// Shave and a Haircut
// (c) 2019 Epic Games
// US Patent 6720962

/**********************************************************************
 *<
	FILE:			shaveVraySharedFunctions.cpp  

	DESCRIPTION:	Various shared functions

	CREATED BY:		Vladimir Dubovoy <vladimir@3dgears.com>

	HISTORY:		created  21-08-2008 ( as part of 3ds Max + VRay hair shaders)
					merged   31-03-2010 

 *>
 **********************************************************************/

#include "shaveVraySharedFunctions.h"
#include "shaveVrayPlugin.h"

#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>

#ifdef LINUX
#include <unistd.h>
#endif


#ifdef WIN32
HINSTANCE hInstance = NULL;
static HINSTANCE lib_handle = NULL;
#else
#include <dlfcn.h>
#include <unistd.h>
static void *lib_handle = NULL;
#endif

PFNCREATEBSDFPOOL CreateShaveBSDFPool = NULL;

static char separator = 
#ifdef WIN32
';'
#else  
':'
#endif
;

int GetNumPaths(const char* multi)
{
	unsigned int len = (unsigned int)strlen(multi);
	if(len == 0)
		return 0;

	int n = 1;
	for(int i = 0; i < len; i++)
		if(multi[i] == separator)
			n++;

	return n;
}

bool GetPath(const char* multi, int idx, char* path)
{
	unsigned int len = (unsigned int)strlen(multi);
	if(len == 0)
		return false;

	assert(idx >= 0);

	int start = 0;
	int end   = 0;
	if(idx == 0)
	{
		bool found = false;
		for(int i = 1; i < len; i++)
		{
			if(multi[i] == separator)
			{
				end = i-1;
				found = true;
				break;
			}
		}
		if(!found)
			end = len-1;
		
		int j = 0;
		for(int i = start; i <= end; i++)
		{
			path[j] = multi[i];
			j++;
		}
		return true;
		
	}
	else
	{
		bool found = false;
		int  n = 0;
		for(int i = 0; i < len; i++)
		{
			if(multi[i] == separator)
			{
				n++;
				if(n == idx)
				{
					if(i+1 < len)
					{
						start = i+1;
						found = true;
					}
					break;
				}
			}
		}
		if(found)
		{
			for(int i = start; i < len; i++)
			{
				if(multi[i] == separator)
				{
					end = i-1;
					break;
				}
			}
			if(end == 0)
				end = len-1;

			if(end > start)
			{
				int j = 0;
				for(int i = start; i <= end; i++)
				{
					path[j] = multi[i];
					j++;
				}
				return true;
			}
		}
	}
	return false;
}

bool LoadShaveBSDFPoolLib(const char* libPath)
{
	LOGMSGS("SHADE","LoadShaveBSDFPoolLib from",libPath);
#if defined(WIN32)
#   ifdef VRAY_DUAL
#       ifdef VRAY30
#           if VRAY_DLL_VERSION < 0x31000
	            const char* dllName = "shaveSh30.dll";
#           elif VRAY_DLL_VERSION < 0x36000
	            const char* dllName = "shaveSh31.dll";
#           else
	            const char* dllName = "shaveSh36.dll";
#           endif
#		elif defined(VRAY40)
				const char* dllName = "shaveSh40.dll";
#       else
	       const char* dllName = "shaveSh.dll";
#       endif
#   else
	    char* dllName = "shaveSh.dll";
#   endif

	if(!lib_handle)
	{
		//look up the paths passed from maya
		bool found = false;
		char libname[MAX_PATH]= {'\0'};
		if(libPath != NULL && strlen(libPath) > 1)
		{
			//parse multiple paths
			int  npaths = GetNumPaths(libPath);
			for(int i = 0; i < npaths; i++)
			{
				char libname1[MAX_PATH]= {'\0'};
				char libPath1[MAX_PATH]= {'\0'};
				if(GetPath(libPath,i,libPath1))
				{
					LOGMSGI("SHADE","File 1 :",i);

					sprintf(libname1,"%s/%s",libPath1,dllName);

