X-Git-Url: https://git.sesse.net/?p=remoteglot;a=blobdiff_plain;f=Board.pm;h=579adbd1c0809b4596218185a746af6d1a5ffeaf;hp=1bedd56a23d704f458384a858f69b4120cf652d4;hb=6dd4f0d4b11f86cc8490bbb0462259232fa80a7a;hpb=3f2c87e7a476de25d87fd413dba7fef912838bee

diff --git a/Board.pm b/Board.pm
index 1bedd56..579adbd 100644
--- a/Board.pm
+++ b/Board.pm
@@ -42,56 +42,52 @@ sub make_move {
 		die "Invalid move $move";
 	}
 
-	# white short castling
-	if ($move eq 'e1g1' && $piece eq 'K') {
-		# king
-		$nb->[7][4] = '-';
-		$nb->[7][6] = $piece;
-
-		# rook
-		$nb->[7][7] = '-';
-		$nb->[7][5] = 'R';
-
-		return $nb;
-	}
-
-	# white long castling
-	if ($move eq 'e1c1' && $piece eq 'K') {
-		# king
-		$nb->[7][4] = '-';
-		$nb->[7][2] = $piece;
-
-		# rook
-		$nb->[7][0] = '-';
-		$nb->[7][3] = 'R';
-
-		return $nb;
-	}
+	if ($piece eq 'K') {
+		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)) {
+			# king
+			$nb->[7][$from_col] = '-';
+			$nb->[7][$to_col] = '-';
+			$nb->[7][6] = 'K';
+			$nb->[7][5] = 'R';
+
+			return $nb;
+		}
 
-	# black short castling
-	if ($move eq 'e8g8' && $piece eq 'k') {
-		# king
-		$nb->[0][4] = '-';
-		$nb->[0][6] = $piece;
+		# White long castling (regular or Chess960 king-takes-rook)
+		if ($move eq 'e1c1' || ($dst_piece eq 'R' && $to_col < $from_col)) {
+			$nb->[7][$from_col] = '-';
+			$nb->[7][$to_col] = '-';
+			$nb->[7][2] = 'K';
+			$nb->[7][3] = 'R';
 
-		# rook
-		$nb->[0][7] = '-';
-		$nb->[0][5] = 'r';
+			return $nb;
+		}
+	} elsif ($piece eq 'k') {
+		my $dst_piece = $board->[$to_row][$to_col];
 
-		return $nb;
-	}
+		# Black short castling (regular or Chess960 king-takes-rook)
+		if ($move eq 'e8g8' || ($dst_piece eq 'r' && $to_col > $from_col)) {
+			$nb->[0][$from_col] = '-';
+			$nb->[0][$to_col] = '-';
+			$nb->[0][6] = 'k';
+			$nb->[0][5] = 'r';
 
-	# black long castling
-	if ($move eq 'e8c8' && $piece eq 'k') {
-		# king
-		$nb->[0][4] = '-';
-		$nb->[0][2] = $piece;
+			return $nb;
+		}
 
-		# rook
-		$nb->[0][0] = '-';
-		$nb->[0][3] = 'r';
+		# black long castling
+		if ($move eq 'e8c8' || ($dst_piece eq 'r' && $to_col < $from_col)) {
+			# king
+			$nb->[0][$from_col] = '-';
+			$nb->[0][$to_col] = '-';
+			$nb->[0][2] = 'k';
+			$nb->[0][3] = 'r';
 
-		return $nb;
+			return $nb;
+		}
 	}
 
 	# check if the from-piece is a pawn
@@ -136,9 +132,12 @@ sub _row_letter_to_num {
         return 7 - (ord(shift) - ord('1'));
 }
 
+use Carp;
+
 sub _square_to_pos {
 	my ($square) = @_;
-	$square =~ /^([a-h])([1-8])$/ or die "Invalid square $square";	
+	#$square =~ /^([a-h])([1-8])$/ or die "Invalid square $square";	
+	$square =~ /^([a-h])([1-8])$/ or Carp::confess("Invalid square $square");
 	return (_row_letter_to_num($2), _col_letter_to_num($1));
 }
 
@@ -148,60 +147,100 @@ sub move_to_uci_notation {
 	return _pos_to_square($from_row, $from_col) . _pos_to_square($to_row, $to_col) . $promo;
 }
 
+sub _find_piece_col {
+	my ($row, $piece) = @_;
+	for my $col (0..7) {
+		return $col if ($row->[$col] eq $piece);
+	}
+	die "Could not find piece $piece";
+}
+
+# Note: This is in general not a validation that the move is actually allowed
+# (e.g. you can castle even though you're in check).
 sub parse_pretty_move {
-	my ($board, $move, $toplay) = @_;
+	my ($board, $move, $toplay, $chess960, $white_castle_k, $white_castle_q, $black_castle_k, $black_castle_q) = @_;
 
