Fix a bug where fathom would cause all winning multi-PV lines to be the same.
[remoteglot] / remoteglot.pl
index e1da304..9439a4b 100755 (executable)
@@ -5,38 +5,46 @@
 #              analysis, or for live analysis of relayed games. (Do not use for
 #              cheating! Cheating is bad for your karma, and your abuser flag.)
 #
-# Copyright 2007 Steinar H. Gunderson <sgunderson@bigfoot.com>
+# Copyright 2007 Steinar H. Gunderson <steinar+remoteglot@gunderson.no>
 # Licensed under the GNU General Public License, version 2.
 #
 
+use AnyEvent;
+use AnyEvent::Handle;
+use AnyEvent::HTTP;
+use Chess::PGN::Parse;
+use EV;
 use Net::Telnet;
-use FileHandle;
+use File::Slurp;
 use IPC::Open2;
 use Time::HiRes;
 use JSON::XS;
+use URI::Escape;
+use DBI;
+use DBD::Pg;
+require 'Position.pm';
+require 'Engine.pm';
+require 'config.pm';
 use strict;
 use warnings;
-
-# Configuration
-my $server = "freechess.org";
-my $target = "GMCarlsen";
-my $engine_cmdline = "'./Deep Rybka 4 SSE42 x64'";
-my $engine2_cmdline = "./stockfish_13111119_x64_modern_sse42";
-my $telltarget = undef;   # undef to be silent
-my @tell_intervals = (5, 20, 60, 120, 240, 480, 960);  # after each move
-my $uci_assume_full_compliance = 0;                    # dangerous :-)
-my $update_max_interval = 1.0;
-my @masters = (
-       'Sesse',
-       'Sessse',
-       'Sesssse',
-       'greatestguns',
-       'beuki'
-);
+no warnings qw(once);
 
 # Program starts here
-$SIG{ALRM} = sub { output(); };
 my $latest_update = undef;
+my $output_timer = undef;
+my $http_timer = undef;
+my $stop_pgn_fetch = 0;
+my $tb_retry_timer = undef;
+my %tb_cache = ();
+my $tb_lookup_running = 0;
+my $last_written_json = undef;
+
+# Persisted so we can restart.
+# TODO: Figure out an appropriate way to deal with database restarts
+# and/or Postgres going away entirely.
+my $dbh = DBI->connect($remoteglotconf::dbistr, $remoteglotconf::dbiuser, $remoteglotconf::dbipass)
+       or die DBI->errstr;
+$dbh->{RaiseError} = 1;
 
 $| = 1;
 
@@ -51,38 +59,45 @@ open(UCILOG, ">ucilog.txt")
 print UCILOG "Log starting.\n";
 select(UCILOG);
 $| = 1;
+
+open(TBLOG, ">tblog.txt")
+       or die "tblog.txt: $!";
+print TBLOG "Log starting.\n";
+select(TBLOG);
+$| = 1;
+
 select(STDOUT);
+umask 0022;
 
 # open the chess engine
-my $engine = open_engine($engine_cmdline, 'E1');
-my $engine2 = open_engine($engine2_cmdline, 'E2');
-my ($last_move, $last_tell);
+my $engine = open_engine($remoteglotconf::engine_cmdline, 'E1', sub { handle_uci(@_, 1); });
+my $engine2 = open_engine($remoteglotconf::engine2_cmdline, 'E2', sub { handle_uci(@_, 0); });
+my $last_move;
 my $last_text = '';
-my $last_told_text = '';
 my ($pos_waiting, $pos_calculating, $pos_calculating_second_engine);
 
 uciprint($engine, "setoption name UCI_AnalyseMode value true");
-# uciprint($engine, "setoption name NalimovPath value /srv/tablebase");
-uciprint($engine, "setoption name NalimovUsage value Rarely");
-uciprint($engine, "setoption name Hash value 1024");
-# uciprint($engine, "setoption name MultiPV value 2");
+while (my ($key, $value) = each %remoteglotconf::engine_config) {
+       uciprint($engine, "setoption name $key value $value");
+}
 uciprint($engine, "ucinewgame");
 
-uciprint($engine2, "setoption name UCI_AnalyseMode value true");
-# uciprint($engine2, "setoption name NalimovPath value /srv/tablebase");
-uciprint($engine2, "setoption name NalimovUsage value Rarely");
-uciprint($engine2, "setoption name Hash value 1024");
-uciprint($engine2, "setoption name Threads value 8");
-uciprint($engine2, "setoption name MultiPV value 500");
-uciprint($engine2, "ucinewgame");
+if (defined($engine2)) {
+       uciprint($engine2, "setoption name UCI_AnalyseMode value true");
+       while (my ($key, $value) = each %remoteglotconf::engine2_config) {
+               uciprint($engine2, "setoption name $key value $value");
+       }
+       uciprint($engine2, "setoption name MultiPV value 500");
+       uciprint($engine2, "ucinewgame");
+}
 
 print "Chess engine ready.\n";
 
 # now talk to FICS
 my $t = Net::Telnet->new(Timeout => 10, Prompt => '/fics% /');
 $t->input_log(\*FICSLOG);
-$t->open($server);
-$t->print("SesseBOT");
+$t->open($remoteglotconf::server);
+$t->print($remoteglotconf::nick);
 $t->waitfor('/Press return to enter the server/');
 $t->cmd("");
 
@@ -90,129 +105,38 @@ $t->cmd("");
 $t->cmd("set shout 0");
 $t->cmd("set seek 0");
 $t->cmd("set style 12");
-$t->cmd("observe $target");
 
