8 files changed, 50 insertions, 49 deletions

diff --git a/src/crepe/api/Script.cpp b/src/crepe/api/Script.cpp
index 4091fd4..753a9e3 100644
--- a/src/crepe/api/Script.cpp
+++ b/src/crepe/api/Script.cpp
@@ -8,8 +8,7 @@ using namespace crepe;
 using namespace std;
 
 Script::~Script() {
-	Mediator & mediator = this->mediator;
-	EventManager & mgr = mediator.event_manager;
+	EventManager & mgr = this->mediator->event_manager;
 	for (auto id : this->listeners) {
 		mgr.unsubscribe(id);
 	}
@@ -21,7 +20,8 @@ void Script::subscribe(const EventHandler<CollisionEvent> & callback) {
 }
 
 void Script::set_next_scene(const string & name) {
-	Mediator & mediator = this->mediator;
-	SceneManager & mgr = mediator.scene_manager;
+	SceneManager & mgr = this->mediator->scene_manager;
 	mgr.set_next_scene(name);
 }
+
+SaveManager & Script::get_save_manager() const { return this->mediator->save_manager; }
diff --git a/src/crepe/api/Script.h b/src/crepe/api/Script.h
index 49bdcf5..668e5d1 100644
--- a/src/crepe/api/Script.h
+++ b/src/crepe/api/Script.h
@@ -132,6 +132,9 @@ protected:
 	 */
 	void set_next_scene(const std::string & name);
 
+	//! Retrieve SaveManager reference
+	SaveManager & get_save_manager() const;
+
 	//! \}
 
 private:
diff --git a/src/crepe/api/Script.hpp b/src/crepe/api/Script.hpp
index 16e0dc5..225a51c 100644
--- a/src/crepe/api/Script.hpp
+++ b/src/crepe/api/Script.hpp
@@ -31,8 +31,7 @@ void Script::logf(Args &&... args) {
 template <typename EventType>
 void Script::subscribe_internal(const EventHandler<EventType> & callback,
 								event_channel_t channel) {
-	Mediator & mediator = this->mediator;
-	EventManager & mgr = mediator.event_manager;
+	EventManager & mgr = this->mediator->event_manager;
 	subscription_t listener = mgr.subscribe<EventType>(
 		[this, callback](const EventType & data) -> bool {
 			bool & active = this->active;
diff --git a/src/crepe/manager/Mediator.h b/src/crepe/manager/Mediator.h
index ba0b41f..35ac181 100644
--- a/src/crepe/manager/Mediator.h
+++ b/src/crepe/manager/Mediator.h
@@ -5,13 +5,13 @@
 // TODO: remove these singletons:
 #include "../facade/SDLContext.h"
 #include "EventManager.h"
-#include "SaveManager.h"
 #include "api/LoopTimer.h"
 
 namespace crepe {
 
 class ComponentManager;
 class SceneManager;
+class SaveManager;
 class ResourceManager;
 
 /**
@@ -29,7 +29,7 @@ class ResourceManager;
 struct Mediator {
 	OptionalRef<ComponentManager> component_manager;
 	OptionalRef<SceneManager> scene_manager;
-	OptionalRef<SaveManager> save_manager = SaveManager::get_instance();
+	OptionalRef<SaveManager> save_manager;
 	OptionalRef<EventManager> event_manager = EventManager::get_instance();
 	OptionalRef<ResourceManager> resource_manager;
 	OptionalRef<SDLContext> sdl_context = SDLContext::get_instance();
diff --git a/src/crepe/manager/SaveManager.cpp b/src/crepe/manager/SaveManager.cpp
index d4ed1c1..292e8fd 100644
--- a/src/crepe/manager/SaveManager.cpp
+++ b/src/crepe/manager/SaveManager.cpp
@@ -1,13 +1,24 @@
 #include "../ValueBroker.h"
 #include "../api/Config.h"
 #include "../facade/DB.h"
-#include "../util/Log.h"
 
 #include "SaveManager.h"
 
 using namespace std;
 using namespace crepe;
 
+SaveManager::SaveManager(Mediator & mediator) : Manager(mediator) {
+	mediator.save_manager = *this;
+}
+
+DB & SaveManager::get_db() {
+	if (this->db == nullptr) {
+		Config & cfg = Config::get_instance();
+		this->db = make_unique<DB>(cfg.savemgr.location);
+	}
+	return *this->db;
+}
+
 template <>
 string SaveManager::serialize(const string & value) const noexcept {
 	return value;
@@ -90,22 +101,6 @@ int32_t SaveManager::deserialize(const string & value) const noexcept {
 	return deserialize<int64_t>(value);
 }
 
