#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdint.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <pthread.h>
#include <errno.h>

#include <linux/dvb/mod.h>

int main(int argc, char* argv[])
{
  int fd;
  struct dvb_mod_params mp;
  struct dvb_mod_channel_params mc;

  if (argc != 7)
  {
    printf("Usage: device base_frequency[Hz] attenuation[dB]"
      " modulation[qam_16, qam32, qam_64, qam_128, qam256] pcr_correction[1/0]"
      " bitrate[bps]\n");
    exit(EXIT_FAILURE);
  }

  char *device = argv[1];
  uint32_t base_freq = strtoul(argv[2], NULL, 10);
  if (base_freq < 114000000 || base_freq > 794000000)
  {
    printf("Invalid frequency \'%i\'\n", base_freq);
    exit(EXIT_FAILURE);
  }
  uint32_t attenuation = strtoul(argv[3], NULL, 10);

  enum fe_modulation modulation;
  char *modulation_str = argv[4];
  if (strcmp(modulation_str, "qam_16") == 0)
  {
    modulation = QAM_16;
  }
  else if (strcmp(modulation_str, "qam_32") == 0)
  {
    modulation = QAM_32;
  }
  else if (strcmp(modulation_str, "qam_64") == 0)
  {
    modulation = QAM_64;
  }
  else if (strcmp(modulation_str, "qam_128") == 0)
  {
    modulation = QAM_128;
  }
  else if (strcmp(modulation_str, "qam_256") == 0)
  {
    modulation = QAM_256;
  }
  else
  {
    printf("Invalid modulation \'%s\'\n", modulation_str);
    exit(EXIT_FAILURE);
  }
  int pcr_correction = strtoul(argv[5], NULL, 10);
  uint64_t bitrate = strtoul(argv[6], NULL, 10);

  fd = open(device, O_RDONLY);
  if (fd == -1)
  {
    printf("Invalid device \'%s\': %s\n", device, strerror(errno));
    exit(EXIT_FAILURE);
  }

  printf("Setting base_freq=%u attenuation=%u modulation=%s, pcr_correction=%d"
    "input_bitrate=%u on %s\n",
    base_freq, attenuation, modulation_str, pcr_correction, bitrate, device);

  mp.base_frequency = base_freq;
  mp.attenuator = attenuation;
  ioctl(fd, DVB_MOD_SET, &mp);

  mc.modulation = modulation;
  mc.input_bitrate = bitrate << 32;
  mc.pcr_correction = pcr_correction;
  if (ioctl(fd, DVB_MOD_CHANNEL_SET, &mc) != 0)
  {
    printf("Invalid options: %s\n", strerror(errno));
    exit(EXIT_FAILURE);
  }
  close(fd);
}