/*      $OpenBSD: hack.mklev.c,v 1.9 2021/01/26 20:42:49 millert Exp $  */

/*
 * Copyright (c) 1985, Stichting Centrum voor Wiskunde en Informatica,
 * Amsterdam
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Stichting Centrum voor Wiskunde en
 * Informatica, nor the names of its contributors may be used to endorse or
 * promote products derived from this software without specific prior
 * written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1982 Jay Fenlason <hack@gnu.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>

#include "hack.h"

#define somex() ((random()%(croom->hx-croom->lx+1))+croom->lx)
#define somey() ((random()%(croom->hy-croom->ly+1))+croom->ly)

#define XLIM    4       /* define minimum required space around a room */
#define YLIM    3
boolean secret;         /* TRUE while making a vault: increase [XY]LIM */
int smeq[MAXNROFROOMS+1];
int doorindex;
struct rm zerorm;
schar nxcor;
boolean goldseen;
int nroom;

/* Definitions used by makerooms() and addrs() */
#define MAXRS   50      /* max lth of temp rectangle table - arbitrary */
struct rectangle {
        xchar rlx,rly,rhx,rhy;
} rs[MAXRS+1];
int rscnt,rsmax;        /* 0..rscnt-1: currently under consideration */
                        /* rscnt..rsmax: discarded */

static void addrs(int, int, int, int);
static void addrsx(int, int, int, int, boolean);
int comp(const void *, const void *);
static coord finddpos(int, int, int, int);
static int  okdoor(int, int);
static void dodoor(int, int, struct mkroom *);
static void dosdoor(int, int, struct mkroom *, int);
static int  maker(schar, schar, schar, schar);
static void makecorridors(void);
static void join(int, int);
static void make_niches(void);
static void makevtele(void);
static void makeniche(boolean);

void
makelevel(void)
{
        struct mkroom *croom, *troom;
        unsigned tryct;
        int x,y;

        nroom = 0;
        doorindex = 0;
        rooms[0].hx = -1;       /* in case we are in a maze */

        for(x=0; x<COLNO; x++) for(y=0; y<ROWNO; y++)
                levl[x][y] = zerorm;

        oinit();        /* assign level dependent obj probabilities */

        if(dlevel >= rn1(3, 26)) {      /* there might be several mazes */
                makemaz();
                return;
        }

        /* construct the rooms */
        nroom = 0;
        secret = FALSE;
        (void) makerooms();

        /* construct stairs (up and down in different rooms if possible) */
        croom = &rooms[rn2(nroom)];
        xdnstair = somex();
        ydnstair = somey();
        levl[(int)xdnstair][(int)ydnstair].scrsym ='>';
        levl[(int)xdnstair][(int)ydnstair].typ = STAIRS;
        if(nroom > 1) {
                troom = croom;
                croom = &rooms[rn2(nroom-1)];
                if(croom >= troom) croom++;
        }
        xupstair = somex();     /* %% < and > might be in the same place */
        yupstair = somey();
        levl[(int)xupstair][(int)yupstair].scrsym ='<';
        levl[(int)xupstair][(int)yupstair].typ = STAIRS;

        /* for each room: put things inside */
        for(croom = rooms; croom->hx > 0; croom++) {

                /* put a sleeping monster inside */
                /* Note: monster may be on the stairs. This cannot be
                   avoided: maybe the player fell through a trapdoor
                   while a monster was on the stairs. Conclusion:
                   we have to check for monsters on the stairs anyway. */
                if(!rn2(3)) (void)
                        makemon((struct permonst *) 0, somex(), somey());

                /* put traps and mimics inside */
                goldseen = FALSE;
                while(!rn2(8-(dlevel/6))) mktrap(0,0,croom);
                if(!goldseen && !rn2(3)) mkgold(0L,somex(),somey());
                if(!rn2(3)) {
                        (void) mkobj_at(0, somex(), somey());
                        tryct = 0;
                        while(!rn2(5)) {
                                if(++tryct > 100){
                                        printf("tryct overflow4\n");
                                        break;
                                }
                                (void) mkobj_at(0, somex(), somey());
                        }
                }
        }

        qsort((char *) rooms, nroom, sizeof(struct mkroom), comp);
        makecorridors();
        make_niches();

