#include <dirent.h>
#include <stdio.h>
#include <string.h>

int main() {
  DIR *dir = opendir("/sys/class/power_supply");
  if (!dir)
    return 1;

  struct dirent *entry;
  int total = 0, count = 0, charging = 0;

  // Iterate every battery
  while ((entry = readdir(dir))) {
    if (strncmp(entry->d_name, "BAT", 3) != 0)
      continue;

    char path[512];
    FILE *fp;
    int capacity;
    char status[20];

    // Read current charge value
    snprintf(path, sizeof(path), "/sys/class/power_supply/%s/capacity",
             entry->d_name);
    fp = fopen(path, "r");
    if (!fp)
      return 1;
    if (fscanf(fp, "%d", &capacity) == 1) {
      total += capacity;
      count++;
      fclose(fp);
    }

    // Check if charging
    snprintf(path, sizeof(path), "/sys/class/power_supply/%s/status",
             entry->d_name);
    fp = fopen(path, "r");
    if (!fp)
      return 1;
    if (fscanf(fp, "%19s", status) == 1) {
      if (strncmp(status, "Charging", 8) == 0)
        charging = 1;
      fclose(fp);
    }
  }
  closedir(dir);

  if (count > 0)
    printf("Bat: %s%d%%\n", charging ? "+" : "", total / count);
  return 0;
}