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use crossterm::event::{Event as CrosstermEvent, KeyEvent};
use futures::{FutureExt, StreamExt};
use tokio::sync::mpsc;
use crate::app::AppResult;
/// Terminal events.
#[derive(Clone, Copy, Debug)]
pub enum Event {
/// Terminal tick.
Tick,
/// Key press.
Key(KeyEvent),
/// Terminal resize.
Resize(u16, u16),
}
/// Terminal event handler.
#[allow(dead_code)]
#[derive(Debug)]
pub struct EventHandler {
/// Event sender channel.
pub sender: mpsc::UnboundedSender<Event>,
/// Event receiver channel.
receiver: mpsc::UnboundedReceiver<Event>,
/// Event handler thread.
handler: tokio::task::JoinHandle<()>,
}
impl EventHandler {
/// Constructs a new instance of [`EventHandler`].
pub fn new() -> Self {
let (sender, receiver) = mpsc::unbounded_channel();
let _sender = sender.clone();
let handler = tokio::spawn(async move {
let mut reader = crossterm::event::EventStream::new();
loop {
let crossterm_event = reader.next().fuse();
tokio::select! {
_ = _sender.closed() => {
break;
}
Some(Ok(evt)) = crossterm_event => {
match evt {
CrosstermEvent::Key(key) => {
if key.kind == crossterm::event::KeyEventKind::Press {
_sender.send(Event::Key(key)).unwrap();
}
},
CrosstermEvent::Resize(x, y) => {
_sender.send(Event::Resize(x, y)).unwrap();
},
_ => {},
}
}
};
}
});
Self {
sender,
receiver,
handler,
}
}
/// Receive the next event from the handler thread.
///
/// This function will always block the current thread if
/// there is no data available and it's possible for more data to be sent.
pub async fn next(&mut self) -> AppResult<Event> {
self.receiver
.recv()
.await
.ok_or(Box::new(std::io::Error::new(
std::io::ErrorKind::Other,
"This is an IO error",
)))
}
}