        /* make a secret treasure vault, not connected to the rest */
        if(nroom <= (2*MAXNROFROOMS/3)) if(rn2(3)) {
                troom = &rooms[nroom];
                secret = TRUE;
                if(makerooms()) {
                        troom->rtype = VAULT;           /* treasure vault */
                        for(x = troom->lx; x <= troom->hx; x++)
                        for(y = troom->ly; y <= troom->hy; y++)
                                mkgold((long)(rnd(dlevel*100) + 50), x, y);
                        if(!rn2(3))
                                makevtele();
                }
        }

#ifndef QUEST
#ifdef WIZARD
        if(wizard && getenv("SHOPTYPE")) mkshop(); else
#endif /* WIZARD */
        if(dlevel > 1 && dlevel < 20 && rn2(dlevel) < 3) mkshop();
        else
        if(dlevel > 6 && !rn2(7)) mkzoo(ZOO);
        else
        if(dlevel > 9 && !rn2(5)) mkzoo(BEEHIVE);
        else
        if(dlevel > 11 && !rn2(6)) mkzoo(MORGUE);
        else
        if(dlevel > 18 && !rn2(6)) mkswamp();
#endif /* QUEST */
}

int
makerooms(void)
{
        struct rectangle *rsp;
        int lx, ly, hx, hy, lowx, lowy, hix, hiy, dx, dy;
        int tryct = 0, xlim, ylim;

        /* init */
        xlim = XLIM + secret;
        ylim = YLIM + secret;
        if(nroom == 0) {
                rsp = rs;
                rsp->rlx = rsp->rly = 0;
                rsp->rhx = COLNO-1;
                rsp->rhy = ROWNO-1;
                rsmax = 1;
        }
        rscnt = rsmax;

        /* make rooms until satisfied */
        while(rscnt > 0 && nroom < MAXNROFROOMS-1) {
                if(!secret && nroom > (MAXNROFROOMS/3) &&
                   !rn2((MAXNROFROOMS-nroom)*(MAXNROFROOMS-nroom)))
                        return(0);

                /* pick a rectangle */
                rsp = &rs[rn2(rscnt)];
                hx = rsp->rhx;
                hy = rsp->rhy;
                lx = rsp->rlx;
                ly = rsp->rly;

                /* find size of room */
                if(secret)
                        dx = dy = 1;
                else {
                        dx = 2 + rn2((hx-lx-8 > 20) ? 12 : 8);
                        dy = 2 + rn2(4);
                        if(dx*dy > 50)
                                dy = 50/dx;
                }

                /* look whether our room will fit */
                if(hx-lx < dx + dx/2 + 2*xlim || hy-ly < dy + dy/3 + 2*ylim) {
                                        /* no, too small */
                                        /* maybe we throw this area out */
                        if(secret || !rn2(MAXNROFROOMS+1-nroom-tryct)) {
                                rscnt--;
                                rs[rsmax] = *rsp;
                                *rsp = rs[rscnt];
                                rs[rscnt] = rs[rsmax];
                                tryct = 0;
                        } else
                                tryct++;
                        continue;
                }

                lowx = lx + xlim + rn2(hx - lx - dx - 2*xlim + 1);
                lowy = ly + ylim + rn2(hy - ly - dy - 2*ylim + 1);
                hix = lowx + dx;
                hiy = lowy + dy;

                if(maker(lowx, dx, lowy, dy)) {
                        if(secret)
                                return(1);
                        addrs(lowx-1, lowy-1, hix+1, hiy+1);
                        tryct = 0;
                } else
                        if(tryct++ > 100)
                                break;
        }
        return(0);      /* failed to make vault - very strange */
}

static void
addrs(int lowx, int lowy, int hix, int hiy)
{
        struct rectangle *rsp;
        int lx,ly,hx,hy,xlim,ylim;
        boolean discarded;

        xlim = XLIM + secret;
        ylim = YLIM + secret;

