From f484cfd4fbe1dccf172cd18e9e195a80726e20e1 Mon Sep 17 00:00:00 2001
From: cross-of-north <cross.of.north@gmail.com>
Date: Sat, 13 Apr 2024 13:56:59 +0700
Subject: [PATCH] musketeer xboard castling fixes

---
 src/position.cpp | 21 ++++++++++++++++-----
 src/position.h   |  2 +-
 src/uci.cpp      | 21 +++++++++++++++------
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/src/position.cpp b/src/position.cpp
index b285a44fe..fe0ba7b51 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -3379,15 +3379,26 @@ bool Position::pos_is_ok() const {
   return true;
 }
 
-PieceType Position::committed_piece_type(Move m) const {
+PieceType Position::committed_piece_type(Move m, bool castlingRook) const {
     PieceType result = NO_PIECE_TYPE;
     if (commit_gates()) {
         Square from = from_sq(m);
         Rank r = rank_of(from);
-        if(r == RANK_1){
-            result = committed_piece_type(WHITE, file_of( from ));
-        } else if(r == max_rank()){
-            result = committed_piece_type(BLACK, file_of(from));
+        if (castlingRook){
+            if (type_of(m) == CASTLING){
+                from = to_sq(m);
+            } else {
+                from = SQ_NONE;
+            }
+        }
+        if (from != SQ_NONE){
+            if (r == RANK_1){
+                result = committed_piece_type(WHITE, file_of(from));
+            } else if (r == max_rank()){
+                result = committed_piece_type(BLACK, file_of(from));
+            } else{
+                assert(false);
+            }
         }
     }
     return result;
diff --git a/src/position.h b/src/position.h
index be12a6fcb..40bd05cec 100644
--- a/src/position.h
+++ b/src/position.h
@@ -283,7 +283,7 @@ class Position {
   bool gives_check(Move m) const;
   Piece moved_piece(Move m) const;
   Piece captured_piece() const;
-  PieceType committed_piece_type(Move m) const;
+  PieceType committed_piece_type(Move m, bool castlingRook) const;
 
   // Piece specific
   bool pawn_passed(Color c, Square s) const;
diff --git a/src/uci.cpp b/src/uci.cpp
index ebb6e0e05..e62cc9439 100644
--- a/src/uci.cpp
+++ b/src/uci.cpp
@@ -577,15 +577,24 @@ Move UCI::to_move(const Position& pos, string& str) {
   for (const auto& m : MoveList<LEGAL>(pos)) {
       auto move_str = UCI::move(pos, m);
       
-      // special processing of optional gating suffix
+      // special processing of optional gating suffix from xboard
       // like "b1c3o" => "b1c3"
       if (CurrentProtocol == XBOARD && str.length() == 5 && move_str.length() == 4) {
-          if (str[1] == move_str[1] && str[2] == move_str[2] && str[3] == move_str[3]) {
-              PieceType pt = pos.committed_piece_type(m);
+          if (memcmp(str.c_str(), move_str.c_str(), 4) == 0){
+              PieceType pt = pos.committed_piece_type(m, false);
+              PieceType ptCastling = pos.committed_piece_type(m, true);
               if (
-                  pt != NO_PIECE_TYPE
-                  &&
-                  pos.piece_to_char()[make_piece(BLACK, pos.committed_piece_type(m))] == str[4]
+                    (
+                        pt != NO_PIECE_TYPE
+                        &&
+                        pos.piece_to_char()[make_piece(BLACK, pt)] == str[4]
+                    )
+                    ||
+                    (
+                        ptCastling != NO_PIECE_TYPE
+                        &&
+                        pos.piece_to_char()[make_piece(BLACK, ptCastling)] == str[4]
+                    )
               ) {
                   return m;
               }