-# main loop
-print "FICS ready.\n";
-while (1) {
-       my $rin = '';
-       my $rout;
-       vec($rin, fileno($engine->{'read'}), 1) = 1;
-       vec($rin, fileno($engine2->{'read'}), 1) = 1;
-       vec($rin, fileno($t), 1) = 1;
-
-       my ($nfound, $timeleft) = select($rout=$rin, undef, undef, 5.0);
-       my $sleep = 1.0;
-
-       while (1) {
-               my $line = $t->getline(Timeout => 0, errmode => 'return');
-               last if (!defined($line));
-
-               chomp $line;
-               $line =~ tr/\r//d;
-               if ($line =~ /^<12> /) {
-                       my $pos = style12_to_pos($line);
-                       
-                       # if this is already in the queue, ignore it
-                       next if (defined($pos_waiting) && $pos->{'fen'} eq $pos_waiting->{'fen'});
-
-                       # if we're already chewing on this and there's nothing else in the queue,
-                       # also ignore it
-                       next if (!defined($pos_waiting) && defined($pos_calculating) &&
-                                $pos->{'fen'} eq $pos_calculating->{'fen'});
-
-                       # if we're already thinking on something, stop and wait for the engine
-                       # to approve
-                       if (defined($pos_calculating)) {
-                               if (!defined($pos_waiting)) {
-                                       uciprint($engine, "stop");
-                               }
-                               if ($uci_assume_full_compliance) {
-                                       $pos_waiting = $pos;
-                               } else {
-                                       uciprint($engine, "position fen " . $pos->{'fen'});
-                                       uciprint($engine, "go infinite");
-                                       $pos_calculating = $pos;
-                               }
-                       } else {
-                               # it's wrong just to give the FEN (the move history is useful,
-                               # and per the UCI spec, we should really have sent "ucinewgame"),
-                               # but it's easier
-                               uciprint($engine, "position fen " . $pos->{'fen'});
-                               uciprint($engine, "go infinite");
-                               $pos_calculating = $pos;
-                       }
-
-                       if (defined($pos_calculating_second_engine)) {
-                               uciprint($engine2, "stop");
-                       } else {
-                               uciprint($engine2, "position fen " . $pos->{'fen'});
-                               uciprint($engine2, "go infinite");
-                               $pos_calculating_second_engine = $pos;
-                       }
-
-                       $engine->{'info'} = {};
-                       $engine2->{'info'} = {};
-                       $last_move = time;
-
-                       # 
-                       # Output a command every move to note that we're
-                       # still paying attention -- this is a good tradeoff,
-                       # since if no move has happened in the last half
-                       # hour, the analysis/relay has most likely stopped
-                       # and we should stop hogging server resources.
-                       #
-                       $t->cmd("date");
-               }
-               if ($line =~ /^([A-Za-z]+)(?:\([A-Z]+\))* tells you: (.*)$/) {
-                       my ($who, $msg) = ($1, $2);
-
-                       next if (grep { $_ eq $who } (@masters) == 0);
-       
-                       if ($msg =~ /^fics (.*?)$/) {
-                               $t->cmd("tell $who Executing '$1' on FICS.");
-                               $t->cmd($1);
-                       } elsif ($msg =~ /^uci (.*?)$/) {
-                               $t->cmd("tell $who Sending '$1' to the engine.");
-                               print { $engine->{'write'} } "$1\n";
-                       } else {
-                               $t->cmd("tell $who Couldn't understand '$msg', sorry.");
-                       }
+my $ev1 = AnyEvent->io(
+       fh => fileno($t),
+       poll => 'r',
+       cb => sub {    # what callback to execute
+               while (1) {
+                       my $line = $t->getline(Timeout => 0, errmode => 'return');
+                       return if (!defined($line));
+
+                       chomp $line;
+                       $line =~ tr/\r//d;
+                       handle_fics($line);
                }
-               #print "FICS: [$line]\n";
-               $sleep = 0;
        }
-       
-       # any fun on the UCI channel?
-       if ($nfound > 0 && vec($rout, fileno($engine->{'read'}), 1) == 1) {
-               my @lines = read_lines($engine);
-               for my $line (@lines) {
-                       next if $line =~ /(upper|lower)bound/;
-                       handle_uci($engine, $line, 1);
-               }
-               $sleep = 0;
-
-               output();
-       }
-       if ($nfound > 0 && vec($rout, fileno($engine2->{'read'}), 1) == 1) {
-               my @lines = read_lines($engine2);
-               for my $line (@lines) {
-                       next if $line =~ /(upper|lower)bound/;
-                       handle_uci($engine2, $line, 0);
-               }
-               $sleep = 0;
-
-               output();
+);
+if (defined($remoteglotconf::target)) {
+       if ($remoteglotconf::target =~ /^http:/) {
+               fetch_pgn($remoteglotconf::target);
+       } else {
+               $t->cmd("observe $remoteglotconf::target");
        }
-
-       sleep $sleep;
 }
+print "FICS ready.\n";
+
+# Engine events have already been set up by Engine.pm.
+EV::run;
 
 sub handle_uci {
        my ($engine, $line, $primary) = @_;
 
-       chomp $line;
-       $line =~ tr/\r//d;
+       return if $line =~ /(upper|lower)bound/;
+
        $line =~ s/  / /g;  # Sometimes needed for Zappa Mexico
        print UCILOG localtime() . " $engine->{'tag'} <= $line\n";
        if ($line =~ /^info/) {
@@ -229,9 +153,9 @@ sub handle_uci {
        }
        if ($line =~ /^bestmove/) {
                if ($primary) {
-                       return if (!$uci_assume_full_compliance);
+                       return if (!$remoteglotconf::uci_assume_full_compliance);
                        if (defined($pos_waiting)) {
-                               uciprint($engine, "position fen " . $pos_waiting->{'fen'});
+                               uciprint($engine, "position fen " . $pos_waiting->fen());
                                uciprint($engine, "go infinite");
 
