/* ======== SourceMM ========
 * Copyright (C) 2004-2010 Metamod:Source Development Team
 * No warranties of any kind
 *
 * License: zlib/libpng
 *
 * Author(s): David "BAILOPAN" Anderson
 * ============================
 */

#include "convar_smm.h"
#include "CSmmAPI.h"
#include "sourcemm.h"
#include "concommands.h"
#include "CPlugin.h"
#include "util.h"
#include "sh_memory.h"
#include <setjmp.h>
#if defined __linux__
#include <sys/stat.h>
#endif

/**
 * @brief Implementation of main API interface
 * @file CSmmAPI.cpp
 */

using namespace SourceMM;
using namespace SourceHook;

struct UsrMsgInfo
{
	UsrMsgInfo()
	{
	}
	UsrMsgInfo(int s, const char *t) : size(s), name(t)
	{
	}
	int size;
	String name;
};

CSmmAPI g_SmmAPI;

static CVector<UsrMsgInfo> usermsgs_list;
static jmp_buf usermsg_end;

CSmmAPI::CSmmAPI()
{
	m_ConPrintf = NULL;
	m_CmdCache = false;
	m_VSP = false;
}

void CSmmAPI::LogMsg(ISmmPlugin *pl, const char *msg, ...)
{
	va_list ap;
	static char buffer[2048];

	va_start(ap, msg);
	UTIL_FormatArgs(buffer, sizeof(buffer), msg, ap);
	va_end(ap);

	LogMessage("[%s] %s", pl->GetLogTag(), buffer);
}

CreateInterfaceFn CSmmAPI::engineFactory(bool syn)
{
	if (syn)
		return EngineFactory;
	return g_Engine.engineFactory;
}

CreateInterfaceFn CSmmAPI::physicsFactory(bool syn)
{
	if (syn)
		return PhysicsFactory;
	return g_Engine.physicsFactory;
}

CreateInterfaceFn CSmmAPI::fileSystemFactory(bool syn)
{
	if (syn)
		return FileSystemFactory;
	return g_Engine.fileSystemFactory;
}

CreateInterfaceFn CSmmAPI::serverFactory(bool syn)
{
	if (syn)
		return ServerFactory;
	return g_GameDll.factory;
}

CGlobalVars *CSmmAPI::pGlobals()
{
	return g_Engine.pGlobals;
}

void CSmmAPI::SetLastMetaReturn(META_RES res)
{
	m_Res = res;
}

META_RES CSmmAPI::GetLastMetaReturn()
{
	return m_Res;
}

IConCommandBaseAccessor *CSmmAPI::GetCvarBaseAccessor()
{
	return static_cast<IConCommandBaseAccessor *>(&g_SMConVarAccessor);
}

bool CSmmAPI::RegisterConCmdBase(ISmmPlugin *plugin, ConCommandBase *pCommand)
{
	if (pCommand->IsCommand())
	{
		g_PluginMngr.AddPluginCmd(plugin, pCommand);
	} else {
		g_PluginMngr.AddPluginCvar(plugin, pCommand);
	}

	return g_SMConVarAccessor.Register(pCommand);
}

void CSmmAPI::UnregisterConCmdBase(ISmmPlugin *plugin, ConCommandBase *pCommand)
{
	if (pCommand->IsCommand())
	{
		g_PluginMngr.RemovePluginCmd(plugin, pCommand);
	} else {
		g_PluginMngr.RemovePluginCvar(plugin, pCommand);
	}

	CPluginManager::CPlugin *pPlugin = g_PluginMngr.FindByAPI(plugin);
	PluginId id = (pPlugin != NULL) ? pPlugin->m_Id : Pl_BadLoad;

	NotifyConCommandBaseDrop(id, pCommand);

	g_SMConVarAccessor.Unregister(pCommand);
}

void CSmmAPI::ConPrint(const char *fmt)
{
	(m_ConPrintf)("%s", fmt);
}

void CSmmAPI::ConPrintf(const char *fmt, ...)
{
	va_list ap;
	static char buffer[4096];

	va_start(ap, fmt);
	UTIL_FormatArgs(buffer, sizeof(buffer), fmt, ap);
	va_end(ap);

