Fix a castling edge case in Chess960 positions where the kings start on the e-file...

[remoteglot] / Board.pm

diff --git a/Board.pm b/Board.pm
index 783aef09df46c2ef2674c390eca3d861ead36e85..6fb413ac906ed5670930f3d62750f8519260207f 100644 (file)
--- a/Board.pm
+++ b/Board.pm
@@ -43,57 +43,55 @@ sub make_move {
        }
 
        if ($piece eq 'K') {
+               # Convert to Chess960 king-takes-rook.
+               $to_col = 7 if ($move eq 'e1g1' && $board->[$to_row][$to_col] ne 'R');
+               $to_col = 0 if ($move eq 'e1c1' && $board->[$to_row][$to_col] ne 'R');
+
                my $dst_piece = $board->[$to_row][$to_col];
 
-               # White short castling (regular or Chess960 king-takes-rook)
-               if ($move eq 'e1g1' || $dst_piece eq 'R') {
+               # White short castling.
+               if ($dst_piece eq 'R' && $to_col > $from_col) {
                        # king
                        $nb->[7][$from_col] = '-';
-                       $nb->[7][6] = $piece;
-
-                       # rook
                        $nb->[7][$to_col] = '-';
+                       $nb->[7][6] = 'K';
                        $nb->[7][5] = 'R';
 
                        return $nb;
                }
 
-               # White long castling (regular or Chess960 king-takes-rook)
-               if ($move eq 'e1c1' || $dst_piece eq 'R') {
-                       # king
+               # Black short castling.
+               if ($dst_piece eq 'R' && $to_col < $from_col) {
                        $nb->[7][$from_col] = '-';
-                       $nb->[7][2] = $piece;
-
-                       # rook
                        $nb->[7][$to_col] = '-';
+                       $nb->[7][2] = 'K';
                        $nb->[7][3] = 'R';
 
                        return $nb;
                }
        } elsif ($piece eq 'k') {
-               my $dst_piece = $board->[$to_row][$to_col];
+               # Convert to Chess960 king-takes-rook.
+               $to_col = 7 if ($move eq 'e8g8' && $board->[$to_row][$to_col] ne 'r');
+               $to_col = 0 if ($move eq 'e8c8' && $board->[$to_row][$to_col] ne 'r');
 
-               # Black short castling (regular or Chess960 king-takes-rook)
-               if ($move eq 'e8g8' || $dst_piece eq 'r') {
-                       # king
-                       $nb->[0][$from_col] = '-';
-                       $nb->[0][6] = $piece;
+               my $dst_piece = $board->[$to_row][$to_col];
 
-                       # rook
+               # Black short castling.
+               if ($dst_piece eq 'r' && $to_col > $from_col) {
                        $nb->[0][$from_col] = '-';
+                       $nb->[0][$to_col] = '-';
+                       $nb->[0][6] = 'k';
                        $nb->[0][5] = 'r';
 
                        return $nb;
                }
 
-               # black long castling
-               if ($move eq 'e8c8' || $dst_piece eq 'r') {
+               # Black long castling.
+               if ($dst_piece eq 'r' && $to_col < $from_col) {
                        # king
                        $nb->[0][$from_col] = '-';
-                       $nb->[0][2] = $piece;
-
-                       # rook
                        $nb->[0][$to_col] = '-';
+                       $nb->[0][2] = 'k';
                        $nb->[0][3] = 'r';
 
                        return $nb;