                                $pos_calculating = $pos_waiting;
@@ -240,11 +164,266 @@ sub handle_uci {
                } else {
                        $engine2->{'info'} = {};
                        my $pos = $pos_waiting // $pos_calculating;
-                       uciprint($engine2, "position fen " . $pos->{'fen'});
+                       uciprint($engine2, "position fen " . $pos->fen());
                        uciprint($engine2, "go infinite");
                        $pos_calculating_second_engine = $pos;
                }
        }
+       output();
+}
+
+my $getting_movelist = 0;
+my $pos_for_movelist = undef;
+my @uci_movelist = ();
+my @pretty_movelist = ();
+
+sub handle_fics {
+       my $line = shift;
+       if ($line =~ /^<12> /) {
+               handle_position(Position->new($line));
+               $t->cmd("moves");
+       }
+       if ($line =~ /^Movelist for game /) {
+               my $pos = $pos_waiting // $pos_calculating;
+               if (defined($pos)) {
+                       @uci_movelist = ();
+                       @pretty_movelist = ();
+                       $pos_for_movelist = Position->start_pos($pos->{'player_w'}, $pos->{'player_b'});
+                       $getting_movelist = 1;
+               }
+       }
+       if ($getting_movelist &&
+           $line =~ /^\s* \d+\. \s+                     # move number
+                       (\S+) \s+ \( [\d:.]+ \) \s*       # first move, then time
+                      (?: (\S+) \s+ \( [\d:.]+ \) )?    # second move, then time 
+                    /x) {
+               eval {
+                       my $uci_move;
+                       ($pos_for_movelist, $uci_move) = $pos_for_movelist->make_pretty_move($1);
+                       push @uci_movelist, $uci_move;
+                       push @pretty_movelist, $1;
+
+                       if (defined($2)) {
+                               ($pos_for_movelist, $uci_move) = $pos_for_movelist->make_pretty_move($2);
+                               push @uci_movelist, $uci_move;
+                               push @pretty_movelist, $2;
+                       }
+               };
+               if ($@) {
+                       warn "Error when getting FICS move history: $@";
+                       $getting_movelist = 0;
+               }
+       }
+       if ($getting_movelist &&
+           $line =~ /^\s+ \{.*\} \s+ (?: \* | 1\/2-1\/2 | 0-1 | 1-0 )/x) {
+               # End of movelist.
+               for my $pos ($pos_waiting, $pos_calculating) {
+                       next if (!defined($pos));
+                       if ($pos->fen() eq $pos_for_movelist->fen()) {
+                               $pos->{'history'} = \@pretty_movelist;
+                       }
+               }
+               $getting_movelist = 0;
+       }
+       if ($line =~ /^([A-Za-z]+)(?:\([A-Z]+\))* tells you: (.*)$/) {
+               my ($who, $msg) = ($1, $2);
+
+               next if (grep { $_ eq $who } (@remoteglotconf::masters) == 0);
+
+               if ($msg =~ /^fics (.*?)$/) {
+                       $t->cmd("tell $who Executing '$1' on FICS.");
+                       $t->cmd($1);
+               } elsif ($msg =~ /^uci (.*?)$/) {
+                       $t->cmd("tell $who Sending '$1' to the engine.");
+                       print { $engine->{'write'} } "$1\n";
+               } elsif ($msg =~ /^pgn (.*?)$/) {
+                       my $url = $1;
+                       $t->cmd("tell $who Starting to poll '$url'.");
+                       fetch_pgn($url);
+               } elsif ($msg =~ /^stoppgn$/) {
+                       $t->cmd("tell $who Stopping poll.");
+                       $stop_pgn_fetch = 1;
+                       $http_timer = undef;
+               } elsif ($msg =~ /^quit$/) {
+                       $t->cmd("tell $who Bye bye.");
+                       exit;
+               } else {
+                       $t->cmd("tell $who Couldn't understand '$msg', sorry.");
+               }
+       }
+       #print "FICS: [$line]\n";
+}
+
+# Starts periodic fetching of PGNs from the given URL.
+sub fetch_pgn {
+       my ($url) = @_;
+       AnyEvent::HTTP::http_get($url, sub {
+               handle_pgn(@_, $url);
+       });
+}
+
+my ($last_pgn_white, $last_pgn_black);
+my @last_pgn_uci_moves = ();
+my $pgn_hysteresis_counter = 0;
+
+sub handle_pgn {
+       my ($body, $header, $url) = @_;
+
+       if ($stop_pgn_fetch) {
+               $stop_pgn_fetch = 0;
+               $http_timer = undef;
+               return;
+       }
+
+       my $pgn = Chess::PGN::Parse->new(undef, $body);
+       if (!defined($pgn)) {
+               warn "Error in parsing PGN from $url [body='$body']\n";
+       } elsif (!$pgn->read_game()) {
+               warn "Error in reading PGN game from $url [body='$body']\n";
+       } elsif ($body !~ /^\[/) {
+               warn "Malformed PGN from $url [body='$body']\n";
+       } else {
+               eval {
+                       # Skip to the right game.
+                       while (defined($remoteglotconf::pgn_filter) &&
+                              !&$remoteglotconf::pgn_filter($pgn)) {
+                               $pgn->read_game() or die "Out of games during filtering";
+                       }
+
+                       $pgn->parse_game({ save_comments => 'yes' });
+                       my $white = $pgn->white;
+                       my $black = $pgn->black;
+                       $white =~ s/,.*//;  # Remove first name.
+                       $black =~ s/,.*//;  # Remove first name.
+                       my $pos = Position->start_pos($white, $black);
+                       my $moves = $pgn->moves;
+                       my @uci_moves = ();
+                       my @repretty_moves = ();
+                       for my $move (@$moves) {
+                               my ($npos, $uci_move) = $pos->make_pretty_move($move);
+                               push @uci_moves, $uci_move;
+
+                               # Re-prettyprint the move.
+                               my ($from_row, $from_col, $to_row, $to_col, $promo) = parse_uci_move($uci_move);
+                               my ($pretty, undef) = $pos->{'board'}->prettyprint_move($from_row, $from_col, $to_row, $to_col, $promo);
+                               push @repretty_moves, $pretty;
+                               $pos = $npos;
+                       }
+                       if ($pgn->result eq '1-0' || $pgn->result eq '1/2-1/2' || $pgn->result eq '0-1') {
+                               $pos->{'result'} = $pgn->result;
+                       }
+                       $pos->{'history'} = \@repretty_moves;
+
+                       extract_clock($pgn, $pos);
+
+                       # Sometimes, PGNs lose a move or two for a short while,
+                       # or people push out new ones non-atomically. 
+                       # Thus, if we PGN doesn't change names but becomes
+                       # shorter, we mistrust it for a few seconds.
+                       my $trust_pgn = 1;
+                       if (defined($last_pgn_white) && defined($last_pgn_black) &&
+                           $last_pgn_white eq $pgn->white &&
+                           $last_pgn_black eq $pgn->black &&
+                           scalar(@uci_moves) < scalar(@last_pgn_uci_moves)) {
+                               if (++$pgn_hysteresis_counter < 3) {
+                                       $trust_pgn = 0; 
+                               }
+                       }
+                       if ($trust_pgn) {
+                               $last_pgn_white = $pgn->white;
+                               $last_pgn_black = $pgn->black;
+                               @last_pgn_uci_moves = @uci_moves;
+                               $pgn_hysteresis_counter = 0;
+                               handle_position($pos);
+                       }
+               };
+               if ($@) {
+                       warn "Error in parsing moves from $url: $@\n";
+               }
+       }
+       
+       $http_timer = AnyEvent->timer(after => 1.0, cb => sub {
+               fetch_pgn($url);
+       });
+}
+
+sub handle_position {
+       my ($pos) = @_;
+       find_clock_start($pos, $pos_calculating);
+               
+       # if this is already in the queue, ignore it (just update the result)
+       if (defined($pos_waiting) && $pos->fen() eq $pos_waiting->fen()) {
+               $pos_waiting->{'result'} = $pos->{'result'};
+               return;
+       }
+
+       # if we're already chewing on this and there's nothing else in the queue,
+       # also ignore it
+       if (!defined($pos_waiting) && defined($pos_calculating) &&
+           $pos->fen() eq $pos_calculating->fen()) {
+               $pos_calculating->{'result'} = $pos->{'result'};
+               return;
+       }
+
+       # if we're already thinking on something, stop and wait for the engine
+       # to approve
+       if (defined($pos_calculating)) {
+               # Store the final data we have for this position in the history,
+               # with the precise clock information we just got from the new
+               # position. (Historic positions store the clock at the end of
+               # the position.)
+               #
+               # Do not output anything new to the main analysis; that's
+               # going to be obsolete really soon.
+               $pos_calculating->{'white_clock'} = $pos->{'white_clock'};
+               $pos_calculating->{'black_clock'} = $pos->{'black_clock'};
+               delete $pos_calculating->{'white_clock_target'};
+               delete $pos_calculating->{'black_clock_target'};
+               output_json(1);
+
+               if (!defined($pos_waiting)) {
+                       uciprint($engine, "stop");
+               }
+               if ($remoteglotconf::uci_assume_full_compliance) {
+                       $pos_waiting = $pos;
+               } else {
+                       uciprint($engine, "position fen " . $pos->fen());
+                       uciprint($engine, "go infinite");
+                       $pos_calculating = $pos;
+               }
+       } else {
+               # it's wrong just to give the FEN (the move history is useful,
+               # and per the UCI spec, we should really have sent "ucinewgame"),
+               # but it's easier
+               uciprint($engine, "position fen " . $pos->fen());
+               uciprint($engine, "go infinite");
+               $pos_calculating = $pos;
+       }
+
+       if (defined($engine2)) {
+               if (defined($pos_calculating_second_engine)) {
+                       uciprint($engine2, "stop");
+               } else {
+                       uciprint($engine2, "position fen " . $pos->fen());
+                       uciprint($engine2, "go infinite");
+                       $pos_calculating_second_engine = $pos;
+               }
+               $engine2->{'info'} = {};
+       }
+
+       $engine->{'info'} = {};
+       $last_move = time;
+
+       schedule_tb_lookup();
+
+       # 
+       # Output a command every move to note that we're
+       # still paying attention -- this is a good tradeoff,
+       # since if no move has happened in the last half
+       # hour, the analysis/relay has most likely stopped
+       # and we should stop hogging server resources.
+       #
+       $t->cmd("date");
 }
 