        /* walk down since rscnt and rsmax change */
        for(rsp = &rs[rsmax-1]; rsp >= rs; rsp--) {
                
                if((lx = rsp->rlx) > hix || (ly = rsp->rly) > hiy ||
                   (hx = rsp->rhx) < lowx || (hy = rsp->rhy) < lowy)
                        continue;
                if((discarded = (rsp >= &rs[rscnt]))) {
                        *rsp = rs[--rsmax];
                } else {
                        rsmax--;
                        rscnt--;
                        *rsp = rs[rscnt];
                        if(rscnt != rsmax)
                                rs[rscnt] = rs[rsmax];
                }
                if(lowy - ly > 2*ylim + 4)
                        addrsx(lx,ly,hx,lowy-2,discarded);
                if(lowx - lx > 2*xlim + 4)
                        addrsx(lx,ly,lowx-2,hy,discarded);
                if(hy - hiy > 2*ylim + 4)
                        addrsx(lx,hiy+2,hx,hy,discarded);
                if(hx - hix > 2*xlim + 4)
                        addrsx(hix+2,ly,hx,hy,discarded);
        }
}

static void
addrsx(int lx, int ly, int hx, int hy, boolean discarded)
/* boolean discarded;            piece of a discarded area */
{
        struct rectangle *rsp;

        /* check inclusions */
        for(rsp = rs; rsp < &rs[rsmax]; rsp++) {
                if(lx >= rsp->rlx && hx <= rsp->rhx &&
                   ly >= rsp->rly && hy <= rsp->rhy)
                        return;
        }

        /* make a new entry */
        if(rsmax >= MAXRS) {
#ifdef WIZARD
                if(wizard) pline("MAXRS may be too small.");
#endif /* WIZARD */
                return;
        }
        rsmax++;
        if(!discarded) {
                *rsp = rs[rscnt];
                rsp = &rs[rscnt];
                rscnt++;
        }
        rsp->rlx = lx;
        rsp->rly = ly;
        rsp->rhx = hx;
        rsp->rhy = hy;
}

int
comp(const void *x, const void *y)
{
        if(((struct mkroom *)x)->lx < ((struct mkroom *)y)->lx)
                return(-1);
        return(((struct mkroom *)x)->lx > ((struct mkroom *)y)->lx);
}

static coord
finddpos(int xl, int yl, int xh, int yh)
{
        coord ff;
        int x,y;

        x = (xl == xh) ? xl : (xl + rn2(xh-xl+1));
        y = (yl == yh) ? yl : (yl + rn2(yh-yl+1));
        if(okdoor(x, y))
                goto gotit;

        for(x = xl; x <= xh; x++) for(y = yl; y <= yh; y++)
                if(okdoor(x, y))
                        goto gotit;

        for(x = xl; x <= xh; x++) for(y = yl; y <= yh; y++)
                if(levl[x][y].typ == DOOR || levl[x][y].typ == SDOOR)
                        goto gotit;
        /* cannot find something reasonable -- strange */
        x = xl;
        y = yh;
gotit:
        ff.x = x;
        ff.y = y;
        return(ff);
}

/* see whether it is allowable to create a door at [x,y] */
static int
okdoor(int x, int y)
{
        if(levl[x-1][y].typ == DOOR || levl[x+1][y].typ == DOOR ||
           levl[x][y+1].typ == DOOR || levl[x][y-1].typ == DOOR ||
           levl[x-1][y].typ == SDOOR || levl[x+1][y].typ == SDOOR ||
           levl[x][y-1].typ == SDOOR || levl[x][y+1].typ == SDOOR ||
           (levl[x][y].typ != HWALL && levl[x][y].typ != VWALL) ||
           doorindex >= DOORMAX)
                return(0);
        return(1);
}

static void
dodoor(int x, int y, struct mkroom *aroom)
{
        if(doorindex >= DOORMAX) {
                impossible("DOORMAX exceeded?");
                return;
        }
        if(!okdoor(x,y) && nxcor)
                return;
        dosdoor(x,y,aroom,rn2(8) ? DOOR : SDOOR);
}

static void
dosdoor(int x, int y, struct mkroom *aroom, int type)
{
        struct mkroom *broom;
        int tmp;

        if(!IS_WALL(levl[x][y].typ))    /* avoid SDOORs with '+' as scrsym */
                type = DOOR;
        levl[x][y].typ = type;
        if(type == DOOR)
                levl[x][y].scrsym = '+';
        aroom->doorct++;
        broom = aroom+1;
        if(broom->hx < 0) tmp = doorindex; else
        for(tmp = doorindex; tmp > broom->fdoor; tmp--)
                doors[tmp] = doors[tmp-1];
        doorindex++;
        doors[tmp].x = x;
        doors[tmp].y = y;
        for( ; broom->hx >= 0; broom++) broom->fdoor++;
}

