event.hpp

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#pragma once
 
#include <functional>
#include <string_view>
#include <unordered_map>
#include <vector>
#include <wren/utils/enums.hpp>
 
#include "keycode.hpp"
 
namespace wren::event {
 
BOOST_DEFINE_ENUM(Category, WINDOW, KEYBOARD, MOUSE)
 
// NOLINTNEXTLINE
#define APPEND_EVENT_INFO(name, cat)                      \
  inline static const std::string_view debug_name = name; \
  inline static const Category category = cat;
 
struct WindowClose {
  APPEND_EVENT_INFO("WindowClose", Category::WINDOW);
};
 
struct WindowResized {
  WindowResized() = default;
  explicit WindowResized(const std::pair<float, float>& size)
      : width(size.first), height(size.second) {}
 
  float width = 0;
  float height = 0;
 
  APPEND_EVENT_INFO("WindowResized", Category::WINDOW)
};
 
struct MouseMoved {
  float x = 0;
  float y = 0;
  bool relative = false;
 
  APPEND_EVENT_INFO("MouseMoved", Category::MOUSE)
};
 
struct MouseWheel {
  float x = 0;
  float y = 0;
 
  APPEND_EVENT_INFO("MouseWheel", Category::MOUSE)
};
 
struct MouseButtonDown {
  MouseCode button;
  APPEND_EVENT_INFO("MouseButtonDown", Category::MOUSE)
};
 
struct MouseButtonUp {
  MouseCode button;
  APPEND_EVENT_INFO("MouseButtonUp", Category::MOUSE)
};
 
struct KeyDown {
  KeyCode key;
  APPEND_EVENT_INFO("KeyDown", Category::KEYBOARD)
};
 
struct KeyUp {
  KeyCode key;
  APPEND_EVENT_INFO("KeyUp", Category::KEYBOARD)
};
 
struct KeyTyped {
  std::string_view text;
  APPEND_EVENT_INFO("KeyTyped", Category::KEYBOARD);
};
 
class Dispatcher {
 public:
  template <typename T>
  void dispatch(T&& value) const;
  template <typename T>
  void on(std::function<void(const T& t)> cb);
 
 private:
  std::unordered_map<size_t, std::vector<std::function<void(void*)>>> handlers_;
};
 
template <typename Type>
// NOLINTNEXTLINE
void Dispatcher::dispatch(Type&& value) const {
  const auto id = typeid(Type{}).hash_code();
  if (handlers_.contains(id)) {
    for (auto& cb : handlers_.at(id)) {
      if (cb) cb(&value);
    }
  }
}
 
template <typename Type>
void Dispatcher::on(std::function<void(const Type&)> func) {
  const auto id = typeid(Type{}).hash_code();
  handlers_[id].push_back([func = std::move(func)](void* value) {
    func(*static_cast<Type*>(value));
  });
}
 
}  // namespace wren::event