	(m_ConPrintf)("%s", buffer);
}

void CSmmAPI::AddListener(ISmmPlugin *plugin, IMetamodListener *pListener)
{
	CPluginManager::CPlugin *pl = g_PluginMngr.FindByAPI(plugin);
	CPluginEventHandler cpeh;

	cpeh.event = pListener;
	cpeh.got_vsp = false;

	pl->m_Events.push_back(cpeh);
}

void *CSmmAPI::MetaFactory(const char *iface, int *_ret, PluginId *id)
{
	if (id)
	{
		*id = 0;
	}

	if (!iface)
	{
		return NULL;
	}

	//first check ours... we get first chance!
	if (strcmp(iface, MMIFACE_SOURCEHOOK) == 0)
	{
		if (_ret)
		{
			*_ret = META_IFACE_OK;
		}
		return static_cast<void *>(static_cast<SourceHook::ISourceHook *>(&g_SourceHook));
	} else if (strcmp(iface, MMIFACE_PLMANAGER) == 0) {
		if (_ret)
		{
			*_ret = META_IFACE_OK;
		}
		return static_cast<void *>(static_cast<ISmmPluginManager *>(&g_PluginMngr));
	}

	CPluginManager::CPlugin *pl;
	SourceHook::List<CPluginEventHandler>::iterator event;
	IMetamodListener *api;
	int ret = 0;
	void *val = NULL;

	for (PluginIter iter = g_PluginMngr._begin(); iter != g_PluginMngr._end(); iter++)
	{
		pl = (*iter);
		for (event=pl->m_Events.begin(); event!=pl->m_Events.end(); event++)
		{
			api = (*event).event;
			ret = META_IFACE_FAILED;
			if ( (val=api->OnMetamodQuery(iface, &ret)) != NULL )
			{
				if (_ret)
					*_ret = ret;
				if (id)
					*id = pl->m_Id;
				return val;
			}
		}
	}

	if (_ret)
		*_ret = META_IFACE_FAILED;

	return NULL;
}

//////////////////////////////////////////////////////////////////////////
//THERE BE HAX HERE!!!! DON'T TELL ALFRED, BUT GABE WANTED IT THAT WAY. //
// (note: you can find the offset by looking for the text               //
//   "Echo text to console", you'll find the callback cmd pushed on the //
//   stack.)                                                            //
//////////////////////////////////////////////////////////////////////////

#define SIGLEN			8
#define ENGINE486_SIG	"\x55\x89\xE5\x53\x83\xEC\x14\xBB"
#define ENGINE486_OFFS	40
#define ENGINE686_SIG	"\x53\x83\xEC\x08\xBB\x01\x00\x00"
#define ENGINE686_OFFS	50
#define	ENGINEAMD_SIG	"\x53\x51\xBB\x01\x00\x00\x00\x51"
#define	ENGINEAMD_OFFS	47
#define ENGINEW32_SIG	"\xA1\x2A\x2A\x2A\x2A\x56\xBE\x01"
#define ENGINEW32_OFFS	38
#define IA32_CALL		0xE8

//Thanks to fysh for the idea of extracting info from "echo" and for
// having the original offsets at hand!
bool CSmmAPI::CacheCmds()
{
	ICvar *pCvar = g_Engine.icvar;

	ConCommandBase *pBase = pCvar->GetCommands();
	unsigned char *ptr = NULL;
	FnCommandCallback callback = NULL;
	int offs = 0;

	while (pBase)
	{
		if ( strcmp(pBase->GetName(), "echo") == 0 )
		{
			//callback = //*((FnCommandCallback *)((char *)pBase + offsetof(ConCommand, m_fnCommandCallback)));
			callback = ((ConCommand *)pBase)->GetCallback();
			ptr = (unsigned char *)callback;
		#ifdef OS_LINUX
			if (UTIL_VerifySignature(ptr, ENGINE486_SIG, SIGLEN))
			{
				offs = ENGINE486_OFFS;
			}
			else if (UTIL_VerifySignature(ptr, ENGINE686_SIG, SIGLEN))
			{
				offs = ENGINE686_OFFS;
			}
			else if (UTIL_VerifySignature(ptr, ENGINEAMD_SIG, SIGLEN))
			{
				offs = ENGINEAMD_OFFS;
			}
		#elif defined OS_WIN32 // Only one Windows engine binary so far...
			if (UTIL_VerifySignature(ptr, ENGINEW32_SIG, SIGLEN))
			{
				offs = ENGINEW32_OFFS;
			}
		#endif

			if (!offs || ptr[offs - 1] != IA32_CALL)
			{
				m_ConPrintf = (CONPRINTF_FUNC)Msg;
				return false;
			}
			//get the relative offset
			m_ConPrintf = *((CONPRINTF_FUNC *)(ptr + offs));
			//add the base offset, to the ip (which is the address+offset + 4 bytes for next instruction)
			m_ConPrintf = (CONPRINTF_FUNC)((unsigned long)m_ConPrintf + (unsigned long)(ptr + offs) + 4);

			m_CmdCache = true;

			return true;
		}
		pBase = const_cast<ConCommandBase *>(pBase->GetNext());
	}

	m_ConPrintf = (CONPRINTF_FUNC)Msg;

