// https://stackoverflow.com/questions/20943322/accessing-keys-from-linux-input-device

#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <linux/input.h>
#include <string.h>
#include <stdio.h>

static const char *const evval[3] = {
    "RELEASED",
    "PRESSED ",
    "REPEATED"
};

/**
 * +--+--+--+--+
 * |30|48|46|32|
 * +--+--+--+--+
 * |18|33|34|35|
 * +--+--+--+--+
 * |23|36|37|38|
 * +--+--+--+--+
 * |50|49|24|25|
 * +--+--+--+--+
 * |16|19|31|20|
 * +--+--+--+--+
* */

enum p_key {
    p11 = 30,
    p12 = 48,
    p13 = 46,
    p14 = 32,
    p21 = 18,
    p22 = 33,
    p23 = 34,
    p24 = 35,
    p31 = 23,
    p32 = 36,
    p33 = 37,
    p34 = 38,
    p41 = 50,
    p42 = 49,
    p43 = 24,
    p44 = 25,
    p51 = 16,
    p52 = 19,
    p53 = 31,
    p54 = 20
};

int main(void)
{
    const char* dev = "/dev/input/by-id/usb-MAX_Falcon_20_RGB-if02-event-kbd"; //at.event26
    struct input_event ev;
    ssize_t n;
    int fd;

    fd = open(dev, O_RDONLY);
    if (fd == -1) {
        fprintf(stderr, "Cannot open %s: %s.\n", dev, strerror(errno));
        return EXIT_FAILURE;
    }

    // This grabs the device, so the we do not just listen to events but we actually consume them! This way the keypresses are not handled by any other handler!
    // https://stackoverflow.com/questions/29942421/read-barcodes-from-input-event-linux-c/29956584#29956584
    if (ioctl(fd, EVIOCGRAB, 1)) {
        const int saved_errno = errno;
        close(fd);
        return errno = (saved_errno) ? errno : EACCES;
    }

    // Main-Loop
    while (1) {
        n = read(fd, &ev, sizeof ev);
        //n = ioctl(fd, EVIOCGRAB, 1);
        if (n == (ssize_t)-1) {
            if (errno == EINTR)
                continue;
            else
                break;
        } else
        if (n != sizeof ev) {
            errno = EIO;
            break;
        }
        if (ev.type == EV_KEY && ev.value >= 0 && ev.value <= 2) {
            //printf("%s 0x%04x (%d)\n", evval[ev.value], (int)ev.code, (int)ev.code);
            if (evval[ev.value] == "RELEASED") {
                switch((int)ev.code) {
                    case p11: 
                        system("notify-send 'Screenlayout: default'; /home/tbehrendt/.screenlayout/default.sh"); 
                        break;
                    case p12: 
                        system("notify-send 'Screenlayout: main low res'; /home/tbehrendt/.screenlayout/main_low_res.sh"); 
                        break;
                    case p13: 
                        system("notify-send 'Screenlayout: tv mirror'; /home/tbehrendt/.screenlayout/tv_mirror.sh"); 
                        break;
                    case p14: 
                        system("notify-send 'Screenlayout: tv standalone'; /home/tbehrendt/.screenlayout/tv_standalone.sh");
                        break;
                    case p21: printf("p21\n"); break;
                    case p22: printf("p22\n"); break;
                    case p23: printf("p23\n"); break;
                    case p24: printf("p24\n"); break;
                    case p31: printf("p31\n"); break;
                    case p32: printf("p32\n"); break;
                    case p33: printf("p33\n"); break;
                    case p34: printf("p34\n"); break;
                    case p41: printf("p41\n"); break;
                    case p42: printf("p42\n"); break;
                    case p43: printf("p43\n"); break;
                    case p44: printf("p44\n"); break;
                    case p51: 
                        system("notify-send mute toggled;pactl set-sink-mute @DEFAULT_SINK@ toggle");
                        break;
                    case p52: 
                        system("notify-send 'VOL +5%'; pactl set-sink-volume @DEFAULT_SINK@ +5%");
                        break;
                    case p53:
                        system("notify-send 'VOL -5%'; pactl set-sink-volume @DEFAULT_SINK@ -5%");
                        break;
                    case p54: 
                        system("/home/tbehrendt/.scripts/makroboard/p51.sh &");
                        break;
                }
            }
        }

    }
    fflush(stdout);
    fprintf(stderr, "%s.\n", strerror(errno));
    return EXIT_FAILURE;
}