1 files changed, 67 insertions, 4 deletions

diff --git a/src/crepe/Component.h b/src/crepe/Component.h
index 00b2164..52e06d5 100644
--- a/src/crepe/Component.h
+++ b/src/crepe/Component.h
@@ -1,16 +1,79 @@
 #pragma once
 
+#include <memory>
+
+#include "types.h"
+
 namespace crepe {
 
+class ComponentManager;
+
+/**
+ * \brief Base class for all components
+ *
+ * This class is the base class for all components. It provides a common interface for all
+ * components.
+ */
 class Component {
+public:
+	//! Whether the component is active
+	bool active = true;
+	/**
+	 * \brief The id of the GameObject this component belongs to
+	 *
+	 * \note Only systems are supposed to use this member, but since friend
+	 * relations aren't inherited this needs to be public.
+	 */
+	const game_object_id_t game_object_id;
+
 protected:
-	Component() = default;
+	/**
+	 * \param id The id of the GameObject this component belongs to
+	 */
+	Component(game_object_id_t id);
+	//! Only ComponentManager can create components
+	friend class ComponentManager;
+
+	// components are never moved
+	Component(Component &&) = delete;
+	virtual Component & operator=(Component &&) = delete;
+
+protected:
+	/**
+	 * \name ReplayManager (Memento) functions
+	 * \{
+	 */
+	/**
+	 * \brief Save a snapshot of this component's state
+	 * \note This function should only be implemented on components that should be saved/restored
+	 * by ReplayManager.
+	 * \returns Unique pointer to a deep copy of this component
+	 */
+	virtual std::unique_ptr<Component> save() const;
+	//! Copy constructor (used by \c save())
+	Component(const Component &) = default;
+	/**
+	 * \brief Restore this component from a snapshot
+	 * \param snapshot Data to fill this component with (as returned by \c save())
+	 */
+	virtual void restore(const Component & snapshot);
+	//! Copy assignment operator (used by \c restore())
+	virtual Component & operator=(const Component &);
+	//! \}
+
 public:
 	virtual ~Component() = default;
-	// TODO: shouldn't this constructor be deleted because this class will never
-	// directly be instantiated?
 
-	bool active = true;
+public:
+	/**
+	 * \brief Get the maximum number of instances for this component
+	 *
+	 * This method returns -1 by default, which means that there is no limit for the number of
+	 * instances. Concrete components can override this method to set a limit.
+	 *
+	 * \return The maximum number of instances for this component
+	 */
+	virtual int get_instances_max() const { return -1; }
 };
 
 } // namespace crepe