 sub parse_infos {
@@ -255,26 +434,28 @@ sub parse_infos {
 
        # Search for "multipv" first of all, since e.g. Stockfish doesn't put it first.
        for my $i (0..$#x - 1) {
-               if ($x[$i] =~ 'multipv') {
+               if ($x[$i] eq 'multipv') {
                        $mpv = $x[$i + 1];
                        next;
                }
        }
 
        while (scalar @x > 0) {
-               if ($x[0] =~ 'multipv') {
+               if ($x[0] eq 'multipv') {
                        # Dealt with above
                        shift @x;
                        shift @x;
                        next;
                }
-               if ($x[0] =~ /^(currmove|currmovenumber|cpuload)$/) {
+               if ($x[0] eq 'currmove' || $x[0] eq 'currmovenumber' || $x[0] eq 'cpuload') {
                        my $key = shift @x;
                        my $value = shift @x;
                        $info->{$key} = $value;
                        next;
                }
-               if ($x[0] =~ /^(depth|seldepth|hashfull|time|nodes|nps|tbhits)$/) {
+               if ($x[0] eq 'depth' || $x[0] eq 'seldepth' || $x[0] eq 'hashfull' ||
+                   $x[0] eq 'time' || $x[0] eq 'nodes' || $x[0] eq 'nps' ||
+                   $x[0] eq 'tbhits') {
                        my $key = shift @x;
                        my $value = shift @x;
                        $info->{$key . $mpv} = $value;
@@ -286,7 +467,7 @@ sub parse_infos {
                        delete $info->{'score_cp' . $mpv};
                        delete $info->{'score_mate' . $mpv};
 
-                       while ($x[0] =~ /^(cp|mate|lowerbound|upperbound)$/) {
+                       while ($x[0] eq 'cp' || $x[0] eq 'mate') {
                                if ($x[0] eq 'cp') {
                                        shift @x;
                                        $info->{'score_cp' . $mpv} = shift @x;
@@ -318,10 +499,9 @@ sub parse_ids {
        my ($engine, @x) = @_;
 
        while (scalar @x > 0) {
-               if ($x[0] =~ /^(name|author)$/) {
-                       my $key = shift @x;
+               if ($x[0] eq 'name') {
                        my $value = join(' ', @x);
-                       $engine->{'id'}{$key} = $value;
+                       $engine->{'id'}{'author'} = $value;
                        last;
                }
 
