| 1 | use crate::app::AppResult; |
| 2 | use crossterm::event::{self, Event as CrosstermEvent, KeyEvent, MouseEvent}; |
| 3 | use std::sync::mpsc; |
| 4 | use std::thread; |
| 5 | use std::time::{Duration, Instant}; |
| 6 | |
| 7 | /// Terminal events. |
| 8 | #[derive(Clone, Copy, Debug)] |
| 9 | pub enum Event { |
| 10 | /// Terminal tick. |
| 11 | Tick, |
| 12 | /// Key press. |
| 13 | Key(KeyEvent), |
| 14 | /// Mouse click/scroll. |
| 15 | Mouse(MouseEvent), |
| 16 | /// Terminal resize. |
| 17 | Resize(u16, u16), |
| 18 | } |
| 19 | |
| 20 | /// Terminal event handler. |
| 21 | #[allow(dead_code)] |
| 22 | #[derive(Debug)] |
| 23 | pub struct EventHandler { |
| 24 | /// Event sender channel. |
| 25 | sender: mpsc::Sender<Event>, |
| 26 | /// Event receiver channel. |
| 27 | receiver: mpsc::Receiver<Event>, |
| 28 | /// Event handler thread. |
| 29 | handler: thread::JoinHandle<()>, |
| 30 | } |
| 31 | |
| 32 | impl EventHandler { |
| 33 | /// Constructs a new instance of [`EventHandler`]. |
| 34 | pub fn new(tick_rate: u64) -> Self { |
| 35 | let tick_rate = Duration::from_millis(tick_rate); |
| 36 | let (sender, receiver) = mpsc::channel(); |
| 37 | let handler = { |
| 38 | let sender = sender.clone(); |
| 39 | thread::spawn(move || { |
| 40 | let mut last_tick = Instant::now(); |
| 41 | loop { |
| 42 | let timeout = tick_rate |
| 43 | .checked_sub(last_tick.elapsed()) |
| 44 | .unwrap_or(tick_rate); |
| 45 | |
| 46 | if event::poll(timeout).expect("failed to poll new events") { |
| 47 | match event::read().expect("unable to read event") { |
| 48 | CrosstermEvent::Key(e) => sender.send(Event::Key(e)), |
| 49 | CrosstermEvent::Mouse(e) => sender.send(Event::Mouse(e)), |
| 50 | CrosstermEvent::Resize(w, h) => sender.send(Event::Resize(w, h)), |
| 51 | CrosstermEvent::FocusGained => Ok(()), |
| 52 | CrosstermEvent::FocusLost => Ok(()), |
| 53 | CrosstermEvent::Paste(_) => unimplemented!(), |
| 54 | } |
| 55 | .expect("failed to send terminal event") |
| 56 | } |
| 57 | |
| 58 | if last_tick.elapsed() >= tick_rate { |
| 59 | sender.send(Event::Tick).expect("failed to send tick event"); |
| 60 | last_tick = Instant::now(); |
| 61 | } |
| 62 | } |
| 63 | }) |
| 64 | }; |
| 65 | Self { |
| 66 | sender, |
| 67 | receiver, |
| 68 | handler, |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | /// Receive the next event from the handler thread. |
| 73 | /// |
| 74 | /// This function will always block the current thread if |
| 75 | /// there is no data available and it's possible for more data to be sent. |
| 76 | pub fn next(&self) -> AppResult<Event> { |
| 77 | Ok(self.receiver.recv()?) |
| 78 | } |
| 79 | } |