15 files changed, 209 insertions, 36 deletions

diff --git a/src/crepe/Component.cpp b/src/crepe/Component.cpp
index 141e1a8..8086492 100644
--- a/src/crepe/Component.cpp
+++ b/src/crepe/Component.cpp
@@ -1,6 +1,7 @@
 #include "Component.h"
 
 using namespace crepe;
+using namespace std;
 
 Component::Component(game_object_id_t id) : game_object_id(id) {}
 
@@ -8,3 +9,11 @@ Component & Component::operator=(const Component &) {
 	return *this;
 }
 
+unique_ptr<Component> Component::save() const {
+	return unique_ptr<Component>(new Component(*this));
+}
+
+void Component::restore(const Component & snapshot) {
+	*this = snapshot;
+}
+
diff --git a/src/crepe/Component.h b/src/crepe/Component.h
index 47c5c34..fc0268c 100644
--- a/src/crepe/Component.h
+++ b/src/crepe/Component.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <memory>
+
 #include "types.h"
 
 namespace crepe {
@@ -32,15 +34,16 @@ protected:
 	//! Only ComponentManager can create components
 	friend class ComponentManager;
 
-	// create snapshot
-	Component(const Component &) = default;
-	// restore snapshot
-	virtual Component & operator=(const Component &);
-
 	// components are never moved
 	Component(Component &&) = delete;
 	virtual Component & operator=(Component &&) = delete;
 
+protected:
+	virtual std::unique_ptr<Component> save() const;
+	Component(const Component &) = default;
+	virtual void restore(const Component & snapshot);
+	virtual Component & operator=(const Component &);
+
 public:
 	virtual ~Component() = default;
 
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index ea9c425..68b074e 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -11,13 +11,9 @@ GameObject::GameObject(Mediator & mediator, game_object_id_t id,
 					   const std::string & name, const std::string & tag,
 					   const vec2 & position, double rotation, double scale)
 	: id(id),
-	  mediator(mediator) {
-
-	// Add Transform and Metadata components
-	ComponentManager & mgr = this->mediator.component_manager;
-	mgr.add_component<Transform>(this->id, position, rotation, scale);
-	mgr.add_component<Metadata>(this->id, name, tag);
-}
+	  mediator(mediator),
+		transform(mediator.component_manager->add_component<Transform>(this->id, position, rotation, scale)),
+		metadata(mediator.component_manager->add_component<Metadata>(this->id, name, tag)) { }
 
 void GameObject::set_parent(const GameObject & parent) {
 	ComponentManager & mgr = this->mediator.component_manager;
diff --git a/src/crepe/api/GameObject.h b/src/crepe/api/GameObject.h
index a311c21..6203f81 100644
--- a/src/crepe/api/GameObject.h
+++ b/src/crepe/api/GameObject.h
@@ -7,6 +7,8 @@
 namespace crepe {
 
 class Mediator;
+class Transform;
+class Metadata;
 
 /**
  * \brief Represents a GameObject
@@ -35,6 +37,13 @@ private:
 	friend class ComponentManager;
 
 public:
+	//! The id of the GameObject
+	const game_object_id_t id;
+
+	Transform & transform;
+	Metadata & metadata;
+
+public:
 	/**
 	 * \brief Set the parent of this GameObject
 	 *
@@ -68,10 +77,6 @@ public:
 	 */
 	void set_persistent(bool persistent = true);
 
