5 files changed, 113 insertions, 0 deletions

diff --git a/src/crepe/manager/CMakeLists.txt b/src/crepe/manager/CMakeLists.txt
index 517b8a2..480c8ee 100644
--- a/src/crepe/manager/CMakeLists.txt
+++ b/src/crepe/manager/CMakeLists.txt
@@ -4,6 +4,7 @@ target_sources(crepe PUBLIC
 	Manager.cpp
 	SaveManager.cpp
 	SceneManager.cpp
+	ResourceManager.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -16,5 +17,7 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	SaveManager.h
 	SceneManager.h
 	SceneManager.hpp
+	ResourceManager.h
+	ResourceManager.hpp
 )
 
diff --git a/src/crepe/manager/Mediator.h b/src/crepe/manager/Mediator.h
index a91509e..475aed9 100644
--- a/src/crepe/manager/Mediator.h
+++ b/src/crepe/manager/Mediator.h
@@ -10,6 +10,7 @@ namespace crepe {
 
 class ComponentManager;
 class SceneManager;
+class ResourceManager;
 
 /**
  * Struct to pass references to classes that would otherwise need to be singletons down to
@@ -28,6 +29,7 @@ struct Mediator {
 	OptionalRef<SceneManager> scene_manager;
 	OptionalRef<SaveManager> save_manager = SaveManager::get_instance();
 	OptionalRef<EventManager> event_manager = EventManager::get_instance();
+	OptionalRef<ResourceManager> resource_manager;
 };
 
 }
diff --git a/src/crepe/manager/ResourceManager.cpp b/src/crepe/manager/ResourceManager.cpp
new file mode 100644
index 0000000..87585ad
--- /dev/null
+++ b/src/crepe/manager/ResourceManager.cpp
@@ -0,0 +1,34 @@
+#include "util/Log.h"
+
+#include "ResourceManager.h"
+
+using namespace crepe;
+using namespace std;
+
+ResourceManager::ResourceManager(Mediator & mediator) : Manager(mediator) {
+	mediator.resource_manager = *this;
+	dbg_trace();
+}
+ResourceManager::~ResourceManager() { dbg_trace(); }
+
+void ResourceManager::clear() {
+	std::erase_if(this->resources, [](const pair<const Asset, CacheEntry> & pair) {
+		const CacheEntry & entry = pair.second;
+		return entry.persistent == false;
+	});
+}
+
+void ResourceManager::clear_all() {
+	this->resources.clear();
+}
+
+void ResourceManager::set_persistent(const Asset & asset, bool persistent) {
+	this->get_entry(asset).persistent = persistent;
+}
+
+ResourceManager::CacheEntry & ResourceManager::get_entry(const Asset & asset) {
+	if (!this->resources.contains(asset))
+		this->resources[asset] = {};
+	return this->resources.at(asset);
+}
+
diff --git a/src/crepe/manager/ResourceManager.h b/src/crepe/manager/ResourceManager.h
new file mode 100644
index 0000000..e7e6abc
--- /dev/null
+++ b/src/crepe/manager/ResourceManager.h
@@ -0,0 +1,48 @@
+#pragma once
+
+#include <memory>
+#include <unordered_map>
+
+#include "../Resource.h"
+#include "../api/Asset.h"
+
+#include "Manager.h"
+
+namespace crepe {
+
+/**
+ * \brief The ResourceManager is responsible for storing and managing assets over
+ * multiple scenes.
+ * 
+ * The ResourceManager ensures that assets are loaded once and can be accessed
+ * across different scenes. It caches assets to avoid reloading them every time
+ * a scene is loaded. Assets are retained in memory until the ResourceManager is
+ * destroyed, at which point the cached assets are cleared.
+ */
+class ResourceManager : public Manager {
+public:
+	ResourceManager(Mediator & mediator);
+	virtual ~ResourceManager(); // dbg_trace
+
+private:
+	struct CacheEntry {
+		std::unique_ptr<Resource> resource = nullptr;
+		bool persistent = false;
+	};
+	//! A cache that holds all the assets, accessible by their file path, over multiple scenes.
+	std::unordered_map<const Asset, CacheEntry> resources;
+	CacheEntry & get_entry(const Asset & asset);
+
+public:
+	void set_persistent(const Asset & asset, bool persistent);
+
+	template <typename Resource>
+	Resource & get(const Asset & asset);
+
+	void clear();
+	void clear_all();
+};
+
+} // namespace crepe
+
+#include "ResourceManager.hpp"
diff --git a/src/crepe/manager/ResourceManager.hpp b/src/crepe/manager/ResourceManager.hpp
new file mode 100644
index 0000000..8270bc5
--- /dev/null
+++ b/src/crepe/manager/ResourceManager.hpp
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <format>
+
+#include "ResourceManager.h"
+
+namespace crepe {
+
+template <typename T>
+T & ResourceManager::get(const Asset & asset) {
+	using namespace std;
+	static_assert(is_base_of<Resource, T>::value, "cache must recieve a derivative class of Resource");
+
+	CacheEntry & entry = this->get_entry(asset);
+	if (entry.resource == nullptr)
+		entry.resource = make_unique<T>(asset);
+
+	T * concrete_resource = dynamic_cast<T *>(entry.resource.get());
+	if (concrete_resource == nullptr)
+		throw runtime_error(format("ResourceManager: mismatch between requested type and actual type of resource ({})", asset.get_path()));
+
+	return *concrete_resource;
+}
+
+}
+