[tui] Add TitleBar popups for drop-down menus.

src/tui/app.rs

@@ -199,7 +199,6 @@ impl<'a> Widget for &mut App<'a> {
             ])
             .split(horizontal[1]);
 
-        self.title_bar.render(vertical[0], buf);
         self.draw_bottom_status(vertical[3], buf);
         self.draw_tabs(editor_layout[0], buf);
         let id = App::id().to_string();
@@ -209,6 +208,9 @@ impl<'a> Widget for &mut App<'a> {
             .context("Failed to render Explorer")
             .unwrap_or_else(|e| error!(target:id.as_str(), "{}", e));
         self.logger.render(vertical[2], buf);
+
+        // The title bar is rendered last to overlay any popups created for drop-down menus.
+        self.title_bar.render(vertical[0], buf);
     }
 }
 

src/tui/title_bar.rs

@@ -2,21 +2,22 @@ use crate::tui::component::{Action, Component, ComponentState};
 use ratatui::buffer::Buffer;
 use ratatui::crossterm::event::{KeyCode, KeyEvent};
 use ratatui::layout::Rect;
-use ratatui::style::{Color, Style};
+use ratatui::style::{Color, Modifier, Style};
 use ratatui::text::Line;
-use ratatui::widgets::{Block, Borders, Tabs, Widget};
+use ratatui::widgets::{
+    Block, Borders, Clear, List, ListItem, ListState, StatefulWidget, Tabs, Widget,
+};
 use strum::{EnumIter, FromRepr, IntoEnumIterator};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, FromRepr, EnumIter)]
 enum TitleBarItem {
     File,
-    Edit,
     View,
     Help,
 }
 
 impl TitleBarItem {
-    pub fn next(mut self) -> Self {
+    pub fn next(self) -> Self {
         let cur = self as usize;
         let next = cur.saturating_add(1);
         Self::from_repr(next).unwrap_or(self)
@@ -31,26 +32,35 @@ impl TitleBarItem {
     pub fn id(&self) -> &str {
         match self {
             TitleBarItem::File => "File",
-            TitleBarItem::Edit => "Edit",
             TitleBarItem::View => "View",
             TitleBarItem::Help => "Help",
         }
     }
+
+    pub fn options(&self) -> &[&str] {
+        match self {
+            TitleBarItem::File => &["Save", "Reload"],
+            TitleBarItem::View => &["Show/hide explorer", "Show/hide logger"],
+            TitleBarItem::Help => &["About"],
+        }
+    }
 }
 
 pub struct TitleBar {
     selected: TitleBarItem,
     opened: Option<TitleBarItem>,
     pub(crate) component_state: ComponentState,
+    list_state: ListState,
 }
 
 impl TitleBar {
+    const DEFAULT_HELP: &str = "(←/h)/(→/l): Select option | Enter: Choose selection";
     pub fn new() -> Self {
         Self {
             selected: TitleBarItem::File,
             opened: None,
-            component_state: ComponentState::default()
-                .with_help_text(concat!("TODO: Title bar help text.").as_ref()),
+            component_state: ComponentState::default().with_help_text(Self::DEFAULT_HELP),
+            list_state: ListState::default().with_selected(Some(0)),
         }
     }
 
@@ -71,10 +81,44 @@ impl TitleBar {
             .select(self.selected as usize)
             .render(area, buf);
     }
-}
 
-impl Widget for &TitleBar {
-    fn render(self, area: Rect, buf: &mut Buffer)
+    fn render_drop_down(
+        &mut self,
+        title_bar_anchor: Rect,
+        area: Rect,
+        buf: &mut Buffer,
+        opened: TitleBarItem,
+    ) {
+        let popup_area = Self::rect_under_option(title_bar_anchor, area, 40, 10);
+        Clear::default().render(popup_area, buf);
+        let options = opened.options().iter().map(|i| ListItem::new(*i));
+        StatefulWidget::render(
+            List::new(options)
+                .block(Block::bordered().title(self.selected.id()))
+                .highlight_style(
+                    Style::default()
+                        .bg(Color::Blue)
+                        .fg(Color::White)
+                        .add_modifier(Modifier::BOLD),
+                )
+                .highlight_symbol(">> "),
+            popup_area,
+            buf,
+            &mut self.list_state,
+        );
+    }
+
+    fn rect_under_option(anchor: Rect, area: Rect, width: u16, height: u16) -> Rect {
+        // TODO: X offset for item option? It's fine as-is, but it might look nicer.
+        Rect {
+            x: anchor.x,
+            y: anchor.y + anchor.height,
+            width: width.min(area.width),
+            height,
+        }
+    }
+
+    pub fn render(&mut self, area: Rect, buf: &mut Buffer)
     where
         Self: Sized,
     {
@@ -85,14 +129,40 @@ impl Widget for &TitleBar {
             height: 3,
         };
         self.render_title_bar(title_bar_area, buf);
+        if let Some(opened) = self.opened {
+            self.render_drop_down(title_bar_area, area, buf, opened);
+        }
     }
 }
 
 impl Component for TitleBar {
     fn handle_key_events(&mut self, key: KeyEvent) -> anyhow::Result<Action> {
+        if self.opened.is_some() {
+            // Keybinds for popup menu.
+            match key.code {
+                KeyCode::Up | KeyCode::Char('k') => {
+                    self.list_state.select_previous();
+                    Ok(Action::Handled)
+                }
+                KeyCode::Down | KeyCode::Char('j') => {
+                    self.list_state.select_next();
+                    Ok(Action::Handled)
+                }
+                KeyCode::Enter => {
+                    // TODO: Handle action for the item.
+                    Ok(Action::Handled)
+                }
+                KeyCode::Esc | KeyCode::Char('q') => {
+                    self.opened = None;
+                    self.component_state.help_text = Self::DEFAULT_HELP.to_string();
+                    self.list_state.select_first();
+                    Ok(Action::Handled)
+                }
+                _ => Ok(Action::Noop),
+            }
+        } else {
+            // Keybinds for title bar.
             match key.code {
-            // KeyCode::Up | KeyCode::Char('k') => self.selected.key_up(),
-            // KeyCode::Down | KeyCode::Char('j') => self.selected.key_down(),
                 KeyCode::Left | KeyCode::Char('h') => {
                     self.selected = self.selected.prev();
                     Ok(Action::Handled)
@@ -103,9 +173,15 @@ impl Component for TitleBar {
                 }
                 KeyCode::Enter => {
                     self.opened = Some(self.selected);
+                    self.component_state.help_text = concat!(
+                        "(↑/k)/(↓/j): Select option | Enter: Choose selection |",
+                        " ESC/Q: Close drop-down menu"
+                    )
+                    .to_string();
                     Ok(Action::Handled)
                 }
                 _ => Ok(Action::Noop),
             }
         }
+    }
 }