@@ -330,190 +510,7 @@ sub parse_ids {
        }
 }
 
-sub style12_to_pos {
-       my $str = shift;
-       my %pos = ();
-       my (@x) = split / /, $str;
-       
-       $pos{'board'} = [ @x[1..8] ];
-       $pos{'toplay'} = $x[9];
-       $pos{'ep_file_num'} = $x[10];
-       $pos{'white_castle_k'} = $x[11];
-       $pos{'white_castle_q'} = $x[12];
-       $pos{'black_castle_k'} = $x[13];
-       $pos{'black_castle_q'} = $x[14];
-       $pos{'time_to_100move_rule'} = $x[15];
-       $pos{'move_num'} = $x[26];
-       if ($x[27] =~ /([a-h][1-8])-([a-h][1-8])/) {
-               $pos{'last_move_uci'} = $1 . $2;
-       } else {
-               $pos{'last_move_uci'} = undef;
-       }
-       $pos{'last_move'} = $x[29];
-       $pos{'fen'} = make_fen(\%pos);
-
-       return \%pos;
-}
-
-sub make_fen {
-       my $pos = shift;
-
-       # the board itself
-       my (@board) = @{$pos->{'board'}};
-       for my $rank (0..7) {
-               $board[$rank] =~ s/(-+)/length($1)/ge;
-       }
-       my $fen = join('/', @board);
-
-       # white/black to move
-       $fen .= " ";
-       $fen .= lc($pos->{'toplay'});
-
-       # castling
-       my $castling = "";
-       $castling .= "K" if ($pos->{'white_castle_k'} == 1);
-       $castling .= "Q" if ($pos->{'white_castle_q'} == 1);
-       $castling .= "k" if ($pos->{'black_castle_k'} == 1);
-       $castling .= "q" if ($pos->{'black_castle_q'} == 1);
-       $castling = "-" if ($castling eq "");
-       # $castling = "-"; # chess960
-       $fen .= " ";
-       $fen .= $castling;
-
-       # en passant
-       my $ep = "-";
-       if ($pos->{'ep_file_num'} != -1) {
-               my $col = $pos->{'ep_file_num'};
-               my $nep = (qw(a b c d e f g h))[$col];
-
-               if ($pos->{'toplay'} eq 'B') {
-                       $nep .= "3";
-               } else {
-                       $nep .= "6";
-               }
-
-               #
-               # Showing the en passant square when actually no capture can be made
-               # seems to confuse at least Rybka. Thus, check if there's actually
-               # a pawn of the opposite side that can do the en passant move, and if
-               # not, just lie -- it doesn't matter anyway. I'm unsure what's the
-               # "right" thing as per the standard, though.
-               #
-               if ($pos->{'toplay'} eq 'B') {
-                       $ep = $nep if ($col > 0 && substr($pos->{'board'}[4], $col-1, 1) eq 'p');
-                       $ep = $nep if ($col < 7 && substr($pos->{'board'}[4], $col+1, 1) eq 'p');
-               } else {
-                       $ep = $nep if ($col > 0 && substr($pos->{'board'}[3], $col-1, 1) eq 'P');
-                       $ep = $nep if ($col < 7 && substr($pos->{'board'}[3], $col+1, 1) eq 'P');
-               }
-       }
-       $fen .= " ";
-       $fen .= $ep;
-
-       # half-move clock
-       $fen .= " ";
-       $fen .= $pos->{'time_to_100move_rule'};
-
-       # full-move clock
-       $fen .= " ";
-       $fen .= $pos->{'move_num'};
-
-       return $fen;
-}
-
-sub make_move {
-       my ($board, $from_row, $from_col, $to_row, $to_col, $promo) = @_;
-       my $move = move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
-       my $piece = substr($board->[$from_row], $from_col, 1);
-       my @nb = @$board;
-
-       if ($piece eq '-') {
-               die "Invalid move $move";
-       }
-
-       # white short castling
-       if ($move eq 'e1g1' && $piece eq 'K') {
-               # king
-               substr($nb[7], 4, 1, '-');
-               substr($nb[7], 6, 1, $piece);
-               
-               # rook
-               substr($nb[7], 7, 1, '-');
-               substr($nb[7], 5, 1, 'R');
-                               
-               return \@nb;
-       }
-
-       # white long castling
-       if ($move eq 'e1c1' && $piece eq 'K') {
-               # king
-               substr($nb[7], 4, 1, '-');
-               substr($nb[7], 2, 1, $piece);
-               
-               # rook
-               substr($nb[7], 0, 1, '-');
-               substr($nb[7], 3, 1, 'R');
-                               
-               return \@nb;
-       }
-
-       # black short castling
-       if ($move eq 'e8g8' && $piece eq 'k') {
-               # king
-               substr($nb[0], 4, 1, '-');
-               substr($nb[0], 6, 1, $piece);
-               
-               # rook
-               substr($nb[0], 7, 1, '-');
-               substr($nb[0], 5, 1, 'r');
-                               
-               return \@nb;
-       }
-
-       # black long castling
-       if ($move eq 'e8c8' && $piece eq 'k') {
-               # king
-               substr($nb[0], 4, 1, '-');
-               substr($nb[0], 2, 1, $piece);
-               
-               # rook
-               substr($nb[0], 0, 1, '-');
-               substr($nb[0], 3, 1, 'r');
-                               
-               return \@nb;
-       }
-
-       # check if the from-piece is a pawn
-       if (lc($piece) eq 'p') {
-               # attack?
-               if ($from_col != $to_col) {
-                       # en passant?
-                       if (substr($board->[$to_row], $to_col, 1) eq '-') {
-                               if ($piece eq 'p') {
-                                       substr($nb[$to_row + 1], $to_col, 1, '-');
-                               } else {
-                                       substr($nb[$to_row - 1], $to_col, 1, '-');
-                               }
-                       }
-               } else {
-                       if ($promo ne '') {
-                               if ($piece eq 'p') {
-                                       $piece = $promo;
-                               } else {
-                                       $piece = uc($promo);
-                               }
-                       }
-               }
-       }
-
-       # update the board
-       substr($nb[$from_row], $from_col, 1, '-');
-       substr($nb[$to_row], $to_col, 1, $piece);
-
-       return \@nb;
-}
-
-sub prettyprint_pv {
+sub prettyprint_pv_no_cache {
        my ($board, @pvs) = @_;
 
        if (scalar @pvs == 0 || !defined($pvs[0])) {
@@ -521,112 +518,84 @@ sub prettyprint_pv {
        }
 
        my $pv = shift @pvs;
-       my $from_col = col_letter_to_num(substr($pv, 0, 1));
-       my $from_row = row_letter_to_num(substr($pv, 1, 1));
-       my $to_col   = col_letter_to_num(substr($pv, 2, 1));
-       my $to_row   = row_letter_to_num(substr($pv, 3, 1));
-       my $promo    = substr($pv, 4, 1);
-
-       my $nb = make_move($board, $from_row, $from_col, $to_row, $to_col, $promo);
-       my $piece = substr($board->[$from_row], $from_col, 1);
-
-       if ($piece eq '-') {
-               die "Invalid move $pv";
-       }
-
-       # white short castling
-       if ($pv eq 'e1g1' && $piece eq 'K') {
-               return ('0-0', prettyprint_pv($nb, @pvs));
-       }
+       my ($from_row, $from_col, $to_row, $to_col, $promo) = parse_uci_move($pv);
+       my ($pretty, $nb) = $board->prettyprint_move($from_row, $from_col, $to_row, $to_col, $promo);
+       return ( $pretty, prettyprint_pv_no_cache($nb, @pvs) );
+}
 
-       # white long castling
-       if ($pv eq 'e1c1' && $piece eq 'K') {
-               return ('0-0-0', prettyprint_pv($nb, @pvs));
-       }
+sub prettyprint_pv {
+       my ($pos, @pvs) = @_;
 
-       # black short castling
-       if ($pv eq 'e8g8' && $piece eq 'k') {
-               return ('0-0', prettyprint_pv($nb, @pvs));
+       my $cachekey = join('', @pvs);
+       if (exists($pos->{'prettyprint_cache'}{$cachekey})) {
+               return @{$pos->{'prettyprint_cache'}{$cachekey}};
+       } else {
+               my @res = prettyprint_pv_no_cache($pos->{'board'}, @pvs);
+               $pos->{'prettyprint_cache'}{$cachekey} = \@res;
+               return @res;
        }
+}
 