 	# Strip check or mate
 	$move =~ s/[+#]$//;
 
 	if ($move eq '0-0' or $move eq 'O-O') {
 		if ($toplay eq 'W') {
-			return (_square_to_pos('e1'), _square_to_pos('g1'));
+			if ($chess960) {
+				# King takes rook.
+				return (7, _find_piece_col($board->[7], 'K'), _square_to_pos($white_castle_k . '1'));
+			} else {
+				return (_square_to_pos('e1'), _square_to_pos('g1'));
+			}
 		} else {
-			return (_square_to_pos('e8'), _square_to_pos('g8'));
+			if ($chess960) {
+				# King takes rook.
+				return (0, _find_piece_col($board->[0], 'k'), _square_to_pos($black_castle_k . '8'));
+			} else {
+				return (_square_to_pos('e8'), _square_to_pos('g8'));
+			}
 		}
 	} elsif ($move eq '0-0-0' or $move eq 'O-O-O') {
 		if ($toplay eq 'W') {
-			return (_square_to_pos('e1'), _square_to_pos('c1'));
+			if ($chess960) {
+				# King takes rook.
+				return (7, _find_piece_col($board->[7], 'K'), _square_to_pos($white_castle_q . '1'));
+			} else {
+				return (_square_to_pos('e1'), _square_to_pos('c1'));
+			}
 		} else {
-			return (_square_to_pos('e8'), _square_to_pos('c8'));
+			if ($chess960) {
+				# King takes rook.
+				return (0, _find_piece_col($board->[0], 'k'), _square_to_pos($black_castle_q . '8'));
+			} else {
+				return (_square_to_pos('e8'), _square_to_pos('c8'));
+			}
 		}
 	}
 
 	# Parse promo
 	my $promo;
-	if ($move =~ s/=([QRNB])$//) {
+	if ($move =~ s/=?([QRNB])$//) {
 		$promo = $1;
 	}
 
 	$move =~ /^([KQRBN])?([a-h])?([1-8])?x?([a-h][1-8])$/ or die "Invalid move $move";
-	my $piece = $1 // 'P';
+	my $piece = $1;
 	my $from_col = defined($2) ? _col_letter_to_num($2) : undef;
 	my $from_row = defined($3) ? _row_letter_to_num($3) : undef;
+	if (!defined($piece) && (!defined($from_col) || !defined($from_row))) {
+		$piece = 'P';
+	}
 	my ($to_row, $to_col) = _square_to_pos($4);
 	
 	# Find all possible from-squares that could have been meant.
 	my @squares = ();
 	my $side = 'K';
 	if ($toplay eq 'B') {
-		$piece = lc($piece);
+		$piece = lc($piece) if defined($piece);
 		$side = 'k';
 	}
 	for my $row (0..7) {
 		next if (defined($from_row) && $from_row != $row);
 		for my $col (0..7) {
 			next if (defined($from_col) && $from_col != $col);
-			next if ($board->[$row][$col] ne $piece);
-			next if (!$board->can_reach($piece, $row, $col, $to_row, $to_col));
-
-			# See if doing this move would put us in check
-			# (yes, there are clients that expect us to do this).
-			next if ($board->make_move($row, $col, $to_row, $to_col, $promo)->in_check($side));
+			next if (defined($piece) && $board->[$row][$col] ne $piece);
 			push @squares, [ $row, $col ];
 		}
 	}
+	if (scalar @squares > 1) {
+		# Filter out pieces which cannot reach this square.
+		@squares = grep { $board->can_reach($piece, $_->[0], $_->[1], $to_row, $to_col) } @squares;
+	}
+	if (scalar @squares > 1) {
+		# See if doing this move would put us in check
+		# (yes, there are clients that expect us to do this).
+		@squares = grep { !$board->make_move($_->[0], $_->[1], $to_row, $to_col, $promo)->in_check($side) } @squares;
+	}
+	if (scalar @squares == 0) {
+		die "Impossible move $move";
+	}
 	if (scalar @squares != 1) {
-		die "Ambigious or impossible move $move";
+		die "Ambigious move $move";
 	}
 	return (@{$squares[0]}, $to_row, $to_col, $promo);
 }
@@ -221,15 +260,52 @@ sub fen {
 sub can_reach {
 	my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
 	