					//check file existance
					struct stat buf;
					int result = stat( libname1, &buf );
					if( result != 0 )
					{
						LOGMSGS("SHADE",libname1,"not found or can not be opened.");
					}
					else
					{
						LOGMSGS("SHADE","Found",libname1);
						strcpy(libname,libname1);
						found = true;
						break;
					}
				}
			}
		}
		//look into mayaroot/vray/plugins
		if(!found)
		{
			char libname1[MAX_PATH]= {'\0'};
			char to[MAX_PATH] = {'\0'};
			char path[MAX_PATH] = {'\0'};
			if( GetModuleFileName(hInstance, path, MAX_PATH ) )
			{
				char drive[6];
				char dir[MAX_PATH];
				char file[100];
				char ext[6];

				errno_t err = _splitpath_s(path,drive,6,dir,MAX_PATH,file,100,ext,6);
				if(err == 0)
				{
					sprintf(to,"%s%s",drive,dir);
				}
			}
			sprintf(libname1,"%s%s",to,dllName);
#ifdef _DEBUG
			fprintf(stdout,"LoadShaveBSDFPoolLib: load %s\n",libname);fflush(stdout);	
#endif
			//check file existance
			struct stat buf;
			int result = stat( libname1, &buf );
			LOGMSG("SHADE","File 2");
			if( result != 0 )
			{
				LOGMSGS("SHADE",libname1,"not found or can not be opened.");
			}
			else
			{
				LOGMSGS("SHADE","Found",libname1);
				strcpy(libname,libname1);
				found = true;
			}
		}
		if(!found)	//standalone
		{
			char libname1[MAX_PATH]= {'\0'};
#ifdef _WIN64
			char* libPath = getenv("VRAY_PLUGINS_x64");
#else
			char* libPath = getenv("VRAY_PLUGINS_x86");
#endif
			if(libPath && strlen(libPath) > 0)
			{
				//parse multiple paths
				int  npaths = GetNumPaths(libPath);
				for(int i = 0; i < npaths; i++)
				{
					char libPath1[MAX_PATH]= {'\0'};
					char libname1[MAX_PATH]= {'\0'};
					if(GetPath(libPath,i,libPath1))
					{
						sprintf(libname1,"%s/%s",libPath1,dllName);

						LOGMSGI("SHADE","File 3 :",i);

						//check file existance
						struct stat buf;
						int result = stat( libname1, &buf );
						if( result != 0 )
						{
							LOGMSGS("SHADE",libname1,"not found or can not be opened.");
						}
						else
						{
							LOGMSGS("SHADE","Found",libname1);
							strcpy(libname,libname1);
							found = true;
							break;
						}
					}
				}
			}
		}
		fflush(stdout);	
		if(!found)
		{
			//do not specify path excplicitly let system find it in libdirs
			sprintf(libname,"%s",dllName);
		}
		lib_handle = LoadLibrary(libname);
		if (!lib_handle) 
		{
			int err = GetLastError();
			LOGMSGI("SHADE","LoadShaveBSDFPoolLib: can not load shaveSh**.dll, error ",err);
			return false;
		}
		CreateShaveBSDFPool = (PFNCREATEBSDFPOOL)GetProcAddress(lib_handle, "CreateShaveBSDFPool");
		if(CreateShaveBSDFPool == NULL)
		{
			int err = GetLastError();
			LOGMSGI("SHADE","LoadShaveBSDFPoolLib: can not load 'CreateShaveBSDFPool' function, error ",err);
			return false;
		}
		
		
	}
#elif defined(LINUX)
#   ifdef VRAY_DUAL
#       ifdef VRAY30
#           if VRAY_DLL_VERSION < 0x31000
	            const char* soName = "ShaveSh30.so";
#           elif VRAY_DLL_VERSION < 0x36000
	            const char* soName = "ShaveSh31.so";
#           else
	            const char* soName = "ShaveSh36.so";
#           endif
#		elif defined(VRAY40)
				const char* soName = "ShaveSh40.so";
#       else
	        const char* soName = "ShaveSh.so";
#       endif
#   else
	    const char* soName = "ShaveSh.so";
#   endif

	if(!lib_handle)
	{
		bool found = false;
		char libname[MAX_PATH]= {'\0'};
		if(libPath != NULL && strlen(libPath) > 1)
		{
			//parse multiple paths
			int  npaths = GetNumPaths(libPath);
			for(int i = 0; i < npaths; i++)
			{
				char libname1[MAX_PATH]= {'\0'};
				char libPath1[MAX_PATH]= {'\0'};
				if(GetPath(libPath,i,libPath1))
				{
					sprintf(libname1,"%s/%s",libPath1,soName);

