Better code structure: snake game object, player game object, bot game object

include/Snake.hpp

@@ -3,19 +3,21 @@
 #include <deque>
 
 #include "Canvas.hpp"
+#include "Map.hpp"
 
 namespace canvas {
 
-struct SnakeObject : public Object {
-  size_t length;
-  int radius;
-};
-
-} // namespace canvas
-
-class Snake : protected canvas::SnakeObject {
+class SnakeObject {
 public:
-  Snake(canvas::SnakeObject obj) : SnakeObject(obj), track_{pos} {}
+  struct Config {
+    Object obj;
+    size_t initial_length;
+    int radius;
+  };
+
+  SnakeObject(Config config)
+      : canvas_config_(config), length_{config.initial_length},
+        track_{config.obj.pos} {}
 
   void add(Veci pos);
 
@@ -23,26 +25,80 @@ public:
 
   //
 
-  Veci get_pos() { return pos; }
+  Veci get_pos() {
+    if (track_.empty()) {
+      throw std::exception();
+    }
+    return track_.back();
+  }
 
   //
 
-  size_t get_length() { return length; }
+  size_t get_length() { return length_; }
 
-  void set_length(size_t length) { this->length = length; }
+  void set_length(size_t length) { length_ = length; }
 
   void inc_length(int inc) {
-    if (-inc > static_cast<int>(length)) {
-      length = 0;
+    if (-inc > static_cast<int>(length_)) {
+      length_ = 1;
     } else {
-      length += inc;
+      length_ += inc;
     }
   }
 
   //
 
-  bool touches(const Snake &other);
+  bool touches(const SnakeObject &other);
 
 protected:
+  const Config canvas_config_;
+
+  size_t length_;
   std::deque<Veci> track_;
 };
+
+} // namespace canvas
+
+class Snake : public canvas::SnakeObject, public GameObject {
+public:
+  struct Config {
+    double speed;
+    float move_interval;
+  };
+
+  Snake(canvas::SnakeObject::Config canvas_config, Config snake_config,
+        Map &map)
+      : SnakeObject(canvas_config), snake_config_(snake_config), map_(map),
+        real_pos_(canvas_config.obj.pos) {}
+
+  void act(float dt) override {
+    int eaten = map_.eat(utils::to_world_coord(get_pos()), 20);
+    inc_length(eaten);
+
+    change_direction(dt);
+
+    move(dt);
+  }
+
+  void draw(Veci offset) override { SnakeObject::draw(offset); }
+
+protected:
+  virtual void change_direction(float dt) = 0;
+
+  virtual void move(float dt) {
+    real_pos_ += direction_ * dt * snake_config_.speed;
+    move_time_delta_ += dt;
+    if (move_time_delta_ > snake_config_.move_interval) {
+      move_time_delta_ -= snake_config_.move_interval;
+      add(Veci(real_pos_));
+    }
+  }
+
+protected:
+  const Config snake_config_;
+  Map &map_;
+
+  Vecf real_pos_;
+  Vecf direction_ = {};
+  float move_time_delta_ = 0;
+};