title.push_str("  ✓");
+    }
+
+    let mut meta_parts: Vec<String> = Vec::new();
     if let Some(detail) = detail {
         if let Some(parameters) = detail
             .parameter_size
@@ -2737,24 +2839,54 @@ fn build_model_selector_label(
             .or(detail.parameters.as_ref())
             && !parameters.trim().is_empty()
         {
-            parts.push(parameters.trim().to_string());
+            meta_parts.push(parameters.trim().to_string());
         }
 
         if let Some(size) = detail.size {
-            parts.push(format_short_size(size));
+            meta_parts.push(format_short_size(size));
         }
 
         if let Some(ctx) = detail.context_length {
-            parts.push(format!("ctx {}", ctx));
+            meta_parts.push(format!("ctx {}", ctx));
+        }
+
+        if let Some(quant) = detail
+            .quantization
+            .as_ref()
+            .filter(|q| !q.trim().is_empty())
+        {
+            meta_parts.push(quant.trim().to_string());
         }
     }
 
-    let mut label = format!("  {}", parts.join(" • "));
+    if let Some(desc) = model.description.as_deref() {
-    if !badges.is_empty() {
+        let trimmed = desc.trim();
-        label.push(' ');
+        if !trimmed.is_empty() {
-        label.push_str(&badges.join(" "));
+            meta_parts.push(ellipsize(trimmed, 80));
+        }
     }
-    label
+
+    let metadata = if meta_parts.is_empty() {
+        None
+    } else {
+        Some(format!("    {}", meta_parts.join(" • ")))
+    };
+
+    (title, metadata)
+}
+
+fn ellipsize(text: &str, max_chars: usize) -> String {
+    if text.chars().count() <= max_chars {
+        return text.to_string();
+    }
+
+    let target = max_chars.saturating_sub(1).max(1);
+    let mut truncated = String::new();
+    for ch in text.chars().take(target) {
+        truncated.push(ch);
+    }
+    truncated.push('…');
+    truncated
 }
 
 fn format_short_size(bytes: u64) -> String {
@@ -3634,123 +3766,142 @@ fn render_session_browser(frame: &mut Frame<'_>, app: &ChatApp) {
 
 fn render_theme_browser(frame: &mut Frame<'_>, app: &ChatApp) {
     let theme = app.theme();
-    let area = centered_rect(60, 70, frame.area());
+    let area = frame.area();
-    frame.render_widget(Clear, area);
+    if area.width == 0 || area.height == 0 {
+        return;
+    }
 
     let themes = app.available_themes();
     let current_theme_name = &app.theme().name;
 
-    if themes.is_empty() {
+    let max_width: u16 = 80;
-        let text = vec![
+    let min_width: u16 = 40;
-            Line::from(""),
+    let mut width = area.width.min(max_width);
-            Line::from("No themes available."),
+    if area.width >= min_width {
-            Line::from(""),
+        width = width.max(min_width);
-            Line::from("Press Esc to close."),
+    } else {
-        ];
+        width = area.width;
+    }
+    width = width.max(1);
 
-        let paragraph = Paragraph::new(text)
+    let visible_rows = themes.len().clamp(1, 12) as u16;
-            .style(Style::default().bg(theme.background))
+    let mut height = visible_rows.saturating_mul(2).saturating_add(6);
-            .block(
+    height = height.clamp(6, area.height);
-                Block::default()
-                    .title(Span::styled(
-                        " Themes ",
-                        Style::default()
-                            .fg(theme.mode_help)
-                            .add_modifier(Modifier::BOLD),
-                    ))
-                    .borders(Borders::ALL)
-                    .border_style(Style::default().fg(theme.mode_help))
-                    .style(Style::default().bg(theme.background).fg(theme.text)),
-            )
-            .alignment(Alignment::Center);
 
-        frame.render_widget(paragraph, area);
+    let x = area.x + (area.width.saturating_sub(width)) / 2;
+    let mut y = area.y + (area.height.saturating_sub(height)) / 3;
+    if y < area.y {
+        y = area.y;
+    }
+
+    let popup_area = Rect::new(x, y, width, height);
+    frame.render_widget(Clear, popup_area);
+
+    let title_line = Line::from(vec![
+        Span::styled(
+            " Theme Selector ",
+            Style::default().fg(theme.info).add_modifier(Modifier::BOLD),
+        ),
+        Span::styled(
+            format!("· Current: {}", current_theme_name),
+            Style::default()
+                .fg(theme.placeholder)
+                .add_modifier(Modifier::DIM),
+        ),
+    ]);
+
+    let block = Block::default()
+        .title(title_line)
+        .borders(Borders::ALL)
+        .border_style(Style::default().fg(theme.info))
+        .style(Style::default().bg(theme.background).fg(theme.text));
+
+    let inner = block.inner(popup_area);
+    frame.render_widget(block, popup_area);
+    if inner.width == 0 || inner.height == 0 {
         return;
     }
 