-public:
-	//! The id of the GameObject
-	const game_object_id_t id;
-
 protected:
 	Mediator & mediator;
 };
diff --git a/src/crepe/api/LoopManager.cpp b/src/crepe/api/LoopManager.cpp
index 3511bca..2855455 100644
--- a/src/crepe/api/LoopManager.cpp
+++ b/src/crepe/api/LoopManager.cpp
@@ -25,6 +25,8 @@ LoopManager::LoopManager() {
 	this->load_system<InputSystem>();
 	this->load_system<EventSystem>();
 	this->load_system<AudioSystem>();
+
+	this->mediator.loop_manager = *this;
 }
 
 void LoopManager::start() {
diff --git a/src/crepe/api/Transform.cpp b/src/crepe/api/Transform.cpp
index a85b792..5fc886b 100644
--- a/src/crepe/api/Transform.cpp
+++ b/src/crepe/api/Transform.cpp
@@ -3,6 +3,7 @@
 #include "Transform.h"
 
 using namespace crepe;
+using namespace std;
 
 Transform::Transform(game_object_id_t id, const vec2 & point, double rotation, double scale)
 	: Component(id),
@@ -11,3 +12,12 @@ Transform::Transform(game_object_id_t id, const vec2 & point, double rotation, d
 	  scale(scale) {
 	dbg_trace();
 }
+
+unique_ptr<Component> Transform::save() const {
+	return unique_ptr<Component>{new Transform(*this)};
+}
+
+void Transform::restore(const Component & snapshot) {
+	*this = static_cast<const Transform &>(snapshot);
+}
+
diff --git a/src/crepe/api/Transform.h b/src/crepe/api/Transform.h
index 7ee6d65..bbd23e0 100644
--- a/src/crepe/api/Transform.h
+++ b/src/crepe/api/Transform.h
@@ -35,6 +35,13 @@ protected:
 	virtual int get_instances_max() const { return 1; }
 	//! ComponentManager instantiates all components
 	friend class ComponentManager;
+
+protected:
+	virtual std::unique_ptr<Component> save() const;
+	Transform(const Transform &) = default;
+	virtual void restore(const Component & snapshot);
+	virtual Transform & operator=(const Transform &) = default;
+
 };
 
 } // namespace crepe
diff --git a/src/crepe/manager/ComponentManager.cpp b/src/crepe/manager/ComponentManager.cpp
index 24ba0d7..5f5c050 100644
--- a/src/crepe/manager/ComponentManager.cpp
+++ b/src/crepe/manager/ComponentManager.cpp
@@ -72,3 +72,29 @@ set<game_object_id_t> ComponentManager::get_objects_by_tag(const string & tag) c
 	return this->get_objects_by_predicate<Metadata>(
 		[tag](const Metadata & data) { return data.tag == tag; });
 }
+
+ComponentManager::Snapshot ComponentManager::save() {
+	Snapshot snapshot{};
+	for (const auto & [type, by_id_index] : this->components) {
+		for (game_object_id_t id = 0; id < by_id_index.size(); id++) {
+			const auto & components = by_id_index[id];
+			for (size_t index = 0; index < components.size(); index++) {
+				const Component & component = *components[index];
+				snapshot.components.push_back(SnapshotComponent{
+					.type = type,
+					.id = id,
+					.index = index,
+					.component = component.save(),
+				});
+			}
+		}
+	}
+	return snapshot;
+}
+
+void ComponentManager::restore(const Snapshot & snapshot) {
+	for (const SnapshotComponent & info : snapshot.components) {
+		this->components[info.type][info.id][info.index]->restore(*info.component);
+	}
+}
+
diff --git a/src/crepe/manager/ComponentManager.h b/src/crepe/manager/ComponentManager.h
index dd7c154..457a196 100644
--- a/src/crepe/manager/ComponentManager.h
+++ b/src/crepe/manager/ComponentManager.h
@@ -143,10 +143,15 @@ public:
 	RefVector<T> get_components_by_tag(const std::string & tag) const;
 
 	struct SnapshotComponent {
-		Component component;
+		std::type_index type;
+		game_object_id_t id;
+		size_t index;
+		std::unique_ptr<Component> component;
 	};
 	struct Snapshot {
-		
+		// TODO: some kind of hash code that ensures components exist in all the same places as
+		// this snapshot
+		std::vector<SnapshotComponent> components;
 	};
 	Snapshot save();
 	void restore(const Snapshot &);
diff --git a/src/crepe/manager/Mediator.h b/src/crepe/manager/Mediator.h
index eef4432..f5864e7 100644
--- a/src/crepe/manager/Mediator.h
+++ b/src/crepe/manager/Mediator.h
@@ -14,6 +14,7 @@ class ResourceManager;
 class SDLContext;
 class LoopTimer;
 class ReplayManager;
+class LoopManager;
 
