initial commit

1 files changed, 97 insertions, 0 deletions

diff --git a/src/frontend/event.rs b/src/frontend/event.rs
new file mode 100644
index 0000000..f83dfea
--- /dev/null
+++ b/src/frontend/event.rs
@@ -0,0 +1,97 @@
+use std::time::Duration;
+
+use crossterm::event::{Event as CrosstermEvent, KeyEvent, MouseEvent};
+use futures::{FutureExt, StreamExt};
+use tokio::sync::mpsc;
+
+use crate::frontend::app::AppResult;
+
+/// 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::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(tick_rate: u64) -> Self {
+        let tick_rate = Duration::from_millis(tick_rate);
+        let (sender, receiver) = mpsc::unbounded_channel();
+        let _sender = sender.clone();
+        let handler = tokio::spawn(async move {
+            let mut reader = crossterm::event::EventStream::new();
+            let mut tick = tokio::time::interval(tick_rate);
+            loop {
+                let tick_delay = tick.tick();
+                let crossterm_event = reader.next().fuse();
+                tokio::select! {
+                  _ = _sender.closed() => {
+                    break;
+                  }
+                  _ = tick_delay => {
+                    _sender.send(Event::Tick).unwrap();
+                  }
+                  Some(Ok(evt)) = crossterm_event => {
+                    match evt {
+                      CrosstermEvent::Key(key) => {
+                        if key.kind == crossterm::event::KeyEventKind::Press {
+                          _sender.send(Event::Key(key)).unwrap();
+                        }
+                      },
+                      CrosstermEvent::Mouse(mouse) => {
+                        _sender.send(Event::Mouse(mouse)).unwrap();
+                      },
+                      CrosstermEvent::Resize(x, y) => {
+                        _sender.send(Event::Resize(x, y)).unwrap();
+                      },
+                      CrosstermEvent::FocusLost => {
+                      },
+                      CrosstermEvent::FocusGained => {
+                      },
+                      CrosstermEvent::Paste(_) => {
+                      },
+                    }
+                  }
+                };
+            }
+        });
+        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",
+            )))
+    }
+}