/* See LICENSE file for copyright and license details. */

/* global libraries */
#include <alsa/asoundlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <X11/Xlib.h>

/* local libraries */
#include "config.h"

/* functions */
void setstatus(char *str);
char *battery();
char *cpu_temperature();
char *cpu_usage();
char *datetime();
char *ram_usage();
char *smprintf(char *fmt, ...);
char *volume();
char *wifi_signal();

/* global variables */
static Display *dpy;

/* set statusbar (WM_NAME) */
void
setstatus(char *str)
{
  XStoreName(dpy, DefaultRootWindow(dpy), str);
  XSync(dpy, False);
}

/* battery percentage */
char *
battery()
{
  int battery_now, battery_full, battery_perc;
  FILE *fp;

  /* open battery now file */
  if (!(fp = fopen(batterynowfile, "r"))) {
    fprintf(stderr, "Error opening battery file.");
    exit(1);
  }

  /* read value */
  fscanf(fp, "%i", &battery_now);

  /* close battery now file */
  fclose(fp);

  /* open battery full file */
  if (!(fp = fopen(batteryfullfile, "r"))) {
    fprintf(stderr, "Error opening battery file.");
    exit(1);
  }

  /* read value */
  fscanf(fp, "%i", &battery_full);

  /* close battery full file */
  fclose(fp);

  /* calculate percent */
  battery_perc = battery_now / (battery_full / 100);

  /* return batt_perc as string */
  return smprintf("%d%%", battery_perc);
}

/* cpu temperature */
char *
cpu_temperature()
{
  int temperature;
  FILE *fp;

  /* open temperature file */
  if (!(fp = fopen(tempfile, "r"))) {
    fprintf(stderr, "Could not open temperature file.\n");
    exit(1);
  }

  /* extract temperature */
  fscanf(fp, "%d", &temperature);

  /* close temperature file */
  fclose(fp);

  /* return temperature in degrees */
  return smprintf("%d°C", temperature / 1000);
}

/* cpu percentage */
char *
cpu_usage()
{
  int cpu_perc;
  long double a[4], b[4];
  FILE *fp;

  /* open stat file */
  if (!(fp = fopen("/proc/stat","r"))) {
    fprintf(stderr, "Error opening stat file.");
    exit(1);
  }

  /* read values */
  fscanf(fp, "%*s %Lf %Lf %Lf %Lf", &a[0], &a[1], &a[2], &a[3]);

  /* close stat file */
  fclose(fp);

  /* wait a second (for avg values) */
  sleep(1);

  /* open stat file */
  if (!(fp = fopen("/proc/stat","r"))) {
    fprintf(stderr, "Error opening stat file.");
    exit(1);
  }

  /* read values */
  fscanf(fp, "%*s %Lf %Lf %Lf %Lf", &b[0], &b[1], &b[2], &b[3]);

  /* close stat file */
  fclose(fp);

  /* calculate avg in this second */
  cpu_perc = 100 * ((b[0]+b[1]+b[2]) - (a[0]+a[1]+a[2])) / ((b[0]+b[1]+b[2]+b[3]) - (a[0]+a[1]+a[2]+a[3]));

  /* return cpu_perc as string */
  return smprintf("%d%%", cpu_perc);
}

/* date and time */
char *
datetime()
{
  time_t tm;
  size_t bufsize = 19;
  char *buf = malloc(bufsize);

  /* get time in format */
  time(&tm);
  if(!strftime(buf, bufsize, timeformat, localtime(&tm))) {
    fprintf(stderr, "Strftime failed.\n");
    exit(1);
  }

  /* return time */
  return buf;
}

/* ram percentage */
char *
ram_usage()
{
  int ram_perc;
  long total, free, available;
  FILE *fp;

  /* open meminfo file */
  if (!(fp = fopen("/proc/meminfo", "r"))) {
    fprintf(stderr, "Error opening meminfo file.");
    exit(1);
  }

  /* read the values */
  fscanf(fp, "MemTotal: %ld kB\n", &total);
  fscanf(fp, "MemFree: %ld kB\n", &free);
  fscanf(fp, "MemAvailable: %ld kB\n", &available);

  /* close meminfo file */
  fclose(fp);

  /* calculate percentage */
  ram_perc = 100 * (total - available) / total;

  /* return ram_perc as string */
  return smprintf("%d%%",ram_perc);
}

/* smprintf function */
char *
smprintf(char *fmt, ...)
{
  va_list fmtargs;
  char *ret;
  int len;

  va_start(fmtargs, fmt);
  len = vsnprintf(NULL, 0, fmt, fmtargs);
  va_end(fmtargs);

  ret = malloc(++len);
  if (ret == NULL) {
    fprintf(stderr, "Malloc error.");
    exit(1);
  }

  va_start(fmtargs, fmt);
  vsnprintf(ret, len, fmt, fmtargs);
  va_end(fmtargs);

  return ret;
}

/* alsa volume percentage */
char *
volume()
{
  int mute = 0;
  long vol = 0, max = 0, min = 0;

