/*
 * Code for one object to chase another
 *
 * Advanced Rogue
 * Copyright (C) 1984, 1985 Michael Morgan, Ken Dalka and AT&T
 * All rights reserved.
 *
 * Based on "Rogue: Exploring the Dungeons of Doom"
 * Copyright (C) 1980, 1981 Michael Toy, Ken Arnold and Glenn Wichman
 * All rights reserved.
 *
 * See the file LICENSE.TXT for full copyright and licensing information.
 */

#include <ctype.h>
#include <limits.h>
#include "curses.h"
#include "rogue.h"
#define	MAXINT	INT_MAX
#define	MININT	INT_MIN

coord ch_ret;				/* Where chasing takes you */





/*
 * Canblink checks if the monster can teleport (blink).  If so, it will
 * try to blink the monster next to the player.
 */

bool
can_blink(tp)
register struct thing *tp;
{
    register int y, x, index=9;
    coord tryp;	/* To hold the coordinates for use in diag_ok */
    bool spots[9], found_one=FALSE;

    /*
     * First, can the monster even blink?  And if so, there is only a 50%
     * chance that it will do so.  And it won't blink if it is running or
     * held.
     */
    if (off(*tp, CANBLINK) || (on(*tp, ISHELD)) ||
	on(*tp, ISFLEE) ||
	(on(*tp, ISSLOW) && off(*tp, ISHASTE) && !(tp->t_turn)) ||
	tp->t_no_move ||
	(rnd(12) < 6)) return(FALSE);


    /* Initialize the spots as illegal */
    do {
	spots[--index] = FALSE;
    } while (index > 0);

    /* Find a suitable spot next to the player */
    for (y=hero.y-1; y<hero.y+2; y++)
	for (x=hero.x-1; x<hero.x+2; x++, index++) {
	    /* Make sure x coordinate is in range and that we are
	     * not at the player's position
	     */
	    if (x<0 || x >= COLS || index == 4) continue;

	    /* Is it OK to move there? */
	    if (step_ok(y, x, NOMONST, tp) &&
		(!isatrap(mvwinch(cw, y, x)) ||
		  rnd(10) >= tp->t_stats.s_intel ||
		  on(*tp, ISFLY))) {
		/* OK, we can go here.  But don't go there if
		 * monster can't get at player from there
		 */
		tryp.y = y;
		tryp.x = x;
		if (diag_ok(&tryp, &hero, tp)) {
		    spots[index] = TRUE;
		    found_one = TRUE;
		}
	    }
	}

    /* If we found one, go to it */
    if (found_one) {
	char rch;	/* What's really where the creatures moves to */

	/* Find a legal spot */
	while (spots[index=rnd(9)] == FALSE) continue;

	/* Get the coordinates */
	y = hero.y + (index/3) - 1;
	x = hero.x + (index % 3) - 1;

	/* Move the monster from the old space */
	mvwaddch(cw, tp->t_pos.y, tp->t_pos.x, tp->t_oldch);

	/* Move it to the new space */
	tp->t_oldch = CCHAR( mvwinch(cw, y, x) );

	/* Display the creature if our hero can see it */
	if (cansee(y, x) &&
	    off(*tp, ISINWALL) &&
	    !invisible(tp))
	    mvwaddch(cw, y, x, tp->t_type);

	/* Fix the monster window */
	mvwaddch(mw, tp->t_pos.y, tp->t_pos.x, ' '); /* Clear old position */
	mvwaddch(mw, y, x, tp->t_type);

	/* Record the new position */
	tp->t_pos.y = y;
	tp->t_pos.x = x;

	/* If the monster is on a trap, trap it */
	rch = CCHAR( mvinch(y, x) );
	if (isatrap(rch)) {
	    if (cansee(y, x)) tp->t_oldch = rch;
	    be_trapped(tp, &(tp->t_pos));
	}
    }

    return(found_one);
}

/* 
 * Can_shoot determines if the monster (er) has a direct line of shot 
 * at the player (ee).  If so, it returns the direction in which to shoot.
 */

coord *
can_shoot(er, ee)
register coord *er, *ee;
{
    static coord shoot_dir;

    /* Make sure we are chasing the player */
    if (!ce((*ee), hero)) return(NULL);

    /* 
     * They must be in the same room or very close (at door)
     */
    if (roomin(er) != roomin(&hero) && DISTANCE(er->y,er->x,ee->y,ee->x) > 1)
	return(NULL);

    /* Do we have a straight shot? */
    if (!straight_shot(er->y, er->x, ee->y, ee->x, &shoot_dir)) return(NULL);
    else return(&shoot_dir);
}

/*
 * chase:
 *	Find the spot for the chaser(er) to move closer to the
 *	chasee(ee).  Returns TRUE if we want to keep on chasing later
 *	FALSE if we reach the goal.
 */

chase(tp, ee, flee, mdead)
register struct thing *tp;
register coord *ee;
bool flee; /* True if destination (ee) is player and monster is running away
	    * or the player is in a wall and the monster can't get to it
	    */
bool *mdead;
{
    int damage, dist, thisdist, monst_dist = MAXINT; 
    struct linked_list *weapon;
    register coord *er = &tp->t_pos; 
    coord *shoot_dir;
    char ch, mch;
    bool next_player = FALSE;

    if (mdead != NULL)
	*mdead = 0;

    /*