From 2430ee4ec3581b9ab988f5ef38d179eeb0d80086 Mon Sep 17 00:00:00 2001
From: Joseph Chung <84266961+CLIDragon@users.noreply.github.com>
Date: Wed, 28 Aug 2024 09:04:26 +1000
Subject: [PATCH] Extract game::find_stairs from game::find_or_make_stairs
 (#75963)

Part of #74945. Sometimes we want to find stairs without spontaneously
generating them.
---
 src/game.cpp | 38 ++++++++++++++++++++++++--------------
 src/game.h   |  1 +
 2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/src/game.cpp b/src/game.cpp
index dbece2bb4850d..82af9c1a5ade3 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -12307,31 +12307,29 @@ void game::start_hauling( const tripoint &pos )
     u.assign_activity( actor );
 }
 
-std::optional<tripoint> game::find_or_make_stairs( map &mp, const int z_after, bool &rope_ladder,
-        bool peeking, const tripoint &pos )
+std::optional<tripoint> game::find_stairs( const map &mp, int z_after, const tripoint &pos )
 {
-    const bool is_avatar = u.pos() == pos;
-    const int omtilesz = SEEX * 2;
-    real_coords rc( mp.getabs( pos.xy() ) );
-    tripoint omtile_align_start( mp.getlocal( rc.begin_om_pos() ), z_after );
-    tripoint omtile_align_end( omtile_align_start + point( -1 + omtilesz, -1 + omtilesz ) );
-
-    // Try to find the stairs.
-    std::optional<tripoint> stairs;
-    int best = INT_MAX;
     const int movez = z_after - pos.z;
     const bool going_down_1 = movez == -1;
     const bool going_up_1 = movez == 1;
+
     // If there are stairs on the same x and y as we currently are, use those
     if( going_down_1 && mp.has_flag( ter_furn_flag::TFLAG_GOES_UP, pos + tripoint_below ) ) {
-        stairs.emplace( pos + tripoint_below );
+        return pos + tripoint_below;
     }
     if( going_up_1 && mp.has_flag( ter_furn_flag::TFLAG_GOES_DOWN, pos + tripoint_above ) ) {
-        stairs.emplace( pos + tripoint_above );
+        return pos + tripoint_above;
     }
     // We did not find stairs directly above or below, so search the map for them
     // If there's empty space right below us, we can just go down that way.
-    if( !stairs.has_value() && get_map().tr_at( u.pos() ) != tr_ledge ) {
+    int best = INT_MAX;
+    std::optional<tripoint> stairs;
+    const int omtilesz = SEEX * 2 - 1;
+    real_coords rc( mp.getabs( pos.xy() ) );
+    tripoint omtile_align_start( mp.getlocal( rc.begin_om_pos() ), z_after );
+    tripoint omtile_align_end( omtile_align_start + point( omtilesz, omtilesz ) );
+
+    if( get_map().tr_at( u.pos() ) != tr_ledge ) {
         for( const tripoint &dest : mp.points_in_rectangle( omtile_align_start, omtile_align_end ) ) {
             if( rl_dist( u.pos(), dest ) <= best &&
                 ( ( going_down_1 && mp.has_flag( ter_furn_flag::TFLAG_GOES_UP, dest ) ) ||
@@ -12344,6 +12342,18 @@ std::optional<tripoint> game::find_or_make_stairs( map &mp, const int z_after, b
         }
     }
 
+    return stairs;
+}
+
+std::optional<tripoint> game::find_or_make_stairs( map &mp, const int z_after, bool &rope_ladder,
+        bool peeking, const tripoint &pos )
+{
+    const bool is_avatar = u.pos() == pos;
+    const int movez = z_after - pos.z;
+
+    // Try to find the stairs.
+    std::optional<tripoint> stairs = find_stairs( mp, z_after, pos );
+
     creature_tracker &creatures = get_creature_tracker();
     if( stairs.has_value() ) {
         if( !is_avatar ) {
diff --git a/src/game.h b/src/game.h
index 517fb0520e85c..92244afa65774 100644
--- a/src/game.h
+++ b/src/game.h
@@ -289,6 +289,7 @@ class game
         /** Returns the other end of the stairs (if any). May query, affect u etc.
         * @param pos Disable queries and msgs if not the same position as player.
         */
+        std::optional<tripoint> find_stairs( const map &mp, int z_after, const tripoint &pos );
         std::optional<tripoint> find_or_make_stairs( map &mp, int z_after, bool &rope_ladder,
                 bool peeking, const tripoint &pos );
         /*