#include <windows.h>

#include <iostream>

#include "gpu.h"

// magic numbers, do not change them

#define NVAPI_MAX_PHYSICAL_GPUS 64

#define NVAPI_MAX_USAGES_PER_GPU 34

// function pointer types

typedef int *(*NvAPI_QueryInterface_t)(unsigned int offset);

typedef int (*NvAPI_Initialize_t)();

typedef int (*NvAPI_EnumPhysicalGPUs_t)(int **handles, int *count);

typedef int (*NvAPI_GPU_GetUsages_t)(int *handle, unsigned int *usages);

NvAPI_QueryInterface_t NvAPI_QueryInterface = NULL;

NvAPI_Initialize_t NvAPI_Initialize = NULL;

NvAPI_EnumPhysicalGPUs_t NvAPI_EnumPhysicalGPUs = NULL;

NvAPI_GPU_GetUsages_t NvAPI_GPU_GetUsages = NULL;

HMODULE hmod;

bool init_nvapi_bool;

int *gpuHandles[NVAPI_MAX_PHYSICAL_GPUS] = { NULL };

int gpuCount = 0;

unsigned int gpuUsages[NVAPI_MAX_USAGES_PER_GPU] = { 0 };

bool checkNVAPI(){

#if _WIN64

hmod = LoadLibraryA("nvapi64.dll");

#else

hmod = LoadLibraryA("nvapi.dll");

#endif

if (hmod == NULL)

{

printf("Failed to load nvapi.dll");

return false;

}

NvAPI_QueryInterface = (NvAPI_QueryInterface_t) GetProcAddress(hmod, "nvapi_QueryInterface");

NvAPI_Initialize = (NvAPI_Initialize_t) (*NvAPI_QueryInterface)(0x0150E828);

NvAPI_EnumPhysicalGPUs = (NvAPI_EnumPhysicalGPUs_t) (*NvAPI_QueryInterface)(0xE5AC921F);

NvAPI_GPU_GetUsages = (NvAPI_GPU_GetUsages_t) (*NvAPI_QueryInterface)(0x189A1FDF);

if (NvAPI_Initialize == NULL || NvAPI_EnumPhysicalGPUs == NULL ||

NvAPI_EnumPhysicalGPUs == NULL || NvAPI_GPU_GetUsages == NULL)

{

std::cerr << "Couldn't get functions in nvapi.dll" << std::endl;

return 2;

}

(*NvAPI_Initialize)();

int *gpuHandles[NVAPI_MAX_PHYSICAL_GPUS] = { NULL };

return true;

}

void nvapi_util()

{

if (!init_nvapi_bool){

init_nvapi_bool = checkNVAPI();

}

gpuUsages[0] = (NVAPI_MAX_USAGES_PER_GPU * 4) | 0x10000;

(*NvAPI_EnumPhysicalGPUs)(gpuHandles, &gpuCount);

(*NvAPI_GPU_GetUsages)(gpuHandles[0], gpuUsages);

// TODO: create a GPU class for nvapi

// otherwise we can't display information

// gpu_info.load = gpuUsages[3];

}