/**

  * 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.   If the extension is an "external" extension, 

 		 * the file path is specified by the extension itself, and may be 

 		 * arbitrary (not real).

 		 *

 		 * @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 Returns whether the extension is local (from the extensions 

 		 * folder), or is from an external source (such as Metamod:Source).

 		 *

 		 * @return				True if from an external source, 

 		 *						false if local to SourceMod.

 		 */

 		virtual bool IsExternal() =0;

 	};

 	/**

 	 * @brief Version code of the IExtensionInterface API itself.

 	 */

 	#define SMINTERFACE_EXTENSIONAPI_VERSION	2

 	/**

 	 * @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:

 		/**

 		 * @brief For extensions loaded through SourceMod, this should return true 

 		 * if the extension needs to attach to Metamod:Source.  If the extension 

 		 * is loaded through Metamod:Source, and uses SourceMod optionally, it must 

 		 * return false.

 		 *

 		 * @return					True if Metamod:Source is needed.

 		 */

 		virtual bool IsMetamodExtension() =0;

 		/**

 		 * @brief Must return a string containing the extension's short name.

 		 *

 		 * @return					String containing extension name.

 		 */

 		virtual const char *GetExtensionName() =0;

 		/**

 		 * @brief Must return a string containing the extension's URL.

 		 *

 		 * @return					String containing extension URL.

 		 */

 		virtual const char *GetExtensionURL() =0;

 		/**

 		 * @brief Must return a string containing a short identifier tag.

 		 *

 		 * @return					String containing extension tag.

 		 */

 		virtual const char *GetExtensionTag() =0;

 		/**

 		 * @brief Must return a string containing a short author identifier.

 		 *

 		 * @return					String containing extension author.

 		 */

 		virtual const char *GetExtensionAuthor() =0;

 		/**

 		 * @brief Must return a string containing version information.

 		 *

 		 * Any version string format can be used, however, SourceMod 

 		 * makes a special guarantee version numbers in the form of 

 		 * A.B.C.D will always be fully displayed, where:

 		 * 

 		 * A is a major version number of at most one digit.

 		 * B is a minor version number of at most two digits.

 		 * C is a minor version number of at most two digits.

 		 * D is a build number of at most 5 digits.

 		 *

 		 * Thus, thirteen characters of display is guaranteed.

 		 *

 		 * @return					String containing extension version.

 		 */

 		virtual const char *GetExtensionVerString() =0;

 		/**

 		 * @brief Must return a string containing description text.

 		 *

 		 * The description text may be longer than the other identifiers, 

 		 * as it is only displayed when viewing one extension at a time.

 		 * However, it should not have newlines, or any other characters 

 		 * which would otherwise disrupt the display pattern.

 		 * 

 		 * @return					String containing extension description.

 		 */

 		virtual const char *GetExtensionDescription() =0;

 		/**

 		 * @brief Must return a string containing the compilation date.

 		 *

 		 * @return					String containing the compilation date.

 		 */

 		virtual const char *GetExtensionDateString() =0;

 	};

 	#define SMINTERFACE_EXTENSIONMANAGER_NAME			"IExtensionManager"

 	#define SMINTERFACE_EXTENSIONMANAGER_VERSION		2

 	/**

 	 * @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;

 		}

 		virtual bool IsVersionCompatible(unsigned int version)

 		{

 			if (version < 2)

 			{

 				return false;

 			}

 			return SMInterface::IsVersionCompatible(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.

 		 *						If	NULL is returned, the error buffer will be 

 		 *						filled with a null-terminated string.

 		 */

 		virtual IExtension *LoadExtension(const char *path, 

 			char *error,

 			size_t maxlength) =0;

 		/**

 		 * @brief Loads an extension into the extension system, directly, 

 		 * as an external extension.  

 		 *

 		 * The extension receives all normal callbacks.  However, it is 

 		 * never opened via LoadLibrary/dlopen or closed via FreeLibrary

 		 * or dlclose.

 		 *

 		 * @param pInterface	Pointer to an IExtensionInterface instance.

 		 * @param filepath		Absolute path to the extension's file.

 		 * @param filename		Name to use to uniquely identify the extension. 

 		 *						The name should be generic, without any 

 		 *						platform-specific suffices.  For example, 

 		 *						sdktools.ext instead of sdktools.ext.so.

 		 *						This filename is used to detect if the 

 		 *						extension is already loaded, and to verify 

 		 *						plugins that require the same extension.

 		 * @param error			Buffer to store error message.

 		 * @param maxlength		Maximum size of the error buffer.

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

 		 *						If NULL is returned, the error buffer will be 

 		 *						filled with a null-terminated string.

 		 */

 		virtual IExtension *LoadExternal(IExtensionInterface *pInterface,

 			const char *filepath,

 			const char *filename,

 			char *error,

 			size_t maxlength) =0;

 		/**

 		 * @brief Attempts to unload an extension.  External extensions must 

 		 * call this before unloading.

 		 *

 		 * @param pExt			IExtension pointer.

 		 * @return				True if successful, false otherwise.

 		 */

 		virtual bool UnloadExtension(IExtension *pExt) =0;

 	};

 }

 #endif //_INCLUDE_SOURCEMOD_MODULE_INTERFACE_H_