/*	SCCS Id: @(#)teleport.c	3.3	1999/11/27	*/
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/* NetHack may be freely redistributed.  See license for details. */

#include "hack.h"

STATIC_DCL boolean FDECL(tele_jump_ok, (int,int,int,int));
STATIC_DCL boolean FDECL(teleok, (int,int,BOOLEAN_P));
STATIC_DCL void NDECL(vault_tele);
STATIC_DCL boolean FDECL(rloc_pos_ok, (int,int,struct monst *));
STATIC_DCL void FDECL(mvault_tele, (struct monst *));

/*
 * Is (x,y) a good position of mtmp?  If mtmp is NULL, then is (x,y) good
 * for an object?
 *
 * This function will only look at mtmp->mdat, so makemon, mplayer, etc can
 * call it to generate new monster positions with fake monster structures.
 */
boolean
goodpos(x, y, mtmp)
int x,y;
struct monst *mtmp;
{
	struct permonst *mdat = NULL;

	if (!isok(x, y)) return FALSE;

	/* in many cases, we're trying to create a new monster, which
	 * can't go on top of the player or any existing monster.
	 * however, occasionally we are relocating engravings or objects,
	 * which could be co-located and thus get restricted a bit too much.
	 * oh well.
	 */
	if (mtmp != &youmonst && x == u.ux && y == u.uy
#ifdef STEED
			&& (!u.usteed || mtmp != u.usteed)
#endif
			)
		return FALSE;

	if (mtmp) {
	    struct monst *mtmp2 = m_at(x,y);

	    if (mtmp2 && mtmp2 != mtmp)
		return FALSE;

	    mdat = mtmp->data;
	    if (is_pool(x,y)) {
		if (mtmp == &youmonst)
			return !!(HLevitation || Flying || Wwalking ||
					Swimming || Amphibious);
		else	return (is_flyer(mdat) || is_swimmer(mdat) ||
							is_clinger(mdat));
	    } else if (mdat->mlet == S_EEL && rn2(13)) {
		return FALSE;
	    } else if (is_lava(x,y)) {
		if (mtmp == &youmonst)
		    return !!HLevitation;
		else
		    return (is_flyer(mdat) || likes_lava(mdat));
	    }
	    if (passes_walls(mdat) && may_passwall(x,y)) return TRUE;
	}
	if (!ACCESSIBLE(levl[x][y].typ)) return FALSE;
	if (closed_door(x, y) && (!mdat || !amorphous(mdat)))
		return FALSE;
	if (sobj_at(BOULDER, x, y) && (!mdat || !throws_rocks(mdat)))
		return FALSE;
	return TRUE;
}

/*
 * "entity next to"
 *
 * Attempt to find a good place for the given monster type in the closest
 * position to (xx,yy).  Do so in successive square rings around (xx,yy).
 * If there is more than one valid positon in the ring, choose one randomly.
 * Return TRUE and the position chosen when successful, FALSE otherwise.
 */
boolean
enexto(cc, xx, yy, mdat)
coord *cc;
register xchar xx, yy;
struct permonst *mdat;
{
#define MAX_GOOD 15
    coord good[MAX_GOOD], *good_ptr;
    int x, y, range, i;
    int xmin, xmax, ymin, ymax;
    struct monst fakemon;	/* dummy monster */

    if (!mdat) {
#ifdef DEBUG
	pline("enexto() called with mdat==0");
#endif
	/* default to player's original monster type */
	mdat = &mons[u.umonster];
    }
    fakemon.data = mdat;	/* set up for goodpos */
    good_ptr = good;
    range = 1;
    /*
     * Walk around the border of the square with center (xx,yy) and
     * radius range.  Stop when we find at least one valid position.
     */
    do {
	xmin = max(1, xx-range);
	xmax = min(COLNO-1, xx+range);
	ymin = max(0, yy-range);
	ymax = min(ROWNO-1, yy+range);

	for (x = xmin; x <= xmax; x++)
	    if (goodpos(x, ymin, &fakemon)) {
		good_ptr->x = x;
		good_ptr->y = ymin ;
		/* beware of accessing beyond segment boundaries.. */
		if (good_ptr++ == &good[MAX_GOOD-1]) goto full;
	    }
	for (x = xmin; x <= xmax; x++)
	    if (goodpos(x, ymax, &fakemon)) {
		good_ptr->x = x;
		good_ptr->y = ymax ;
		/* beware of accessing beyond segment boundaries.. */
		if (good_ptr++ == &good[MAX_GOOD-1]) goto full;
	    }
	for (y = ymin+1; y < ymax; y++)
	    if (goodpos(xmin, y, &fakemon)) {
		good_ptr->x = xmin;
		good_ptr-> y = y ;
		/* beware of accessing beyond segment boundaries.. */
		if (good_ptr++ == &good[MAX_GOOD-1]) goto full;
	    }
	for (y = ymin+1; y < ymax; y++)
	    if (goodpos(xmax, y, &fakemon)) {
		good_ptr->x = xmax;
		good_ptr->y = y ;
		/* beware of accessing beyond segment boundaries.. */
		if (good_ptr++ == &good[MAX_GOOD-1]) goto full;
	    }
	range++;

