[tui] Add bottom status bar with help text.

Fixes #3

src/tui/app.rs

@@ -9,7 +9,8 @@ use ratatui::crossterm::event;
 use ratatui::crossterm::event::{Event, KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
 use ratatui::layout::{Constraint, Direction, Layout, Rect};
 use ratatui::prelude::{Color, Style, Widget};
-use ratatui::widgets::{Block, Borders, Padding, Tabs};
+use ratatui::text::Text;
+use ratatui::widgets::{Block, Borders, Padding, Paragraph, Tabs, Wrap};
 use ratatui::{DefaultTerminal, symbols};
 use std::path::PathBuf;
 use std::time::Duration;
@@ -93,7 +94,7 @@ impl<'a> App<'a> {
         Ok(())
     }
 
-    fn draw_status(&self, area: Rect, buf: &mut Buffer) {
+    fn draw_top_status(&self, area: Rect, buf: &mut Buffer) {
         // TODO: Status bar should have drop down menus
         Tabs::new(["File", "Edit", "View", "Help"])
             .style(Style::default())
@@ -101,6 +102,21 @@ impl<'a> App<'a> {
             .render(area, buf);
     }
 
+    fn draw_bottom_status(&self, area: Rect, buf: &mut Buffer) {
+        // TODO: Set help text based on most recent component enabled.
+        Paragraph::new(
+            self.get_component::<Logger>()
+                .unwrap()
+                .component_state
+                .help_text
+                .clone(),
+        )
+        .style(Color::Gray)
+        .wrap(Wrap { trim: false })
+        .centered()
+        .render(area, buf);
+    }
+
     fn draw_tabs(&self, area: Rect, buf: &mut Buffer) {
         // Determine the tab title from the current file (or use a fallback).
         let mut title: Option<&str> = None;
@@ -153,9 +169,10 @@ impl<'a> Widget for &mut App<'a> {
         let vertical = Layout::default()
             .direction(Direction::Vertical)
             .constraints([
-                Constraint::Length(3),      // status bar
+                Constraint::Length(3),      // top status bar
                 Constraint::Percentage(70), // horizontal layout
                 Constraint::Percentage(30), // terminal
+                Constraint::Length(3),      // bottom status bar
             ])
             .split(area);
 
@@ -175,7 +192,8 @@ impl<'a> Widget for &mut App<'a> {
             ])
             .split(horizontal[1]);
 
-        self.draw_status(vertical[0], buf);
+        self.draw_top_status(vertical[0], buf);
+        self.draw_bottom_status(vertical[3], buf);
         self.draw_tabs(editor_layout[0], buf);
         let id = self.id().to_string();
         for component in &mut self.components {
@@ -225,7 +243,7 @@ impl<'a> Component for App<'a> {
                 AppComponents::AppEditor(e) => e as &mut dyn Component,
                 AppComponents::AppExplorer(e) => e as &mut dyn Component,
                 AppComponents::AppLogger(e) => e as &mut dyn Component,
-                AppComponents::AppComponent(e) => e.as_mut() as &mut dyn Component,
+                AppComponents::AppComponent(e) => e.as_mut(),
             };
             if !c.is_active() {
                 if let Some(mouse) = event.as_mouse_event() {

src/tui/component.rs

@@ -51,17 +51,24 @@ pub trait Component {
     }
 }
 
-#[derive(Debug, Clone, Copy, Default)]
+#[derive(Debug, Clone, Default)]
 pub struct ComponentState {
     pub(crate) focus: Focus,
+    pub(crate) help_text: String,
 }
 
 impl ComponentState {
     fn new() -> Self {
         Self {
             focus: Focus::Active,
+            help_text: String::new(),
         }
     }
+
+    pub(crate) fn with_help_text(mut self, help_text: &str) -> Self {
+        self.help_text = help_text.into();
+        self
+    }
 }
 
 #[derive(Debug, Clone, Copy, Default, PartialEq)]
@@ -79,7 +86,10 @@ pub trait FocusState {
 
 impl FocusState for ComponentState {
     fn with_focus(self, focus: Focus) -> Self {
-        Self { focus }
+        Self {
+            focus,
+            help_text: self.help_text,
+        }
     }
 
     fn set_focus(&mut self, focus: Focus) {

src/tui/editor.rs

@@ -46,7 +46,7 @@ impl Editor {
             event_handler: EditorEventHandler::default(),
             file_path: None,
             syntax_set: SyntaxSet::load_defaults_nonewlines(),
-            component_state: Default::default(),
+            component_state: ComponentState::default().with_help_text("TODO: Vim help text"),
         }
     }
 

src/tui/explorer.rs

@@ -39,7 +39,7 @@ impl<'a> Explorer<'a> {
             root_path: path.to_owned(),
             tree_items: Self::build_tree_from_path(path.to_owned())?,
             tree_state: TreeState::default(),
-            component_state: Default::default(),
+            component_state: ComponentState::default().with_help_text("TODO: Explorer help text."),
         };
         Ok(explorer)
     }

src/tui/logger.rs

@@ -33,7 +33,11 @@ impl Logger {
     pub fn new() -> Self {
         Self {
             state: TuiWidgetState::new(),
-            component_state: Default::default(),
+            component_state: ComponentState::default().with_help_text(concat!(
+                "Q: Quit | Tab: Switch state | ↑/↓: Select target | f: Focus target",
+                " | ←/→: Display level | +/-: Filter level | Space: Toggle hidden targets",
+                " | h: Hide target selector | PageUp/Down: Scroll | Esc: Cancel scroll"
+            )),
         }
     }
 }