add 'montelecontrol' option (wizard-mode only)

Add a new debugging option, 'montelecontrol', that allows a wizard-
mode player to choose a teleporting monster's destination.  If player
picks a bad spot, confirmation will be requested.  If accepted, the
spot will be used even though the consequences could be bad; that's
on the player.  If rejected, the destination will be assigned as if
no control had been attempted rather than try again.

The fuzzer isn't allowed to override a bad spot if it tries to pick
one.  That would probably trigger a sanity_check warning; the fuzzer
causes impossible warnings to behave as if panic, so accepting a bad
spot would just be fuzzer suicide.  It is allowed to randomly set the
option and maybe--though extremely unlikely--randomly pick a valid
controlled destination.

dat/opthelp

@@ -135,6 +135,7 @@ tiled_map      show map as tiles, forces ascii_map Off; Qt, X11
 Boolean options available when running in debug mode (aka wizard mode):
 menu_tab_sep   menu formatting--do not touch
 monpolycontrol have player choose shape-changing monsters' new shapes
+montelecontrol let player choose destination for teleported monsters
 travel_debug   show state of travel pathfinding algorithm on the map
 wizweight      include item weights in inventory display
 

doc/Guidebook.mn

@@ -37,7 +37,7 @@
 .ds f0 "\*(vr
 .ds f1
 .\"DO NOT REMOVE NH_DATESUB .ds f2 "DATE(%B %-d, %Y)
-.ds f2 "May 7, 2023
+.ds f2 "June 8, 2023
 .
 .\" A note on some special characters:
 .\" \(lq = left double quote
@@ -4121,6 +4121,9 @@ Default \(oq}\(cq.
 .lp monpolycontrol
 Prompt for new form whenever any monster changes shape (default off).
 Debug mode only.
+.lp montelecontrol
+Prompt for destination whenever any monster gets teleported (default off).
+Debug mode only.
 .lp mouse_support
 Allow use of the mouse for input and travel.
 Valid settings are:

doc/Guidebook.tex

@@ -46,7 +46,7 @@
 \author{Original version - Eric S. Raymond\\
 (Edited and expanded for 3.7.0 by Mike Stephenson and others)}
 %DO NOT REMOVE NH_DATESUB \date{DATE(%B %-d, %Y)}
-\date{May 7, 2023}
+\date{June 8, 2023}
 
 \maketitle
 
@@ -4511,6 +4511,10 @@ Default `{\tt \verb+}+}'.
 Prompt for new form whenever any monster changes shape (default off).
 Debug mode only.
 %.lp
+\item[\ib{montelecontrol}]
+Prompt for destination whenever any monster gets teleported (default off).
+Debug mode only.
+%.lp
 \item[\ib{mouse\verb+_+support}]
 Allow use of the mouse for input and travel.
 Valid settings are:

include/extern.h

@@ -2820,6 +2820,7 @@ extern void level_tele_trap(struct trap *, unsigned);
 extern void rloc_to(struct monst *, coordxy, coordxy);
 extern void rloc_to_flag(struct monst *, coordxy, coordxy, unsigned);
 extern boolean rloc(struct monst *, unsigned);
+extern boolean control_mon_tele(struct monst *, coord *cc, unsigned, boolean);
 extern boolean tele_restrict(struct monst *);
 extern void mtele_trap(struct monst *, struct trap *, int);
 extern int mlevel_tele_trap(struct monst *, struct trap *, boolean, int);

include/flag.h

@@ -236,6 +236,7 @@ struct instance_flags {
     boolean debug_mongen;  /* debug: prevent monster generation */
     boolean debug_hunger;  /* debug: prevent hunger */
     boolean mon_polycontrol; /* debug: control monster polymorphs */
+    boolean mon_telecontrol; /* debug: control monster teleports */
     boolean in_dumplog;    /* doing the dumplog right now? */
     boolean in_parse;      /* is a command being parsed? */
      /* suppress terminate during options parsing, for --showpaths */

include/optlist.h

@@ -454,6 +454,9 @@ static int optfn_##a(int, int, boolean, char *, char *);
     NHOPTB(monpolycontrol, Advanced, 0, opt_in, set_wizonly,
            Off, Yes, No, No, NoAlias, &iflags.mon_polycontrol, Term_False,
            "control monster polymorphs")
+    NHOPTB(montelecontrol, Advanced, 0, opt_in, set_wizonly,
+           Off, Yes, No, No, NoAlias, &iflags.mon_telecontrol, Term_False,
+           "control monster teleport destinations")
     NHOPTC(monsters, Advanced, MAXMCLASSES, opt_in, set_in_config,
                 No, Yes, No, No, NoAlias,
                 "list of symbols to use for monsters")

