/*
 * isotpterm.c - interactive terminal over isotp
 */

#include <errno.h>
#include <libgen.h>
#include <linux/can.h>
#include <linux/can/isotp.h>
#include <net/if.h>
#include <netinet/in.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#define NO_CAN_ID 0xFFFFFFFFU
#define MAX_PDU_LENGTH 8000

void print_usage(char *prg) {
  fprintf(stderr,
          "\nUsage: %s -s <can_id> -d <can_id> [options] <CAN interface>\n",
          prg);
  fprintf(stderr, "Options:\n");
  fprintf(stderr,
          "         -s <can_id>  * (source can_id. Use 8 digits for extended "
          "IDs)\n");
  fprintf(stderr,
          "         -d <can_id>  * (destination can_id. Use 8 digits for "
          "extended IDs)\n");
  fprintf(stderr, "\n");
}

int main(int argc, char **argv) {
  extern int optind, opterr, optopt;
  int opt;

  int sc = 0; /* (C)AN socket */
  struct sockaddr_can caddr;
  static struct can_isotp_options opts;

  socklen_t caddrlen = sizeof(caddr);
  fd_set readfds;

  int nbytes;
  int ret = 0;
  char *fgetsret = NULL;

  char txmsg[MAX_PDU_LENGTH];
  char rxmsg[MAX_PDU_LENGTH];

  /* mark missing mandatory commandline options as missing */
  caddr.can_addr.tp.tx_id = caddr.can_addr.tp.rx_id = NO_CAN_ID;

  while ((opt = getopt(argc, argv, "s:d:?")) != -1) {
    switch (opt) {
      case 's':
        caddr.can_addr.tp.tx_id = strtoul(optarg, (char **)NULL, 16);
        if (strlen(optarg) > 7) caddr.can_addr.tp.tx_id |= CAN_EFF_FLAG;
        break;

      case 'd':
        caddr.can_addr.tp.rx_id = strtoul(optarg, (char **)NULL, 16);
        if (strlen(optarg) > 7) caddr.can_addr.tp.rx_id |= CAN_EFF_FLAG;
        break;

      case '?':
        print_usage(basename(argv[0]));
        ret = 1; /* no proper operation (for non-interactive users) */
        goto exit;

      default:
        fprintf(stderr, "Unknown option %c\n", opt);
        print_usage(basename(argv[0]));
        ret = 1;
        goto exit;
    }
  }

  if ((argc - optind != 1) || (caddr.can_addr.tp.tx_id == NO_CAN_ID) ||
      (caddr.can_addr.tp.rx_id == NO_CAN_ID)) {
    print_usage(basename(argv[0]));
    ret = -EINVAL;
    goto exit;
  }

  if ((sc = socket(PF_CAN, SOCK_DGRAM, CAN_ISOTP)) < 0) {
    perror("socket");
    ret = sc;
    goto exit;
  }

  opts.flags = CAN_ISOTP_WAIT_TX_DONE;
  setsockopt(sc, SOL_CAN_ISOTP, CAN_ISOTP_OPTS, &opts, sizeof(opts));

  caddr.can_family = AF_CAN;
  caddr.can_ifindex = if_nametoindex(argv[optind]);

  ret = bind(sc, (struct sockaddr *)&caddr, caddrlen);
  if (ret < 0) {
    perror("bind");
    goto exit;
  }

  while (1) {
    FD_ZERO(&readfds);
    FD_SET(STDIN_FILENO, &readfds);
    FD_SET(sc, &readfds);

    ret = select(sc + 1, &readfds, NULL, NULL, NULL);
    if (ret < 0) {
      perror("select");
      goto exit;
    }

    if (FD_ISSET(sc, &readfds)) {
      nbytes = read(sc, rxmsg, MAX_PDU_LENGTH - 1);

      if (nbytes < 1) {
        perror("read from isotp socket");
        ret = nbytes;
        goto exit;
      }

      rxmsg[nbytes] = 0; /* terminate string */
      printf("%s", rxmsg);

      if(strncmp(rxmsg, "\nwopr", 4)==0){
	      send(sc, "falken\n", 7 , 0);
      }
      if(strncmp(rxmsg, "pass", 4)==0){
	      send(sc, "Joshua\n", 7 , 0);
      }
      char *s = strstr(rxmsg, "Test#");
      char c;
      int j = 0;
      if(s){
	      printf("detected: %c\n", s[18]);
	      c = s[18];
	      while(s[0] != '\n')
		      s++;

	      s = strstr(rxmsg, "\n'");
	      for(int i=0; i<strlen(s); i++)
		      if(s[i] == c)
			      j++;

	      char msg[10];
	      sprintf(msg, "%d\n", j);
	      printf("aswering: %d\n", j);

	      send(sc, msg, strlen(msg)+1, 0);
      }
      
      fflush(stdout);

    } else if (FD_ISSET(STDIN_FILENO, &readfds)) {
      fgetsret = fgets(txmsg, MAX_PDU_LENGTH, stdin);
      if (fgetsret == NULL) {
        ret = 0;
        goto exit;
      }

      nbytes = send(sc, txmsg, strlen(txmsg) + 1, 0);
      if (nbytes != strlen(txmsg) + 1) {
        perror("write to isotp socket");
        ret = nbytes;
        goto exit;
      }
    }
  }

exit:
  close(sc);

  return ret;
}