/**

 * 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: $Id$

 */

#include <ISmmPluginExt.h>

#include <stdarg.h>

#include <string.h>

#include <stdio.h>

#if defined _MSC_VER

	#define DLL_EXPORT				extern "C" __declspec(dllexport)

	#define openlib(lib)			LoadLibrary(lib)

	#define closelib(lib)			FreeLibrary(lib)

	#define findsym(lib, sym)		GetProcAddress(lib, sym)

	#define PLATFORM_EXT			".dll"

	#define vsnprintf				_vsnprintf

	#define PATH_SEP_CHAR			"\\"

	inline bool IsPathSepChar(char c) 

	{

		return (c == '/' || c == '\\');

	}

	#include <Windows.h>

#else

	#define DLL_EXPORT				extern "C" __attribute__((visibility("default")))

	#define openlib(lib)			dlopen(lib, RTLD_NOW)

	#define closelib(lib)			dlclose(lib)

	#define findsym(lib, sym)		dlsym(lib, sym)

	#define PLATFORM_EXT			".so"

	typedef void *					HINSTANCE;

	#define PATH_SEP_CHAR			"/"

	inline bool IsPathSepChar(char c) 

	{

		return (c == '/');

	}

	#include <dlfcn.h>

#endif

#define METAMOD_API_MAJOR			2

#define FILENAME_1_4_EP1			"sourcemod.1.ep1" PLATFORM_EXT

#define FILENAME_1_6_EP2			"sourcemod.2.ep2" PLATFORM_EXT

#define FILENAME_1_6_EP1			"sourcemod.2.ep1" PLATFORM_EXT

HINSTANCE g_hCore = NULL;

bool load_attempted = false;

size_t UTIL_Format(char *buffer, size_t maxlength, const char *fmt, ...);

class FailPlugin : public SourceMM::ISmmFailPlugin

{

public:

	int GetApiVersion()

	{

		return fail_version;

	}

	bool Load(SourceMM::PluginId id, SourceMM::ISmmAPI *ismm, char *error, size_t maxlength, bool late)

	{

		if (error != NULL && maxlength != 0)

		{

			UTIL_Format(error, maxlength, "%s", error_buffer);

		}

		return false;

	}

	int fail_version;

	char error_buffer[512];

} s_FailPlugin;

size_t UTIL_Format(char *buffer, size_t maxlength, const char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	size_t len = vsnprintf(buffer, maxlength, fmt, ap);

	va_end(ap);

	if (len >= maxlength)

	{

		len = maxlength - 1;

		buffer[len] = '\0';

	}

	return len;

}

METAMOD_PLUGIN *_GetPluginPtr(const char *path, int fail_api)

{

	METAMOD_FN_ORIG_LOAD fn;

	METAMOD_PLUGIN *pl;

	int ret;

	if (!(g_hCore=openlib(path)))

	{

#if defined __linux__

		UTIL_Format(s_FailPlugin.error_buffer, 

			sizeof(s_FailPlugin.error_buffer),

			"%s",

			dlerror());

#else

		DWORD err = GetLastError();

		if (FormatMessageA(

				FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,

				NULL,

				err,

				MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),

				s_FailPlugin.error_buffer,

				sizeof(s_FailPlugin.error_buffer),

				NULL)

			== 0)

		{

			UTIL_Format(s_FailPlugin.error_buffer, 

				sizeof(s_FailPlugin.error_buffer),

				"unknown error %x",

				err);

		}

#endif

		s_FailPlugin.fail_version = fail_api;

		return (METAMOD_PLUGIN *)&s_FailPlugin;

	}

	if (!(fn=(METAMOD_FN_ORIG_LOAD)findsym(g_hCore, "CreateInterface")))

	{

		goto error;

	}

	pl = (METAMOD_PLUGIN *)fn(METAMOD_PLAPI_NAME, &ret);

	if (!pl)

	{

		goto error;

	}

	return pl;

error:

	closelib(g_hCore);

	g_hCore = NULL;

	return NULL;

}

bool GetFileOfAddress(void *pAddr, char *buffer, size_t maxlength)

{

#if defined _MSC_VER

	MEMORY_BASIC_INFORMATION mem;

	if (!VirtualQuery(pAddr, &mem, sizeof(mem)))

		return false;

	if (mem.AllocationBase == NULL)

		return false;

	HMODULE dll = (HMODULE)mem.AllocationBase;

	GetModuleFileName(dll, (LPTSTR)buffer, maxlength);

#else

	Dl_info info;

	if (!dladdr(pAddr, &info))

		return false;

	if (!info.dli_fbase || !info.dli_fname)

		return false;

	const char *dllpath = info.dli_fname;

	snprintf(buffer, maxlength, "%s", dllpath);

#endif

	return true;

}

DLL_EXPORT METAMOD_PLUGIN *CreateInterface_MMS(const MetamodVersionInfo *mvi, const MetamodLoaderInfo *mli)

{

	char *filename;

	load_attempted = true;

	if (mvi->api_major > METAMOD_API_MAJOR)

	{

		return NULL;

	}

	switch (mvi->source_engine)

	{

	case SOURCE_ENGINE_ORANGEBOX:

		{

			filename = FILENAME_1_6_EP2;

			break;

		}

	case SOURCE_ENGINE_EPISODEONE:

	case SOURCE_ENGINE_ORIGINAL:

		{

			filename = FILENAME_1_6_EP1;

			break;

		}

	default:

		{

			return NULL;

		}

	}

	char abspath[256];

	UTIL_Format(abspath, sizeof(abspath), "%s" PATH_SEP_CHAR "%s", mli->pl_path, filename);

	return _GetPluginPtr(abspath, METAMOD_FAIL_API_V2);

}

DLL_EXPORT void UnloadInterface_MMS()

{

	if (g_hCore)

	{

		closelib(g_hCore);

		g_hCore = NULL;

	}

}

DLL_EXPORT void *CreateInterface(const char *iface, int *ret)

{

	/**

	 * If a load has already been attempted, bail out immediately.

	 */

	if (load_attempted)

	{

		return NULL;

	}

	if (strcmp(iface, METAMOD_PLAPI_NAME) == 0)

	{

		char thisfile[256];

		char targetfile[256];

		if (!GetFileOfAddress((void *)CreateInterface_MMS, thisfile, sizeof(thisfile)))

		{

			return NULL;

		}

		size_t len = strlen(thisfile);

		for (size_t iter=len-1; iter>=0 && iter<len; iter--)

		{

			if (IsPathSepChar(thisfile[iter]))

			{

				thisfile[iter] = '\0';

				break;

			}

		}

		UTIL_Format(targetfile, sizeof(targetfile), "%s" PATH_SEP_CHAR FILENAME_1_4_EP1, thisfile);

		return _GetPluginPtr(targetfile, METAMOD_FAIL_API_V1);

	}

	return NULL;

}

#if defined _MSC_VER

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpReserved)

{

	if (fdwReason == DLL_PROCESS_DETACH)

	{

		UnloadInterface_MMS();

	}

	return TRUE;

}

#else

__attribute__((destructor)) static void gcc_fini()

{

	UnloadInterface_MMS();

}

#endif