/*

	 @@@        @@@    @@@@@@@@@@     @@@@@@@@@@@    @@@@@@@@@@@@
	 @@@        @@@   @@@@@@@@@@@@    @@@@@@@@@@@@   @@@@@@@@@@@@@
	 @@@        @@@  @@@@      @@@@   @@@@           @@@@ @@@  @@@@
	 @@@   @@   @@@  @@@        @@@   @@@            @@@  @@@   @@@
	 @@@  @@@@  @@@  @@@        @@@   @@@            @@@  @@@   @@@
	 @@@@ @@@@ @@@@  @@@        @@@   @@@            @@@  @@@   @@@
	  @@@@@@@@@@@@   @@@@      @@@@   @@@            @@@  @@@   @@@
	   @@@@  @@@@     @@@@@@@@@@@@    @@@            @@@  @@@   @@@
	    @@    @@       @@@@@@@@@@     @@@            @@@  @@@   @@@

				 Eric P. Scott
			  Caltech High Energy Physics
				 October, 1980

*/

#ifdef SLANG
#include "slcurses.h"
#else
#include <curses.h>
#define MALLOC malloc
#endif
#include <stdio.h>
#include <signal.h>

#ifndef NO_STDLIB_H
#include <stdlib.h>
#endif

unsigned char *safe_malloc (unsigned int size)
{
   unsigned char *p;
   p = MALLOC (size);
   if (p == NULL)
     {
	fprintf(stderr, "Malloc error.");
	exit (-1);
     }
   
   return p;
}


#define cursor(col,row) move(row,col)

int Wrap;
short *ref[128];
static char flavor[]={
   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
   'A', 'B', 'C', 'D', 'E', 'F'
};
static short xinc[]={
     1,  1,  1,  0, -1, -1, -1,  0
}, yinc[]={
    -1,  0,  1,  1,  1,  0, -1, -1
};
static struct worm {
    int orientation, head;
    short *xpos, *ypos;
} worm[40];
static char *field;
static int length=16, number=3, trail=' ';
static struct options {
    int nopts;
    int opts[3];
} normal[8]={
    { 3, { 7, 0, 1 } },
    { 3, { 0, 1, 2 } },
    { 3, { 1, 2, 3 } },
    { 3, { 2, 3, 4 } },
    { 3, { 3, 4, 5 } },
    { 3, { 4, 5, 6 } },
    { 3, { 5, 6, 7 } },
    { 3, { 6, 7, 0 } }
}, upper[8]={
    { 1, { 1, 0, 0 } },
    { 2, { 1, 2, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 2, { 4, 5, 0 } },
    { 1, { 5, 0, 0 } },
    { 2, { 1, 5, 0 } }
}, left[8]={
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 2, { 2, 3, 0 } },
    { 1, { 3, 0, 0 } },
    { 2, { 3, 7, 0 } },
    { 1, { 7, 0, 0 } },
    { 2, { 7, 0, 0 } }
}, right[8]={
    { 1, { 7, 0, 0 } },
    { 2, { 3, 7, 0 } },
    { 1, { 3, 0, 0 } },
    { 2, { 3, 4, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 2, { 6, 7, 0 } }
}, lower[8]={
    { 0, { 0, 0, 0 } },
    { 2, { 0, 1, 0 } },
    { 1, { 1, 0, 0 } },
    { 2, { 1, 5, 0 } },
    { 1, { 5, 0, 0 } },
    { 2, { 5, 6, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }
}, upleft[8]={
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 1, { 3, 0, 0 } },
    { 2, { 1, 3, 0 } },
    { 1, { 1, 0, 0 } }
}, upright[8]={
    { 2, { 3, 5, 0 } },
    { 1, { 3, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 1, { 5, 0, 0 } }
}, lowleft[8]={
    { 3, { 7, 0, 1 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 1, { 1, 0, 0 } },
    { 2, { 1, 7, 0 } },
    { 1, { 7, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }
}, lowright[8]={
    { 0, { 0, 0, 0 } },
    { 1, { 7, 0, 0 } },
    { 2, { 5, 7, 0 } },
    { 1, { 5, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }
};

static void onsig (int);
static float ranf (void);

int main(int argc, char *argv[])
{
int x, y;
int n;
struct worm *w;
struct options *op;
int h;
short *ip;
int last, bottom;
int counts = -1;
   
    for (x=1;x<argc;x++) {
		register char *p;
		p=argv[x];
		if (*p=='-') p++;
		switch (*p) {
		case 'f':
		    field="WORM";
		    break;
		case 'l':
		    if (++x==argc) goto usage;
		    if ((length=atoi(argv[x]))<2||length>1024) {
				fprintf(stderr,"%s: Invalid length\n",*argv);
				exit(1);
		    }
		    break;
		case 'n':
		    if (++x==argc) goto usage;
		    if ((number=atoi(argv[x]))<1||number>40) {
				fprintf(stderr,"%s: Invalid number of worms\n",*argv);
				exit(1);
		    }
		    break;
		case 't':
		    trail='.';
		    break;
		default:
		usage:
		    fprintf(stderr, "usage: %s [-field] [-length #] [-number #] [-trail]\n",*argv);
		    exit(1);
		    break;
		}
    }

