/**

 * vim: set ts=4 sw=4 tw=99 noet :

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

 * SourceMod SDKTools Extension

 * Copyright (C) 2004-2009 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>.

 */

#include "extension.h"

#include "vcallbuilder.h"

#include "vglobals.h"

enum SDKLibrary

{

	SDKLibrary_Server,	/**< server.dll/server_i486.so */

	SDKLibrary_Engine,	/**< engine.dll/engine_*.so */

};

enum SDKPassMethod

{

	SDKPass_Pointer,		/**< Pass as a pointer */

	SDKPass_Plain,			/**< Pass as plain data */

	SDKPass_ByValue,		/**< Pass an object by value */

	SDKPass_ByRef,			/**< Pass an object by reference */

};

int s_vtbl_index = -1;

void *s_call_addr = NULL;

ValveCallType s_vcalltype = ValveCall_Static;

bool s_has_return = false;

ValvePassInfo s_return;

unsigned int s_numparams = 0;

ValvePassInfo s_params[SP_MAX_EXEC_PARAMS];

inline void DecodePassMethod(ValveType vtype, SDKPassMethod method, PassType &type, unsigned int &flags)

{

	if (method == SDKPass_Pointer || method == SDKPass_ByRef)

	{

		type = PassType_Basic;

		if (vtype == Valve_POD

			|| vtype == Valve_Float

			|| vtype == Valve_Bool)

		{

			flags = PASSFLAG_BYVAL | PASSFLAG_ASPOINTER;

		} else {

			flags = PASSFLAG_BYVAL;

		}

	} else if (method == SDKPass_Plain) {

		type = PassType_Basic;

		flags = PASSFLAG_BYVAL;

	} else if (method == SDKPass_ByValue) {

		if (vtype == Valve_Vector

			|| vtype == Valve_QAngle)

		{

			type = PassType_Object;

		} else {

			type = PassType_Basic;

		}

		flags = PASSFLAG_BYVAL;

	}

}

static cell_t StartPrepSDKCall(IPluginContext *pContext, const cell_t *params)

{

	s_numparams = 0;

	s_vtbl_index = -1;

	s_call_addr = NULL;

	s_has_return = false;

	s_vcalltype = (ValveCallType)params[1];

	return 1;

}

static cell_t PrepSDKCall_SetVirtual(IPluginContext *pContext, const cell_t *params)

{

	s_vtbl_index = params[1];

	return 1;

}

static cell_t PrepSDKCall_SetSignature(IPluginContext *pContext, const cell_t *params)

{

	void *addrInBase = NULL;

	if (params[1] == SDKLibrary_Server)

	{

		addrInBase = (void *)g_SMAPI->GetServerFactory(false);

	} else if (params[1] == SDKLibrary_Engine) {

		addrInBase = (void *)g_SMAPI->GetEngineFactory(false);

	}

	if (addrInBase == NULL)

	{

		return 0;

	}

	char *sig;

	pContext->LocalToString(params[2], &sig);

#if defined PLATFORM_POSIX

	if (sig[0] == '@')

	{

		Dl_info info;

		if (dladdr(addrInBase, &info) == 0)

		{

			return 0;

		}

		void *handle = dlopen(info.dli_fname, RTLD_NOW);

		if (!handle)

		{

			return 0;

		}

#if (SOURCE_ENGINE == SE_ORANGEBOXVALVE) || (SOURCE_ENGINE == SE_LEFT4DEAD2)

		s_call_addr = memutils->ResolveSymbol(handle, &sig[1]);

#else

		s_call_addr = dlsym(handle, &sig[1]);

#endif

		dlclose(handle);

		return (s_call_addr != NULL) ? 1 : 0;

	}

#endif

	s_call_addr = memutils->FindPattern(addrInBase, sig, params[3]);

	return (s_call_addr != NULL) ? 1 : 0;

}

static cell_t PrepSDKCall_SetFromConf(IPluginContext *pContext, const cell_t *params)

{

	IGameConfig *conf;

	if (params[1] == BAD_HANDLE)

	{

		conf = g_pGameConf;

	} else {

		HandleError err;

		if ((conf = gameconfs->ReadHandle(params[1], pContext->GetIdentity(), &err)) == NULL)

		{

			return pContext->ThrowNativeError("Invalid Handle %x (error %d)", params[1], err);

		}

	}

	char *key;

	pContext->LocalToString(params[3], &key);

	if (params[2] == 0)

	{

		return conf->GetOffset(key, &s_vtbl_index) ? 1 : 0;

	} else if (params[2] == 1) {

		bool result = conf->GetMemSig(key, &s_call_addr) ? 1 : 0;

		return (result && s_call_addr != NULL) ? 1 : 0;

	}

	return 0;

