Making the tail follow the snake

src/main.rs

@@ -125,10 +125,16 @@ fn spawn_segment(
 fn snake_movement(
     keyboard_input: Res<Input<KeyCode>>,
     snake_timer: ResMut<SnakeMoveTimer>,
+    segments: ResMut<SnakeSegments>,
     mut heads: Query<(Entity, &mut SnakeHead)>,
     mut positions: Query<&mut Position>,
 ) {
     if let Some((head_entity, mut head)) = heads.iter_mut().next() {
+        let segment_positions = segments
+            .0
+            .iter()
+            .map(|e| *positions.get_mut(*e).unwrap())
+            .collect::<Vec<Position>>();
         let mut head_pos = positions.get_mut(head_entity).unwrap();
         let dir: Direction = if keyboard_input.pressed(KeyCode::Left) {
             Direction::Left
@@ -161,6 +167,12 @@ fn snake_movement(
                 head_pos.y -= 1;
             }
         };
+        segment_positions
+            .iter()
+            .zip(segments.0.iter().skip(1))
+            .for_each(|(pos, segment)| {
+                *positions.get_mut(*segment).unwrap() = *pos;
+            })
     }
 }