	return false;
}

bool CSmmAPI::CmdCacheSuccessful()
{
	return m_CmdCache;
}

void CSmmAPI::GetApiVersions(int &major, int &minor, int &plvers, int &plmin)
{
	major = SM_VERS_API_MAJOR;
	minor = SM_VERS_API_MINOR;
	plvers = PLAPI_VERSION;
	plmin = PLAPI_MIN_VERSION;
}

void CSmmAPI::GetShVersions(int &shvers, int &shimpl)
{
	shvers = SH_IFACE_VERSION;
	shimpl = SH_IMPL_VERSION;
}

int CSmmAPI::FormatIface(char iface[], unsigned int maxlength)
{
	int length = (int)strlen(iface);
	int i;
	int num = 0;

	for (i = length - 1; i >= 0; i--)
	{
		if (!isdigit(iface[i]))
		{
			if (i != length - 1)
			{
				num = 1;
			}
			break;
		}
	}

	if ( (num && ((int)maxlength <= length)) || (!num && ((int)maxlength <= length + 3)) )
	{
		return -1;
	}

	if (i != length - 1)
		num = atoi(&(iface[++i]));

	num++;

	snprintf(&(iface[i]), 4, "%03d", num);

	return num;
}

void *CSmmAPI::InterfaceSearch(CreateInterfaceFn fn, const char *iface, int max, int *ret)
{
	char _if[256];	/* assume no interface goes beyond this */
	size_t len = strlen(iface);
	int num = 0;
	void *pf = NULL;

	if (max > 999)
		max = 999;

	if (len + 4 > sizeof(_if))
	{
		if (ret)
		{
			*ret = META_IFACE_FAILED;
		}
		return NULL;
	}

	strcpy(_if, iface);

	do
	{
		if ( (pf = (fn)(_if, ret)) != NULL )
			break;
		if (num > max)
			break;
	} while (( num = FormatIface(_if, len+1) ));

	return pf;
}

void *CSmmAPI::VInterfaceMatch(CreateInterfaceFn fn, const char *iface, int min)
{
	char buffer[256];	/* assume no interface will go beyond this */
	size_t len = strlen(iface);
	int ret;			/* just in case something doesn't handle NULL properly */

	if (len > sizeof(buffer) - 4)
	{
		return NULL;
	}

	strcpy(buffer, iface);

	if (min != -1)
	{
		char *ptr = &buffer[len - 1];
		int digits = 0;
		while (isdigit(*ptr) && digits <=3)
		{
			*ptr = '\0';
			digits++;
			ptr--;
		}
		if (digits != 3)
		{
			/* for now, assume this is an error */
			strcpy(buffer, iface);
		} else {
			char num[4];
			min = (min == 0) ? 1 : min;
			snprintf(num, sizeof(num), "%03d", min);
			strcat(buffer, num);
		}
	}

	return InterfaceSearch(fn, buffer, IFACE_MAXNUM, &ret);
}

const char *CSmmAPI::GetBaseDir()
{
	return g_ModPath.c_str();
}

void CSmmAPI::PathFormat(char *buffer, size_t len, const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	size_t mylen = UTIL_FormatArgs(buffer, len, fmt, ap);
	va_end(ap);

	for (size_t i = 0; i < mylen; i++)
	{
		if (buffer[i] == ALT_SEP_CHAR)
		{
			buffer[i] = PATH_SEP_CHAR;
		}
	}
}

void CSmmAPI::ClientConPrintf(edict_t *client, const char *fmt, ...)
{
	va_list ap;
	static char buffer[4096];

	va_start(ap, fmt);
	UTIL_FormatArgs(buffer, sizeof(buffer), fmt, ap);
	va_end(ap);

	g_Engine.engine->ClientPrintf(client, buffer);
}

void CSmmAPI::LoadAsVSP()
{
	size_t len;
	char engine_file[PATH_SIZE];
	char rel_path[PATH_SIZE * 2];

	GetFileOfAddress(g_Engine.engine, engine_file, sizeof(engine_file));

	/* Chop off the "engine" file part */
	len = strlen(engine_file);
	for (size_t i = len - 1; i < len; i--)
	{
		if (engine_file[i] == '/'
			|| engine_file[i] == '\\')
		{
			engine_file[i] = '\0';
			break;
		}
	}

	const char *usepath = g_MetamodPath.c_str();
	if (UTIL_Relatize(rel_path, sizeof(rel_path), engine_file, g_MetamodPath.c_str()))
	{
		usepath = rel_path;
	}
	
	char command[PATH_SIZE * 2];
	UTIL_Format(command, sizeof(command), "plugin_load \"%s\"\n", usepath);
	g_Engine.engine->ServerCommand(command);
}

void CSmmAPI::EnableVSPListener()
{
	/* If GameInit already passed and we're not already enabled or loaded, go ahead and LoadAsVSP load */
	if (g_bGameInit && !m_VSP && !g_bIsBridgedAsVsp)
	{
		LoadAsVSP();
	}
	m_VSP = true;
}

int CSmmAPI::GetGameDLLVersion()
{
	return g_GameDllVersion;
}

/* This only gets called if IServerGameDLL::GetUserMessageInfo() triggers it */
void Detour_Error(const tchar *pMsg, ...)
{
	/* Jump back to setjmp() in CacheUserMessages() */
	longjmp(usermsg_end, 1);
}