	/* return if we've grown too big (nothing is valid) */
	if (range > ROWNO && range > COLNO) return FALSE;
    } while (good_ptr == good);

full:
    i = rn2((int)(good_ptr - good));
    cc->x = good[i].x;
    cc->y = good[i].y;
    return TRUE;
}

/*
 * Check for restricted areas present in some special levels.  (This might
 * need to be augmented to allow deliberate passage in wizard mode, but
 * only for explicitly chosen destinations.)
 */
STATIC_OVL boolean
tele_jump_ok(x1, y1, x2, y2)
int x1, y1, x2, y2;
{
	if (dndest.nlx > 0) {
	    /* if inside a restricted region, can't teleport outside */
	    if (within_bounded_area(x1, y1, dndest.nlx, dndest.nly,
						dndest.nhx, dndest.nhy) &&
		!within_bounded_area(x2, y2, dndest.nlx, dndest.nly,
						dndest.nhx, dndest.nhy))
		return FALSE;
	    /* and if outside, can't teleport inside */
	    if (!within_bounded_area(x1, y1, dndest.nlx, dndest.nly,
						dndest.nhx, dndest.nhy) &&
		within_bounded_area(x2, y2, dndest.nlx, dndest.nly,
						dndest.nhx, dndest.nhy))
		return FALSE;
	}
	if (updest.nlx > 0) {		/* ditto */
	    if (within_bounded_area(x1, y1, updest.nlx, updest.nly,
						updest.nhx, updest.nhy) &&
		!within_bounded_area(x2, y2, updest.nlx, updest.nly,
						updest.nhx, updest.nhy))
		return FALSE;
	    if (!within_bounded_area(x1, y1, updest.nlx, updest.nly,
						updest.nhx, updest.nhy) &&
		within_bounded_area(x2, y2, updest.nlx, updest.nly,
						updest.nhx, updest.nhy))
		return FALSE;
	}
	return TRUE;
}

STATIC_OVL boolean
teleok(x, y, trapok)
register int x, y;
boolean trapok;
{
	if (!trapok && t_at(x, y)) return FALSE;
	if (!goodpos(x, y, &youmonst)) return FALSE;
	if (!tele_jump_ok(u.ux, u.uy, x, y)) return FALSE;
	return TRUE;
}

void
teleds(nux, nuy)
register int nux,nuy;
{
	if (Punished) unplacebc();
	u.utrap = 0;
	u.ustuck = 0;
	u.ux0 = u.ux;
	u.uy0 = u.uy;
	u.ux = nux;
	u.uy = nuy;
	fill_pit(u.ux0, u.uy0); /* do this now so that cansee() is correct */

	if (hides_under(youmonst.data))
		u.uundetected = OBJ_AT(nux, nuy);
	else if (youmonst.data->mlet == S_EEL)
		u.uundetected = is_pool(u.ux, u.uy);
	else {
		u.uundetected = 0;
		/* mimics stop being unnoticed */
		if (youmonst.data->mlet == S_MIMIC)
		    youmonst.m_ap_type = M_AP_NOTHING;
	}

	if (u.uswallow) {
		u.uswldtim = u.uswallow = 0;
		docrt();
	}
	if (Punished) placebc();
	initrack(); /* teleports mess up tracking monsters without this */
	update_player_regions();
#ifdef STEED
	/* Move your steed, too */
	if (u.usteed) {
		u.usteed->mx = nux;
		u.usteed->my = nuy;
	}
#endif
	/*
	 *  Make sure the hero disappears from the old location.  This will
	 *  not happen if she is teleported within sight of her previous
	 *  location.  Force a full vision recalculation because the hero
	 *  is now in a new location.
	 */
	newsym(u.ux0,u.uy0);
	vision_full_recalc = 1;
	nomul(0);
	spoteffects();
	invocation_message();
}

boolean
safe_teleds()
{
	register int nux, nuy, tcnt = 0;