					//check file existance
					struct stat buf;
					int result = stat( libname1, &buf );
					if( result != 0 )
						fprintf(stdout,"File %s (1:%i) \nnot found or can not be opened.\n", libname1,i);
					else
					{
						fprintf(stdout,"Found %s (1:%i).\n", libname1,i);
						strcpy(libname,libname1);
						found = true;
						break;
					}
				}
			}
		}
		if(!found)
		{
			char id[526] = {'\0'};
			char path[526] = {'\0'};

			pid_t pid = getpid();
			sprintf(id, "/proc/%d/exe", getpid());
			readlink(id, path, 526);
#ifdef _DEBUG
			fprintf(stdout,"pid: %d bin path: %s \n",pid,path);
#endif
			char* ptr = strstr(path,"bin");
			if(ptr)
			{
				int pos = (ptr - path);
				int len = (int)strlen(path);
				for(int i = pos; i < len; i++)
					path[i] = '\0';

				strcat(path,"vray/vrayplugins/");
				strcat(path,soName);
			}
			else
			{
				fprintf(stdout,"LoadShaveBSDFPoolLib: can not find %s dir (%s).\n",soName,path);fflush(stdout);	
				return false;
			}
			struct stat buf;
			int result = stat( path, &buf );
			if( result != 0 )
				fprintf(stdout,"File %s (2) not found in \n%s \nor can not be opened.\n",soName, path);
			else
			{
				fprintf(stdout,"File %s (2) is found in \n %s.\n",soName, path);
				strcpy(libname,path);
				found = true;
			}
		}
		if(!found) //standalone vray
		{
			char libname1[MAX_PATH]= {'\0'};
#ifdef Bits64_
			char* libPath = getenv("VRAY_PLUGINS_x64");
#else
			char* libPath = getenv("VRAY_PLUGINS_x86");
#endif
			if(libPath)
			{
				//parse multiple paths
				int  npaths = GetNumPaths(libPath);
				for(int i = 0; i < npaths; i++)
				{
					char libname1[MAX_PATH]= {'\0'};
					char libPath1[MAX_PATH]= {'\0'};
					if(GetPath(libPath,i,libPath1))
					{
						sprintf(libname1,"%s/%s",libPath1,soName);

						//check file existance
						struct stat buf;
						int result = stat( libname1, &buf );
						if( result != 0 )
							fprintf(stdout,"File %s (3:%i) \nnot found or can not be opened.\n", libname1,i);
						else
						{
							fprintf(stdout,"Found %s (3:%i).\n", libname1,i);
							strcpy(libname,libname1);
							found = true;
							break;
						}
					}
				}
			}
		}
		if(!found)
		{
			//do not specify path excplicitly let system find it in libdirs
			sprintf(libname,"%s",soName);
		}
		lib_handle = dlopen(libname, RTLD_NOW | RTLD_GLOBAL);
		if (!lib_handle) 
		{
			printf("LoadShaveBSDFPoolLib: can not load %s\n",soName);
			char* errstr = dlerror();
			if (errstr != NULL)
				fprintf(stdout,"A dynamic linking error occurred: (%s).\n", errstr);
			fflush(stdout);
			return false;
		}
		CreateShaveBSDFPool = (PFNCREATEBSDFPOOL)dlsym(lib_handle, "CreateShaveBSDFPool");
		const char* dlsym_error = dlerror();
		if (dlsym_error || CreateShaveBSDFPool == NULL) 
		{
			fprintf(stdout,"LoadShaveBSDFPoolLib: can not load 'CreateShaveBSDFPool' function (%s).\n",dlsym_error);fflush(stdout);	
			return false;
		}
		
	}
#else // osx
	//	For MacOS/OS X CreateShaveBSDFPool() is built directly into libvray_Shave*.so. There's
	//	no separate lib to load.
#endif
	return true;
}

void UnLoadShaveBSDFPoolLib()
{
#if defined(WIN32) || defined(LINUX)
	if(lib_handle)
	{
#ifdef WIN32
		FreeLibrary(lib_handle);
#else
		dlclose(lib_handle);
#endif
	}
	CreateShaveBSDFPool = NULL;
	lib_handle = NULL;
#else // osx
	//	For MacOS/OS X CreateShaveBSDFPool() is built directly into libvray_Shave*.so. There's
	//	no separate lib to unload.
#endif
}