/**

 * vim: set ts=4 :

 * ================================================================

 * SourceMod

 * Copyright (C) 2004-2007 AlliedModders LLC.  All rights reserved.

 * ================================================================

 *

 * This program is free software; you can redistribute it and/or 

 * modify it under the terms of the GNU General Public License, 

 * version 3.0, as published by the Free Software Foundation.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to 

 * link the code of this program (as well as its derivative works) to 

 * "Half-Life 2," the "Source Engine," the "SourcePawn JIT," and any 

 * Game MODs that run on software by the Valve Corporation.  You must 

 * obey the GNU General Public License in all respects for all other 

 * code used. Additionally, AlliedModders LLC grants this exception 

 * to all derivative works. AlliedModders LLC defines further 

 * exceptions, found in LICENSE.txt (as of this writing, version 

 * JULY-31-2007), or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#ifndef _INCLUDE_SOURCEMOD_MODULE_INTERFACE_H_

#define _INCLUDE_SOURCEMOD_MODULE_INTERFACE_H_

#include <IShareSys.h>

#include <ILibrarySys.h>

/**

 * @file IExtensionSys.h

 * @brief Defines the interface for loading/unloading/managing extensions.

 */

namespace SourceMod

{

	class IExtensionInterface;

	typedef void *		ITERATOR;		/**< Generic pointer for dependency iterators */

	/** 

	 * @brief Encapsulates an IExtensionInterface and its dependencies.

	 */

	class IExtension

	{

	public:

		/**

		 * @brief Returns whether or not the extension is properly loaded.

		 */

		virtual bool IsLoaded() =0;

		/**

		 * @brief Returns the extension's API interface

		 *

		 * @return			An IExtensionInterface pointer.

		 */

		virtual IExtensionInterface *GetAPI() =0;

		/**

		 * @brief Returns the filename of the extension, relative to the

		 * extension folder.

		 *

		 * @return			A string containing the extension file name.

		 */

		virtual const char *GetFilename() =0;

		/**

		 * @brief Returns the extension's identity token.

		 *

		 * @return			An IdentityToken_t pointer.

		 */

		virtual IdentityToken_t *GetIdentity() =0;

		/**

		 * @brief Retrieves the extension dependency list for this extension.

		 *

		 * @param pOwner		Optional pointer to store the first interface's owner.

		 * @param pInterface	Optional pointer to store the first interface.

		 * @return				An ITERATOR pointer for the results, or NULL if no results at all.

		 */

		virtual ITERATOR *FindFirstDependency(IExtension **pOwner, SMInterface **pInterface) =0;

		/**

		 * @brief Finds the next dependency in the dependency list.

		 *

		 * @param iter			Pointer to iterator from FindFirstDependency.

		 * @param pOwner		Optional pointer to store the interface's owner.

		 * @param pInterface	Optional pointer to store the interface.

		 * @return				True if there are more results after this, false otherwise.

		 */

		virtual bool FindNextDependency(ITERATOR *iter, IExtension **pOwner, SMInterface **pInterface) =0;

		/**

		 * @brief Frees an ITERATOR handle from FindFirstDependency.

		 *

		 * @param iter			Pointer to iterator to free.

		 */

		virtual void FreeDependencyIterator(ITERATOR *iter) =0;

		/**

		 * @brief Queries the extension to see its run state.

		 *

		 * @param error			Error buffer (may be NULL).

		 * @param maxlength		Maximum length of buffer.

		 * @return				True if extension is okay, false if not okay.

		 */

		virtual bool IsRunning(char *error, size_t maxlength) =0;

	};

	/**

	 * @brief Version code of the IExtensionInterface API itself.

	 */

	#define SMINTERFACE_EXTENSIONAPI_VERSION	1

	/**

	 * @brief The interface an extension must expose.

	 */

	class IExtensionInterface

	{

	public:

		/** Returns the interface API version */

		virtual unsigned int GetExtensionVersion()

		{

			return SMINTERFACE_EXTENSIONAPI_VERSION;

		}

	public:

		/**

		 * @brief Called when the extension is loaded.

		 * 

		 * @param me		Pointer back to extension.

