From 137fd252df56a42eac5ba1ad7d251b633846ed4f Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 13 Jan 2018 14:29:21 +0100
Subject: [PATCH] Fix non-Chess960 castling.

---
 Board.pm | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/Board.pm b/Board.pm
index 579adbd..8565c84 100644
--- a/Board.pm
+++ b/Board.pm
@@ -43,10 +43,14 @@ sub make_move {
 	}
 
 	if ($piece eq 'K') {
+		# Convert to Chess960 king-takes-rook.
+		$to_col = 7 if ($move eq 'e1g1');
+		$to_col = 0 if ($move eq 'e1c1');
+
 		my $dst_piece = $board->[$to_row][$to_col];
 
-		# White short castling (regular or Chess960 king-takes-rook)
-		if ($move eq 'e1g1' || ($dst_piece eq 'R' && $to_col > $from_col)) {
+		# White short castling.
+		if ($dst_piece eq 'R' && $to_col > $from_col) {
 			# king
 			$nb->[7][$from_col] = '-';
 			$nb->[7][$to_col] = '-';
@@ -56,8 +60,8 @@ sub make_move {
 			return $nb;
 		}
 
-		# White long castling (regular or Chess960 king-takes-rook)
-		if ($move eq 'e1c1' || ($dst_piece eq 'R' && $to_col < $from_col)) {
+		# Black short castling.
+		if ($dst_piece eq 'R' && $to_col < $from_col) {
 			$nb->[7][$from_col] = '-';
 			$nb->[7][$to_col] = '-';
 			$nb->[7][2] = 'K';
@@ -66,10 +70,14 @@ sub make_move {
 			return $nb;
 		}
 	} elsif ($piece eq 'k') {
+		# Convert to Chess960 king-takes-rook.
+		$to_col = 7 if ($move eq 'e8g8');
+		$to_col = 0 if ($move eq 'e8c8');
+
 		my $dst_piece = $board->[$to_row][$to_col];
 
-		# Black short castling (regular or Chess960 king-takes-rook)
-		if ($move eq 'e8g8' || ($dst_piece eq 'r' && $to_col > $from_col)) {
+		# Black short castling.
+		if ($dst_piece eq 'r' && $to_col > $from_col) {
 			$nb->[0][$from_col] = '-';
 			$nb->[0][$to_col] = '-';
 			$nb->[0][6] = 'k';
@@ -78,8 +86,8 @@ sub make_move {
 			return $nb;
 		}
 
-		# black long castling
-		if ($move eq 'e8c8' || ($dst_piece eq 'r' && $to_col < $from_col)) {
+		# Black long castling.
+		if ($dst_piece eq 'r' && $to_col < $from_col) {
 			# king
 			$nb->[0][$from_col] = '-';
 			$nb->[0][$to_col] = '-';
-- 
2.39.2