/* child.c        input buffer, fork child, main loop */

/*
 * xcheckers:     a point and click checkerboard
 * (C):           1999, 2000 Peter Chiocchetti <girbal@tacheles.de>
 *                this part from xics-2.3 bye Shirish Chinchalkar,
 *                Urban Koistinen, Nelson Minar and Patrick Surry
 */


#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <X11/Xlib.h>
#include "xcheckers.h"
#include "resource.h"
#include "status.h"
#include "read.h"
#include "events.h"


#define syserr(string) (perror(string), exit(1))
#define fatal(string) (printf("ERROR : %s\n", string), exit(1))


int             pfdout[2];


/* split engine output into lines */
static void
packbuf(char *buf, int nbytes, int icds)
{
  /* packs buffer; eliminates CR's and calls readPos[S5] */
  static char     savebuf[512];
  static int      index = 0;
  int             i;

  /* search for a CR */
  for (i = 0; i < nbytes; i++) {
    if (buf[i] != '\n' && buf[i] != (char) 13) {
      savebuf[index] = buf[i];
      index++;
    }
    if (buf[i] == '\n') {
      /* buffer ready. display it */
      savebuf[index] = '\0';
      readPos5(savebuf);
      readPosS(savebuf);
      index = 0;
    }
  }
}


/* start engine, process engine and player input */
void
loop(char *hostname, char *portnum, int icds)
{
  int             pfdin[2], nbytes;
  char            buf[512];
  char            move[80];
  int             done = 0;
  fd_set          fileSet;	/* nelson@reed.edu  */
  fd_set         *readFDs = &fileSet;	/* used for select  */
  int             xServerFD = ConnectionNumber(dpy);	/* watch here, too! */
  int             nds;
  int             childpid;
  int             rc;
  struct timeval  timeout;

  setvbuf(stdout, NULL, _IONBF, 0);

  if (pipe(pfdout) == -1 || pipe(pfdin) == -1)
    syserr("pipe");

  childpid = fork();
  switch (childpid) {
  case -1:
    syserr("fork");
    break;

  case 0:
    if (close(0) == -1)
      syserr("close");
    if (dup(pfdout[0]) != 0)
      fatal("dup");
    if (close(1) == -1)
      syserr("close");
    if (dup(pfdin[1]) != 1)
      fatal("dup");
    if (close(pfdout[0]) == -1 || close(pfdout[1]) == -1 ||
	close(pfdin[0]) == -1 || close(pfdin[1]) == -1)
      syserr("close");
    if (close(xServerFD) == -1)
      syserr("close");

    if (icds)
      execlp("telnet", "telnet", hostname, portnum, NULL);
    else
      execlp("sh", "sh", "-c", hostname, NULL);
    syserr("execlp");
  }

  if (close(pfdout[0]) == -1 || close(pfdin[1]) == -1)
    syserr("close");

  /*
   * main read loop for the program. Look for things from the keyboard, from
   * telnet, or from the X server. nelson@reed.edu - replace original non
   * blocking IO with regular blocking IO, by calling select() to allow for
   * multiple input sources. this is much more efficient and fixes bugs.
   */

  nds = (pfdin[0] > xServerFD ? pfdin[0] : xServerFD) + 1;

  while (!done) {
    FD_ZERO(readFDs);		/* nelson@reed.edu       */
    FD_SET(0, readFDs);		/* we care about these 3 */
    FD_SET(pfdin[0], readFDs);	/* file descriptors      */
    FD_SET(xServerFD, readFDs);	/* kbd, telnet, and X    */

    checkClock();
    timeout.tv_sec = 1;
    timeout.tv_usec = 0;

    rc = select(nds, readFDs, 0, 0, &timeout);	/* wait for input */
    if (rc < 0)
      syserr("select");

    if (FD_ISSET(0, readFDs)) {
      nbytes = read(0, buf, sizeof(buf));
      if (nbytes <= 0)
	syserr("read stdin");
      if (write(pfdout[1], buf, nbytes) == -1)
	syserr("pfdout[1]");
    }
    if (FD_ISSET(pfdin[0], readFDs)) {
      nbytes = read(pfdin[0], buf, sizeof(buf));
      if (nbytes == 0) {
	if (icds)
	  fprintf(stderr, "%s: Server hung up!\n",
		  progname);
	else
	  fprintf(stderr, "%s: Engine shut down!\n",
		  progname);
	return;
      } else if (nbytes < 0) {
	syserr("read pfdin[0]");
      }
      if (write(1, buf, nbytes) == -1)
	syserr("write stdout");
      packbuf(buf, nbytes, icds);
    }
    if (FD_ISSET(xServerFD, readFDs)) {
      if (events(move)) {
	/*
	 * made a move. print it on the screen and
	 * send it to ICS
	 */
	if (strcmp(move, "exit") == 0) {
	  fprintf(stdout, "\n");
	  done = 1;		/* will exit soon */
	} else {
	  fprintf(stdout, "%s", move);
	  fflush(stdout);
	  nbytes = strlen(move);
	  if (write(pfdout[1], move, nbytes) == -1)
	    syserr("write");
	}
      }
    }
  }

  if (close(pfdin[0]) == -1)
    syserr("close");
  if (close(pfdout[1]) == -1)
    syserr("close");		/* telnet quits */

  /* in case telnet is still alive, kill it */
  if (!kill(childpid, SIGKILL))
    waitpid(childpid, NULL, 0);
}


/* send a string to the engine */
void
message(char *mess)
{
  int             nbytes = strlen(mess);

  fprintf(stdout, "%s", mess);
  fflush(stdout);
  if (write(pfdout[1], mess, nbytes) == -1)
    syserr("write");
  free(mess);
}