add: example of simple_async copy and pasted

Cargo.toml

@@ -4,3 +4,9 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+color-eyre = "0.6.3"
+crossterm = { version = "0.28.1", features = ["event-stream"] }
+futures = "0.3.31"
+ratatui = "0.29.0"
+smol = "2.0.2"
+upower_dbus = "0.3.2"

src/main.rs

@@ -1,3 +1,83 @@
+use crossterm::event::{Event, EventStream, KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
+use futures::{FutureExt, StreamExt};
+use ratatui::{
+    DefaultTerminal, Frame, buffer::Buffer, style::Stylize, text::Line, widgets::{Block, Gauge, Paragraph, Widget}
+};
+
 fn main() {
-    println!("Hello, world!");
+    smol::block_on(async {
+        color_eyre::install().unwrap();
+        let terminal = ratatui::init();
+        let result = App::new().run(terminal).await;
+        ratatui::restore();
+    });
+}
+
+#[derive(Debug, Default)]
+pub struct App {
+    /// Is the application running?
+    running: bool,
+    // Event stream.
+    event_stream: EventStream,
+}
+
+impl App {
+    /// Construct a new instance of [`App`].
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Run the application's main loop.
+    pub async fn run(mut self, mut terminal: DefaultTerminal) -> color_eyre::Result<()> {
+        self.running = true;
+        while self.running {
+            terminal.draw(|frame| self.draw(frame))?;
+            self.handle_crossterm_events().await?;
+        }
+        Ok(())
+    }
+
+    /// Renders the user interface.
+    ///
+    /// This is where you add new widgets. See the following resources for more information:
+    /// - <https://docs.rs/ratatui/latest/ratatui/widgets/index.html>
+    /// - <https://github.com/ratatui/ratatui/tree/master/examples>
+    fn draw(&mut self, frame: &mut Frame, buf &mut Buffer) {
+        let title = Line::from("Ratatui Simple Template")
+            .bold()
+            .blue()
+            .centered();
+        let text = "Hello, Ratatui!\n\n\
+            Created using https://github.com/ratatui/templates\n\
+            Press `Esc`, `Ctrl-C` or `q` to stop running.";
+        frame.render_widget();
+    /// Reads the crossterm events and updates the state of [`App`].
+    async fn handle_crossterm_events(&mut self) -> color_eyre::Result<()> {
+        let event = self.event_stream.next().fuse().await;
+        match event {
+            Some(Ok(evt)) => match evt {
+                Event::Key(key) if key.kind == KeyEventKind::Press => self.on_key_event(key),
+                Event::Mouse(_) => {}
+                Event::Resize(_, _) => {}
+                _ => {}
+            },
+            _ => {}
+        }
+        Ok(())
+    }
+
+    /// Handles the key events and updates the state of [`App`].
+    fn on_key_event(&mut self, key: KeyEvent) {
+        match (key.modifiers, key.code) {
+            (_, KeyCode::Esc | KeyCode::Char('q'))
+            | (KeyModifiers::CONTROL, KeyCode::Char('c') | KeyCode::Char('C')) => self.quit(),
+            // Add other key handlers here.
+            _ => {}
+        }
+    }
+
+    /// Set running to false to quit the application.
+    fn quit(&mut self) {
+        self.running = false;
+    }
 }