use core::time::Duration;
use std::time::Instant;
use ratatui::backend::{Backend, CrosstermBackend};
use ratatui::crossterm::event::{Event, KeyCode, KeyEventKind, KeyModifiers, MouseEventKind};
use ratatui::layout::{Position, Rect};
use ratatui::style::{Color, Modifier, Style};
use ratatui::text::Span;
use ratatui::widgets::{Block, Scrollbar, ScrollbarOrientation};
use ratatui::{Frame, Terminal, crossterm};
use tui_tree_widget::{Tree, TreeItem, TreeState};
#[must_use]
struct App {
state: TreeState<&'static str>,
items: Vec<TreeItem<'static, &'static str>>,
}
impl App {
fn new() -> Self {
Self {
state: TreeState::default(),
items: vec![
TreeItem::new_leaf("a", "Alfa"),
TreeItem::new(
"b",
"Bravo",
vec![
TreeItem::new_leaf("c", "Charlie"),
TreeItem::new(
"d",
"Delta",
vec![
TreeItem::new_leaf("e", "Echo"),
TreeItem::new_leaf("f", "Foxtrot"),
],
)
.expect("all item identifiers are unique"),
TreeItem::new_leaf("g", "Golf"),
],
)
.expect("all item identifiers are unique"),
TreeItem::new_leaf("h", "Hotel"),
TreeItem::new(
"i",
"India",
vec![
TreeItem::new_leaf("j", "Juliett"),
TreeItem::new_leaf("k", "Kilo"),
TreeItem::new_leaf("l", "Lima"),
TreeItem::new_leaf("m", "Mike"),
TreeItem::new_leaf("n", "November"),
],
)
.expect("all item identifiers are unique"),
TreeItem::new_leaf("o", "Oscar"),
TreeItem::new(
"p",
"Papa",
vec![
TreeItem::new_leaf("q", "Quebec"),
TreeItem::new_leaf("r", "Romeo"),
TreeItem::new_leaf("s", "Sierra"),
TreeItem::new_leaf("t", "Tango"),
TreeItem::new_leaf("u", "Uniform"),
TreeItem::new(
"v",
"Victor",
vec![
TreeItem::new_leaf("w", "Whiskey"),
TreeItem::new_leaf("x", "Xray"),
TreeItem::new_leaf("y", "Yankee"),
],
)
.expect("all item identifiers are unique"),
],
)
.expect("all item identifiers are unique"),
TreeItem::new_leaf("z", "Zulu"),
],
}
}
fn draw(&mut self, frame: &mut Frame) {
let area = frame.area();
let widget = Tree::new(&self.items)
.expect("all item identifiers are unique")
.block(
Block::bordered()
.title("Tree Widget")
.title_bottom(format!("{:?}", self.state)),
)
.experimental_scrollbar(Some(
Scrollbar::new(ScrollbarOrientation::VerticalRight)
.begin_symbol(None)
.track_symbol(None)
.end_symbol(None),
))
.highlight_style(
Style::new()
.fg(Color::Black)
.bg(Color::LightGreen)
.add_modifier(Modifier::BOLD),
)
.highlight_symbol(">> ");
frame.render_stateful_widget(widget, area, &mut self.state);
}
}
fn main() -> std::io::Result<()> {
crossterm::terminal::enable_raw_mode()?;
let mut stdout = std::io::stdout();
crossterm::execute!(
stdout,
crossterm::terminal::EnterAlternateScreen,
crossterm::event::EnableMouseCapture
)?;
let mut terminal = Terminal::new(CrosstermBackend::new(stdout))?;
let app = App::new();
let res = run_app(&mut terminal, app);
crossterm::terminal::disable_raw_mode()?;
crossterm::execute!(
terminal.backend_mut(),
crossterm::terminal::LeaveAlternateScreen,
crossterm::event::DisableMouseCapture
)?;
terminal.show_cursor()?;
if let Err(err) = res {
println!("{err:?}");
}
Ok(())
}
fn run_app<B>(terminal: &mut Terminal<B>, mut app: App) -> Result<(), B::Error>
where
B: Backend,
B::Error: From<std::io::Error>,
{
const DEBOUNCE: Duration = Duration::from_millis(20);
let before = Instant::now();
terminal.draw(|frame| app.draw(frame))?;
let mut last_render_took = before.elapsed();
let mut debounce: Option<Instant> = None;
loop {
let timeout = debounce.map_or(DEBOUNCE, |start| DEBOUNCE.saturating_sub(start.elapsed()));
if crossterm::event::poll(timeout)? {
let update = match crossterm::event::read()? {
Event::Key(key) if !matches!(key.kind, KeyEventKind::Press) => false,
Event::Key(key) => match key.code {
KeyCode::Char('c') if key.modifiers.contains(KeyModifiers::CONTROL) => {
return Ok(());
}
KeyCode::Char('q') => return Ok(()),
KeyCode::Char('\n' | ' ') => app.state.toggle_selected(),
KeyCode::Left => app.state.key_left(),
KeyCode::Right => app.state.key_right(),
KeyCode::Down => app.state.key_down(),
KeyCode::Up => app.state.key_up(),
KeyCode::Esc => app.state.select(Vec::new()),
KeyCode::Home => app.state.select_first(),
KeyCode::End => app.state.select_last(),
KeyCode::PageDown => app.state.scroll_down(3),
KeyCode::PageUp => app.state.scroll_up(3),
_ => false,
},
Event::Mouse(mouse) => match mouse.kind {
MouseEventKind::ScrollDown => app.state.scroll_down(1),
MouseEventKind::ScrollUp => app.state.scroll_up(1),
MouseEventKind::Down(_button) => {
app.state.click_at(Position::new(mouse.column, mouse.row))
}
_ => false,
},
Event::Resize(_, _) => true,
_ => false,
};
if update {
debounce.get_or_insert_with(Instant::now);
}
}
if debounce.is_some_and(|debounce| debounce.elapsed() > DEBOUNCE) {
let before = Instant::now();
terminal.draw(|frame| {
app.draw(frame);
{
let text = format!(
" {} {last_render_took:?} {:.1} FPS",
frame.count(),
1.0 / last_render_took.as_secs_f64()
);
#[expect(clippy::cast_possible_truncation)]
let area = Rect {
y: 0,
height: 1,
x: frame.area().width.saturating_sub(text.len() as u16),
width: text.len() as u16,
};
frame.render_widget(
Span::styled(text, Style::new().fg(Color::Black).bg(Color::Gray)),
area,
);
}
})?;
last_render_took = before.elapsed();
debounce = None;
}
}
}