-       # black long castling
-       if ($pv eq 'e8c8' && $piece eq 'k') {
-               return ('0-0-0', prettyprint_pv($nb, @pvs));
-       }
+sub complete_using_tbprobe {
+       my ($pos, $info, $mpv) = @_;
 
-       my $pretty;
+       # We need Fathom installed to do standalone TB probes.
+       return if (!defined($remoteglotconf::fathom_cmdline));
 
-       # check if the from-piece is a pawn
-       if (lc($piece) eq 'p') {
-               # attack?
-               if ($from_col != $to_col) {
-                       $pretty = substr($pv, 0, 1) . 'x' . substr($pv, 2, 2);
-               } else {
-                       $pretty = substr($pv, 2, 2);
+       # If we already have a mate, don't bother; in some cases, it would even be
+       # better than a tablebase score.
+       return if defined($info->{'score_mate' . $mpv});
 
-                       if (length($pv) == 5) {
-                               # promotion
-                               $pretty .= "=";
-                               $pretty .= uc(substr($pv, 4, 1));
+       # If we have a draw or near-draw score, there's also not much interesting
+       # we could add from a tablebase. We only really want mates.
+       return if ($info->{'score_cp' . $mpv} >= -12250 && $info->{'score_cp' . $mpv} <= 12250);
 
-                               if ($piece eq 'p') {
-                                       $piece = substr($pv, 4, 1);
-                               } else {
-                                       $piece = uc(substr($pv, 4, 1));
-                               }
-                       }
-               }
+       # Run through the PV until we are at a 6-man position.
+       # TODO: We could in theory only have 5-man data.
+       my @pv = @{$info->{'pv' . $mpv}};
+       my $key = join('', @pv);
+       my @moves = ();
+       if (exists($pos->{'tbprobe_cache'}{$key})) {
+               @moves = $pos->{'tbprobe_cache'}{$key};
        } else {
-               $pretty = uc($piece);
-
-               # see how many of these pieces could go here, in all
-               my $num_total = 0;
-               for my $col (0..7) {
-                       for my $row (0..7) {
-                               next unless (substr($board->[$row], $col, 1) eq $piece);
-                               ++$num_total if (can_reach($board, $piece, $row, $col, $to_row, $to_col));
-                       }
+               if ($mpv ne '') {
+                       # Force doing at least one move of the PV.
+                       my $move = shift @pv;
+                       push @moves, $move;
+                       $pos = $pos->make_move(parse_uci_move($move));
                }
 
-               # see how many of these pieces from the given row could go here
-               my $num_row = 0;
-               for my $col (0..7) {
-                       next unless (substr($board->[$from_row], $col, 1) eq $piece);
-                       ++$num_row if (can_reach($board, $piece, $from_row, $col, $to_row, $to_col));
-               }
-               
-               # and same for columns
-               my $num_col = 0;
-               for my $row (0..7) {
-                       next unless (substr($board->[$row], $from_col, 1) eq $piece);
-                       ++$num_col if (can_reach($board, $piece, $row, $from_col, $to_row, $to_col));
-               }
-               
-               # see if we need to disambiguate
-               if ($num_total > 1) {
-                       if ($num_col == 1) {
-                               $pretty .= substr($pv, 0, 1);
-                       } elsif ($num_row == 1) {
-                               $pretty .= substr($pv, 1, 1);
-                       } else {
-                               $pretty .= substr($pv, 0, 2);
-                       }
+               while ($pos->num_pieces() > 6 && $#pv > -1) {
+                       my $move = shift @pv;
+                       push @moves, $move;
+                       $pos = $pos->make_move(parse_uci_move($move));
                }
 
-               # attack?
-               if (substr($board->[$to_row], $to_col, 1) ne '-') {
-                       $pretty .= 'x';
-               }
+               return if ($pos->num_pieces() > 6);
 
-               $pretty .= substr($pv, 2, 2);
+               my $fen = $pos->fen();
+               my $pgn_text = `fathom --path=/srv/syzygy "$fen"`;
+               my $pgn = Chess::PGN::Parse->new(undef, $pgn_text);
+               return if (!defined($pgn) || !$pgn->read_game() || ($pgn->result ne '0-1' && $pgn->result ne '1-0'));
+               $pgn->quick_parse_game;
+               $info->{'pv' . $mpv} = \@moves;
+
+               # Splice the PV from the tablebase onto what we have so far.
+               for my $move (@{$pgn->moves}) {
+                       my $uci_move;
+                       ($pos, $uci_move) = $pos->make_pretty_move($move);
+                       push @moves, $uci_move;
+               }
        }
 
-       if (in_mate($nb)) {
-               $pretty .= '#';
-       } elsif (in_check($nb) ne 'none') {
-               $pretty .= '+';
+       $info->{'pv' . $mpv} = \@moves;
+
+       my $matelen = int((1 + scalar @moves) / 2);
+       if ((scalar @moves) % 2 == 0) {
+               $info->{'score_mate' . $mpv} = -$matelen;
+       } else {
+               $info->{'score_mate' . $mpv} = $matelen;
        }
-       return ($pretty, prettyprint_pv($nb, @pvs));
 }
 
 sub output {
@@ -636,12 +605,53 @@ sub output {
 
        # Don't update too often.
        my $age = Time::HiRes::tv_interval($latest_update);
-       if ($age < $update_max_interval) {
-               Time::HiRes::alarm($update_max_interval + 0.01 - $age);
+       if ($age < $remoteglotconf::update_max_interval) {
+               my $wait = $remoteglotconf::update_max_interval + 0.01 - $age;
+               $output_timer = AnyEvent->timer(after => $wait, cb => \&output);
                return;
        }
        
        my $info = $engine->{'info'};
+
+       #
+       # If we have tablebase data from a previous lookup, replace the
+       # engine data with the data from the tablebase.
+       #
+       my $fen = $pos_calculating->fen();
+       if (exists($tb_cache{$fen})) {
+               for my $key (qw(pv score_cp score_mate nodes nps depth seldepth tbhits)) {
+                       delete $info->{$key . '1'};
+                       delete $info->{$key};
+               }
+               $info->{'nodes'} = 0;
+               $info->{'nps'} = 0;
+               $info->{'depth'} = 0;
+               $info->{'seldepth'} = 0;
+               $info->{'tbhits'} = 0;
+
+               my $t = $tb_cache{$fen};
+               my $pv = $t->{'pv'};
+               my $matelen = int((1 + $t->{'score'}) / 2);
+               if ($t->{'result'} eq '1/2-1/2') {
+                       $info->{'score_cp'} = 0;
+               } elsif ($t->{'result'} eq '1-0') {
+                       if ($pos_calculating->{'toplay'} eq 'B') {
+                               $info->{'score_mate'} = -$matelen;
+                       } else {
+                               $info->{'score_mate'} = $matelen;
+                       }
+               } else {
+                       if ($pos_calculating->{'toplay'} eq 'B') {
+                               $info->{'score_mate'} = $matelen;
+                       } else {
+                               $info->{'score_mate'} = -$matelen;
+                       }
+               }
+               $info->{'pv'} = $pv;
+               $info->{'tablebase'} = 1;
+       } else {
+               $info->{'tablebase'} = 0;
+       }
        