-SaveManager::SaveManager() { dbg_trace(); }
-
-SaveManager & SaveManager::get_instance() {
-	dbg_trace();
-	static SaveManager instance;
-	return instance;
-}
-
-DB & SaveManager::get_db() {
-	Config & cfg = Config::get_instance();
-	// TODO: make this path relative to XDG_DATA_HOME on Linux and whatever the
-	// default equivalent is on Windows using some third party library
-	static DB db(cfg.savemgr.location);
-	return db;
-}
-
 bool SaveManager::has(const string & key) {
 	DB & db = this->get_db();
 	return db.has(key);
@@ -155,7 +150,8 @@ ValueBroker<T> SaveManager::get(const string & key) {
 	return {
 		[this, key](const T & target) { this->set<T>(key, target); },
 		[this, key, value]() mutable -> const T & {
-			value = this->deserialize<T>(this->get_db().get(key));
+			DB & db = this->get_db();
+			value = this->deserialize<T>(db.get(key));
 			return value;
 		},
 	};
diff --git a/src/crepe/manager/SaveManager.h b/src/crepe/manager/SaveManager.h
index 3d8c852..1b55a22 100644
--- a/src/crepe/manager/SaveManager.h
+++ b/src/crepe/manager/SaveManager.h
@@ -4,6 +4,8 @@
 
 #include "../ValueBroker.h"
 
+#include "Manager.h"
+
 namespace crepe {
 
 class DB;
@@ -18,7 +20,7 @@ class DB;
  *
  * The underlying database is a key-value store.
  */
-class SaveManager {
+class SaveManager : public Manager {
 public:
 	/**
 	 * \brief Get a read/write reference to a value and initialize it if it does not yet exist
@@ -63,8 +65,8 @@ public:
 	 */
 	bool has(const std::string & key);
 
-private:
-	SaveManager();
+public:
+	SaveManager(Mediator & mediator);
 	virtual ~SaveManager() = default;
 
 private:
@@ -89,26 +91,12 @@ private:
 	template <typename T>
 	T deserialize(const std::string & value) const noexcept;
 
-public:
-	// singleton
-	static SaveManager & get_instance();
-	SaveManager(const SaveManager &) = delete;
-	SaveManager(SaveManager &&) = delete;
-	SaveManager & operator=(const SaveManager &) = delete;
-	SaveManager & operator=(SaveManager &&) = delete;
-
+protected:
+	//! Create or return DB
+	virtual DB & get_db();
 private:
-	/**
-	 * \brief Create an instance of DB and return its reference
-	 *
-	 * \returns DB instance
-	 *
-	 * This function exists because DB is a facade class, which can't directly be used in the API
-	 * without workarounds
-	 *
-	 * TODO: better solution
-	 */
-	static DB & get_db();
+	//! Database
+	std::unique_ptr<DB> db = nullptr;
 };
 
 } // namespace crepe
diff --git a/src/crepe/util/OptionalRef.h b/src/crepe/util/OptionalRef.h
index 3201667..1b2cb3f 100644
--- a/src/crepe/util/OptionalRef.h
+++ b/src/crepe/util/OptionalRef.h
@@ -25,7 +25,7 @@ public:
 	 */
 	OptionalRef<T> & operator=(T & ref);
 	/**
-	 * \brief Retrieve this reference
+	 * \brief Retrieve this reference (cast)
 	 *
 	 * \returns Internal reference if it is set
 	 *
@@ -33,6 +33,14 @@ public:
 	 */
 	operator T &() const;
 	/**
+	 * \brief Retrieve this reference (member access)
+	 *
+	 * \returns Internal reference if it is set
+	 *
+	 * \throws std::runtime_error if this function is called while the reference it not set
+	 */
+	T * operator->() const;
+	/**
 	 * \brief Check if this reference is not empty
 	 *
 	 * \returns `true` if reference is set, or `false` if it is not
diff --git a/src/crepe/util/OptionalRef.hpp b/src/crepe/util/OptionalRef.hpp
index 4608c9e..5e36b3a 100644
--- a/src/crepe/util/OptionalRef.hpp
+++ b/src/crepe/util/OptionalRef.hpp
@@ -19,6 +19,13 @@ OptionalRef<T>::operator T &() const {
 }
 
 template <typename T>
+T * OptionalRef<T>::operator->() const {
+	if (this->ref == nullptr)
+		throw std::runtime_error("OptionalRef: attempt to dereference nullptr");
+	return this->ref;
+}
+
+template <typename T>
 OptionalRef<T> & OptionalRef<T>::operator=(T & ref) {
 	this->ref = &ref;
 	return *this;