	do {
		nux = rnd(COLNO-1);
		nuy = rn2(ROWNO);
	} while (!teleok(nux, nuy, (boolean)(tcnt > 200)) && ++tcnt <= 400);

	if (tcnt <= 400) {
		teleds(nux, nuy);
		return TRUE;
	} else
		return FALSE;
}

STATIC_OVL void
vault_tele()
{
	register struct mkroom *croom = search_special(VAULT);
	coord c;

	if (croom && somexy(croom, &c) && teleok(c.x,c.y,FALSE)) {
		teleds(c.x,c.y);
		return;
	}
	tele();
}

boolean
teleport_pet(mtmp, force_it)
register struct monst *mtmp;
boolean force_it;
{
	register struct obj *otmp;

#ifdef STEED
	if (mtmp == u.usteed)
		return (FALSE);
#endif

	if (mtmp->mleashed) {
	    otmp = get_mleash(mtmp);
	    if (!otmp) {
		impossible("%s is leashed, without a leash.", Monnam(mtmp));
		goto release_it;
	    }
	    if (otmp->cursed && !force_it) {
		yelp(mtmp);
		return FALSE;
	    } else {
		Your("leash goes slack.");
 release_it:
		m_unleash(mtmp);
		return TRUE;
	    }
	}
	return TRUE;
}

void
tele()
{
	coord cc;

	/* Disable teleportation in stronghold && Vlad's Tower */
	if (level.flags.noteleport) {
#ifdef WIZARD
		if (!wizard) {
#endif
		    pline("A mysterious force prevents you from teleporting!");
		    return;
#ifdef WIZARD
		}
#endif
	}

	/* don't show trap if "Sorry..." */
	if (!Blinded) make_blinded(0L,FALSE);

	if ((u.uhave.amulet || On_W_tower_level(&u.uz)) && !rn2(3)) {
	    You_feel("disoriented for a moment.");
	    return;
	}
	if (Teleport_control
#ifdef WIZARD
			    || wizard
#endif
					) {
	    if (unconscious()) {
		pline("Being unconscious, you cannot control your teleport.");
	    } else {
#ifdef STEED
		    char buf[BUFSZ];
		    if (u.usteed) Sprintf(buf," and %s", mon_nam(u.usteed));
#endif
		    pline("To what position do you%s want to be teleported?",
#ifdef STEED
				u.usteed ? buf :
#endif
			   "");
		    cc.x = u.ux;
		    cc.y = u.uy;
		    if (getpos(&cc, TRUE, "the desired position") < 0)
			return;	/* abort */
		    /* possible extensions: introduce a small error if
		       magic power is low; allow transfer to solid rock */
		    if (teleok(cc.x, cc.y, FALSE)) {
			teleds(cc.x, cc.y);
			return;
		    }
		    pline("Sorry...");
		}
	}

	(void) safe_teleds();
}

int
dotele()
{
	struct trap *trap;

	trap = t_at(u.ux, u.uy);
	if (trap && (!trap->tseen || trap->ttyp != TELEP_TRAP))
		trap = 0;

	if (trap) {
		if (trap->once) {
			pline("This is a vault teleport, usable once only.");
			if (yn("Jump in?") == 'n')
				trap = 0;
			else {
				deltrap(trap);
				newsym(u.ux, u.uy);
			}
		}
		if (trap)
			You("%s onto the teleportation trap.",
			    locomotion(youmonst.data, "jump"));
	}
	if (!trap) {
	    boolean castit = FALSE;
	    register int sp_no = 0, energy = 0;

	    if (!Teleportation || (u.ulevel < (Role_if(PM_WIZARD) ? 8 : 12)
					&& !can_teleport(youmonst.data))) {
		/* Try to use teleport away spell. */
		if (objects[SPE_TELEPORT_AWAY].oc_name_known && !Confusion)
		    for (sp_no = 0; sp_no < MAXSPELL; sp_no++)
			if (spl_book[sp_no].sp_id == SPE_TELEPORT_AWAY) {
				castit = TRUE;
				break;
			}
#ifdef WIZARD
		if (!wizard) {
#endif
		    if (!castit) {
			if (!Teleportation)
			    You("don't know that spell.");
			else You("are not able to teleport at will.");
			return(0);
		    }
#ifdef WIZARD
		}
#endif
	    }

	    if (u.uhunger <= 100 || ACURR(A_STR) < 6) {
#ifdef WIZARD
		if (!wizard) {
#endif
			You("lack the strength %s.",
			    castit ? "for a teleport spell" : "to teleport");
			return 1;
#ifdef WIZARD
		}
#endif
	    }