 /**
  * Struct to pass references to classes that would otherwise need to be singletons down to
@@ -36,6 +37,7 @@ struct Mediator {
 	OptionalRef<ResourceManager> resource_manager;
 	OptionalRef<LoopTimer> timer;
 	OptionalRef<ReplayManager> replay_manager;
+	OptionalRef<LoopManager> loop_manager;
 };
 
 } // namespace crepe
diff --git a/src/crepe/manager/ReplayManager.cpp b/src/crepe/manager/ReplayManager.cpp
index 82c2275..81ff114 100644
--- a/src/crepe/manager/ReplayManager.cpp
+++ b/src/crepe/manager/ReplayManager.cpp
@@ -1,4 +1,4 @@
-#include "../util/Log.h"
+#include <format>
 
 #include "ReplayManager.h"
 #include "Manager.h"
@@ -11,26 +11,29 @@ ReplayManager::ReplayManager(Mediator & mediator) : Manager(mediator) {
 }
 
 void ReplayManager::record_start() {
-	if (this->recording) this->release(this->current_recording);
-	this->current_recording++;
-	this->recording = true;
+	if (this->state == RECORDING) this->release(this->id);
+	this->id++;
+	this->memory[this->id] = make_unique<Recording>();
+	this->recording = *this->memory.at(this->id);
+	this->state = RECORDING;
 }
 
 recording_t ReplayManager::record_end() {
-	this->recording = false;
-	return this->current_recording;
+	this->state = IDLE;
+	return this->id;
 }
 
 void ReplayManager::play(recording_t handle) {
 	if (!this->memory.contains(handle))
 		throw out_of_range(format("ReplayManager: no recording for handle {}", handle));
-	Recording & recording = *this->memory.at(handle);
-
-	dbg_log("TODO: magic");
+	this->recording = *this->memory.at(handle);
+	this->recording->frame = 0;
+	this->state = PLAYING;
 }
 
 void ReplayManager::release(recording_t handle) {
-	dbg_log("release");
-
+	if (!this->memory.contains(handle))
+		return;
+	this->memory.erase(handle);
 }
 
diff --git a/src/crepe/manager/ReplayManager.h b/src/crepe/manager/ReplayManager.h
index c50196c..672d093 100644
--- a/src/crepe/manager/ReplayManager.h
+++ b/src/crepe/manager/ReplayManager.h
@@ -1,13 +1,14 @@
 #pragma once
 
+#include <unordered_map>
+
 #include "Manager.h"
 #include "ComponentManager.h"
-#include <unordered_map>
+#include "util/OptionalRef.h"
 
 namespace crepe {
 
 class ReplaySystem;
-class Memento;
 
 typedef size_t recording_t;
 
@@ -20,11 +21,20 @@ protected:
 	void record_frame();
 
 private:
-	typedef std::vector<ComponentManager::Snapshot> Recording;
-
-	bool recording = false;
-	recording_t current_recording = -1;
-
+	struct Recording {
+		size_t frame = 0;
+		std::vector<ComponentManager::Snapshot> frames;
+	};
+
+	enum State {
+		IDLE,
+		RECORDING,
+		PLAYING,
+	};
+
+	State state = IDLE;
+	OptionalRef<Recording> recording;
+	recording_t id = -1;
 
 	std::unordered_map<recording_t, std::unique_ptr<Recording>> memory;
 public:
diff --git a/src/crepe/system/ReplaySystem.cpp b/src/crepe/system/ReplaySystem.cpp
index 3aabb58..85595a2 100644
--- a/src/crepe/system/ReplaySystem.cpp
+++ b/src/crepe/system/ReplaySystem.cpp
@@ -1,7 +1,77 @@
+#include "system/ScriptSystem.h"
+
+#include "../manager/ReplayManager.h"
+
 #include "ReplaySystem.h"
 