-	# can't eat your own piece
+	# Can't eat your own piece (Chess960 uses king-takes-rook for castling,
+	# but castling is irrelevant for reachability)
 	my $dest_piece = $board->[$to_row][$to_col];
 	if ($dest_piece ne '-') {
 		return 0 if (($piece eq lc($piece)) == ($dest_piece eq lc($dest_piece)));
 	}
-
-	if (lc($piece) eq 'k') {
-		return (abs($from_row - $to_row) <= 1 && abs($from_col - $to_col) <= 1);
+	
+	if ($piece eq 'p') {
+		# black pawn
+		if ($to_col == $from_col && $to_row == $from_row + 1) {
+			return ($dest_piece eq '-');
+		}
+		if ($to_col == $from_col && $from_row == 1 && $to_row == 3) {
+			my $middle_piece = $board->[2][$to_col];
+			return ($dest_piece eq '-' && $middle_piece eq '-');
+		}
+		if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
+			if ($dest_piece eq '-') {
+				# En passant. TODO: check that the last move was indeed an EP move
+				return ($to_row == 5 && $board->[4][$to_col] eq 'P');
+			} else {
+				return 1;
+			}
+		}
+		return 0;
+	}
+	if ($piece eq 'P') {
+		# white pawn
+		if ($to_col == $from_col && $to_row == $from_row - 1) {
+			return ($dest_piece eq '-');
+		}
+		if ($to_col == $from_col && $from_row == 6 && $to_row == 4) {
+			my $middle_piece = $board->[5][$to_col];
+			return ($dest_piece eq '-' && $middle_piece eq '-');
+		}
+		if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
+			if ($dest_piece eq '-') {
+				# En passant. TODO: check that the last move was indeed an EP move
+				return ($to_row == 2 && $board->[3][$to_col] eq 'p');
+			} else {
+				return 1;
+			}
+		}
+		return 0;
 	}
+	
 	if (lc($piece) eq 'r') {
 		return 0 unless ($from_row == $to_row || $from_col == $to_col);
 
@@ -292,57 +368,41 @@ sub can_reach {
 		return (can_reach($board, 'R', $from_row, $from_col, $to_row, $to_col) ||
 		        can_reach($board, 'B', $from_row, $from_col, $to_row, $to_col));
 	}
-
-	if ($piece eq 'p') {
-		# black pawn
-		if ($to_col == $from_col && $to_row == $from_row + 1) {
-			return ($dest_piece eq '-');
-		}
-		if ($to_col == $from_col && $from_row == 1 && $to_row == 3) {
-			my $middle_piece = $board->[2][$to_col];
-			return ($dest_piece eq '-' && $middle_piece eq '-');
-		}
-		if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
-			if ($dest_piece eq '-') {
-				# En passant. TODO: check that the last move was indeed an EP move
-				return ($to_row == 5 && $board->[4][$to_col] eq 'P');
-			} else {
-				return 1;
-			}
-		}
-		return 0;
-	}
-	if ($piece eq 'P') {
-		# white pawn
-		if ($to_col == $from_col && $to_row == $from_row - 1) {
-			return ($dest_piece eq '-');
-		}
-		if ($to_col == $from_col && $from_row == 6 && $to_row == 4) {
-			my $middle_piece = $board->[5][$to_col];
-			return ($dest_piece eq '-' && $middle_piece eq '-');
-		}
-		if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
-			if ($dest_piece eq '-') {
-				# En passant. TODO: check that the last move was indeed an EP move
-				return ($to_row == 2 && $board->[3][$to_col] eq 'p');
-			} else {
-				return 1;
-			}
-		}
-		return 0;
+	if (lc($piece) eq 'k') {
+		return (abs($from_row - $to_row) <= 1 && abs($from_col - $to_col) <= 1);
 	}
-	
+
 	# unknown piece
 	return 0;
 }
 
+# Like can_reach, but also checks the move doesn't put the side in check.
+# We use this in prettyprint_move to reduce the disambiguation, because Chess.js
+# needs moves to be in minimally disambiguated form.
+sub can_legally_reach {
+	my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
+
+	return 0 if (!can_reach($board, $piece, $from_row, $from_col, $to_row, $to_col));
+
+	my $nb = $board->make_move($from_row, $from_col, $to_row, $to_col);
+	my $side = ($piece eq lc($piece)) ? 'k' : 'K';
+
+	return !in_check($nb, $side);
+}
+
+my %pieces_against_side = (
+	k => { K => 1, Q => 1, R => 1, N => 1, B => 1, P => 1 },
+	K => { k => 1, q => 1, r => 1, n => 1, b => 1, p => 1 },
+);
+
 # Returns whether the given side (given as k or K for black and white) is in check.
 sub in_check {
-	my ($board, $piece) = @_;
-	my ($kr, $kc) = _find_piece($board, $piece);
+	my ($board, $side) = @_;
+	my ($kr, $kc) = _find_piece($board, $side);
 