/* Only called from makerooms() */
static int
maker(schar lowx, schar ddx, schar lowy, schar ddy)
{
        struct mkroom *croom;
        int x, y, hix = lowx+ddx, hiy = lowy+ddy;
        int xlim = XLIM + secret, ylim = YLIM + secret;

        if(nroom >= MAXNROFROOMS) return(0);
        if(lowx < XLIM) lowx = XLIM;
        if(lowy < YLIM) lowy = YLIM;
        if(hix > COLNO-XLIM-1) hix = COLNO-XLIM-1;
        if(hiy > ROWNO-YLIM-1) hiy = ROWNO-YLIM-1;
chk:
        if(hix <= lowx || hiy <= lowy) return(0);

        /* check area around room (and make room smaller if necessary) */
        for(x = lowx - xlim; x <= hix + xlim; x++) {
                for(y = lowy - ylim; y <= hiy + ylim; y++) {
                        if(levl[x][y].typ) {
#ifdef WIZARD
                            if(wizard && !secret)
                                pline("Strange area [%d,%d] in maker().",x,y);
#endif /* WIZARD */
                                if(!rn2(3)) return(0);
                                if(x < lowx)
                                        lowx = x+xlim+1;
                                else
                                        hix = x-xlim-1;
                                if(y < lowy)
                                        lowy = y+ylim+1;
                                else
                                        hiy = y-ylim-1;
                                goto chk;
                        }
                }
        }

        croom = &rooms[nroom];

        /* on low levels the room is lit (usually) */
        /* secret vaults are always lit */
        if((rnd(dlevel) < 10 && rn2(77)) || (ddx == 1 && ddy == 1)) {
                for(x = lowx-1; x <= hix+1; x++)
                        for(y = lowy-1; y <= hiy+1; y++)
                                levl[x][y].lit = 1;
                croom->rlit = 1;
        } else
                croom->rlit = 0;
        croom->lx = lowx;
        croom->hx = hix;
        croom->ly = lowy;
        croom->hy = hiy;
        croom->rtype = croom->doorct = croom->fdoor = 0;

        for(x = lowx-1; x <= hix+1; x++)
            for(y = lowy-1; y <= hiy+1; y += (hiy-lowy+2)) {
                levl[x][y].scrsym = '-';
                levl[x][y].typ = HWALL;
        }
        for(x = lowx-1; x <= hix+1; x += (hix-lowx+2))
            for(y = lowy; y <= hiy; y++) {
                levl[x][y].scrsym = '|';
                levl[x][y].typ = VWALL;
        }
        for(x = lowx; x <= hix; x++)
            for(y = lowy; y <= hiy; y++) {
                levl[x][y].scrsym = '.';
                levl[x][y].typ = ROOM;
        }

        smeq[nroom] = nroom;
        croom++;
        croom->hx = -1;
        nroom++;
        return(1);
}

static void
makecorridors(void)
{
        int a,b;

        nxcor = 0;
        for(a = 0; a < nroom-1; a++)
                join(a, a+1);
        for(a = 0; a < nroom-2; a++)
            if(smeq[a] != smeq[a+2])
                join(a, a+2);
        for(a = 0; a < nroom; a++)
            for(b = 0; b < nroom; b++)
                if(smeq[a] != smeq[b])
                    join(a, b);
        if(nroom > 2)
            for(nxcor = rn2(nroom) + 4; nxcor; nxcor--) {
                a = rn2(nroom);
                b = rn2(nroom-2);
                if(b >= a) b += 2;
                join(a, b);
            }
}

static void
join(int a, int b)
{
        coord cc,tt;
        int tx, ty, xx, yy;
        struct rm *crm;
        struct mkroom *croom, *troom;
        int dx, dy, dix, diy, cct;

        croom = &rooms[a];
        troom = &rooms[b];