#ifdef SLANG
   SLang_init_tty (7, 0, 0);
   SLtt_init_video ();
#endif
#ifdef SIGINT
    signal(SIGINT, onsig);
#endif
   
#ifdef SLANG
   SLtt_Use_Ansi_Colors = 1;
#endif
   
    initscr();
    bottom = LINES-1;
    last = COLS-1;

    ip=(short *)safe_malloc(LINES*COLS*sizeof (short));

    for (n=0;n<LINES;) {
		ref[n++]=ip; ip+=COLS;
    }
    for (ip=ref[0],n=LINES*COLS;--n>=0;) *ip++=0;
    ref[bottom][last]=0;
    for (n=number, w= &worm[0];--n>=0;w++) {
		w->orientation=w->head=0;
		if (!(ip=(short *)safe_malloc(length*sizeof (short)))) {
		    fprintf(stderr,"%s: out of memory\n",*argv);
		    exit(1);
		}
		w->xpos=ip;
		for (x=length;--x>=0;) *ip++ = -1;
		if (!(ip=(short *)safe_malloc(length*sizeof (short)))) {
		    fprintf(stderr,"%s: out of memory\n",*argv);
		    exit(1);
		}
		w->ypos=ip;
		for (y=length;--y>=0;) *ip++ = -1;
    }
    if (field) {
		register char *p;
		p=field;
		for (y=bottom;--y>=0;) {
		    for (x=COLS;--x>=0;) {
				addch(*p++);
				if (!*p) p=field;
		    }
		   move(y, 0);
        }
    }
   refresh();

   while (counts--) 
     {
	for (n=0, w = &worm[0]; n < number;n++,w++) 
	  {
#ifdef SLANG
	     SLsmg_set_color (n % 16);
#endif
	     /* Worm starts at bottom left */
	     if ((x=w->xpos[h=w->head])<0) 
	       {
		  cursor(x=w->xpos[h]=0,y=w->ypos[h]=bottom);
		  addch(flavor[n%16]);
		  ref[y][x]++;
	       }
	     else y=w->ypos[h];
	     
	     if (++h==length) h=0;
	     
	     if (w->xpos[w->head=h]>=0) 
	       {
		  /* No need to worry about ypos since it is greater than 
		   * zero from above */
		  register int x1, y1;
		  x1=w->xpos[h]; y1=w->ypos[h];
		  if (--ref[y1][x1]==0) 
		    {
		       cursor(x1,y1); 
#ifdef SLANG
		       SLsmg_set_color (0);
#endif
		       addch(trail);
#ifdef SLANG
		       SLsmg_set_color (n % 16);
#endif
		    }
	       }
	     
	     op= &(x==0 ? (y==0 ? upleft : (y==bottom ? lowleft : left)) :
                (x==last ? (y==0 ? upright : (y==bottom ? lowright : right)) :
			(y==0 ? upper : (y==bottom ? lower : normal))))[w->orientation];
	     switch (op->nopts) 
	       {
		case 0:
		  refresh();
		  endwin();
		  abort();
		  return -1;
		case 1:
		  w->orientation=op->opts[0];
		  break;
		default:
		  w->orientation=op->opts[(int)(ranf()*(float)op->nopts)];
	       }
	     
	     cursor(x += xinc[w->orientation], y += yinc[w->orientation]);
	     if (!Wrap || x!=last || y!=bottom)
	       {
		  addch(flavor[n%16]);
	       }
		   
	     ref[w->ypos[h]=y][w->xpos[h]=x]++;
	  }
	refresh();
#ifdef SLANG
	if (SLang_input_pending (1)) break;
#endif
     }
   refresh ();
   onsig (0);
   return 0;
}

static void onsig (int sig)
{
   endwin();
#ifdef SLANG
   SLtt_reset_video ();
   SLtt_del_eol ();
   SLang_reset_tty ();
#endif
   exit (sig);
}

static float ranf(void)
{
    float rv;
    long r = rand();

    r &= 077777;
    rv =((float)r/32767.);
    return rv;
}