#ifndef _INCLUDE_SOURCEMOD_IFACE_SHARE_SYS_H_

#define _INCLUDE_SOURCEMOD_IFACE_SHARE_SYS_H_

namespace SourceMod

{

	/**

	 * @brief Defines the base functionality required by a shared interface.

	 */

	class SMInterface

	{

	public:

		/**

		 * @brief Must return an integer defining the interface's version.

		 */

		virtual unsigned int GetInterfaceVersion() =0;

		/**

		 * @brief Must return a string defining the interface's unique name.

		 */

		virtual const char *GetInterfaceName() =0;

		/**

		 * @brief Must return whether the requested version number is backwards comaptible.

		 * Note: This can be overridden for breaking changes or custom versioning.

		 * 

		 * @param version		Version number to compare against.

		 * @return				True if compatible, false otherwise.

		 */

		virtual bool IsVersionCompatible(unsigned int version)

		{

			if (version > GetInterfaceVersion())

			{

				return false;

			}

			return true;

		}

	};

	enum UnloadableParentType

	{

		ParentType_Module,

		ParentType_Plugin

	};

	/**

	 * @brief Denotes a top-level unloadable object.

	 */

	class IUnloadableParent

	{

	public:

		virtual UnloadableParentType GetParentType() =0;

		virtual void *GetParentToken() =0;

		/**

		 * @brief Called when an interface this object has requested is removed.

		 *

		 * @param pIface		Interface being removed.

		 */

		virtual void OnInterfaceUnlink(SMInterface *pIface) =0;

	protected:

		void *m_parent_token;

	};

	/**

	 * @brief Listens for unlinked objects.

	 */

	class IUnlinkListener

	{

	public:

		/**

		 * @brief Called when a parent object is unloaded.

		 *

		 * @param parent		The parent object which is dying.

		 */

		virtual void OnParentUnlink(IUnloadableParent *parent)

		{

		}

	};

	/**

	 * @brief Tracks dependencies and fires dependency listeners.

	 */

	class IShareSys

	{

	public:

		/**

		 * @brief Adds an interface to the global interface system

		 *

		 * @param iface			Interface pointer (must be unique).

		 * @param parent		Parent unloadable token given to the module/interface.

		 */

		virtual bool AddInterface(SMInterface *iface, IUnloadableParent *parent) =0;

		/**

		 * @brief Requests an interface from the global interface system.

		 * If found, the interface's internal reference count will be increased.

		 *

		 * @param iface_name	Interface name.

		 * @param iface_vers	Interface version to attempt to match.

		 * @param me			Object requesting this interface, in order to track dependencies.

		 * @param pIface		Pointer to store the return value in.

		 */

		virtual bool RequestInterface(const char *iface_name, 

										unsigned int iface_vers, 

										IUnloadableParent *me,

										void **pIface) =0;

		/**

		 * @brief Unloads an interface.

		 *

		 * @param iface			Interface pointer.

		 * @param parent		Security token, trivial measure to prevent accidental unloads.

		 *                      This token must match the one used with AddInterface().

		 */

		virtual void RemoveInterface(SMInterface *iface, IUnloadableParent *parent) =0;

		/**

		 * @brief Adds an unlink listener.

		 *

		 * @param pListener		Listener pointer.

		 */

		virtual void AddUnlinkListener(IUnlinkListener *pListener) =0;

		/**

		 * @brief Removes an unlink listener.

		 *

		 * @param pListener		Listener pointer.

		 */

		virtual void RemoveUnlinkListener(IUnlinkListener *pListener) =0;

	};

};

#endif //_INCLUDE_SOURCEMOD_IFACE_SHARE_SYS_H_