        /* find positions cc and tt for doors in croom and troom
           and direction for a corridor between them */

        if(troom->hx < 0 || croom->hx < 0 || doorindex >= DOORMAX) return;
        if(troom->lx > croom->hx) {
                dx = 1;
                dy = 0;
                xx = croom->hx+1;
                tx = troom->lx-1;
                cc = finddpos(xx,croom->ly,xx,croom->hy);
                tt = finddpos(tx,troom->ly,tx,troom->hy);
        } else if(troom->hy < croom->ly) {
                dy = -1;
                dx = 0;
                yy = croom->ly-1;
                cc = finddpos(croom->lx,yy,croom->hx,yy);
                ty = troom->hy+1;
                tt = finddpos(troom->lx,ty,troom->hx,ty);
        } else if(troom->hx < croom->lx) {
                dx = -1;
                dy = 0;
                xx = croom->lx-1;
                tx = troom->hx+1;
                cc = finddpos(xx,croom->ly,xx,croom->hy);
                tt = finddpos(tx,troom->ly,tx,troom->hy);
        } else {
                dy = 1;
                dx = 0;
                yy = croom->hy+1;
                ty = troom->ly-1;
                cc = finddpos(croom->lx,yy,croom->hx,yy);
                tt = finddpos(troom->lx,ty,troom->hx,ty);
        }
        xx = cc.x;
        yy = cc.y;
        tx = tt.x - dx;
        ty = tt.y - dy;
        if(nxcor && levl[xx+dx][yy+dy].typ)
                return;
        dodoor(xx,yy,croom);

        cct = 0;
        while(xx != tx || yy != ty) {
            xx += dx;
            yy += dy;

            /* loop: dig corridor at [xx,yy] and find new [xx,yy] */
            if(cct++ > 500 || (nxcor && !rn2(35)))
                return;

            if(xx == COLNO-1 || xx == 0 || yy == 0 || yy == ROWNO-1)
                return;         /* impossible */

            crm = &levl[xx][yy];
            if(!(crm->typ)) {
                if(rn2(100)) {
                        crm->typ = CORR;
                        crm->scrsym = CORR_SYM;
                        if(nxcor && !rn2(50))
                                (void) mkobj_at(ROCK_SYM, xx, yy);
                } else {
                        crm->typ = SCORR;
                        crm->scrsym = ' ';
                }
            } else
            if(crm->typ != CORR && crm->typ != SCORR) {
                /* strange ... */
                return;
            }

            /* find next corridor position */
            dix = abs(xx-tx);
            diy = abs(yy-ty);

            /* do we have to change direction ? */
            if(dy && dix > diy) {
                int ddx = (xx > tx) ? -1 : 1;

                crm = &levl[xx+ddx][yy];
                if(!crm->typ || crm->typ == CORR || crm->typ == SCORR) {
                    dx = ddx;
                    dy = 0;
                    continue;
                }
            } else if(dx && diy > dix) {
                int ddy = (yy > ty) ? -1 : 1;

                crm = &levl[xx][yy+ddy];
                if(!crm->typ || crm->typ == CORR || crm->typ == SCORR) {
                    dy = ddy;
                    dx = 0;
                    continue;
                }
            }

            /* continue straight on? */
            crm = &levl[xx+dx][yy+dy];
            if(!crm->typ || crm->typ == CORR || crm->typ == SCORR)
                continue;

            /* no, what must we do now?? */
            if(dx) {
                dx = 0;
                dy = (ty < yy) ? -1 : 1;
                crm = &levl[xx+dx][yy+dy];
                if(!crm->typ || crm->typ == CORR || crm->typ == SCORR)
                    continue;
                dy = -dy;
                continue;
            } else {
                dy = 0;
                dx = (tx < xx) ? -1 : 1;
                crm = &levl[xx+dx][yy+dy];
                if(!crm->typ || crm->typ == CORR || crm->typ == SCORR)
                    continue;
                dx = -dx;
                continue;
            }
        }

