/**

 * vim: set ts=4 :

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

 * SourceMod

 * Copyright (C) 2004-2008 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_IFACE_SHARE_SYS_H_

#define _INCLUDE_SOURCEMOD_IFACE_SHARE_SYS_H_

/**

 * @file IShareSys.h

 * @brief Defines the Share System, responsible for shared resources and dependencies.

 */

#include <sp_vm_types.h>

#include <sp_vm_api.h>

namespace SourceMod

{

	class IExtension;

	struct IdentityToken_t;

	/** Forward declaration from IHandleSys.h */

	typedef unsigned int		HandleType_t;

	/** Forward declaration from IHandleSys.h */

	typedef HandleType_t		IdentityType_t;

	/**

	 * @brief Types of features.

	 */

	enum FeatureType

	{

		FeatureType_Native,      /**< Native functions for plugins. */

		FeatureType_Capability   /**< Named capabilities. */

	};

	/**

	 * @brief Feature presence status codes.

	 */

	enum FeatureStatus

	{

		FeatureStatus_Available = 0,  /**< Feature is available for use. */

		FeatureStatus_Unavailable,    /**< Feature is unavailable, but known. */

		FeatureStatus_Unknown         /**< Feature is not known. */

	};

	/**

	 * @brief Provides a capability feature.

	 */

	class IFeatureProvider

	{

	public:

		/**

		 * @brief Must return whether a capability is present.

		 *

		 * @param type          Feature type (FeatureType_Capability right now).

		 * @param name          Feature name.

		 * @return              Feature status code.

		 */

		virtual FeatureStatus GetFeatureStatus(FeatureType type, const char *name) = 0;

	};

	/**

	 * @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 compatible.

		 * 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;

		}

	};

	/**

	 * @brief Tracks dependencies and fires dependency listeners.

	 */

	class IShareSys

	{

	public:

		/**

		 * @brief Adds an interface to the global interface system.

		 *

		 * @param myself		Object adding this interface, in order to track dependencies.

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

		 * @return				True on success, false otherwise.

		 */

		virtual bool AddInterface(IExtension *myself, SMInterface *iface) =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 myself		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,

										IExtension *myself,

										SMInterface **pIface) =0;

		/**

		 * @brief Adds a list of natives to the global native pool, to be 

		 * bound on plugin load.

		 *

		 * Adding natives does not bind them to any loaded plugins; the 

		 * plugins must be reloaded for new natives to take effect.  

		 * 

		 * @param myself		Identity token of parent object.

		 * @param natives		Array of natives to add.  The last entry in 

		 *						the array must be filled with NULLs to 

		 *						terminate the array.  The array must be static 

		 *						as Core will cache the pointer for the 

		 *						lifetime of the extension.

		 */

		virtual void AddNatives(IExtension *myself, const sp_nativeinfo_t *natives) =0;

		/**

		 * @brief Creates a new identity type.

		 * NOTE: Module authors should never need to use this.  Due to the current implementation,

		 * there is a hardcoded limit of 15 types.  Core uses up a few, so think carefully!

		 *

		 * @param name			String containing type name.  Must not be empty or NULL.

		 * @return				A new HandleType_t identifier, or 0 on failure.

		 */

		virtual IdentityType_t CreateIdentType(const char *name) =0;

		/**

		 * @brief Finds an identity type by name.

		 * DEFAULT IDENTITY TYPES:

		 *  "PLUGIN"	- An IPlugin object.

		 *  "MODULE"	- An IModule object.

		 *  "CORE"		- An SMGlobalClass or other singleton.

		 * 

		 * @param name			String containing type name to search for.

		 * @return				A HandleType_t identifier if found, 0 otherwise.

		 */

		virtual IdentityType_t FindIdentType(const char *name) =0;

		/**

		 * @brief Creates a new identity token.  This token is guaranteed to be 

		 * unique amongst all other open identities.

		 *

		 * @param type			Identity type.

		 * @param ptr			Private data pointer (cannot be NULL).

		 * @return				A new IdentityToken_t pointer, or NULL on failure.

		 */

		virtual IdentityToken_t *CreateIdentity(IdentityType_t type, void *ptr) =0;

		/** 

		 * @brief Destroys an identity type.  Note that this will delete any identities

		 * that are under this type.  

		 *

		 * @param type			Identity type.

		 */

		virtual void DestroyIdentType(IdentityType_t type) =0;

		/**

		 * @brief Destroys an identity token.  Any handles being owned by this token, or

		 * any handles being 

		 *

		 * @param identity		Identity to remove.

		 */

		virtual void DestroyIdentity(IdentityToken_t *identity) =0;

		/**

		 * @brief Requires an extension.  This tells SourceMod that without this extension,

		 * your extension should not be loaded.  The name should not include the ".dll" or

		 * the ".so" part of the file name.

		 *

		 * @param myself		IExtension pointer to yourself.

		 * @param filename		File of extension to require.

		 * @param require		Whether or not this extension is a required dependency.

		 * @param autoload		Whether or not to autoload this extension.

		 */

		virtual void AddDependency(IExtension *myself, const char *filename, bool require, bool autoload) =0;

		/**

		 * @brief Registers a library name to an extension.

		 *

		 * @param myself		Extension to register library to.

		 * @param name			Library name.

		 */

		virtual void RegisterLibrary(IExtension *myself, const char *name) =0;

		/**

		 * @brief Adds natives that will override Core natives when called.

		 *

		 * A Core version of each native must exist.  If one does not, then 

		 * Core will simply ignore that entry.  No more than one override 

		 * can exist on a given native.

		 *

		 * Override natives represent a weak coupling.  If the extension is 

		 * unloaded, the native will be re-bound to the Core version.  If 

		 * the extension is loaded after plugins are loaded, the override 

		 * will not take effect until those plugins are reloaded.

		 * 

		 * @param myself		Identity token of parent object.

		 * @param natives		Array of natives to add.  The last entry in 

		 *						the array must be filled with NULLs to 

		 *						terminate the array.  The array must be static 

		 *						as Core will cache the pointer for the 

		 *						lifetime of the extension.

		 */

		virtual void OverrideNatives(IExtension *myself, const sp_nativeinfo_t *natives) =0;

		/**

		 * @brief Adds a capability provider. Feature providers are used by

		 * plugins to determine if a feature exists at runtime. This is

		 * distinctly different from checking for a native, because natives

		 * may be backed by underlying functionality which is not available.

		 *

		 * @param myself        Extension.

		 * @param provider      Feature provider implementation.

		 * @param name          Capibility name.

		 */

		virtual void AddCapabilityProvider(IExtension *myself,

		                                   IFeatureProvider *provider,

		                                   const char *name) =0;

		/**

		 * @brief Drops a previously added cap provider.

		 *

		 * @param myself        Extension.

		 * @param provider      Feature provider implementation.

		 * @param name          Capibility name.

		 */

		virtual void DropCapabilityProvider(IExtension *myself,

		                                    IFeatureProvider *provider,

		                                    const char *name) =0;

		/**

		 * Tests for a feature.

		 *

		 * @param rt			Plugin to test.

		 * @param type			Feature type.

		 * @param name			Feature name.

		 * @return				Feature status.

		 */

		virtual FeatureStatus TestFeature(SourcePawn::IPluginRuntime *rt,

										  FeatureType type,

										  const char *name) =0;

	};

}

#endif //_INCLUDE_SOURCEMOD_IFACE_SHARE_SYS_H_