Reorganize weapons

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/features/weapon/weapon.dart

@@ -0,0 +1,48 @@
+enum WeaponState { idle, firing }
+
+abstract class Weapon {
+  final String name;
+  final int idleSprite;
+  final List<int> fireFrames;
+  final int damage;
+  final int msPerFrame;
+
+  WeaponState state = WeaponState.idle;
+  int frameIndex = 0;
+  int lastFrameTime = 0;
+
+  Weapon({
+    required this.name,
+    required this.idleSprite,
+    required this.fireFrames,
+    required this.damage,
+    this.msPerFrame = 100,
+  });
+
+  int get currentSprite =>
+      state == WeaponState.idle ? idleSprite : fireFrames[frameIndex];
+
+  /// Core firing logic. Returns true if a bullet was spent.
+  bool fire(int currentTime, {required int currentAmmo}) {
+    if (state == WeaponState.idle && currentAmmo > 0) {
+      state = WeaponState.firing;
+      frameIndex = 0;
+      lastFrameTime = currentTime;
+      return true;
+    }
+    return false;
+  }
+
+  void update(int currentTime) {
+    if (state == WeaponState.firing) {
+      if (currentTime - lastFrameTime > msPerFrame) {
+        frameIndex++;
+        lastFrameTime = currentTime;
+        if (frameIndex >= fireFrames.length) {
+          state = WeaponState.idle;
+          frameIndex = 0;
+        }
+      }
+    }
+  }
+}