3 files changed, 65 insertions, 26 deletions

diff --git a/src/watch/notify_event.rs b/src/watch/notify_event.rs
index 7471640..9b23525 100644
--- a/src/watch/notify_event.rs
+++ b/src/watch/notify_event.rs
@@ -4,7 +4,7 @@ use std::sync::mpsc::Sender;
 use super::WatchEvent;
 
 pub struct NotifyEventHandler {
-    pub tx: Sender<WatchEvent>,
+    pub sender: Sender<WatchEvent>,
     /// Used to report which exercise was modified.
     pub exercise_names: &'static [&'static [u8]],
 }
@@ -47,6 +47,6 @@ impl notify_debouncer_mini::DebounceEventHandler for NotifyEventHandler {
 
         // An error occurs when the receiver is dropped.
         // After dropping the receiver, the debouncer guard should also be dropped.
-        let _ = self.tx.send(output_event);
+        let _ = self.sender.send(output_event);
     }
 }
diff --git a/src/watch/state.rs b/src/watch/state.rs
index e66cbee..6e76001 100644
--- a/src/watch/state.rs
+++ b/src/watch/state.rs
@@ -5,7 +5,11 @@ use crossterm::{
     },
     terminal, QueueableCommand,
 };
-use std::io::{self, StdoutLock, Write};
+use std::{
+    io::{self, StdoutLock, Write},
+    sync::mpsc::Sender,
+    thread,
+};
 
 use crate::{
     app_state::{AppState, ExercisesProgress},
@@ -14,6 +18,11 @@ use crate::{
     term::progress_bar,
 };
 
+use super::{
+    terminal_event::{terminal_event_handler, InputPauseGuard},
+    WatchEvent,
+};
+
 #[derive(PartialEq, Eq)]
 enum DoneStatus {
     DoneWithSolution(String),
@@ -31,11 +40,19 @@ pub struct WatchState<'a> {
 }
 
 impl<'a> WatchState<'a> {
-    pub fn build(app_state: &'a mut AppState, manual_run: bool) -> Result<Self> {
+    pub fn build(
+        app_state: &'a mut AppState,
+        watch_event_sender: Sender<WatchEvent>,
+        manual_run: bool,
+    ) -> Result<Self> {
         let term_width = terminal::size()
             .context("Failed to get the terminal size")?
             .0;
 
+        thread::Builder::new()
+            .spawn(move || terminal_event_handler(watch_event_sender, manual_run))
+            .context("Failed to spawn a thread to handle terminal events")?;
+
         Ok(Self {
             app_state,
             output: Vec::with_capacity(OUTPUT_CAPACITY),
@@ -47,6 +64,9 @@ impl<'a> WatchState<'a> {
     }
 
     pub fn run_current_exercise(&mut self, stdout: &mut StdoutLock) -> Result<()> {
+        // Ignore any input until running the exercise is done.
+        let _input_pause_guard = InputPauseGuard::scoped_pause();
+
         self.show_hint = false;
 
         writeln!(
diff --git a/src/watch/terminal_event.rs b/src/watch/terminal_event.rs
index ca3a846..2a1dfdc 100644
--- a/src/watch/terminal_event.rs
+++ b/src/watch/terminal_event.rs
@@ -1,8 +1,32 @@
 use crossterm::event::{self, Event, KeyCode, KeyEventKind};
-use std::sync::mpsc::Sender;
+use std::sync::{
+    atomic::{AtomicBool, Ordering::Relaxed},
+    mpsc::Sender,
+};
 
 use super::WatchEvent;
 
+static INPUT_PAUSED: AtomicBool = AtomicBool::new(false);
+
+// Private unit type to force using the constructor function.
+#[must_use = "When the guard is dropped, the input is unpaused"]
+pub struct InputPauseGuard(());
+
+impl InputPauseGuard {
+    #[inline]
+    pub fn scoped_pause() -> Self {
+        INPUT_PAUSED.store(true, Relaxed);
+        Self(())
+    }
+}
+
+impl Drop for InputPauseGuard {
+    #[inline]
+    fn drop(&mut self) {
+        INPUT_PAUSED.store(false, Relaxed);
+    }
+}
+
 pub enum InputEvent {
     Run,
     Next,
@@ -11,46 +35,41 @@ pub enum InputEvent {
     Quit,
 }
 
-pub fn terminal_event_handler(tx: Sender<WatchEvent>, manual_run: bool) {
-    let last_input_event = loop {
-        let terminal_event = match event::read() {
-            Ok(v) => v,
-            Err(e) => {
-                // If `send` returns an error, then the receiver is dropped and
-                // a shutdown has been already initialized.
-                let _ = tx.send(WatchEvent::TerminalEventErr(e));
-                return;
-            }
-        };
-
-        match terminal_event {
-            Event::Key(key) => {
+pub fn terminal_event_handler(sender: Sender<WatchEvent>, manual_run: bool) {
+    let last_watch_event = loop {
+        match event::read() {
+            Ok(Event::Key(key)) => {
                 match key.kind {
                     KeyEventKind::Release | KeyEventKind::Repeat => continue,
                     KeyEventKind::Press => (),
                 }
 
+                if INPUT_PAUSED.load(Relaxed) {
+                    continue;
+                }
+
                 let input_event = match key.code {
                     KeyCode::Char('n') => InputEvent::Next,
                     KeyCode::Char('h') => InputEvent::Hint,
-                    KeyCode::Char('l') => break InputEvent::List,
-                    KeyCode::Char('q') => break InputEvent::Quit,
+                    KeyCode::Char('l') => break WatchEvent::Input(InputEvent::List),
+                    KeyCode::Char('q') => break WatchEvent::Input(InputEvent::Quit),
                     KeyCode::Char('r') if manual_run => InputEvent::Run,
                     _ => continue,
                 };
 
-                if tx.send(WatchEvent::Input(input_event)).is_err() {
+                if sender.send(WatchEvent::Input(input_event)).is_err() {
                     return;
                 }
             }
-            Event::Resize(width, _) => {
-                if tx.send(WatchEvent::TerminalResize { width }).is_err() {
+            Ok(Event::Resize(width, _)) => {
+                if sender.send(WatchEvent::TerminalResize { width }).is_err() {
                     return;
                 }
             }
-            Event::FocusGained | Event::FocusLost | Event::Mouse(_) => continue,
+            Ok(Event::FocusGained | Event::FocusLost | Event::Mouse(_)) => continue,
+            Err(e) => break WatchEvent::TerminalEventErr(e),
         }
     };
 
-    let _ = tx.send(WatchEvent::Input(last_input_event));
+    let _ = sender.send(last_watch_event);
 }