/*
 * Copy me if you can.
 * by 20h
 */

#define _BSD_SOURCE
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <strings.h>
#include <sys/time.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <X11/Xlib.h>

char *colourFaded = "\x01"; // grey on black
char *colourNeutral = "\x02"; // blue on black
char *colourWarning = "\x03"; // yellow on black
char *colourCritical = "\x04"; // red on black
char *colourNormal = "\x05"; // grey on black

char *iconClock = "\uE3D2";

char *tzSaoPaulo = "America/Sao_Paulo";
char *tzLocal = "Europe/Zurich";

static Display *dpy;

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) {
                perror("malloc");
                exit(1);
        }

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

        return ret;
}

void
settz(char *tzname)
{
        setenv("TZ", tzname, 1);
}

char *
mktimes(char *fmt, char *tzname)
{
        char buf[129];
        time_t tim;
        struct tm *timtm;

        settz(tzname);
        tim = time(NULL);
        timtm = localtime(&tim);
        if (timtm == NULL)
                return smprintf("");

        if (!strftime(buf, sizeof(buf)-1, fmt, timtm)) {
                fprintf(stderr, "strftime == 0\n");
                return smprintf("");
        }

        return smprintf("%s", buf);
}

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

char *
loadavg(void)
{
        double avgs[3];

        if (getloadavg(avgs, 3) < 0)
                return smprintf("");

        return smprintf("%.2f %.2f %.2f", avgs[0], avgs[1], avgs[2]);
}

char *
readfile(char *base, char *file)
{
        char *path, line[513];
        FILE *fd;

        memset(line, 0, sizeof(line));

        path = smprintf("%s/%s", base, file);
        fd = fopen(path, "r");
        free(path);
        if (fd == NULL)
                return NULL;

        if (fgets(line, sizeof(line)-1, fd) == NULL)
                return NULL;
        fclose(fd);

        return smprintf("%s", line);
}

char *
getbattery(char *base)
{
    // charging E20D, empty E20E, full E20F, 2/3 E210, 1/3 E211
    char *co, status;
    int descap, remcap;

    descap = -1;
    remcap = -1;

    co = readfile(base, "present");
    if (co == NULL)
            return smprintf("");
    if (co[0] != '1') {
            free(co);
            return smprintf("not present");
    }
    free(co);

    co = readfile(base, "charge_full_design");
    if (co == NULL) {
            co = readfile(base, "energy_full_design");
            if (co == NULL)
                    return smprintf("");
    }
    sscanf(co, "%d", &descap);
    free(co);

    co = readfile(base, "charge_now");
    if (co == NULL) {
            co = readfile(base, "energy_now");
            if (co == NULL)
                    return smprintf("");
    }
    sscanf(co, "%d", &remcap);
    free(co);

    co = readfile(base, "status");
    if (!strncmp(co, "Discharging", 11)) {
            status = '-';
    } else if(!strncmp(co, "Charging", 8)) {
            status = '+';
    } else {
            status = '?';
    }

    if (remcap < 0 || descap < 0)
            return smprintf("invalid");

    return smprintf("%.0f%%%c", ((float)remcap / (float)descap) * 100, status);
}

char *
gettemperature(char *base, char *sensor)
{
        char *co;

        co = readfile(base, sensor);
        if (co == NULL)
                return smprintf("");
        return smprintf("%02.0f°C", atof(co) / 1000);
}

int
main(void)
{
        char *status;
        char *avgs;
        char *bat1;
        char *tmar;
        char *tmutc;
        char *tmbln;
        char *t0, *t1, *t2;

        char *localTime;
        char *spTime;
        char *date;
        char *bat;

        if (!(dpy = XOpenDisplay(NULL))) {
                fprintf(stderr, "dwmstatus: cannot open display.\n");
                return 1;
        }

        for (;;sleep(1)) {
            /*
                bat1 = getbattery("/sys/class/power_supply/BAT1");
                t0 = gettemperature("/sys/devices/virtual/hwmon/hwmon0", "temp1_input");
                t1 = gettemperature("/sys/devices/virtual/hwmon/hwmon2", "temp1_input");
                t2 = gettemperature("/sys/devices/virtual/hwmon/hwmon4", "temp1_input");
                */
                localTime = mktimes("%H:%M", tzLocal);
                spTime = mktimes("%H:%M", tzSaoPaulo);
                date = mktimes("%d.%m.%y", tzLocal);

                avgs = loadavg();
                bat = getbattery("/sys/class/power_supply/BAT0");

                // [wifi] [storage] [cpu usage] [cpu temp] [ram usage] [battery] [backlight] [volume] [time]
                status = smprintf(
                        "%s"
                        " %s"
                        " %s%s%s%s%s%s%s%s",
                        bat,
                        avgs,
                        colourNeutral, iconClock, colourNormal, localTime, colourFaded, spTime, colourNormal, date);
                setstatus(status);

                free(localTime);
                free(spTime);
                free(date);
        }

        XCloseDisplay(dpy);

        return 0;
}