		 * @param sys		Pointer to interface sharing system of SourceMod.

		 * @param error		Error buffer to print back to, if any.

		 * @param maxlength	Maximum size of error buffer.

		 * @param late		If this extension was loaded "late" (i.e. manually).

		 * @return			True if load should continue, false otherwise.

		 */

		virtual bool OnExtensionLoad(IExtension *me,

								  IShareSys *sys, 

								  char *error, 

								  size_t maxlength, 

								  bool late) =0;

		/**

		 * @brief Called when the extension is about to be unloaded.

		 */

		virtual void OnExtensionUnload() =0;

		/**

		 * @brief Called when all extensions are loaded (loading cycle is done).

		 * If loaded late, this will be called right after OnExtensionLoad().

		 */

		virtual void OnExtensionsAllLoaded() =0;

		/**

		 * @brief Called when your pause state is about to change.

		 * 

		 * @param pause		True if pausing, false if unpausing.

		 */

		virtual void OnExtensionPauseChange(bool pause) =0;

		/**

		 * @brief Asks the extension whether it's safe to remove an external interface it's using.

		 * If it's not safe, return false, and the extension will be unloaded afterwards.

		 * NOTE: It is important to also hook NotifyInterfaceDrop() in order to clean up resources.

		 *

		 * @param pInterface		Pointer to interface being dropped.

		 * @return					True to continue, false to unload this extension afterwards.

		 */

		virtual bool QueryInterfaceDrop(SMInterface *pInterface)

		{

			return false;

		}

		/**

		 * @brief Notifies the extension that an external interface it uses is being removed.

		 *

		 * @param pInterface		Pointer to interface being dropped.

		 */

		virtual void NotifyInterfaceDrop(SMInterface *pInterface)

		{

		}

		/**

		 * @brief Return false to tell Core that your extension should be considered unusable.

		 *

		 * @param error				Error buffer.

		 * @param maxlength			Size of error buffer.

		 * @return					True on success, false otherwise.

		 */

		virtual bool QueryRunning(char *error, size_t maxlength)

		{

			return true;

		}

	public:

		virtual bool IsMetamodExtension() =0;

		virtual const char *GetExtensionName() =0;

		virtual const char *GetExtensionURL() =0;

		virtual const char *GetExtensionTag() =0;

		virtual const char *GetExtensionAuthor() =0;

		virtual const char *GetExtensionVerString() =0;

		virtual const char *GetExtensionDescription() =0;

		virtual const char *GetExtensionDateString() =0;

	};

	#define SMINTERFACE_EXTENSIONMANAGER_NAME			"IExtensionManager"

	#define SMINTERFACE_EXTENSIONMANAGER_VERSION		1

	/**

	 * @brief Not currently used.

	 */

	enum ExtensionLifetime

	{

		ExtLifetime_Forever,			//Extension will never be unloaded automatically

		ExtLifetime_Map,				//Extension will be unloaded at the end of the map

	};

	/**

	 * @brief Manages the loading/unloading of extensions.

	 */

	class IExtensionManager : public SMInterface

	{

	public:

		virtual const char *GetInterfaceName()

		{

			return SMINTERFACE_EXTENSIONMANAGER_NAME;

		}

		virtual unsigned int GetInterfaceVersion()

		{

			return SMINTERFACE_EXTENSIONMANAGER_VERSION;

		}

	public:

		/**

		 * @brief Loads a extension into the extension system.

		 *

		 * @param path		Path to extension file, relative to the extensions folder.

		 * @param lifetime	Lifetime of the extension (currently ignored).

		 * @param error		Error buffer.

		 * @param maxlength	Maximum error buffer length.

		 * @return			New IExtension on success, NULL on failure.

		 */

		virtual IExtension *LoadExtension(const char *path, 

									ExtensionLifetime lifetime, 

									char *error,

									size_t maxlength) =0;

		/**

		 * @brief Attempts to unload a module.

		 *

		 * @param pExt		IExtension pointer.

		 * @return			True if successful, false otherwise.

		 */

		virtual bool UnloadExtension(IExtension *pExt) =0;

	};

}

#endif //_INCLUDE_SOURCEMOD_MODULE_INTERFACE_H_