added feature/bug that skips frame wait if input was received which ensures handling all inputs

src/main.rs

@@ -43,7 +43,7 @@ fn main() {
 
         render(&snake, apple, length, (width, height));
         enable_raw_mode().unwrap();
-        change_dir(&mut direction);
+        change_dir(&mut direction, &now);
         disable_raw_mode().unwrap();
         if let Some(crash) = move_snake(&mut snake, &direction, length, (width, height)) {
             match crash {
@@ -56,8 +56,6 @@ fn main() {
             break;
         }
         eat(&snake, &mut apple, &mut length, &mut rng, (width, height));
-
-        while now.elapsed() < FRAME_TIME {}
     }
 
     exit();
@@ -82,8 +80,8 @@ fn exit() {
     std::process::exit(0);
 }
 
-fn change_dir(direction: &mut Direction) {
-    if let Some(k) = key_input(FRAME_TIME) {
+fn change_dir(direction: &mut Direction, now: &Instant) {
+    if let Some(k) = key_input(now) {
         match k {
             'd' => {
                 if *direction != Direction::Left {
@@ -111,23 +109,17 @@ fn change_dir(direction: &mut Direction) {
     }
 }
 
-fn key_input(timeout: Duration) -> Option<char> {
-    let mut result = None;
-    if poll(timeout).ok()? {
-        if let Event::Key(k) = read().ok()? {
-            if let KeyCode::Char(c) = k.code {
-                result = Some(c);
+fn key_input(now: &Instant) -> Option<char> {
+    while now.elapsed() < FRAME_TIME {
+        if poll(Duration::from_secs(0)).ok()? {
+            if let Event::Key(k) = read().ok()? {
+                if let KeyCode::Char(c) = k.code {
+                    return Some(c);
+                }
             }
         }
     }
-    while poll(Duration::from_secs(0)).ok()? {
-        if let Event::Key(k) = read().ok()? {
-            if let KeyCode::Char(c) = k.code {
-                result = Some(c);
-            }
-        }
-    }
-    result
+    None
 }
 
 fn move_snake(