#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <assert.h>

#include <string.h>

#include <limits.h>

#include <unistd.h>

#include <errno.h>

#include "config.h"

#ifdef USE_UDEV

#include <poll.h>

#include <libudev.h>

#endif

char *eights[] = { "ø", "▁", "▂", "▃", "▄", "▅", "▆","▇", "█" };

char *catfile(char *name) {

    struct stat buffer;

    int         status;

    int         f;

    char*       resbuf;

    f = open(name, O_RDONLY);

    if (f == -1) return NULL;

    status = fstat(f, &buffer);

    if (status != 0) return NULL;

    resbuf = malloc(buffer.st_size+1);

    if (resbuf == NULL) return NULL;

    status = read(f,resbuf,buffer.st_size);

    if (status == -1) {

        free(resbuf);

        return NULL;

    }

    if ((status>0)&&(resbuf[status-1]=='\n'))

        resbuf[status-1]='\0';

    resbuf[status]='\0';

    return resbuf;

}

int catint(char *name) {

    char *cont = catfile(name);

    assert (cont != NULL);

    int res = atoi(cont);

    free(cont);

    return res;

}

char *color_stop;

char *color_red;

char *color_orange;

char *color_green;

char *color_none;

char *color(int low,int mid,int rev,int value) {

    if (value>mid) {

        return rev ? color_red : color_green;

    } else if (value>low) {

        return color_orange;

    }

    return rev ? color_green : color_red;

}

int main(int argc, char *argv[]) {

    if (argc<=1) {

        fprintf(stderr, "Usage: %s <BAT1> [term|pango]\n", argv[0]);

        fflush(stderr);

        return 1;

    }

    char *arrow_color;

    char *eights_color;

    char *percent_color;

    char *remtimes_color;

    if (argc>2 && !strcmp(argv[2],"term")) {

        color_stop = "\x1b[0m";

        color_red = "\x1b[1;31m";

        color_green = "\x1b[1;32m";

        color_orange = "\x1b[1;33m";

        color_none = color_stop;

    } else if (argc>2 && !strcmp(argv[2],"pango")) {

        color_stop = "</span>";

        color_red = "<span color='#f33'>";

        color_green = "<span color='#0f0'>";

        color_orange = "<span color='#fa0'>";

        color_none = "<span>";

    } else {

        color_stop = color_red = color_green = color_orange = color_none = "";

    }

#ifdef USE_UDEV

    struct udev *udev;

    struct udev_device *dev;

    struct udev_monitor *mon;

    int mon_fd;

    udev = udev_new();

    if (!udev) {

        printf("Can't create udev\n");

        exit(1);

    }

    mon = udev_monitor_new_from_netlink(udev, "udev");

    udev_monitor_filter_add_match_subsystem_devtype(mon, "power_supply", NULL);

    udev_monitor_enable_receiving(mon);

    mon_fd = udev_monitor_get_fd(mon);

    static struct pollfd fds[1];

    fds[0].fd = mon_fd;

    fds[0].events = POLLIN;

#endif

    char filename[PATH_MAX+1];

    snprintf(filename,PATH_MAX,"/sys/class/power_supply/%s/energy_now",argv[1]);

    struct stat st;

    int energy = 0==stat(filename, &st);

    while (1) {

        snprintf(filename,PATH_MAX,"/sys/class/power_supply/%s/%s_now",argv[1], energy ? "energy" : "charge");

        int charge_now = catint(filename);

        snprintf(filename,PATH_MAX,"/sys/class/power_supply/%s/%s_now",argv[1], energy ? "power" : "current");

        int current_now = catint(filename);

        snprintf(filename,PATH_MAX,"/sys/class/power_supply/%s/%s_full",argv[1], energy ? "energy" : "charge");

        int charge_full = catint(filename);

        snprintf(filename,PATH_MAX,"/sys/class/power_supply/%s/status",argv[1]);

        char *status = catfile(filename);

        int remtime = 0;

        char *arrow;

        remtimes_color = color_none;

        if (!strcmp(status,"Charging")) {

            if (current_now != 0)

                remtime = (charge_full-charge_now) / (current_now/60);

            arrow = "↑";

            arrow_color = color_orange;

        }

        else if (!strcmp(status,"Discharging")) {

            if (current_now != 0)

                remtime = charge_now / (current_now/60);

            arrow_color = color_none;

            remtimes_color = color(20,120,0,remtime);

        } else {

            arrow = "—";

            arrow_color = color_green;

        }

        free(status);

        int percent = charge_now/(charge_full/100);

        eights_color = percent_color = color(15,40,0,percent);

        printf("%s%s%s ",eights_color,eights[charge_now*8/charge_full],color_stop);

        printf("%s%d%%%s ",percent_color,percent,color_stop);

        printf("%s%s%s ",arrow_color,arrow,color_stop);

        fflush(stdout);

#ifdef USE_UDEV

        if (poll_status < 0) {

            if (poll_status != EINTR) {

                perror("poll");

                exit(12);

            }

        }

        if (fds[0].revents & POLLIN) {

            dev = udev_monitor_receive_device(mon);

            if (dev) {

                udev_device_unref(dev);

            } else {

                printf("UDEV DC\n");

                exit(13);

            }

        }

#else

#endif

    }

}