8 files changed, 183 insertions, 28 deletions

diff --git a/src/crepe/api/BehaviorScript.h b/src/crepe/api/BehaviorScript.h
index 9d85d4c..d556fe5 100644
--- a/src/crepe/api/BehaviorScript.h
+++ b/src/crepe/api/BehaviorScript.h
@@ -39,11 +39,14 @@ public:
 	 * \brief Set the concrete script of this component
 	 *
 	 * \tparam T Concrete script type (derived from \c crepe::Script)
+	 * \tparam Args Arguments for concrete script constructor
+	 *
+	 * \param args Arguments for concrete script constructor (forwarded using perfect forwarding)
 	 *
 	 * \returns Reference to BehaviorScript component (`*this`)
 	 */
-	template <class T>
-	BehaviorScript & set_script();
+	template <class T, typename... Args>
+	BehaviorScript & set_script(Args &&... args);
 
 protected:
 	//! Script instance
diff --git a/src/crepe/api/BehaviorScript.hpp b/src/crepe/api/BehaviorScript.hpp
index d80321d..5b5a418 100644
--- a/src/crepe/api/BehaviorScript.hpp
+++ b/src/crepe/api/BehaviorScript.hpp
@@ -9,13 +9,17 @@
 
 namespace crepe {
 
-template <class T>
-BehaviorScript & BehaviorScript::set_script() {
+template <class T, typename... Args>
+BehaviorScript & BehaviorScript::set_script(Args &&... args) {
 	dbg_trace();
 	static_assert(std::is_base_of<Script, T>::value);
-	Script * s = new T();
-	s->game_object_id = this->game_object_id;
+	Script * s = new T(std::forward<Args>(args)...);
+
+	s->game_object_id_ref = &this->game_object_id;
+	s->active_ref = &this->active;
 	s->component_manager_ref = &this->component_manager;
+	s->event_manager_ref = &EventManager::get_instance();
+
 	this->script = std::unique_ptr<Script>(s);
 	return *this;
 }
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index d6b6801..602ab52 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -24,6 +24,7 @@ target_sources(crepe PUBLIC
 	LoopTimer.cpp
 	Asset.cpp
 	EventHandler.cpp
+	Script.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
diff --git a/src/crepe/api/Event.h b/src/crepe/api/Event.h
index 06cf7f3..b267e3e 100644
--- a/src/crepe/api/Event.h
+++ b/src/crepe/api/Event.h
@@ -1,10 +1,12 @@
-// TODO discussing the location of these events
 #pragma once
+// TODO discussing the location of these events
 
 #include <string>
 
 #include "KeyCodes.h"
 
+namespace crepe {
+
 /**
  * \brief Base class for all event types in the system.
  */
@@ -91,11 +93,7 @@ public:
 /**
  * \brief Event triggered during a collision between objects.
  */
-class CollisionEvent : public Event {
-public:
-	//! Data describing the collision (currently not implemented).
-	// Collision collisionData;
-};
+class CollisionEvent : public Event {};
 
 /**
  * \brief Event triggered when text is submitted, e.g., from a text input.
@@ -110,3 +108,5 @@ public:
  * \brief Event triggered to indicate the application is shutting down.
  */
 class ShutDownEvent : public Event {};
+
+} // namespace crepe
diff --git a/src/crepe/api/EventManager.h b/src/crepe/api/EventManager.h
index 348a04d..1a33023 100644
--- a/src/crepe/api/EventManager.h
+++ b/src/crepe/api/EventManager.h
@@ -77,7 +77,7 @@ public:
 	 * \param channel The channel to trigger the event on (default is CHANNEL_ALL, which triggers on all channels).
 	 */
 	template <typename EventType>
-	void trigger_event(const EventType & event, event_channel_t channel = CHANNEL_ALL);
+	void trigger_event(const EventType & event = {}, event_channel_t channel = CHANNEL_ALL);
 
 	/**
 	 * \brief Queue an event for later processing.
@@ -89,7 +89,7 @@ public:
 	 * \param channel The channel to associate with the event (default is CHANNEL_ALL).
 	 */
 	template <typename EventType>
-	void queue_event(const EventType & event, event_channel_t channel = CHANNEL_ALL);
+	void queue_event(const EventType & event = {}, event_channel_t channel = CHANNEL_ALL);
 
