#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/mman.h>
  
#define MSECS 1000
  
int main(void) {
    int fd;
    char buf[2] = "0";
    char *btns;
    char led_pattern = 0;
 
    fd = open("/dev/lms_ui", O_RDWR | O_SYNC);
    printf("device opened\n");
    write(fd, buf, 2);
 
    btns = mmap(0, 6, PROT_READ, MAP_SHARED, fd, 0);
 
    char last_states = 0xff;
 
    while (1) {
        char states = 0 ;
        for (int i = 0 ; i < 6 ; i++)
            states = (states << 1) | (btns[i] & 0x01);
 
        if (states & 0x01)
            break;
 
        if (states != last_states) {
            if (states) {
                if (states & 0x20) { // up
                    led_pattern = (led_pattern + 1) % 10;
                } else if (states & 0x08) { // down
                    if (--led_pattern < 0)
                        led_pattern = 9;
                } 
 
                printf("setting LED pattern to %d\n", led_pattern);
                buf[0] = '0' + led_pattern;
                write(fd, buf, 2);
            }
 
            last_states = states ;
        }
        usleep(100*MSECS);
    }
 
    buf[0] = '1';
    write(fd, buf, 2);
    close(fd);
    printf("Bye bye.\n");
 
    return 0;
}