	    energy = objects[SPE_TELEPORT_AWAY].oc_level * 7 / 2 - 2;
	    if (u.uen <= energy) {
#ifdef WIZARD
		if (wizard)
			energy = u.uen;
		else
#endif
		{
			You("lack the energy %s.",
			    castit ? "for a teleport spell" : "to teleport");
			return 1;
		}
	    }

	    if (check_capacity(
			"Your concentration falters from carrying so much."))
		return 1;

	    if (castit) {
		exercise(A_WIS, TRUE);
		if (spelleffects(sp_no, TRUE))
			return(1);
		else
#ifdef WIZARD
		    if (!wizard)
#endif
			return(0);
	    } else {
		u.uen -= energy;
		flags.botl = 1;
	    }
	}

	if (next_to_u()) {
		if (trap && trap->once) vault_tele();
		else tele();
		(void) next_to_u();
	} else {
		You(shudder_for_moment);
		return(0);
	}
	if (!trap) morehungry(100);
	return(1);
}


void
level_tele()
{
	register int newlev;
	d_level newlevel;
	const char *escape_by_flying = 0;	/* when surviving dest of -N */

	if ((u.uhave.amulet || In_endgame(&u.uz) || In_sokoban(&u.uz))
#ifdef WIZARD
						&& !wizard
#endif
							) {
	    You_feel("very disoriented for a moment.");
	    return;
	}
	if (Teleport_control
#ifdef WIZARD
	   || wizard
#endif
		) {
	    char buf[BUFSZ], qbuf[BUFSZ];
	    int trycnt = 0;

	    Strcpy(qbuf, "To what level do you want to teleport?");
	    do {
		if (++trycnt == 2) Strcat(qbuf, " [type a number]");
		getlin(qbuf, buf);
		if (!strcmp(buf,"\033"))	/* cancelled */
		    return;
		else if (!strcmp(buf,"*"))
		    goto random_levtport;
		if ((newlev = lev_by_name(buf)) == 0) newlev = atoi(buf);
	    } while (!newlev && !digit(buf[0]) &&
		     (buf[0] != '-' || !digit(buf[1])) &&
		     trycnt < 10);

	    /* no dungeon escape via this route */
	    if (newlev == 0) {
		if (trycnt >= 10)
		    goto random_levtport;
		if (ynq("Go to Nowhere.  Are you sure?") != 'y') return;
		You("scream in agony as your body begins to warp...");
		display_nhwindow(WIN_MESSAGE, FALSE);
		You("cease to exist.");
		killer_format = NO_KILLER_PREFIX;
		killer = "committed suicide";
		done(DIED);
		return;
	    }

	    /* if in Knox and the requested level > 0, stay put.
	     * we let negative values requests fall into the "heaven" loop.
	     */
	    if (Is_knox(&u.uz) && newlev > 0) {
		You(shudder_for_moment);
		return;
	    }
	    /* if in Quest, the player sees "Home 1", etc., on the status
	     * line, instead of the logical depth of the level.  controlled
	     * level teleport request is likely to be relativized to the
	     * status line, and consequently it should be incremented to
	     * the value of the logical depth of the target level.
	     *
	     * we let negative values requests fall into the "heaven" loop.
	     */
	    if (In_quest(&u.uz) && newlev > 0)
		newlev = newlev + dungeons[u.uz.dnum].depth_start - 1;
	} else { /* involuntary level tele */
 random_levtport:
	    newlev = random_teleport_level();
	    if (newlev == depth(&u.uz)) {
		You(shudder_for_moment);
		return;
	    }
	}

	if (!next_to_u()) {
		You(shudder_for_moment);
		return;
	}
#ifdef WIZARD
	if (In_endgame(&u.uz)) {	/* must already be wizard */
	    int llimit = dunlevs_in_dungeon(&u.uz);

	    if (newlev >= 0 || newlev <= -llimit) {
		You_cant("get there from here.");
		return;
	    }
	    newlevel.dnum = u.uz.dnum;
	    newlevel.dlevel = llimit + newlev;
	    schedule_goto(&newlevel, FALSE, FALSE, 0, (char *)0, (char *)0);
	    return;
	}
#endif

	killer = 0;		/* still alive, so far... */

	if (newlev < 0) {
		if (newlev <= -10) {
			You("arrive in heaven.");
			verbalize("Thou art early, but we'll admit thee.");
			killer_format = NO_KILLER_PREFIX;
			killer = "went to heaven prematurely";
		} else if (newlev == -9) {
			You_feel("deliriously happy. ");
			pline("(In fact, you're on Cloud 9!) ");
			display_nhwindow(WIN_MESSAGE, FALSE);
		} else
			You("are now high above the clouds...");

