#pragma once

#include <cstddef>
#include <memory>
#include <string>
#include <unordered_map>

namespace boundard {

class Scene;

class Game {
   private:
    size_t id_cnt;
    std::string current_scene_name_;
    std::string pending_scene_;
    std::unordered_map<std::string, std::shared_ptr<Scene>> scenes_;
    std::shared_ptr<Scene> current_scene_;

   public:
    Game();
    ~Game();
    Game(const Game&) = delete;
    Game& operator=(const Game&) = delete;
    Game(Game&&) noexcept = delete;
    Game& operator=(Game&&) noexcept = delete;

    static Game& getInstance();
    void launch();
    size_t new_id();

    // 场景注册与查询。
    void add_scene(std::shared_ptr<Scene> scene);
    std::shared_ptr<Scene> scene(const std::string& name) const;
    std::shared_ptr<Scene> current_scene() const;
    const std::string& current_scene_name() const;
    bool has_scene(const std::string& name) const;

    // 引擎在安全时机调用，把目标场景设为当前场景。
    void set_current_scene(std::shared_ptr<Scene> scene);

    // 供行为函数调用的切换 API。场景会在主循环的安全时机切换。
    bool switch_scene(const std::string& name);
    void request_scene(const std::string& name);
    std::string take_scene_request();
};
}  // namespace boundard