input: Refactor all previous states

src/core/input/cache.rs

@@ -0,0 +1,86 @@
+use std::{
+    collections::HashMap,
+    hash::Hash,
+    ops::{Add, AddAssign, Sub},
+};
+
+use winit::event::ElementState;
+
+pub struct CachedElementState<K: Eq + Hash> {
+    cache: HashMap<K, ElementState>,
+}
+
+impl<K: Eq + Hash> Default for CachedElementState<K> {
+    fn default() -> Self {
+        Self {
+            cache: HashMap::new(),
+        }
+    }
+}
+
+impl<K: Eq + Hash> CachedElementState<K> {
+    pub fn set_key_state(&mut self, key: K, state: ElementState) -> Option<ElementState> {
+        let key_state = self.cache.get(&key);
+        let new_key_state = match key_state {
+            Some(old) => match state {
+                ElementState::Pressed => match old {
+                    ElementState::Released => Some(ElementState::Pressed),
+                    ElementState::Pressed => None,
+                },
+                ElementState::Released => match old {
+                    ElementState::Released => None,
+                    ElementState::Pressed => Some(ElementState::Released),
+                },
+            },
+            None => match state {
+                ElementState::Pressed => Some(ElementState::Pressed),
+                ElementState::Released => Some(ElementState::Released),
+            },
+        };
+        if let Some(new_key_state) = new_key_state {
+            self.cache.insert(key, new_key_state);
+        }
+        new_key_state
+    }
+}
+
+#[derive(Default)]
+pub struct CachedMovement<T>
+where
+    T: Sub<Output = T> + Add<Output = T> + Default + Copy,
+{
+    pub old_value: Option<T>,
+    pub value: T,
+}
+
+impl<T> CachedMovement<T>
+where
+    T: Sub<Output = T> + Add<Output = T> + Default + Copy,
+{
+    pub fn set_value(&mut self, value: T) {
+        self.value = value;
+    }
+
+    pub fn reset(&mut self) -> T {
+        match self.old_value.as_ref() {
+            Some(old_value) => {
+                let diff = self.value - *old_value;
+                self.old_value = Some(self.value);
+                diff
+            }
+            None => {
+                self.old_value = Some(self.value);
+                T::default()
+            }
+        }
+    }
+}
+
+impl<T> AddAssign<T> for CachedMovement<T>
+where
+    T: Add<Output = T> + Sub<Output = T> + Default + Copy,
+{
+    fn add_assign(&mut self, rhs: T) {
+        self.value = self.value + rhs;
+    }
+}