serviceContainer.h

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#pragma once
#include <engine/core/iEngineService.h>
 
#include <format>
#include <memory>
#include <optional>
#include <typeindex>
#include <unordered_map>
 
class ServiceContainer final {
 public:
  ServiceContainer();
 
  template <typename T, typename... Args>
  requires EngineService<T> T& register_service(Args&&... args) {
    auto service = std::make_unique<T>(std::forward<Args>(args)...);
    T& ref = *service;
    services_[std::type_index(typeid(T))] = std::move(service);
    return ref;
  }
 
  template <typename T>
  requires EngineService<T>
  void unregister_service() { services_.erase(std::type_index(typeid(T))); }
 
  template <typename T>
  requires EngineService<T> std::reference_wrapper<T> get_service()
  const {
    const auto it = services_.find(std::type_index(typeid(T)));
    if (it == services_.end()) {
      throw std::runtime_error(
          std::format("Service not found: {}", typeid(T).name()));
    }
    // So we get an EngineServiceBase, but we know it's actually a T. We do not
    // use dynamic cast because we are not storing subtypes of T
    return std::ref(*static_cast<T*>(it->second.get()));
  }
 
  template <typename T>
  requires EngineService<T> std::optional<std::reference_wrapper<T>>
  try_get_service()
  const {
    const auto it = services_.find(std::type_index(typeid(T)));
    if (it == services_.end()) {
      return std::nullopt;
    }
 
    return std::ref(*static_cast<T*>(it->second.get()));
  }
 
 private:
  std::unordered_map<std::type_index, std::unique_ptr<IEngineService>>
      services_;
};