 	/**
 	 * \brief Process all queued events.
diff --git a/src/crepe/api/Script.cpp b/src/crepe/api/Script.cpp
new file mode 100644
index 0000000..0e73848
--- /dev/null
+++ b/src/crepe/api/Script.cpp
@@ -0,0 +1,16 @@
+#include "Script.h"
+
+using namespace crepe;
+
+Script::~Script() {
+	EventManager & evmgr = *this->event_manager_ref;
+	for (auto id : this->listeners) {
+		evmgr.unsubscribe(id);
+	}
+}
+
+template <>
+void Script::subscribe(const EventHandler<CollisionEvent> & callback) {
+	const game_object_id_t & game_object_id = *this->game_object_id_ref;
+	this->subscribe_internal(callback, game_object_id);
+}
diff --git a/src/crepe/api/Script.h b/src/crepe/api/Script.h
index 839d937..43efd15 100644
--- a/src/crepe/api/Script.h
+++ b/src/crepe/api/Script.h
@@ -4,6 +4,8 @@
 
 #include "../types.h"
 
+#include "EventManager.h"
+
 namespace crepe {
 
 class ScriptSystem;
@@ -16,13 +18,19 @@ class ComponentManager;
  * This class is used as a base class for user-defined scripts that can be added to game
  * objects using the \c BehaviorScript component.
  *
- * \note Additional *events* (like Unity's OnDisable and OnEnable) should be implemented as
+ * \info Additional *events* (like Unity's OnDisable and OnEnable) should be implemented as
  * member or lambda methods in derivative user script classes and registered in \c init().
+ *
+ * \see feature_script
  */
 class Script {
 protected:
 	/**
-	 * \brief Script initialization function
+	 * \name Interface functions
+	 * \{
+	 */
+	/**
+	 * \brief Script initialization function (empty by default)
 	 *
 	 * This function is called during the ScriptSystem::update() routine *before*
 	 * Script::update() if it (a) has not yet been called and (b) the \c BehaviorScript component
@@ -30,24 +38,32 @@ protected:
 	 */
 	virtual void init() {}
 	/**
-	 * \brief Script update function
+	 * \brief Script update function (empty by default)
 	 *
 	 * This function is called during the ScriptSystem::update() routine if the \c BehaviorScript
 	 * component holding this script instance is active.
 	 */
 	virtual void update() {}
+	//! \}
+
 	//! ScriptSystem calls \c init() and \c update()
 	friend class crepe::ScriptSystem;
 
 protected:
 	/**
-	 * \brief Get single component of type \c T on this game object (utility)
+	 * \name Utility functions
+	 * \{
+	 */
+
+	/**
+	 * \brief Get single component of type \c T on this game object
 	 *
 	 * \tparam T Type of component
 	 *
 	 * \returns Reference to component
 	 *
-	 * \throws nullptr if this game object does not have a component matching type \c T
+	 * \throws std::runtime_error if this game object does not have a component matching type \c
+	 * T
 	 */
 	template <typename T>
 	T & get_component() const;
@@ -55,7 +71,7 @@ protected:
 	// cause compile-time errors
 
 	/**
-	 * \brief Get all components of type \c T on this game object (utility)
+	 * \brief Get all components of type \c T on this game object
 	 *
 	 * \tparam T Type of component
 	 *
@@ -64,25 +80,110 @@ protected:
 	template <typename T>
 	RefVector<T> get_components() const;
 
+	/**
+	 * \brief Log a message using Log::logf
+	 *
+	 * \tparam Args Log::logf parameters
+	 * \param args  Log::logf parameters
+	 */
+	template <typename... Args>
+	void logf(Args &&... args);
+
+	/**
+	 * \brief Subscribe to an event with an explicit channel
+	 * \see EventManager::subscribe
+	 */
+	template <typename EventType>
+	void subscribe(const EventHandler<EventType> & callback, event_channel_t channel);
+	/**
+	 * \brief Subscribe to an event on EventManager::CHANNEL_ALL
+	 * \see EventManager::subscribe
+	 */
+	template <typename EventType>
+	void subscribe(const EventHandler<EventType> & callback);
+
+	//! \}
+
+private:
+	/**
+	 * \brief Internal subscribe function
+	 *
+	 * This function exists so certain template specializations of Script::subscribe can be
+	 * explicitly deleted, and does the following:
+	 * - Wrap the user-provided callback in a check that tests if the parent BehaviorScript
+	 *   component is still active
+	 * - Store the subscriber handle returned by the event manager so this listener is
+	 *   automatically unsubscribed at the end of this Script instance's life
+	 *
+	 * \tparam EventType concrete Event class
+	 * \param callback User-provided callback function
+	 * \param channel Event channel (may have been overridden by template specializations)
+	 */
+	template <typename EventType>
+	void subscribe_internal(const EventHandler<EventType> & callback, event_channel_t channel);
+
 protected:
-	// NOTE: Script must have a constructor without arguments so the game programmer doesn't need
-	// to manually add `using Script::Script` to their concrete script class.
+	// NOTE: This must be the only constructor on Script, see "Late references" below
 	Script() = default;
 	//! Only \c BehaviorScript instantiates Script
 	friend class BehaviorScript;
 