        #
        # Some programs _always_ report MultiPV, even with only one PV.
@@ -652,6 +662,8 @@ sub output {
                for my $key (qw(pv score_cp score_mate nodes nps depth seldepth tbhits)) {
                        if (exists($info->{$key . '1'})) {
                                $info->{$key} = $info->{$key . '1'};
+                       } else {
+                               delete $info->{$key};
                        }
                }
        }
@@ -664,12 +676,12 @@ sub output {
        eval {
                my $dummy;
                if (exists($info->{'pv'})) {
-                       $dummy = prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv'}});
+                       $dummy = prettyprint_pv($pos_calculating, @{$info->{'pv'}});
                }
        
                my $mpv = 1;
                while (exists($info->{'pv' . $mpv})) {
-                       $dummy = prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv' . $mpv}});
+                       $dummy = prettyprint_pv($pos_calculating, @{$info->{'pv' . $mpv}});
                        ++$mpv;
                }
        };
@@ -678,8 +690,19 @@ sub output {
                return;
        }
 
+       # Now do our own Syzygy tablebase probes to convert scores like +123.45 to mate.
+       if (exists($info->{'pv'})) {
+               complete_using_tbprobe($pos_calculating, $info, '');
+       }
+
+       my $mpv = 1;
+       while (exists($info->{'pv' . $mpv})) {
+               complete_using_tbprobe($pos_calculating, $info, $mpv);
+               ++$mpv;
+       }
+
        output_screen();
-       output_json();
+       output_json(0);
        $latest_update = [Time::HiRes::gettimeofday];
 }
 
@@ -730,7 +753,7 @@ sub output_screen {
                        }
 
                        $text .= ":\n";
-                       $text .= "  " . join(', ', prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv' . $mpv}})) . "\n";
+                       $text .= "  " . join(', ', prettyprint_pv($pos_calculating, @{$info->{'pv' . $mpv}})) . "\n";
                        $text .= "\n";
                        ++$mpv;
                }
@@ -738,7 +761,7 @@ sub output_screen {
                # single-PV
                my $score = long_score($info, $pos_calculating, '');
                $text .= "  $score\n" if defined($score);
-               $text .=  "  PV: " . join(', ', prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv'}}));
+               $text .=  "  PV: " . join(', ', prettyprint_pv($pos_calculating, @{$info->{'pv'}}));
                $text .=  "\n";
 
                if (exists($info->{'nodes'}) && exists($info->{'nps'}) && exists($info->{'depth'})) {
@@ -750,37 +773,39 @@ sub output_screen {
                }
                if (exists($info->{'tbhits'}) && $info->{'tbhits'} > 0) {
                        if ($info->{'tbhits'} == 1) {
-                               $text .= ", one Nalimov hit";
+                               $text .= ", one Syzygy hit";
                        } else {
-                               $text .= sprintf ", %u Nalimov hits", $info->{'tbhits'};
+                               $text .= sprintf ", %u Syzygy hits", $info->{'tbhits'};
                        }
                }
                $text .= "\n\n";
        }
 
-       #$text .= book_info($pos_calculating->{'fen'}, $pos_calculating->{'board'}, $pos_calculating->{'toplay'});
+       #$text .= book_info($pos_calculating->fen(), $pos_calculating->{'board'}, $pos_calculating->{'toplay'});
 
        my @refutation_lines = ();
-       for (my $mpv = 1; $mpv < 500; ++$mpv) {
-               my $info = $engine2->{'info'};
-               last if (!exists($info->{'pv' . $mpv}));
-               eval {
-                       my $pv = $info->{'pv' . $mpv};
-
-                       my $pretty_move = join('', prettyprint_pv($pos_calculating_second_engine->{'board'}, $pv->[0]));
-                       my @pretty_pv = prettyprint_pv($pos_calculating_second_engine->{'board'}, @$pv);
-                       if (scalar @pretty_pv > 5) {
-                               @pretty_pv = @pretty_pv[0..4];
-                               push @pretty_pv, "...";
-                       }
-                       my $key = $pretty_move;
-                       my $line = sprintf("  %-6s %6s %3s  %s",
-                               $pretty_move,
-                               short_score($info, $pos_calculating_second_engine, $mpv, 0),
-                               "d" . $info->{'depth' . $mpv},
-                               join(', ', @pretty_pv));
-                       push @refutation_lines, [ $key, $line ];
-               };
+       if (defined($engine2)) {
+               for (my $mpv = 1; $mpv < 500; ++$mpv) {
+                       my $info = $engine2->{'info'};
+                       last if (!exists($info->{'pv' . $mpv}));
+                       eval {
+                               complete_using_tbprobe($pos_calculating_second_engine, $info, $mpv);
+                               my $pv = $info->{'pv' . $mpv};
+                               my $pretty_move = join('', prettyprint_pv($pos_calculating_second_engine, $pv->[0]));
+                               my @pretty_pv = prettyprint_pv($pos_calculating_second_engine, @$pv);
+                               if (scalar @pretty_pv > 5) {
+                                       @pretty_pv = @pretty_pv[0..4];
+                                       push @pretty_pv, "...";
+                               }
+                               my $key = $pretty_move;
+                               my $line = sprintf("  %-6s %6s %3s  %s",
+                                       $pretty_move,
+                                       short_score($info, $pos_calculating_second_engine, $mpv),
+                                       "d" . $info->{'depth' . $mpv},
+                                       join(', ', @pretty_pv));
+                               push @refutation_lines, [ $key, $line ];
+                       };
+               }
        }
 
