#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/select.h>
#include <stdio.h>  
#include <string.h> 
#include <fcntl.h>  
#include <errno.h>  
#include <termios.h>


int open_port(void)
{
  int fd; /* File descriptor for the port */
  
  fd = open("/dev/com4", O_RDWR | O_NOCTTY | O_NDELAY);
  if (fd == -1) {
    /*
     * Could not open the port.
     */
      
    perror("open_port: Unable to open /dev/ttyS0 - ");
  } else {
    fcntl(fd, F_SETFL, 0);
  }

  return (fd);
}


int setup_port(int fd) {
  struct termios options;

  /* get the current options */
  tcgetattr(fd, &options);

  cfsetispeed(&options, B57600);
  cfsetospeed(&options, B57600);

  /* set raw input, 1 second timeout */
  options.c_cflag |= (CLOCAL | CREAD);
  options.c_oflag &= ~OPOST;
  options.c_cc[VMIN] = 0;
  options.c_cc[VTIME] = 10;

  options.c_cflag &= ~PARENB;
  options.c_cflag &= ~CSTOPB;
  options.c_cflag &= ~CSIZE;
  options.c_cflag |= CS8;

  options.c_cflag &= ~CRTSCTS;

  options.c_cflag &= ~(IXON | IXOFF | IXANY); /* no flow control */
  options.c_cflag &= ~(IXON | IXOFF | IXANY); /* no flow control */

  options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // raw processing
  options.c_oflag &= ~OPOST; /* No output processing */
  options.c_oflag &= ~ONLCR; /* Don't convert linefeeds */

  options.c_cflag |= (CLOCAL | CREAD); /* Enable receiver, set local */
  options.c_cflag |= (IXON | IXOFF); /* Software flow control */
  options.c_lflag = 0; /* no local flags */
  options.c_cflag |= HUPCL; /* Drop DTR on close */

  /* Setup non blocking, return on 1 character */
  options.c_cc[VMIN] = 0;
  options.c_cc[VTIME] = 1;

  /* Clear the line */
  tcflush(fd,TCIFLUSH);

  if (tcsetattr(fd,TCSANOW,&options) != 0) {
    perror("coudn't setup serial port...");
    return -1;
  } else {
    return 0;
  }
}


int open_keyboard() {
  int fd;

  if (!isatty(fileno(stdout))) {
    fprintf(stderr,"You are not a terminal, OK.\n");
  }
  
  fd = open("/dev/tty", O_RDONLY | O_NONBLOCK);
  if(!fd) {
    fprintf(stderr, "Unable to open /dev/tty\n");
    exit(1);
  }

  return fd;
}


int setup_keyboard(int kb)
{
   FILE    *input;
   int      selected;
   struct termios initial_settings;
   struct termios new_settings;

   tcgetattr(kb,&initial_settings);
   new_settings = initial_settings;
   new_settings.c_lflag &= ~ICANON;
   new_settings.c_lflag &= ~ECHO;
   new_settings.c_cc[VMIN] = 1;
   new_settings.c_cc[VTIME] = 0;
   new_settings.c_lflag &= ~ISIG;
   if(tcsetattr(fileno(input), TCSANOW, &new_settings) != 0) {
     fprintf(stderr,"could not set attributes\n");
   }
   //   selected = fgetc(input);
   // tcsetattr(fileno(input),TCSANOW,&initial_settings);
   
   // fclose(input);
   // return selected;
}


int process_fd(int keyboard, int serialport)
{
  ssize_t n;
  const int MAX_READ = 1024;
  char ch;

  fcntl(keyboard, F_SETFL, FNDELAY);
  n = read(keyboard, &ch, 1);
  if (n > 0) {
    if (ch == 0x03) {
      close(keyboard);
      close(serialport);
      exit(0);
    } else {
      n = write(serialport, &ch, 1);
      if (n < 0 ) {
	perror("write() to serial port failed!\n");
	return -1;
      }
    }
  } else if (n < 0) {
    perror("read() frp, keyboard failed!\n");
    return -1;
  }

  return 0;
}


int process_socket(int keyboard, int serialport)
{
  ssize_t n;
  const int MAX_READ = 1024;
  char buf[MAX_READ];

  n = read(serialport, buf, MAX_READ);
  if (n > 0) {
    n = write(STDOUT_FILENO, buf, n);
    if (n < 0 ) {
      perror("write() failed!\n");
      return -1;
    }
  } else if (n < 0) {
    perror("read() failed!\n");
    return -1;
  }

  return 0;
}


int main(int argc, char *argv[]) {
    int            n;
    int            sock;
    int            fd;
    int            max_fd;
    fd_set         input;
    struct timeval timeout;
    char           ch;
    int            bytes_written;
    FILE*          infile;

    fd = open_keyboard();
    setup_keyboard(fd);

    sock = open_port();
    if (setup_port(sock) == -1) {
      exit(-1);
    }
    
    // if a program was supplied, then download the program to the
    // board:
    if (argc == 2) {
      printf("Downloading application %s to the board:\n", argv[1]);
      infile = fopen(argv[1], "r");
      if (!infile) {
	fprintf(stderr, "couldn't open file %s\n", argv[1]);
      }
      bytes_written = 0;
      while (fread(&ch, 1, 1, infile)) { /* read one char at a time */
	ch = write(sock, &ch, 1);
	if (ch == 0) {
	  fprintf(stderr, "couldn't write char to serial port");
	  break;
	}
	++bytes_written;
      }
      printf("wrote %d bytes to serial port\n", bytes_written);
    }

    /* Initialize the input set */
    FD_ZERO(&input);
    FD_SET(fd, &input);
    FD_SET(sock, &input);

    max_fd = (sock > fd ? sock : fd) + 1;

    /* Initialize the timeout structure */
    timeout.tv_sec  = 10;
    timeout.tv_usec = 0;

    /* Do the select */
    for (;;) {
      n = select(max_fd, &input, NULL, NULL, &timeout);
      
      /* See if there was an error */
      if (n < 0) {
	perror("select failed");
      } else {
	/* We have input */
	if (FD_ISSET(fd, &input))
	  process_fd(fd, sock);
	if (FD_ISSET(sock, &input))
	  process_socket(fd, sock);
      }

      FD_ZERO(&input);
      FD_SET(fd, &input);
      FD_SET(sock, &input);
    }

    close(fd);
    close(sock);

    return;
}