From bdf7fb246fa3fcf64350d8edd3f3a9ea9c32f46f Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 6 Jan 2018 13:38:13 +0100
Subject: [PATCH] Inform the engine if we have a Chess960 game.

---
 Engine.pm     |  1 +
 Position.pm   |  8 ++++++++
 remoteglot.pl | 12 ++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/Engine.pm b/Engine.pm
index 6ec914f..c46b4a8 100644
--- a/Engine.pm
+++ b/Engine.pm
@@ -30,6 +30,7 @@ sub open {
 		cb => $cb,
 		seen_uciok => 0,
 		stopping => 0,
+		chess960 => 0,
 	};
 
 	print $uciwrite "uci\n";
diff --git a/Position.pm b/Position.pm
index 6976c96..8a42a6f 100644
--- a/Position.pm
+++ b/Position.pm
@@ -221,6 +221,9 @@ sub make_move {
 	if (exists($pos->{'start_fen'})) {
 		$np->{'start_fen'} = $pos->{'start_fen'};
 	}
+	if (exists($pos->{'chess960'})) {
+		$np->{'chess960'} = $pos->{'chess960'};
+	}
 	if (defined($pretty_move)) {
 		$np->{'last_move'} = $pretty_move;
 	} else {
@@ -242,6 +245,11 @@ sub make_pretty_move {
 	return ($pos, $uci_move);
 }
 
+sub is_chess960 {
+	my ($pos) = shift;
+	return (defined($pos->{'chess960'}) && $pos->{'chess960'});
+}
+
 sub _pos_to_square {
         my ($row, $col) = @_;
         return sprintf("%c%d", ord('a') + $col, 8 - $row);
diff --git a/remoteglot.pl b/remoteglot.pl
index 7f4fd3c..66fb2ff 100755
--- a/remoteglot.pl
+++ b/remoteglot.pl
@@ -296,6 +296,10 @@ sub handle_pgn {
 			} else {
 				$pos = Position->start_pos($white, $black);
 			}
+			if (exists($tags->{'Variant'}) &&
+			    $tags->{'Variant'} =~ /960|fischer/i) {
+				$pos->{'chess960'} = 1;
+			}
 			my $moves = $pgn->moves;
 			my @uci_moves = ();
 			my @repretty_moves = ();
@@ -386,6 +390,10 @@ sub handle_position {
 	# It's wrong to just give the FEN (the move history is useful,
 	# and per the UCI spec, we should really have sent "ucinewgame"),
 	# but it's easier, and it works around a Stockfish repetition issue.
+	if ($engine->{'chess960'} != $pos->is_chess960()) {
+		uciprint($engine, "setoption UCI_Chess960 " . ($pos->is_chess960() ? 'true' : 'false'));
+		$engine->{'chess960'} = $pos->is_chess960();
+	}
 	uciprint($engine, "position fen " . $pos->fen());
 	uciprint($engine, "go infinite");
 	$pos_calculating = $pos;
@@ -395,6 +403,10 @@ sub handle_position {
 			$engine2->{'stopping'} = 1;
 			uciprint($engine2, "stop");
 		}
+		if ($engine2->{'chess960'} != $pos->is_chess960()) {
+			uciprint($engine2, "setoption UCI_Chess960 " . ($pos->is_chess960() ? 'true' : 'false'));
+			$engine2->{'chess960'} = $pos->is_chess960();
+		}
 		uciprint($engine2, "position fen " . $pos->fen());
 		uciprint($engine2, "go infinite");
 		$pos_calculating_second_engine = $pos;
-- 
2.39.2