Fix (?) an issue where going from a display line all the back the root would hit...

[remoteglot] / Board.pm

diff --git a/Board.pm b/Board.pm
index 921de3d9c45f715e7084796aeb1a005bc5270093..3e0fd33a52b4fa72a4264a4eff58962dc93cc197 100644 (file)
--- a/Board.pm
+++ b/Board.pm
@@ -177,23 +177,26 @@ sub parse_pretty_move {
        }
 
        $move =~ /^([KQRBN])?([a-h])?([1-8])?x?([a-h][1-8])$/ 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 $piece);
+                       next if (defined($piece) && $board->[$row][$col] ne $piece);
                        push @squares, [ $row, $col ];
                }
        }
@@ -384,6 +387,20 @@ sub can_reach {
        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 },
@@ -497,22 +514,22 @@ sub _prettyprint_move_no_check_or_mate {
 
        # white short castling
        if ($move eq 'e1g1' && $piece eq 'K') {
-               return '0-0';
+               return 'O-O';
        }
 
        # white long castling
        if ($move eq 'e1c1' && $piece eq 'K') {
-               return '0-0-0';
+               return 'O-O-O';
        }
 
        # black short castling
        if ($move eq 'e8g8' && $piece eq 'k') {
-               return '0-0';
+               return 'O-O';
        }
 
        # black long castling
        if ($move eq 'e8c8' && $piece eq 'k') {
-               return '0-0-0';
+               return 'O-O-O';
        }
 
        my $pretty;
@@ -524,12 +541,12 @@ 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 .= "=";
-                               $pretty .= uc($promo);
-                       }
+               if (defined($promo) && $promo ne '') {
+                       # promotion
+                       $pretty .= "=";
+                       $pretty .= uc($promo);
                }
                return $pretty;
        }
@@ -541,7 +558,7 @@ 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));
                }
        }
 
@@ -549,14 +566,14 @@ 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