+#include "../api/LoopManager.h"
+
 using namespace crepe;
+using namespace std;
 
 void ReplaySystem::fixed_update() {
+	ReplayManager & replay = this->mediator.replay_manager;
+
+	switch (replay.state) {
+		case ReplayManager::IDLE: break;
+		case ReplayManager::RECORDING: {
+			this->update_recording();
+			break;
+		}
+		case ReplayManager::PLAYING: {
+			this->update_playing();
+			break;
+		}
+	}
+
+	this->last_state = replay.state;
+}
+
+void ReplaySystem::update_recording() {
+	ReplayManager & replay = this->mediator.replay_manager;
+	ComponentManager & components = this->mediator.component_manager;
+
+	ReplayManager::Recording & recording = replay.recording;
+	recording.frames.push_back(components.save());
+	recording.frame++;
+}
+
+void ReplaySystem::update_playing() {
+	ReplayManager & replay = this->mediator.replay_manager;
+
+	if (this->last_state != ReplayManager::PLAYING) {
+		this->playback_begin();
+	}
+
+	ReplayManager::Recording & recording = replay.recording;
+
+	if (recording.frames.size() == recording.frame) {
+		this->playback_end();
+		return;
+	}
+
+	ComponentManager & components = this->mediator.component_manager;
+	ComponentManager::Snapshot & frame = recording.frames.at(recording.frame);
+
+	components.restore(frame);
+	recording.frame++;
+}
+
+void ReplaySystem::playback_begin() {
+	LoopManager & loop_manager = this->mediator.loop_manager;
+	// TODO: store system active state
+	// TODO: disable most systems
+	// TODO: store components snapshot
+}
+
+void ReplaySystem::playback_end() {
+	ReplayManager & replay = this->mediator.replay_manager;
+
+	replay.state = ReplayManager::IDLE;
+
+	LoopManager & loop_manager = this->mediator.loop_manager;
+
+	// TODO: restore system active state snapshot
+	// TODO: restore components snapshot
 }
 
diff --git a/src/crepe/system/ReplaySystem.h b/src/crepe/system/ReplaySystem.h
index 15ef3fc..fb40176 100644
--- a/src/crepe/system/ReplaySystem.h
+++ b/src/crepe/system/ReplaySystem.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "../manager/ReplayManager.h"
+
 #include "System.h"
 
 namespace crepe {
@@ -9,6 +11,15 @@ public:
 	using System::System;
 
 	void fixed_update() override;
+
+private:
+	ReplayManager::State last_state = ReplayManager::IDLE;
+	void update_recording();
+	void update_playing();
+
+	std::unordered_map<std::type_index, bool> system_active_snapshot;
+	void playback_begin();
+	void playback_end();
 };
 
 }
diff --git a/src/test/ECSTest.cpp b/src/test/ECSTest.cpp
index af2b7b0..8f86a91 100644
--- a/src/test/ECSTest.cpp
+++ b/src/test/ECSTest.cpp
@@ -466,3 +466,17 @@ TEST_F(ECSTest, ComponentsByTag) {
 		EXPECT_EQ(objects.size(), 3);
 	}
 }
+
+TEST_F(ECSTest, Snapshot) {
+	GameObject foo = mgr.new_object("foo");
+
+	foo.transform.position = {1, 1};
+
+	ComponentManager::Snapshot snapshot = mgr.save();
+
+	foo.transform.position = {0, 0};
+
+	mgr.restore(snapshot);
+
+	EXPECT_EQ(foo.transform.position, (vec2{1, 1}));
+}