  /* get volume from alsa */
  snd_mixer_t *handle;
  snd_mixer_elem_t *pcm_mixer, *mas_mixer;
  snd_mixer_selem_id_t *vol_info, *mute_info;
  snd_mixer_open(&handle, 0);
  snd_mixer_attach(handle, soundcard);
  snd_mixer_selem_register(handle, NULL, NULL);
  snd_mixer_load(handle);
  snd_mixer_selem_id_malloc(&vol_info);
  snd_mixer_selem_id_malloc(&mute_info);
  snd_mixer_selem_id_set_name(vol_info, channel);
  snd_mixer_selem_id_set_name(mute_info, channel);
  pcm_mixer = snd_mixer_find_selem(handle, vol_info);
  mas_mixer = snd_mixer_find_selem(handle, mute_info);
  snd_mixer_selem_get_playback_volume_range((snd_mixer_elem_t *)pcm_mixer,
                                            &min, &max);
  snd_mixer_selem_get_playback_volume((snd_mixer_elem_t *)pcm_mixer,
                                      SND_MIXER_SCHN_MONO, &vol);
  snd_mixer_selem_get_playback_switch(mas_mixer, SND_MIXER_SCHN_MONO,
                                      &mute);
  if (vol_info)
    snd_mixer_selem_id_free(vol_info);
  if (mute_info)
    snd_mixer_selem_id_free(mute_info);
  if (handle)
    snd_mixer_close(handle);

  /* return the string (mute) */
  if (!mute)
    return smprintf("mute");
  else
    return smprintf("%d%%", (vol * 100) / max);
}

/* wifi percentage */
char *
wifi_signal()
{
  int bufsize = 255;
  int strength;
  char buf[bufsize];
  char *datastart;
  char path_start[16] = "/sys/class/net/";
  char path_end[11] = "/operstate";
  char path[32];
  char status[5];
  char needle[sizeof wificard + 1];
  FILE *fp;

  /* generate the path name */

  memset(path, 0, sizeof path);
  strcat(path, path_start);
  strcat(path, wificard);
  strcat(path, path_end);

  /* open wifi file */
  if(!(fp = fopen(path, "r"))) {
    fprintf(stderr, "Error opening wifi operstate file.");
    exit(1);
  }

  /* read the status */
  fgets(status, 5, fp);

  /* close wifi file */
  fclose(fp);

  /* check if interface down */
  if(strcmp(status, "up\n") != 0){
    return "n/a";
  }

  /* open wifi file */
  if (!(fp = fopen("/proc/net/wireless", "r"))) {
    fprintf(stderr, "Error opening wireless file.");
    exit(1);
  }

  /* extract the signal strength */
  strcpy(needle, wificard);
  strcat(needle, ":");
  fgets(buf, bufsize, fp);
  fgets(buf, bufsize, fp);
  fgets(buf, bufsize, fp);
  if ((datastart = strstr(buf, needle)) != NULL) {
    datastart = strstr(buf, ":");
    sscanf(datastart + 1, " %*d   %d  %*d  %*d        %*d      %*d      %*d      %*d      %*d        %*d", &strength);
  }

  /* close wifi file */
  fclose(fp);

  /* return strength in percent */
  return smprintf("%d%%", strength);
}

/* main function */
int
main()
{
  char status[1024];

  /* open display */
  if (!(dpy = XOpenDisplay(0x0))) {
    fprintf(stderr, "Cannot open display!\n");
    exit(1);
  }

  char *pWifi_signal = NULL;
  char *pBattery = NULL;
  char *pCpu_usage = NULL;
  char *pCpu_temperature = NULL;
  char *pRam_usage = NULL;
  char *pVolume = NULL;
  char *pDatetime = NULL;

  /* return status every second */
  for (;;) {
    pWifi_signal = wifi_signal();
    pBattery = battery();
    pCpu_usage = cpu_usage();
    pCpu_temperature = cpu_temperature();
    pRam_usage = ram_usage();
    pVolume = volume();
    pDatetime = datetime();
    sprintf(status, FORMATSTRING, ARGUMENTS);
    setstatus(status);
    free(pWifi_signal);
    free(pBattery);
    free(pCpu_usage);
    free(pCpu_temperature);
    free(pRam_usage);
    free(pVolume);
    free(pDatetime);
  }

  /* close display */
  XCloseDisplay(dpy);

  /* exit successfully */
  return 0;
}