		if (killer) {
		    ;		/* arrival in heaven is pending */
		} else if (Levitation) {
		    escape_by_flying = "float gently down to earth";
		} else if (Flying) {
		    escape_by_flying = "fly down to the ground";
		} else {
		    pline("Unfortunately, you don't know how to fly.");
		    You("plummet a few thousand feet to your death.");
		    killer_format = NO_KILLER_PREFIX;
		    killer =
    self_pronoun("teleported out of the dungeon and fell to %s death","his");
		}
	}

	if (killer) {	/* the chosen destination was not survivable */
	    /* set specific death location; this also suppresses bones */
	    u.uz.dnum = 0;	/* main dungeon */
	    u.uz.dlevel = (newlev <= -10) ? -1 : 0;	/* heaven or surface */
	    done(DIED);
	    /* can only get here via life-saving (or declining to die in
	       explore|debug mode); the hero has now left the dungeon... */
	    escape_by_flying = "find yourself back on the surface";
	}

	/* calls done(ESCAPED) if newlevel==0 */
	if (escape_by_flying) {
	    You("%s.", escape_by_flying);
	    newlevel.dnum = 0;		/* specify main dungeon */
	    newlevel.dlevel = 0;	/* escape the dungeon */
	    /* [dlevel used to be set to 1, but it doesn't make sense to
		teleport out of the dungeon and float or fly down to the
		surface but then actually arrive back inside the dungeon] */
	} else if (u.uz.dnum == medusa_level.dnum &&
	    newlev >= dungeons[u.uz.dnum].depth_start +
						dunlevs_in_dungeon(&u.uz)) {
	    find_hell(&newlevel);
	} else {
	    /* if invocation did not yet occur, teleporting into
	     * the last level of Gehennom is forbidden.
	     */
#ifdef WIZARD
		if (!wizard)
#endif
	    if (Inhell && !u.uevent.invoked &&
			newlev >= (dungeons[u.uz.dnum].depth_start +
					dunlevs_in_dungeon(&u.uz) - 1)) {
		newlev = dungeons[u.uz.dnum].depth_start +
					dunlevs_in_dungeon(&u.uz) - 2;
		pline("Sorry...");
	    }
	    /* no teleporting out of quest dungeon */
	    if (In_quest(&u.uz) && newlev < depth(&qstart_level))
		newlev = depth(&qstart_level);
	    /* the player thinks of levels purely in logical terms, so
	     * we must translate newlev to a number relative to the
	     * current dungeon.
	     */
	    get_level(&newlevel, newlev);
	}
	schedule_goto(&newlevel, FALSE, FALSE, 0, (char *)0, (char *)0);
	/* in case player just read a scroll and is about to be asked to
	   call it something, we can't defer until the end of the turn */
	if (u.utotype && !flags.mon_moving) deferred_goto();
}

void
domagicportal(ttmp)
register struct trap *ttmp;
{
	struct d_level target_level;

	if (!next_to_u()) {
		You(shudder_for_moment);
		return;
	}

	/* if landed from another portal, do nothing */
	/* problem: level teleport landing escapes the check */
	if (!on_level(&u.uz, &u.uz0)) return;

	You("activated a magic portal!");

	/* prevent the poor shnook, whose amulet was stolen while in
	 * the endgame, from accidently triggering the portal to the
	 * next level, and thus losing the game
	 */
	if (In_endgame(&u.uz) && !u.uhave.amulet) {
	    You_feel("dizzy for a moment, but nothing happens...");
	    return;
	}

	target_level = ttmp->dst;
	schedule_goto(&target_level, FALSE, FALSE, 1,
		      "You feel dizzy for a moment, but the sensation passes.",
		      (char *)0);
}

void
tele_trap(trap)
struct trap *trap;
{
	if (In_endgame(&u.uz) || Antimagic) {
		if (Antimagic)
			shieldeff(u.ux, u.uy);
		You_feel("a wrenching sensation.");
	} else if (!next_to_u()) {
		You(shudder_for_moment);
	} else if (trap->once) {
		deltrap(trap);
		newsym(u.ux,u.uy);	/* get rid of trap symbol */
		vault_tele();
	} else
		tele();
}

void
level_tele_trap(trap)
struct trap *trap;
{
	You("%s onto a level teleport trap!",
		      Levitation ? (const char *)"float" :
				  locomotion(youmonst.data, "step"));
	if (Antimagic) {
	    shieldeff(u.ux, u.uy);
	}
	if (Antimagic || In_endgame(&u.uz)) {
	    You_feel("a wrenching sensation.");
	    return;
	}
	if (!Blind)
	    You("are momentarily blinded by a flash of light.");
	else
	    You("are momentarily disoriented.");
	deltrap(trap);
	newsym(u.ux,u.uy);	/* get rid of trap symbol */
	level_tele();
}