-    // Get theme metadata to show built-in vs custom
+    if themes.is_empty() {
-    let all_themes = owlen_core::theme::load_all_themes();
+        let empty = Paragraph::new(Line::from(Span::styled(
-    let built_in = owlen_core::theme::built_in_themes();
+            "No themes available · Press Esc to close",
-
+            Style::default()
-    let items: Vec<ListItem> = themes
+                .fg(theme.placeholder)
-        .iter()
+                .add_modifier(Modifier::DIM | Modifier::ITALIC),
-        .enumerate()
+        )))
-        .map(|(idx, theme_name)| {
+        .alignment(Alignment::Center)
-            let is_current = theme_name == current_theme_name;
+        .style(Style::default().bg(theme.background).fg(theme.placeholder));
-            let is_selected = idx == app.selected_theme_index();
+        frame.render_widget(empty, inner);
-            let is_built_in = built_in.contains_key(theme_name);
+        return;
-
+    }
-            // Build display name
-            let mut display = theme_name.clone();
-            if is_current {
-                display.push_str(" ✓");
-            }
-
-            let type_indicator = if is_built_in { "built-in" } else { "custom" };
-
-            let name_style = if is_selected {
-                Style::default()
-                    .fg(theme.selection_fg)
-                    .bg(theme.selection_bg)
-                    .add_modifier(Modifier::BOLD)
-            } else if is_current {
-                Style::default()
-                    .fg(theme.focused_panel_border)
-                    .add_modifier(Modifier::BOLD)
-            } else {
-                Style::default().fg(theme.text)
-            };
-
-            let info_style = if is_selected {
-                Style::default()
-                    .fg(theme.selection_fg)
-                    .bg(theme.selection_bg)
-            } else {
-                Style::default().fg(theme.placeholder)
-            };
-
-            // Try to get theme description or show type
-            let info_text = if all_themes.contains_key(theme_name) {
-                format!("  {} · {}", type_indicator, theme_name)
-            } else {
-                format!("  {}", type_indicator)
-            };
-
-            let lines = vec![
-                Line::from(Span::styled(display, name_style)),
-                Line::from(Span::styled(info_text, info_style)),
-            ];
-
-            ListItem::new(lines)
-        })
-        .collect();
-
-    let list = List::new(items).block(
-        Block::default()
-            .title(Span::styled(
-                format!(" Themes ({}) ", themes.len()),
-                Style::default()
-                    .fg(theme.mode_help)
-                    .add_modifier(Modifier::BOLD),
-            ))
-            .borders(Borders::ALL)
-            .border_style(Style::default().fg(theme.mode_help))
-            .style(Style::default().bg(theme.background).fg(theme.text)),
-    );
-
-    let footer = Paragraph::new(vec![
-        Line::from(""),
-        Line::from("↑/↓ or j/k: Navigate · Enter: Apply theme · g/G: Top/Bottom · Esc: Cancel"),
-    ])
-    .alignment(Alignment::Center)
-    .style(Style::default().fg(theme.placeholder).bg(theme.background));
 
     let layout = Layout::default()
         .direction(Direction::Vertical)
-        .constraints([Constraint::Min(5), Constraint::Length(3)])
+        .constraints([Constraint::Min(4), Constraint::Length(2)])
-        .split(area);
+        .split(inner);
+
+    let built_in = owlen_core::theme::built_in_themes();
+    let mut items: Vec<ListItem> = Vec::with_capacity(themes.len());
+    for theme_name in themes.iter() {
+        let is_current = theme_name == current_theme_name;
+        let descriptor = if built_in.contains_key(theme_name) {
+            "Built-in theme"
+        } else {
+            "Custom theme"
+        };
+
+        let mut title = format!("  {}", theme_name);
+        if is_current {
+            title.push_str("  ✓");
+        }
+
+        let mut title_style = Style::default().fg(theme.text);
+        if is_current {
+            title_style = title_style
+                .fg(theme.focused_panel_border)
+                .add_modifier(Modifier::BOLD);
+        }
+
+        let metadata_style = Style::default()
+            .fg(theme.placeholder)
+            .add_modifier(Modifier::DIM);
+
+        let lines = vec![
+            Line::from(Span::styled(title, title_style)),
+            Line::from(vec![
+                Span::raw("    "),
+                Span::styled(descriptor, metadata_style),
+            ]),
+        ];
+
+        items.push(ListItem::new(lines).style(Style::default().bg(theme.background)));
+    }
+
+    let highlight_style = Style::default()
+        .bg(theme.selection_bg)
+        .fg(theme.selection_fg)
+        .add_modifier(Modifier::BOLD);
+
+    let mut state = ListState::default();
+    let selected_index = app
+        .selected_theme_index()
+        .min(themes.len().saturating_sub(1));
+    state.select(Some(selected_index));
+
+    let list = List::new(items)
+        .highlight_style(highlight_style)
+        .highlight_symbol("  ")
+        .style(Style::default().bg(theme.background).fg(theme.text));
+
+    frame.render_stateful_widget(list, layout[0], &mut state);
+
+    let footer = Paragraph::new(Line::from(Span::styled(
+        "↑/↓ or j/k: Navigate · Enter: Apply theme · g/G: Top/Bottom · Esc: Cancel",
+        Style::default().fg(theme.placeholder),
+    )))
+    .alignment(Alignment::Center)
+    .style(Style::default().bg(theme.background).fg(theme.placeholder));
 
-    frame.render_widget(list, layout[0]);
     frame.render_widget(footer, layout[1]);
 }