}

static cell_t PrepSDKCall_SetReturnInfo(IPluginContext *pContext, const cell_t *params)

{

	s_has_return = true;

	s_return.vtype = (ValveType)params[1];

	DecodePassMethod(s_return.vtype, (SDKPassMethod)params[2], s_return.type, s_return.flags);

	s_return.decflags = params[3];

	s_return.encflags = params[4];

	return 1;

}

static cell_t PrepSDKCall_AddParameter(IPluginContext *pContext, const cell_t *params)

{

	if (s_numparams >= SP_MAX_EXEC_PARAMS)

	{

		return pContext->ThrowNativeError("Parameter limit for SDK calls reached");

	}

	ValvePassInfo *info = &s_params[s_numparams++];

	info->vtype = (ValveType)params[1];

	SDKPassMethod method = (SDKPassMethod)params[2];

	DecodePassMethod(info->vtype, method, info->type, info->flags);

	info->decflags = params[3] | VDECODE_FLAG_BYREF;

	info->encflags = params[4];

	/* Since SDKPass_ByRef acts like SDKPass_Pointer we can't allow NULL, just in case */

	if (method == SDKPass_ByRef)

	{

		info->decflags &= ~VDECODE_FLAG_ALLOWNULL;

	}

	return 1;

}

static cell_t EndPrepSDKCall(IPluginContext *pContext, const cell_t *params)

{

	ValveCall *vc = NULL;

	if (s_vtbl_index > -1)

	{

		vc = CreateValveVCall(s_vtbl_index, s_vcalltype, s_has_return ? &s_return : NULL, s_params, s_numparams);

	} else if (s_call_addr) {

		vc = CreateValveCall(s_call_addr, s_vcalltype, s_has_return ? &s_return : NULL, s_params, s_numparams);

	}

	if (!vc)

	{

		return BAD_HANDLE;

	}

	if (vc->thisinfo)

	{

		vc->thisinfo->decflags |= VDECODE_FLAG_BYREF;

	}

	Handle_t hndl = handlesys->CreateHandle(g_CallHandle, vc, pContext->GetIdentity(), myself->GetIdentity(), NULL);

	if (!hndl)

	{

		delete vc;

	}

	return hndl;

}

static cell_t SDKCall(IPluginContext *pContext, const cell_t *params)

{

	ValveCall *vc;

	HandleError err;

	HandleSecurity sec(pContext->GetIdentity(), myself->GetIdentity());

	if ((err = handlesys->ReadHandle(params[1], g_CallHandle, &sec, (void **)&vc)) != HandleError_None)

	{

		return pContext->ThrowNativeError("Invalid Handle %x (error %d)", params[1], err);

	}

	unsigned char *ptr = vc->stk_get();

	const unsigned int numparams = (unsigned)params[0];

	unsigned int startparam = 2;

	/* Do we need to write a thispointer?  */

	if (vc->thisinfo)

	{

		switch (vc->type)

		{

		case ValveCall_Entity:

		case ValveCall_Player:

			{

				if (startparam > numparams)

				{

					vc->stk_put(ptr);

					return pContext->ThrowNativeError("Expected 1 parameter for entity pointer; found none");

				}

				if (DecodeValveParam(pContext, 

					params[startparam],

					vc,

					vc->thisinfo,

					ptr) == Data_Fail)

				{

					vc->stk_put(ptr);

					return 0;

				}

				startparam++;

			}

			break;

		case ValveCall_GameRules:

			{

				if (g_pGameRules == NULL)

				{

					vc->stk_put(ptr);

					return pContext->ThrowNativeError("GameRules unsupported or not available; file a bug report");

				}

				void *gamerules = *g_pGameRules;

				if (gamerules == NULL)

				{

					vc->stk_put(ptr);

					return pContext->ThrowNativeError("GameRules not available before map is loaded");

				}

				*(void **)ptr = gamerules;

			}

			break;

		case ValveCall_EntityList:

			{

				if (g_EntList == NULL)

				{

					vc->stk_put(ptr);

					return pContext->ThrowNativeError("EntityList unsupported or not available; file a bug report");

				}

				*(void **)ptr = g_EntList;

			}

			break;

		case ValveCall_Raw:

			{

				//params[startparam] is an address to a pointer to THIS

				//params following this are params to the method we will invoke later

				if (startparam > numparams)

				{

					vc->stk_put(ptr);

					return pContext->ThrowNativeError("Expected a ThisPtr address, it wasn't found");

				}

				//note: varargs pawn args are passed by-ref

				cell_t *cell;

				pContext->LocalToPhysAddr(params[startparam], &cell);

				void *thisptr = reinterpret_cast<void*>(*cell);

				*(void **)ptr = thisptr;

				startparam++;