+public:
+	// std::unique_ptr destroys script
+	virtual ~Script();
+
+private:
+	Script(const Script &) = delete;
+	Script(Script &&) = delete;
+	Script & operator=(const Script &) = delete;
+	Script & operator=(Script &&) = delete;
+
 private:
-	// These references are set by BehaviorScript immediately after calling the constructor of
-	// Script.
-	game_object_id_t game_object_id = -1;
+	/**
+	 * \name Late references
+	 *
+	 * These references are set by BehaviorScript immediately after calling the constructor of
+	 * Script.
+	 *
+	 * \note Script must have a constructor without arguments so the game programmer doesn't need
+	 * to manually add `using Script::Script` to their concrete script class if they want to
+	 * implement a non-default constructor (e.g. for passing references to their own concrete
+	 * Script classes).
+	 *
+	 * \todo These should be converted to OptionalRef<> once `loek/util` is merged
+	 *
+	 * \{
+	 */
+	//! Game object ID of game object parent BehaviorScript is attached to
+	const game_object_id_t * game_object_id_ref = nullptr;
+	//! Reference to parent component
+	bool * active_ref = nullptr;
+	//! Reference to component manager instance
 	ComponentManager * component_manager_ref = nullptr;
-	// TODO: use OptionalRef instead of pointer
+	//! Reference to event manager instance
+	EventManager * event_manager_ref = nullptr;
+	//! \}
 
 private:
 	//! Flag to indicate if \c init() has been called already
 	bool initialized = false;
+	//! List of subscribed events
+	std::vector<subscription_t> listeners;
 };
 
+/**
+ * \brief Subscribe to CollisionEvent for the current GameObject
+ *
+ * This is a template specialization for Script::subscribe which automatically sets the event
+ * channel so the callback handler is only called for CollisionEvent events that apply to the
+ * current GameObject the parent BehaviorScript is attached to.
+ */
+template <>
+void Script::subscribe(const EventHandler<CollisionEvent> & callback);
+template <>
+void Script::subscribe(const EventHandler<CollisionEvent> & callback, event_channel_t)
+	= delete;
+
 } // namespace crepe
 
 #include "Script.hpp"
diff --git a/src/crepe/api/Script.hpp b/src/crepe/api/Script.hpp
index a85d814..e94278d 100644
--- a/src/crepe/api/Script.hpp
+++ b/src/crepe/api/Script.hpp
@@ -20,8 +20,38 @@ T & Script::get_component() const {
 
 template <typename T>
 RefVector<T> Script::get_components() const {
-	auto & mgr = *this->component_manager_ref;
-	return mgr.get_components_by_id<T>(this->game_object_id);
+	ComponentManager & mgr = *this->component_manager_ref;
+
+	return mgr.get_components_by_id<T>(*this->game_object_id_ref);
+}
+
+template <typename... Args>
+void Script::logf(Args &&... args) {
+	Log::logf(std::forward<Args>(args)...);
+}
+
+template <typename EventType>
+void Script::subscribe_internal(const EventHandler<EventType> & callback,
+								event_channel_t channel) {
+	EventManager & mgr = *this->event_manager_ref;
+	subscription_t listener = mgr.subscribe<EventType>(
+		[this, callback](const EventType & data) -> bool {
+			bool & active = *this->active_ref;
+			if (!active) return false;
+			return callback(data);
+		},
+		channel);
+	this->listeners.push_back(listener);
+}
+
+template <typename EventType>
+void Script::subscribe(const EventHandler<EventType> & callback, event_channel_t channel) {
+	this->subscribe_internal(callback, channel);
+}
+
+template <typename EventType>
+void Script::subscribe(const EventHandler<EventType> & callback) {
+	this->subscribe_internal(callback, EventManager::CHANNEL_ALL);
 }
 
 } // namespace crepe