1 files changed, 79 insertions, 0 deletions
diff --git a/src/event_handler/event.rs b/src/event_handler/event.rs
new file mode 100644
index 0000000..439c31b
--- /dev/null
+++ b/src/event_handler/event.rs
@@ -0,0 +1,79 @@
+use crate::app::AppResult;
+use crossterm::event::{self, Event as CrosstermEvent, KeyEvent, MouseEvent};
+use std::sync::mpsc;
+use std::thread;
+use std::time::{Duration, Instant};
+
+/// Terminal events.
+#[derive(Clone, Copy, Debug)]
+pub enum Event {
+    /// Terminal tick.
+    Tick,
+    /// Key press.
+    Key(KeyEvent),
+    /// Mouse click/scroll.
+    Mouse(MouseEvent),
+    /// Terminal resize.
+    Resize(u16, u16),
+}
+
+/// Terminal event handler.
+#[allow(dead_code)]
+#[derive(Debug)]
+pub struct EventHandler {
+    /// Event sender channel.
+    sender: mpsc::Sender<Event>,
+    /// Event receiver channel.
+    receiver: mpsc::Receiver<Event>,
+    /// Event handler thread.
+    handler: thread::JoinHandle<()>,
+}
+
+impl EventHandler {
+    /// Constructs a new instance of [`EventHandler`].
+    pub fn new(tick_rate: u64) -> Self {
+        let tick_rate = Duration::from_millis(tick_rate);
+        let (sender, receiver) = mpsc::channel();
+        let handler = {
+            let sender = sender.clone();
+            thread::spawn(move || {
+                let mut last_tick = Instant::now();
+                loop {
+                    let timeout = tick_rate
+                        .checked_sub(last_tick.elapsed())
+                        .unwrap_or(tick_rate);
+
+                    if event::poll(timeout).expect("failed to poll new events") {
+                        match event::read().expect("unable to read event") {
+                            CrosstermEvent::Key(e) => sender.send(Event::Key(e)),
+                            CrosstermEvent::Mouse(e) => sender.send(Event::Mouse(e)),
+                            CrosstermEvent::Resize(w, h) => sender.send(Event::Resize(w, h)),
+                            CrosstermEvent::FocusGained => Ok(()),
+                            CrosstermEvent::FocusLost => Ok(()),
+                            CrosstermEvent::Paste(_) => unimplemented!(),
+                        }
+                        .expect("failed to send terminal event")
+                    }
+
+                    if last_tick.elapsed() >= tick_rate {
+                        sender.send(Event::Tick).expect("failed to send tick event");
+                        last_tick = Instant::now();
+                    }
+                }
+            })
+        };
+        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 fn next(&self) -> AppResult<Event> {
+        Ok(self.receiver.recv()?)
+    }
+}