/* IServerGameDLL::GetUserMessageInfo() crashes on games based on the old engine and
 * early Orange Box. This is because Error() from tier0 gets called when a bad index is
 * passed. This is all due to a bug in CUtlRBTree::IsValidIndex().
 *
 * So we detour Error() to fix this. Our detour then jumps back into CacheUserMessages()
 * to a point before GetUserMessageInfo() is called. The detour is then removed and we
 * exit.
 */
void CSmmAPI::CacheUserMessages()
{
	int q, size;
	char buffer[256];
	unsigned char *target, *detour;
	unsigned char orig_bytes[5];

	target = (unsigned char *)&Error;
	detour = (unsigned char *)&Detour_Error;

	/* Save bytes from target function */
	memcpy(orig_bytes, target, sizeof(orig_bytes));

	/* Patch in relative jump to our Error() detour */
	SetMemAccess(target, sizeof(orig_bytes), SH_MEM_READ|SH_MEM_WRITE|SH_MEM_EXEC);
	target[0] = IA32_JMP_IMM32;
	*(int32_t *)&target[1] = (int32_t)(detour - (target + 5));

	/* This is where longjmp() will end up */
	if (setjmp(usermsg_end))
	{
		/* Restore bytes and memory protection */
		memcpy(target, orig_bytes, sizeof(orig_bytes));
		SetMemAccess(target, sizeof(orig_bytes), SH_MEM_READ|SH_MEM_EXEC);
		return;
	}

	q = 0;

	/* If GetUserMessageInfo() calls Error(), we should end up in our detour */
	while (g_GameDll.pGameDLL->GetUserMessageInfo(q, buffer, sizeof(buffer), size))
	{
		usermsgs_list.push_back(UsrMsgInfo(size, buffer));
		q++;
	}

	/* Jump back to setjmp() */
	longjmp(usermsg_end, 1);
}

int CSmmAPI::GetUserMessageCount()
{
	return (int)usermsgs_list.size();
}

int CSmmAPI::FindUserMessage(const char *name, int *size)
{
	for (size_t i = 0; i < usermsgs_list.size(); i++)
	{
		if (usermsgs_list[i].name.compare(name) == 0)
		{
			if (size)
			{
				*size = usermsgs_list[i].size;
			}
			return (int)i;
		}
	}

	return -1;
}

const char *CSmmAPI::GetUserMessage(int index, int *size)
{
	if (index < 0 || index >= (int)usermsgs_list.size())
	{
		return NULL;
	}

	if (size)
	{
		*size = usermsgs_list[index].size;
	}

	return usermsgs_list[index].name.c_str();
}

IServerPluginCallbacks *CSmmAPI::GetVSPInfo(int *pVersion)
{
	if (pVersion != NULL)
		*pVersion = g_vsp_version;

	return g_pRealVspCallbacks;
}

int CSmmAPI::GetSourceEngineBuild()
{
	return g_Engine.original ? SOURCE_ENGINE_ORIGINAL : SOURCE_ENGINE_EPISODEONE;
}

void CSmmAPI::GetFullPluginPath(const char *plugin, char *buffer, size_t len)
{
	const char *pext, *ext;

	/* First find if it's an absolute path or not... */
	if (plugin[0] == '/' || strncmp(&(plugin[1]), ":\\", 2) == 0)
	{
		UTIL_Format(buffer, len, plugin);
		return;
	}

	/* Attempt to find a file extension */
	pext = UTIL_GetExtension(plugin);
	/* Add an extension if there's none there */
	if (!pext)
	{
#if defined WIN32 || defined _WIN32
		ext = ".dll";
#else
		ext = "_i486.so";
#endif
	}
	else
	{
		ext = "";
	}

	/* Format the new path */
	PathFormat(buffer, len, "%s/%s%s", g_ModPath.c_str(), plugin, ext);

#if defined __linux__
	/* If path was passed without extension and it doesn't exist with "_i486.so" try ".so" */
	struct stat s;
	if (!pext && stat(buffer, &s) != 0)
	{
		PathFormat(buffer, len, "%s/%s.so", g_ModPath.c_str(), plugin);
	}
#endif
}