#include "lptgpib.h"
#include <stdio.h>
#include <string.h>
#include <poll.h>
#include <unistd.h>
#include <assert.h>
#include <sys/io.h>
#include <limits.h>

static const int zdroj_adresa=20;

// lptgpib.c
#define get_control() (inb(lpt_base+2) ^ 0x04)
#define put_control(x) outb((x) ^ 0x04, lpt_base+2)
#define TRI 0x20 /* tristate data lines */
#define NDAC 0x04 /* LPT pin 16 */
#define DAV  0x01 /* LPT pin 1  */
#define NRFD 0x02 /* LPT pin 14 */

extern int lpt_base;

int main(int argc,char **argv) {
  setbuf(stdout,NULL);
  lptgpib_init(0x378);
  int init=1;
  for (;;) {

    // GPIB -> obrazovka
    if (init) {
      lptgpib_command(UNL);
      lptgpib_command(MLA+0);
      lptgpib_command(MTA+zdroj_adresa);
      init=0;
    }
    put_control(TRI | NDAC);	/* clear NRFD */
    usleep(1000000/10);
    if (get_control()&DAV) {	/* wait for DAV */
      char flags,val=lptgpib_read_byte(&flags);
      if (!(flags&ATN))
	putchar(val);
    }
    put_control(TRI | NDAC | NRFD );  /* back to default state */
    usleep(1000000/10); /* chvili pockat, asi zbytecne, jen aby to bylo videt na portu */

    // klavesnice -> GPIB
    struct pollfd pollfd;
    memset(&pollfd,0,sizeof pollfd);
    pollfd.fd=0;
    pollfd.events=POLLIN;
    int i=poll(&pollfd,1,0);
    assert(i==0||i==1);
    if (i==1) {
      char str[LINE_MAX],*s=fgets(str,sizeof(str),stdin);
      assert(s==str);
      s=strchr(str,'\n');
      assert(s);
      assert(s[1]==0);
      *s=0;
      lptgpib_write(zdroj_adresa,str);
      init=1;
    }

  }
}