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

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

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

/* check file macro */
#define CHECK_FILE(X,Y) do { \
    if (stat(X,&Y) < 0) return -1; \
    if (!S_ISREG(Y.st_mode)) return -1; \
} while (0);

/* functions */
int config_check();
void setstatus(char *str);
char *smprintf(char *fmt, ...);
char *get_battery();
char *get_cpu_temperature();
char *get_cpu_usage();
char *get_datetime();
char *get_ram_usage();
char *get_volume();
char *get_wifi_signal();

/* global variables */
static Display *dpy;

/* check configured paths */
int
config_check()
{
    struct stat fs;
    CHECK_FILE(batterynowfile, fs);
    CHECK_FILE(batteryfullfile, fs);
    CHECK_FILE(tempfile, fs);
    return 0;
}

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

/* smprintf function */
char *
smprintf(char *fmt, ...)
{
    va_list fmtargs;
    char *ret = NULL;
    va_start(fmtargs, fmt);
    if (vasprintf(&ret, fmt, fmtargs) < 0)
        return NULL;
    va_end(fmtargs);

    return ret;
}

/* battery percentage */
char *
get_battery()
{
    int now, full, perc;
    FILE *fp;

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

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

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

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

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

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

    /* calculate percent */
    perc = now / (full / 100);

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

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

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

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

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

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

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

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

    /* 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.");
        return smprintf("n/a");
    }

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

/* date and time */
char *
get_datetime()
{
    time_t tm;
    size_t bufsize = 64;
    char *buf = malloc(bufsize);

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

    /* return time */
    return smprintf("%s", buf);
}

/* ram percentage */
char *
get_ram_usage()
{
    int perc;
    long total, free, buffers, cached;
    FILE *fp;

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

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

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

    /* calculate percentage */
    perc = 100 * ((total - free) - (buffers + cached)) / total;

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

/* alsa volume percentage */
char *
get_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 *
get_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.");
        return smprintf("n/a");
    }

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

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

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

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

    /* 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];
    char *battery = NULL;
    char *cpu_temperature = NULL;
    char *cpu_usage = NULL;
    char *datetime = NULL;
    char *ram_usage = NULL;
    char *volume = NULL;
    char *wifi_signal = NULL;

    /* check config for sanity */
    if (config_check() < 0) {
        fprintf(stderr, "Config error, please check paths and recompile\n");
        exit(1);
    }

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

    /* return status every second */
    for (;;) {
        /* assign the values */
        battery = get_battery();
        cpu_temperature = get_cpu_temperature();
        cpu_usage = get_cpu_usage();
        datetime = get_datetime();
        ram_usage = get_ram_usage();
        volume = get_volume();
        wifi_signal = get_wifi_signal();

        /* return the status */
        sprintf(status, FORMATSTRING, ARGUMENTS);
        setstatus(status);

        /* free the values */
        free(battery);
        free(cpu_temperature);
        free(cpu_usage);
        free(datetime);
        free(ram_usage);
        free(volume);
        free(wifi_signal);

        /* wait, "update_interval - 1" because of get_cpu_usage() which uses 1 second */
        sleep(update_interval -1);
    }

    /* close display */
    XCloseDisplay(dpy);

    /* exit successfully */
    return 0;
}