/* check whether monster can arrive at location <x,y> via Tport (or fall) */
STATIC_OVL boolean
rloc_pos_ok(x, y, mtmp)
register int x, y;		/* coordinates of candidate location */
struct monst *mtmp;
{
	register int xx, yy;

	if (!goodpos(x, y, mtmp)) return FALSE;
	/*
	 * Check for restricted areas present in some special levels.
	 *
	 * `xx' is current column; if 0, then `yy' will contain flag bits
	 * rather than row:  bit #0 set => moving upwards; bit #1 set =>
	 * inside the Wizard's tower.
	 */
	xx = mtmp->mx;
	yy = mtmp->my;
	if (!xx) {
	    /* no current location (migrating monster arrival) */
	    if (dndest.nlx && On_W_tower_level(&u.uz))
		return ((yy & 2) != 0) ^	/* inside xor not within */
		       !within_bounded_area(x, y, dndest.nlx, dndest.nly,
						  dndest.nhx, dndest.nhy);
	    if (updest.lx && (yy & 1) != 0)	/* moving up */
		return (within_bounded_area(x, y, updest.lx, updest.ly,
						  updest.hx, updest.hy) &&
		       (!updest.nlx ||
			!within_bounded_area(x, y, updest.nlx, updest.nly,
						   updest.nhx, updest.nhy)));
	    if (dndest.lx && (yy & 1) == 0)	/* moving down */
		return (within_bounded_area(x, y, dndest.lx, dndest.ly,
						  dndest.hx, dndest.hy) &&
		       (!dndest.nlx ||
			!within_bounded_area(x, y, dndest.nlx, dndest.nly,
						   dndest.nhx, dndest.nhy)));
	} else {
	    /* current location is <xx,yy> */
	    if (!tele_jump_ok(xx, yy, x, y)) return FALSE;
	}
	/* <x,y> is ok */
	return TRUE;
}

/*
 * rloc_to()
 *
 * Pulls a monster from its current position and places a monster at
 * a new x and y.  If oldx is 0, then the monster was not in the levels.monsters
 * array.  However, if oldx is 0, oldy may still have a value because mtmp is a
 * migrating_mon.  Worm tails are always placed randomly around the head of
 * the worm.
 */
void
rloc_to(mtmp, x, y)
struct monst *mtmp;
register int x, y;
{
	register int oldx = mtmp->mx, oldy = mtmp->my;

	if (x == mtmp->mx && y == mtmp->my)	/* that was easy */
		return;

	if (oldx) {				/* "pick up" monster */
	    if (mtmp->wormno)
		remove_worm(mtmp);
	    else {
		remove_monster(oldx, oldy);
		newsym(oldx, oldy);		/* update old location */
	    }
	}

	place_monster(mtmp, x, y);		/* put monster down */
	update_monster_region(mtmp);

	if (mtmp->wormno)			/* now put down tail */
		place_worm_tail_randomly(mtmp, x, y);

	if (u.ustuck == mtmp) {
		if (u.uswallow) {
			u.ux = x;
			u.uy = y;
			docrt();
		} else	u.ustuck = 0;
	}

	newsym(x, y);				/* update new location */
	set_apparxy(mtmp);			/* orient monster */
}

/* place a monster at a random location, typically due to teleport */
void
rloc(mtmp)
struct monst *mtmp;	/* mx==0 implies migrating monster arrival */
{
	register int x, y, trycount;
	xchar omx = mtmp->mx, omy = mtmp->my;

	if (mtmp->iswiz && omx) {	/* Wizard, not just arriving */
	    if (!In_W_tower(u.ux, u.uy, &u.uz))
		x = xupstair,  y = yupstair;
	    else if (!xdnladder)	/* bottom level of tower */
		x = xupladder,  y = yupladder;
	    else
		x = xdnladder,  y = ydnladder;
	    /* if the wiz teleports away to heal, try the up staircase,
	       to block the player's escaping before he's healed
	       (deliberately use `goodpos' rather than `rloc_pos_ok' here) */
	    if (goodpos(x, y, mtmp))
		goto found_xy;
	}

	trycount = 0;
	do {
	    x = rn1(COLNO-3,2);
	    y = rn2(ROWNO);
	    if ((trycount < 500) ? rloc_pos_ok(x, y, mtmp)
				 : goodpos(x, y, mtmp))
		goto found_xy;
	} while (++trycount < 1000);