			}

			break;

		}

	}

	/* See if we need to skip any more parameters */

	unsigned int retparam = startparam;

	if (vc->retinfo)

	{

		if (vc->retinfo->vtype == Valve_String)

		{

			startparam += 2;

		} else if (vc->retinfo->vtype == Valve_Vector

					|| vc->retinfo->vtype == Valve_QAngle)

		{

			startparam += 1;

		}

	}

	unsigned int callparams = vc->call->GetParamCount();

	bool will_copyback = false;

	for (unsigned int i=0; i<callparams; i++)

	{

		unsigned int p = startparam + i;

		if (p > numparams)

		{

			vc->stk_put(ptr);

			return pContext->ThrowNativeError("Expected %dth parameter, found none", p);

		}

		if (DecodeValveParam(pContext,

			params[p],

			vc,

			&(vc->vparams[i]),

			ptr) == Data_Fail)

		{

			vc->stk_put(ptr);

			return 0;

		}

		if (vc->vparams[i].encflags & VENCODE_FLAG_COPYBACK)

		{

			will_copyback = true;

		}

	}

	/* Make the actual call */

	vc->call->Execute(ptr, vc->retbuf);

	/* Do we need to copy anything back? */

	if (will_copyback)

	{

		for (unsigned int i=0; i<callparams; i++)

		{

			if (vc->vparams[i].encflags & VENCODE_FLAG_COPYBACK)

			{

				if (EncodeValveParam(pContext, 

					params[startparam + i], 

					vc,

					&vc->vparams[i],

					ptr) == Data_Fail)

				{

					vc->stk_put(ptr);

					return 0;

				}

			}

		}

	}

	/* Save stack once and for all */

	vc->stk_put(ptr);

	/* Figure out how to decode the return information */

	if (vc->retinfo)

	{

		if (vc->retinfo->vtype == Valve_String)

		{

			if (numparams < 3)

			{

				return pContext->ThrowNativeError("Expected arguments (2,3) for string storage");

			}

			cell_t *addr;

			size_t written;

			pContext->LocalToPhysAddr(params[retparam+1], &addr);

			pContext->StringToLocalUTF8(params[retparam], *addr, *(char **)vc->retbuf, &written);

			return (cell_t)written;

		} else if (vc->retinfo->vtype == Valve_Vector

					|| vc->retinfo->vtype == Valve_QAngle)

		{

			if (numparams < 2)

			{

				return pContext->ThrowNativeError("Expected argument (2) for Float[3] storage");

			}

			if (EncodeValveParam(pContext, params[retparam], vc, vc->retinfo, vc->retbuf)

				== Data_Fail)

			{

				return 0;

			}

		} else if (vc->retinfo->vtype == Valve_CBaseEntity

					|| vc->retinfo->vtype == Valve_CBasePlayer)

		{

			CBaseEntity *pEntity = *(CBaseEntity **)(vc->retbuf);

			if (!pEntity)

			{

				return -1;

			}

			edict_t *pEdict = gameents->BaseEntityToEdict(pEntity);

			if (!pEdict || pEdict->IsFree())

			{

				return -1;

			}

			return IndexOfEdict(pEdict);

		} else if (vc->retinfo->vtype == Valve_Edict) {

			edict_t *pEdict = *(edict_t **)(vc->retbuf);

			if (!pEdict || pEdict->IsFree())

			{

				return -1;

			}

			return IndexOfEdict(pEdict);

		} else if (vc->retinfo->vtype == Valve_Bool) {

			bool *addr = (bool  *)vc->retbuf;

			if (vc->retinfo->flags & PASSFLAG_ASPOINTER)

			{

				addr = *(bool **)addr;

			}

			return *addr ? 1 : 0;

		} else {

			cell_t *addr = (cell_t *)vc->retbuf;

			if (vc->retinfo->flags & PASSFLAG_ASPOINTER)

			{

				addr = *(cell_t **)addr;

			}

			return *addr;

		}

	}

	return 0;

}

sp_nativeinfo_t g_CallNatives[] = 

{

	{"StartPrepSDKCall",			StartPrepSDKCall},

	{"PrepSDKCall_SetVirtual",		PrepSDKCall_SetVirtual},

	{"PrepSDKCall_SetSignature",	PrepSDKCall_SetSignature},

	{"PrepSDKCall_SetFromConf",		PrepSDKCall_SetFromConf},

	{"PrepSDKCall_SetReturnInfo",	PrepSDKCall_SetReturnInfo},

	{"PrepSDKCall_AddParameter",	PrepSDKCall_AddParameter},

	{"EndPrepSDKCall",				EndPrepSDKCall},

	{"SDKCall",						SDKCall},

	{NULL,							NULL},

};