// SPDX-License-Identifier: GPL-2.0
/*
 * Hidraw Userspace Example
 *
 * Copyright (c) 2010 Alan Ott <alan@signal11.us>
 * Copyright (c) 2010 Signal 11 Software
 *
 * The code may be used by anyone for any purpose,
 * and can serve as a starting point for developing
 * applications using hidraw.
 */

/* Linux */
#include <linux/types.h>
#include <linux/input.h>
#include <linux/hidraw.h>

/* Unix */
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

/* C */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <stdint.h>


typedef struct
{
  uint8_t r;
  uint8_t g;
  uint8_t b;
} C;

#define N_LEDS	9

static unsigned map[N_LEDS]={2,1,0,3,4,5,8,7,6};

C current[N_LEDS];
C last[N_LEDS];


void
sync_leds (int fd)
{
  unsigned i;
  uint8_t buf[8];

  for (i = 0; i < N_LEDS; ++i)
    {
      /* Send a Report to the Device */
      if ((last[i].r != current[i].r)
          || (last[i].g != current[i].g) || (last[i].b != current[i].b))
        {
          buf[0] = 0x05;
          buf[1] = map[i];
          buf[2] = current[i].r;
          buf[3] = current[i].g;
          buf[4] = current[i].b;
          write (fd, buf, 8);
          last[i] = current[i];
        }
    }
}

unsigned f(int v)
{
v-=5;
if (v<0) return 0;
return v;
}


void fade_leds(int fd)
{
unsigned i;
  for (i = 0; i < N_LEDS; ++i)
    {
	current[i].r=f(current[i].r);
	current[i].g=f(current[i].g);
	current[i].b=f(current[i].b);

	}

	sync_leds(fd);

}

int
open_kb (int *fds)
{
  struct hidraw_devinfo info;
  unsigned i;
  int n = 0;
  for (i = 0; i < 128; ++i)
    {
      int fd;
      char device[128];
      char buf[128];
      sprintf (device, "/dev/hidraw%d", i);
      fd = open (device, O_RDWR | O_NONBLOCK);
      if (fd < 0)
        continue;

      memset (buf, 0, sizeof (buf));
      ioctl (fd, HIDIOCGRAWNAME (256), buf);
      buf[sizeof (buf) - 1] = 0;


      if (strcmp (buf, "YMDK YMD09_32A"))
        {
          close (fd);
          fd = -1;
          continue;
        }

      fds[n++] = fd;

    }


  if (n < 2)
    {
      printf ("Devices not found\n");
      return -1;
    }
  return 0;
}

int
main (int argc, char **argv)
{
  int fds[2];
  fd_set rfds;
  ssize_t len;
  char buf[32];
  struct timeval tv;

  unsigned j, k;

  memset (last, 0xff, sizeof (last));

  if (open_kb (fds))
    return -1;


current[4].g=0xff;

  FD_ZERO (&rfds);
  sync_leds (fds[1]);

	tv.tv_sec=0;
tv.tv_usec=0;

  for (;;)
    {
      FD_SET (fds[0], &rfds);

	if (!tv.tv_usec) 
		tv.tv_usec=20000;
	
      switch (select (fds[0] + 1, &rfds, NULL, NULL, &tv))
        {
        case -1:
          break;
        case 1:

          len = read (fds[0], buf, sizeof (buf));
	  
          if (len < 3)
            break;

          for (j = 2; j < len; ++j)
            {
	if (!buf[j]) continue;
              k = buf[j] - 4;


              current[k].r = rand() & 0xff ;
              current[k].g = rand() & 0xff ;
              current[k].b = rand() & 0xff ;
            }

          sync_leds (fds[1]);

          break;
	case 0:
	  fade_leds(fds[1]);
        }

    }

  close (fds[1]);
  close (fds[0]);
  return 0;
}