//compile hint: gcc statustest.c -I/opt/cuda/include -lnvidia-ml

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#include <sys/uio.h>
#include <dirent.h>
#include <sys/sysinfo.h>
#include <sys/statvfs.h>
#include <nvml.h>
#include <time.h>

int main() {
  FILE *fp;
  char *line = NULL;
  size_t len = 0;
  ssize_t nread;
  fp = fopen("/proc/stat", "r");
  int cores = -2;
  do {
    ++cores;
    nread = getline(&line, &len, fp);
  } while (*line == 'c');
  free(line);
  fclose(fp);
  int user, nice, sys, idle, coretemp;
  int *user_old, *nice_old, *sys_old, *idle_old;
  user_old = malloc(cores*sizeof(int));
  nice_old = malloc(cores*sizeof(int));
  sys_old = malloc(cores*sizeof(int));
  idle_old = malloc(cores*sizeof(int));
  DIR *d;
  struct dirent *dir;
  char hwmonPath[128], name[32], link[128], tstr[32];
  d = opendir("/sys/class/hwmon/");
  if (!d) {
    perror("Failed to open dir");
    return -1;
  }
  while((dir = readdir(d)) != NULL) {
    if (dir->d_type == DT_LNK) {
      snprintf(hwmonPath, sizeof(hwmonPath), "/sys/class/hwmon/%s", dir->d_name);
      realpath(hwmonPath, link);
      snprintf(hwmonPath, sizeof(hwmonPath), "%s/name", link);
      fp = fopen(hwmonPath, "r");
      if (!fp) {
        perror("File opening failed");
        return -1;
      }
      fscanf(fp, "%s", name);
      fclose(fp);
      if (strcmp(name, "coretemp") == 0) {
        snprintf(hwmonPath, sizeof(hwmonPath), "%s/temp1_input", link);
        break;
      }
    }
  }

  fp = fopen("/proc/stat", "r");
  if (!fp) {
    perror("File opening failed");
    return -1;
  }
  while(fgetc(fp) != '\n');
  for (unsigned i = 0; i < cores; ++i) {
    fscanf(fp, "%*s %d %d %d %d %*d %*d %*d %*d %*d %*d\n", &user_old[i], &nice_old[i], &sys_old[i], &idle_old[i]);
  }
  fclose(fp);
  char linefgets[256];
  int ramTotal = 0, ramAvailable, swapTotal, swapFree;
  fp = fopen("/proc/meminfo", "r");
  if (!fp) {
    perror("File opening failed");
    return -1;
  }
  while(fgets(linefgets, sizeof(linefgets), fp)) {
    if (!ramTotal)
      sscanf(linefgets, "MemTotal: %d kB", &ramTotal);
    if (sscanf(linefgets, "SwapTotal: %d kB", &swapTotal) == 1)
      break;
  }
  fclose(fp);

  nvmlReturn_t result;
  nvmlDevice_t* devices;
  nvmlUtilization_t util;
  unsigned temp;
  unsigned device_count;
  result = nvmlInit();
  if (NVML_SUCCESS != result) {
      printf("Failed to initialize NVML: %s\n", nvmlErrorString(result));
      return -1;
  }
  result = nvmlDeviceGetCount(&device_count);
  if (NVML_SUCCESS != result) {
      printf("Failed to query device count: %s\n", nvmlErrorString(result));
      return -1;
  }
  devices = malloc(sizeof(nvmlDevice_t)*device_count);
  for (unsigned i = 0; i < device_count; ++i) {
    result = nvmlDeviceGetHandleByIndex(i, &devices[i]);
    if (NVML_SUCCESS != result) {
        printf("Failed to get handle for device %i: %s\n", i, nvmlErrorString(result));
        return -1;
    }
  }

  struct statvfs fileSysStat;

  time_t t;
  struct tm *tmp;

  while (true) {
    sleep(1);

    printf("CPU Usage:");
    fp = fopen("/proc/stat", "r");
    if (!fp) {
      perror("File opening failed");
      return -1;
    }
    while(fgetc(fp) != '\n');
    for (unsigned i = 0; i < cores; ++i) {
      fscanf(fp, "%*s %d %d %d %d %*d %*d %*d %*d %*d %*d\n", &user, &nice, &sys, &idle);
      printf("%*.1f%%", 5, (float)(user+nice+sys-user_old[i]-nice_old[i]-sys_old[i])/(user+nice+sys+idle-user_old[i]-nice_old[i]-sys_old[i]-idle_old[i])*100);
      if (i != cores-1)
        printf(";");
      user_old[i] = user;
      nice_old[i] = nice;
      sys_old[i] = sys;
      idle_old[i] = idle;
    }
    fclose(fp);

    fp = fopen(hwmonPath, "r");
    if (!fp) {
      perror("File opening failed");
      return -1;
    }
    fscanf(fp, "%d", &coretemp);
    fclose(fp);

    fp = fopen("/proc/meminfo", "r");
    if (!fp) {
      perror("File opening failed");
      return -1;
    }
    ramAvailable = 0;
    while(fgets(linefgets, sizeof(linefgets), fp)) {
      if (!ramAvailable)
        sscanf(linefgets, "MemAvailable: %d kB", &ramAvailable);
      if (sscanf(linefgets, "SwapFree: %d kB", &swapFree) == 1)
        break;
    }
    fclose(fp);
    printf("(%*d°C) | RAM Usage:%*.1f%% | Swap Usage:%*.1f%% | GPU Usage:", 3, coretemp/1000, 5, (float)(ramTotal-ramAvailable)/ramTotal*100, 5, (float)(ramTotal-swapFree)/swapTotal*100);
    for (unsigned i = 0; i < device_count; ++i) {
      result = nvmlDeviceGetUtilizationRates(devices[i], &util);
      if (NVML_SUCCESS != result) {
          printf("Failed utilization for device %i: %s\n", i, nvmlErrorString(result));
          return -1;
      }
      result = nvmlDeviceGetTemperature(devices[i], NVML_TEMPERATURE_GPU, &temp);
      if (NVML_SUCCESS != result) {
          printf("Failed to get temperature for device %i: %s\n", i, nvmlErrorString(result));
          return -1;
      }
      printf("%*d%%(%*d°C)", 3, util.gpu, 2, temp);
      if (i != device_count-1)
        printf(";");
    }

    if (statvfs("/home", &fileSysStat) != 0) {
      perror("Getting the available disk space failed");
      return -1;
    }
    t = time(NULL);
    tmp = localtime(&t);
    strftime(tstr, sizeof(tstr), "%d-%m-%g %T", tmp);
    printf(" | Disk Space: %*dG | %s", 3, fileSysStat.f_bsize*fileSysStat.f_bfree/1073741824, tstr);
    fflush(stdout);
  }

  result = nvmlShutdown();
  if (NVML_SUCCESS != result)
      printf("Failed to shutdown NVML: %s\n", nvmlErrorString(result));
  free(user_old);
  free(nice_old);
  free(sys_old);
  free(idle_old);
  free(devices);
  return 0;
}