        /* we succeeded in digging the corridor */
        dodoor(tt.x, tt.y, troom);

        if(smeq[a] < smeq[b])
                smeq[b] = smeq[a];
        else
                smeq[a] = smeq[b];
}

static void
make_niches(void)
{
        int ct = rnd(nroom/2 + 1);
        while(ct--) makeniche(FALSE);
}

static void
makevtele(void)
{
        makeniche(TRUE);
}

static void
makeniche(boolean with_trap)
{
        struct mkroom *aroom;
        struct rm *rm;
        int vct = 8;
        coord dd;
        int dy,xx,yy;
        struct trap *ttmp;

        if(doorindex < DOORMAX)
          while(vct--) {
            aroom = &rooms[rn2(nroom-1)];
            if(aroom->rtype != 0) continue;     /* not an ordinary room */
            if(aroom->doorct == 1 && rn2(5)) continue;
            if(rn2(2)) {
                dy = 1;
                dd = finddpos(aroom->lx,aroom->hy+1,aroom->hx,aroom->hy+1);
            } else {
                dy = -1;
                dd = finddpos(aroom->lx,aroom->ly-1,aroom->hx,aroom->ly-1);
            }
            xx = dd.x;
            yy = dd.y;
            if((rm = &levl[xx][yy+dy])->typ) continue;
            if(with_trap || !rn2(4)) {
                rm->typ = SCORR;
                rm->scrsym = ' ';
                if(with_trap) {
                    ttmp = maketrap(xx, yy+dy, TELEP_TRAP);
                    ttmp->once = 1;
                    make_engr_at(xx, yy-dy, "ad ae?ar um");
                }
                dosdoor(xx, yy, aroom, SDOOR);
            } else {
                rm->typ = CORR;
                rm->scrsym = CORR_SYM;
                if(rn2(7))
                    dosdoor(xx, yy, aroom, rn2(5) ? SDOOR : DOOR);
                else {
                    mksobj_at(SCR_TELEPORTATION, xx, yy+dy);
                    if(!rn2(3)) (void) mkobj_at(0, xx, yy+dy);
                }
            }
            return;
        }
}

/* make a trap somewhere (in croom if mazeflag = 0) */
void
mktrap(int num, int mazeflag, struct mkroom *croom)
{
        struct trap *ttmp;
        int kind,nopierc,nomimic,fakedoor,fakegold,tryct = 0;
        xchar mx,my;
        extern char fut_geno[];

        if(!num || num >= TRAPNUM) {
                nopierc = (dlevel < 4) ? 1 : 0;
                nomimic = (dlevel < 9 || goldseen ) ? 1 : 0;
                if(strchr(fut_geno, 'M')) nomimic = 1;
                kind = rn2(TRAPNUM - nopierc - nomimic);
                /* note: PIERC = 7, MIMIC = 8, TRAPNUM = 9 */
        } else kind = num;

        if(kind == MIMIC) {
                struct monst *mtmp;

                fakedoor = (!rn2(3) && !mazeflag);
                fakegold = (!fakedoor && !rn2(2));
                if(fakegold) goldseen = TRUE;
                do {
                        if(++tryct > 200) return;
                        if(fakedoor) {
                                /* note: fakedoor maybe on actual door */
                                if(rn2(2)){
                                        if(rn2(2))
                                                mx = croom->hx+1;
                                        else mx = croom->lx-1;
                                        my = somey();
                                } else {
                                        if(rn2(2))
                                                my = croom->hy+1;
                                        else my = croom->ly-1;
                                        mx = somex();
                                }
                        } else if(mazeflag) {
                                coord mm;
                                mx = mm.x;
                                my = mm.y;
                        } else {
                                mx = somex();
                                my = somey();
                        }
                } while(m_at(mx,my) || levl[(int)mx][(int)my].typ == STAIRS);
                if ((mtmp = makemon(PM_MIMIC,mx,my))) {
                    mtmp->mimic = 1;
                    mtmp->mappearance =
                        fakegold ? '$' : fakedoor ? '+' :
                        (mazeflag && rn2(2)) ? AMULET_SYM :
                        "=/)%?![<>" [ rn2(9) ];
                }
                return;
        }

        do {
                if(++tryct > 200)
                        return;
                if(mazeflag){
                        extern coord mazexy();
                        coord mm;
                        mm = mazexy();
                        mx = mm.x;
                        my = mm.y;
                } else {
                        mx = somex();
                        my = somey();
                }
        } while(t_at(mx, my) || levl[(int)mx][(int)my].typ == STAIRS);
        ttmp = maketrap(mx, my, kind);
        if(mazeflag && !rn2(10) && ttmp->ttyp < PIERC)
                ttmp->tseen = 1;
}