event.rs

use std::io;
use std::sync::{
	atomic::{AtomicBool, Ordering},
	Arc,
};
use std::thread;
use std::time::Duration;
use tokio::sync::mpsc;

use termion::event::Key;
use termion::input::TermRead;

pub enum Event<I> {
	Input(I),
	Tick,
}

/// A small event handler that wrap termion input and tick events. Each event
/// type is handled in its own thread and returned to a common `Receiver`
pub struct Events {
	pub rx: mpsc::UnboundedReceiver<Event<Key>>,
	input_handle: thread::JoinHandle<()>,
	ignore_exit_key: Arc<AtomicBool>,
	tick_handle: thread::JoinHandle<()>,
}

#[derive(Debug, Clone, Copy)]
pub struct Config {
	pub exit_key: Key,
	pub tick_rate: Duration,
}

impl Default for Config {
	fn default() -> Config {
		Config {
			exit_key: Key::Char('q'),
			tick_rate: Duration::from_millis(250),
		}
	}
}

impl Events {
	pub fn new() -> Events {
		Events::with_config(Config::default())
	}

	pub fn with_config(config: Config) -> Events {
		let (tx, rx) = mpsc::unbounded_channel();
		let ignore_exit_key = Arc::new(AtomicBool::new(false));
		let input_handle = {
			let tx = tx.clone();
			let ignore_exit_key = ignore_exit_key.clone();
			thread::spawn(move || {
				let stdin = io::stdin();
				for evt in stdin.keys() {
					if let Ok(key) = evt {
						if let Err(err) = tx.send(Event::Input(key)) {
							eprintln!("{}", err);
							return;
						}
						if !ignore_exit_key.load(Ordering::Relaxed) && key == config.exit_key {
							return;
						}
					}
				}
			})
		};
		let tick_handle = {
			thread::spawn(move || loop {
				if tx.send(Event::Tick).is_err() {
					break;
				}
				thread::sleep(config.tick_rate);
			})
		};
		Events {
			rx,
			ignore_exit_key,
			input_handle,
			tick_handle,
		}
	}

	pub fn disable_exit_key(&mut self) {
		self.ignore_exit_key.store(true, Ordering::Relaxed);
	}

	pub fn enable_exit_key(&mut self) {
		self.ignore_exit_key.store(false, Ordering::Relaxed);
	}
}