// Copyright (c) 2023 Dominic Masters
// 
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

#pragma once
#include "dawn.hpp"
#include "util/Flag.hpp"
#include "display/RenderHost.hpp"
#include "input/InputManager.hpp"
#include "time/TimeManager.hpp"
#include "asset/AssetManager.hpp"
#include "locale/LocaleManager.hpp"
#include "save/SaveManager.hpp"
#include "settings/SettingsManager.hpp"
#include "display/shader/ShaderManager.hpp"

#ifdef DAWN_ENABLE_PHYSICS
  #include "physics/PhysicsManager.hpp"
#endif

namespace Dawn {
  class Scene;
  class Game;

  enum class GameState : flag_t {
    INITIAL = FLAG(0),
    INITIALIZED = FLAG(1),
  };

  class IGame : public std::enable_shared_from_this<Game> {
    private:
      std::shared_ptr<Scene> currentScene = nullptr;
      std::shared_ptr<Scene> nextFrameScene = nullptr;
      flag_t state = (flag_t)GameState::INITIAL;

    protected:
      /**
       * Returns the initial scene for the game. Implemented by the main game
       * instance.
       * 
       * @return The initial scene.
       */
      virtual std::string getInitialScene() = 0;
      
      /**
       * Initializes the game managers.
       */
      virtual void initManagers() = 0;

      /**
       * Returns the game instance as a Game instance.
       * 
       * @return The game instance as a Game instance.
       */
      std::shared_ptr<Game> getSelfAsGame();

    public:
      std::shared_ptr<RenderHost> renderHost;
      std::shared_ptr<AssetManager> assetManager;
      std::shared_ptr<LocaleManager> localeManager;
      std::shared_ptr<SettingsManager> settingsManager;
      std::shared_ptr<ShaderManager> shaderManager;
      
      #ifdef DAWN_ENABLE_PHYSICS
        std::shared_ptr<PhysicsManager> physicsManager;
      #endif

      InputManager inputManager;
      TimeManager timeManager;
      SaveManager saveManager;

      /**
       * Constructs the game instance, does not initialize anything.
       */
      IGame();

      /**
       * Initialize the game and all of its components.
       */
      void init();

      /**
       * Deinitialize the game and all of its components.
       */
      void deinit();

      /**
       * Performs a single update tick on the game engine, and in turn all of
       * the game's sub systems.
       */
      void update();

      /**
       * Returns whether the game has been requested to gracefully close at the
       * next available opportunity.
       * 
       * @return True if the game should close.
       */
      bool_t isCloseRequested();

      /**
       * Returns the current scene that is active.
       * 
       * @return The current scene.
       */
      std::shared_ptr<Scene> getCurrentScene();

      /**
       * Deconstructs the game instance, does not deinitialize anything.
       */
      virtual ~IGame();
  };
}