	/* last ditch attempt to find a good place */
	for (x = 2; x < COLNO - 1; x++)
	    for (y = 0; y < ROWNO; y++)
		if (goodpos(x, y, mtmp))
		    goto found_xy;

	/* level either full of monsters or somehow faulty */
	impossible("rloc(): couldn't relocate monster");
	return;

 found_xy:
	rloc_to(mtmp, x, y);
	/* shopkeepers will only teleport if you zap them with a wand of
	   teleportation or if they've been transformed into a jumpy monster;
	   the latter only happens if you've attacked them with polymorph */
	if (mtmp->isshk && !inhishop(mtmp)) make_angry_shk(mtmp, omx, omy);
}

STATIC_OVL void
mvault_tele(mtmp)
struct monst *mtmp;
{
	register struct mkroom *croom = search_special(VAULT);
	coord c;

	if (croom && somexy(croom, &c) &&
				goodpos(c.x, c.y, mtmp)) {
		rloc_to(mtmp, c.x, c.y);
		return;
	}
	rloc(mtmp);
}

boolean
tele_restrict(mon)
struct monst *mon;
{
	if (level.flags.noteleport) {
		if (canseemon(mon))
		    pline("A mysterious force prevents %s from teleporting!",
			mon_nam(mon));
		return TRUE;
	}
	return FALSE;
}

void
mtele_trap(mtmp, trap, in_sight)
struct monst *mtmp;
struct trap *trap;
int in_sight;
{
	char *monname;

	if (tele_restrict(mtmp)) return;
	if (teleport_pet(mtmp, FALSE)) {
	    /* save name with pre-movement visibility */
	    monname = Monnam(mtmp);

	    /* Note: don't remove the trap if a vault.  Other-
	     * wise the monster will be stuck there, since
	     * the guard isn't going to come for it...
	     */
	    if (trap->once) mvault_tele(mtmp);
	    else rloc(mtmp);

	    if (in_sight) {
		if (canseemon(mtmp))
		    pline("%s seems disoriented.", monname);
		else
		    pline("%s suddenly disappears!", monname);
		seetrap(trap);
	    }
	}
}

/* return 0 if still on level, 3 if not */
int
mlevel_tele_trap(mtmp, trap, force_it, in_sight)
struct monst *mtmp;
struct trap *trap;
boolean force_it;
int in_sight;
{
	int tt = trap->ttyp;
	struct permonst *mptr = mtmp->data;

	if (mtmp == u.ustuck)	/* probably a vortex */
	    return 0;		/* temporary? kludge */
	if (teleport_pet(mtmp, force_it)) {
	    d_level tolevel;
	    int migrate_typ = MIGR_RANDOM;

	    if ((tt == HOLE || tt == TRAPDOOR)) {
		if (Is_stronghold(&u.uz)) {
		    assign_level(&tolevel, &valley_level);
		} else if (Is_botlevel(&u.uz)) {
		    if (in_sight && trap->tseen)
			pline("%s avoids the %s.", Monnam(mtmp),
			(tt == HOLE) ? "hole" : "trap");
		    return 0;
		} else {
		    get_level(&tolevel, depth(&u.uz) + 1);
		}
	    } else if (tt == MAGIC_PORTAL) {
		if (In_endgame(&u.uz) &&
		    (mon_has_amulet(mtmp) || is_home_elemental(mptr))) {
		    if (in_sight && mptr->mlet != S_ELEMENTAL) {
			pline("%s seems to shimmer for a moment.",
							Monnam(mtmp));
			seetrap(trap);
		    }
		    return 0;
		} else {
		    assign_level(&tolevel, &trap->dst);
		    migrate_typ = MIGR_PORTAL;
		}
	    } else { /* (tt == LEVEL_TELEP) */
		int nlev;

		if (mon_has_amulet(mtmp) || In_endgame(&u.uz)) {
		    if (in_sight)
			pline("%s seems very disoriented for a moment.",
				Monnam(mtmp));
		    return 0;
		}
		nlev = random_teleport_level();
		if (nlev == depth(&u.uz)) {
		    if (in_sight)
			pline("%s shudders for a moment.", Monnam(mtmp));
		    return 0;
		}
		get_level(&tolevel, nlev);
	    }