src/mon.c

@@ -3564,6 +3564,17 @@ mnexto(struct monst *mtmp, unsigned int rlocflags)
         deal_with_overcrowding(mtmp);
         return;
     }
+    /* wizard-mode player can choose destination by setting 'montelecontrol'
+       option; enexto()'s value for 'mm' will be the default; 'savemm' is
+       used to make sure player doesn't choose hero's location and then
+       answer 'y' to the 'override invalid spot' prompt */
+    if (iflags.mon_telecontrol) {
+        coord savemm = mm;
+
+        if (!control_mon_tele(mtmp, &mm, rlocflags, FALSE))
+            mm = savemm;
+    }
+
     rloc_to_flag(mtmp, mm.x, mm.y, rlocflags);
     return;
 }
@@ -3595,6 +3606,7 @@ maybe_mnexto(struct monst *mtmp)
         if (couldsee(mm.x, mm.y)
             /* don't move grid bugs diagonally */
             && (diagok || mm.x == mtmp->mx || mm.y == mtmp->my)) {
+            /* [this doesn't honor the 'montelecontrol' option] */
             rloc_to(mtmp, mm.x, mm.y);
             return;
         }
@@ -3658,6 +3670,7 @@ mnearto(
         newx = mm.x;
         newy = mm.y;
     }
+    /* [this doesn't honor the 'montelecontrol' option] */
     rloc_to_flag(mtmp, newx, newy, rlocflags);
 
     if (move_other && othermon) {

src/teleport.c

@@ -1735,6 +1735,16 @@ rloc(
             goto found_xy;
     }
 
+    /* wizard-mode player can choose destination by setting 'montelecontrol'
+       option; ignored if/when this is arrival of a migrating monster */
+    if (iflags.mon_telecontrol && mtmp->mx) {
+        cc.x = mtmp->mx, cc.y = mtmp->my;
+        if (control_mon_tele(mtmp, &cc, rlocflags, TRUE)) {
+            x = cc.x, y = cc.y;
+            goto found_xy;
+        }
+    }
+
     /* this used to try randomly 1000 times, then fallback to left-to-right
        top-to-bottom exhaustive check; now that the exhaustive check uses
        randomized order, reduce the number of random attempts to 50;
@@ -1788,6 +1798,45 @@ rloc(
     return TRUE;
 }
 
+/* let wizard-mode player choose a teleporting monster's destination */
+boolean
+control_mon_tele(
+    struct monst *mon,
+    coord *cc_p, /* input: default spot; output: player selected spot */
+    unsigned rlocflags,
+    boolean via_rloc)
+{
+    char tcbuf[BUFSZ];
+
+    if (!isok(cc_p->x, cc_p->y)) {
+        cc_p->x = mon->mx, cc_p->y = mon->my;
+        if (!isok(cc_p->x, cc_p->y))
+            cc_p->x = u.ux, cc_p->y = u.uy;
+    }
+
+    if (!wizard || !iflags.mon_telecontrol)
+        return FALSE;
+
+    pline("Teleport %s @ <%d,%d> where?",
+          noit_mon_nam(mon), mon->mx, mon->my);
+    /* getpos '?' will show "Move the cursor to <where to teleport Foo>:" */
+    Sprintf(tcbuf, "where to teleport %s", noit_mon_nam(mon));
+    if (getpos(cc_p, FALSE, tcbuf) >= 0 && !u_at(cc_p->x, cc_p->y)) {
+        if (via_rloc
+              ? rloc_pos_ok(cc_p->x, cc_p->y, mon)
+              : goodpos(cc_p->x, cc_p->y, mon, rlocflags))
+            return TRUE;
+        if (!iflags.debug_fuzzer) {
+            Sprintf(tcbuf, "<%d,%d> is not considered viable; force anyway?",
+                    mon->mx, mon->my);
+            if (y_n(tcbuf) == 'y')
+                return TRUE;
+        }
+    }
+    pline("%s destination.", via_rloc ? "Picking random" : "Using derived");
+    return FALSE;
+}
+
 static void
 mvault_tele(struct monst* mtmp)
 {