 	# check all pieces for the possibility of threatening this king
 	for my $row (0..7) {
+		next unless grep { exists($pieces_against_side{$side}{$_}) } @{$board->[$row]};
 		for my $col (0..7) {
 			my $piece = $board->[$row][$col];
 			next if ($piece eq '-');
@@ -419,6 +479,19 @@ sub prettyprint_move {
 	return ($pretty, $nb);
 }
 
+sub num_pieces {
+	my ($board) = @_;
+
+	my $num = 0;
+	for my $row (0..7) {
+		for my $col (0..7) {
+			my $piece = $board->[$row][$col];
+			++$num if ($piece ne '-');
+		}
+	}
+	return $num;	
+}
+
 sub _prettyprint_move_no_check_or_mate {
         my ($board, $from_row, $from_col, $to_row, $to_col, $promo) = @_;
 	my $piece = $board->[$from_row][$from_col];
@@ -428,24 +501,26 @@ sub _prettyprint_move_no_check_or_mate {
 		die "Invalid move $move";
 	}
 
-	# white short castling
-	if ($move eq 'e1g1' && $piece eq 'K') {
-		return '0-0';
-	}
+	if ($piece eq 'K') {
+		# white short/long castling
+		return 'O-O' if ($move eq 'e1g1');
+		return 'O-O-O' if ($move eq 'e1c1');
 
-	# white long castling
-	if ($move eq 'e1c1' && $piece eq 'K') {
-		return '0-0-0';
-	}
-
-	# black short castling
-	if ($move eq 'e8g8' && $piece eq 'k') {
-		return '0-0';
-	}
-
-	# black long castling
-	if ($move eq 'e8c8' && $piece eq 'k') {
-		return '0-0-0';
+		# white short/long chess960-style castling (king takes own rook)
+		my $dst_piece = $board->[$to_row][$to_col];
+		if ($dst_piece eq 'R') {
+			return ($to_col > $from_col) ? 'O-O' : 'O-O-O';
+		}
+	} elsif ($piece eq 'k') {
+		# black short/long castling
+		return 'O-O' if ($move eq 'e8g8');
+		return 'O-O-O' if ($move eq 'e8c8');
+
+		# black short/long chess960-style castling (king takes own rook)
+		my $dst_piece = $board->[$to_row][$to_col];
+		if ($dst_piece eq 'r') {
+			return ($to_col > $from_col) ? 'O-O' : 'O-O-O';
+		}
 	}
 
 	my $pretty;
@@ -457,12 +532,12 @@ sub _prettyprint_move_no_check_or_mate {
 			$pretty = substr($move, 0, 1) . 'x' . _pos_to_square($to_row, $to_col);
 		} else {
 			$pretty = _pos_to_square($to_row, $to_col);
+		}
 
-			if (defined($promo) && $promo ne '') {
-				# promotion
-				$pretty .= "=";
-				$pretty .= $promo;
-			}
+		if (defined($promo) && $promo ne '') {
+			# promotion
+			$pretty .= "=";
+			$pretty .= uc($promo);
 		}
 		return $pretty;
 	}
@@ -474,7 +549,7 @@ sub _prettyprint_move_no_check_or_mate {
 	for my $col (0..7) {
 		for my $row (0..7) {
 			next unless ($board->[$row][$col] eq $piece);
-			++$num_total if ($board->can_reach($piece, $row, $col, $to_row, $to_col));
+			++$num_total if ($board->can_legally_reach($piece, $row, $col, $to_row, $to_col));
 		}
 	}
 
@@ -482,14 +557,14 @@ sub _prettyprint_move_no_check_or_mate {
 	my $num_row = 0;
 	for my $col (0..7) {
 		next unless ($board->[$from_row][$col] eq $piece);
-		++$num_row if ($board->can_reach($piece, $from_row, $col, $to_row, $to_col));
+		++$num_row if ($board->can_legally_reach($piece, $from_row, $col, $to_row, $to_col));
 	}
 
 	# and same for columns
 	my $num_col = 0;
 	for my $row (0..7) {
 		next unless ($board->[$row][$from_col] eq $piece);
-		++$num_col if ($board->can_reach($piece, $row, $from_col, $to_row, $to_col));
+		++$num_col if ($board->can_legally_reach($piece, $row, $from_col, $to_row, $to_col));
 	}
 
 	# see if we need to disambiguate