	    if (in_sight) {
		pline("Suddenly, %s disappears out of sight.", mon_nam(mtmp));
		seetrap(trap);
	    }
	    migrate_to_level(mtmp, ledger_no(&tolevel),
			     migrate_typ, (coord *)0);
	    return 3;	/* no longer on this level */
	}
	return 0;
}


void
rloco(obj)
register struct obj *obj;
{
	register xchar tx, ty, otx, oty;
	boolean restricted_fall;
	int try_limit = 4000;

	obj_extract_self(obj);
	otx = obj->ox;
	oty = obj->oy;
	restricted_fall = (otx == 0 && dndest.lx);
	do {
	    tx = rn1(COLNO-3,2);
	    ty = rn2(ROWNO);
	    if (!--try_limit) break;
	} while (!goodpos(tx, ty, (struct monst *)0) ||
		/* bug: this lacks provision for handling the Wizard's tower */
		 (restricted_fall &&
		  (!within_bounded_area(tx, ty, dndest.lx, dndest.ly,
						dndest.hx, dndest.hy) ||
		   (dndest.nlx &&
		    within_bounded_area(tx, ty, dndest.nlx, dndest.nly,
						dndest.nhx, dndest.nhy)))));

	if (flooreffects(obj, tx, ty, "fall")) {
	    return;
	} else if (otx == 0 && oty == 0) {
	    ;	/* fell through a trapdoor; no update of old loc needed */
	} else {
	    if (costly_spot(otx, oty)
	      && (!costly_spot(tx, ty) ||
		  !index(in_rooms(tx, ty, 0), *in_rooms(otx, oty, 0)))) {
		if (costly_spot(u.ux, u.uy) &&
			    index(u.urooms, *in_rooms(otx, oty, 0)))
		    addtobill(obj, FALSE, FALSE, FALSE);
		else (void)stolen_value(obj, otx, oty, FALSE, FALSE);
	    }
	    newsym(otx, oty);	/* update old location */
	}
	place_object(obj, tx, ty);
	newsym(tx, ty);
}

/* Returns an absolute depth */
int
random_teleport_level()
{
	int nlev, max_depth, min_depth;

	if (!rn2(5) || Is_knox(&u.uz))
		return (int)depth(&u.uz);

	/* Get a random value relative to the current dungeon */
	/* Range is 1 to current+3, current not counting */
	nlev = rnd((int)depth(&u.uz) + 2);
	if (nlev >= (int)depth(&u.uz)) nlev++;

	/* What I really want to do is as follows:
	 * -- If in a dungeon that goes down, the new level is to be restricted
	 *    to [top of parent, bottom of current dungeon]
	 * -- If in a dungeon that goes up, the new level is to be restricted
	 *    to [top of current dungeon, bottom of parent]
	 * -- If in a quest dungeon or similar dungeon entered by portals,
	 *    the new level is to be restricted to [top of current dungeon,
	 *    bottom of current dungeon]
	 * The current behavior is not as sophisticated as that ideal, but is
	 * still better what we used to do, which was like this for players
	 * but different for monsters for no obvious reason.  Currently, we
	 * must explicitly check for special dungeons.  We check for Knox
	 * above; endgame is handled in the caller due to its different
	 * message ("disoriented").
	 * --KAA
	 */
	min_depth = 1;
	max_depth = dunlevs_in_dungeon(&u.uz) +
			(dungeons[u.uz.dnum].depth_start - 1);

	if (nlev > max_depth) {
	    nlev = max_depth;
	    /* teleport up if already on bottom */
	    if (Is_botlevel(&u.uz)) nlev -= rnd(3);
	}
	if (nlev < min_depth) {
	    nlev = min_depth;
	    if ((int)depth(&u.uz) == min_depth) {
		nlev += rnd(3);
		if (nlev > max_depth)
		    nlev = max_depth;
	    }
	}
	return nlev;
}

/* you teleport a monster (via wand, spell, or poly'd q.mechanic attack);
   return false iff the attempt fails */
boolean
u_teleport_mon(mtmp, give_feedback)
struct monst *mtmp;
boolean give_feedback;
{
	coord cc;

	if (mtmp->ispriest && *in_rooms(mtmp->mx, mtmp->my, TEMPLE)) {
	    if (give_feedback)
		pline("%s resists your magic!", Monnam(mtmp));
	    return FALSE;
	} else {
	    if (is_rider(mtmp->data) && rn2(13) &&
		    enexto(&cc, u.ux, u.uy, mtmp->data))
		rloc_to(mtmp, cc.x, cc.y);
	    else
		rloc(mtmp);
	    return TRUE;
	}
}

/*teleport.c*/