        if ($#refutation_lines >= 0) {
@@ -796,327 +821,225 @@ sub output_screen {
                print $text;
                $last_text = $text;
        }
-
-       # Now construct the tell text, if any
-       return if (!defined($telltarget));
-
-       my $tell_text = '';
-
-       if (exists($id->{'name'})) {
-               $tell_text .= "Analysis by $id->{'name'} -- see http://analysis.sesse.net/ for more information\n";
-       } else {
-               $tell_text .= "Computer analysis -- http://analysis.sesse.net/ for more information\n";
-       }
-
-       if (exists($info->{'pv1'}) && exists($info->{'pv2'})) {
-               # multi-PV
-               my $mpv = 1;
-               while (exists($info->{'pv' . $mpv})) {
-                       $tell_text .= sprintf "  PV%2u", $mpv;
-                       my $score = short_score($info, $pos_calculating, $mpv);
-                       $tell_text .= "  ($score)" if (defined($score));
-
-                       if (exists($info->{'depth' . $mpv})) {
-                               $tell_text .= sprintf " (%2u ply)", $info->{'depth' . $mpv};
-                       }
-
-                       $tell_text .= ": ";
-                       $tell_text .= join(', ', prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv' . $mpv}}));
-                       $tell_text .= "\n";
-                       ++$mpv;
-               }
-       } else {
-               # single-PV
-               my $score = long_score($info, $pos_calculating, '');
-               $tell_text .= "  $score\n" if defined($score);
-               $tell_text .= "  PV: " . join(', ', prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv'}}));
-               if (exists($info->{'depth'})) {
-                       $tell_text .= sprintf " (depth %u ply)", $info->{'depth'};
-               }
-               $tell_text .=  "\n";
-       }
-
-       # see if a new tell is called for -- it is if the delay has expired _and_
-       # this is not simply a repetition of the last one
-       if ($last_told_text ne $tell_text) {
-               my $now = time;
-               for my $iv (@tell_intervals) {
-                       last if ($now - $last_move < $iv);
-                       next if ($last_tell - $last_move >= $iv);
-
-                       for my $line (split /\n/, $tell_text) {
-                               $t->print("tell $telltarget [$target] $line");
-                       }
-
-                       $last_told_text = $text;
-                       $last_tell = $now;
-
-                       last;
-               }
-       }
 }
 
 sub output_json {
+       my $historic_json_only = shift;
        my $info = $engine->{'info'};
 
        my $json = {};
-       $json->{'position'} = $pos_calculating;
-       $json->{'id'} = $engine->{'id'};
-       $json->{'score'} = long_score($info, $pos_calculating, '');
+       $json->{'position'} = $pos_calculating->to_json_hash();
+       $json->{'engine'} = $engine->{'id'};
+       if (defined($remoteglotconf::engine_url)) {
+               $json->{'engine'}{'url'} = $remoteglotconf::engine_url;
+       }
+       if (defined($remoteglotconf::engine_details)) {
+               $json->{'engine'}{'details'} = $remoteglotconf::engine_details;
+       }
+       if (defined($remoteglotconf::move_source)) {
+               $json->{'move_source'} = $remoteglotconf::move_source;
+       }
+       if (defined($remoteglotconf::move_source_url)) {
+               $json->{'move_source_url'} = $remoteglotconf::move_source_url;
+       }
+       $json->{'score'} = score_digest($info, $pos_calculating, '');
+       $json->{'using_lomonosov'} = defined($remoteglotconf::tb_serial_key);
 
        $json->{'nodes'} = $info->{'nodes'};
        $json->{'nps'} = $info->{'nps'};
        $json->{'depth'} = $info->{'depth'};
        $json->{'tbhits'} = $info->{'tbhits'};
        $json->{'seldepth'} = $info->{'seldepth'};
-
-       # single-PV only for now
-       $json->{'pv_uci'} = $info->{'pv'};
-       $json->{'pv_pretty'} = [ prettyprint_pv($pos_calculating->{'board'}, @{$info->{'pv'}}) ];
+       $json->{'tablebase'} = $info->{'tablebase'};
+       $json->{'pv'} = [ prettyprint_pv($pos_calculating, @{$info->{'pv'}}) ];
 
        my %refutation_lines = ();
        my @refutation_lines = ();
-       for (my $mpv = 1; $mpv < 500; ++$mpv) {
-               my $info = $engine2->{'info'};
-               my $pretty_move = "";
-               my @pretty_pv = ();
-               last if (!exists($info->{'pv' . $mpv}));
-
-               eval {
-                       my $pv = $info->{'pv' . $mpv};
-                       my $pretty_move = join('', prettyprint_pv($pos_calculating->{'board'}, $pv->[0]));
-                       my @pretty_pv = prettyprint_pv($pos_calculating->{'board'}, @$pv);
-                       $refutation_lines{$pv->[0]} = {
-                               sort_key => $pretty_move,
-                               depth => $info->{'depth' . $mpv},
-                               score_sort_key => score_sort_key($info, $pos_calculating, $mpv, 0),
-                               pretty_score => short_score($info, $pos_calculating, $mpv, 0),
-                               pretty_move => $pretty_move,
-                               pv_pretty => \@pretty_pv,
+       if (defined($engine2)) {
+               for (my $mpv = 1; $mpv < 500; ++$mpv) {
+                       my $info = $engine2->{'info'};
+                       my $pretty_move = "";
+                       my @pretty_pv = ();
+                       last if (!exists($info->{'pv' . $mpv}));
+
+                       eval {
+                               complete_using_tbprobe($pos_calculating, $info, $mpv);
+                               my $pv = $info->{'pv' . $mpv};
+                               my $pretty_move = join('', prettyprint_pv($pos_calculating, $pv->[0]));
+                               my @pretty_pv = prettyprint_pv($pos_calculating, @$pv);
+                               $refutation_lines{$pretty_move} = {
+                                       depth => $info->{'depth' . $mpv},
+                                       score => score_digest($info, $pos_calculating, $mpv),
+                                       move => $pretty_move,
+                                       pv => \@pretty_pv,
+                               };
                        };
-                       $refutation_lines{$pv->[0]}->{'pv_uci'} = $pv;
-               };
+               }
        }
        $json->{'refutation_lines'} = \%refutation_lines;
 
-       open my $fh, ">analysis.json.tmp"
-               or return;
-       print $fh JSON::XS::encode_json($json);
-       close $fh;
-       rename("analysis.json.tmp", "analysis.json");   
-}
-
-sub find_kings {
-       my $board = shift;
-       my ($wkr, $wkc, $bkr, $bkc);
-
-       for my $row (0..7) {
-               for my $col (0..7) {
-                       my $piece = substr($board->[$row], $col, 1);
-                       if ($piece eq 'K') {
-                               ($wkr, $wkc) = ($row, $col);
-                       } elsif ($piece eq 'k') {
-                               ($bkr, $bkc) = ($row, $col);
+       # Piece together historic score information, to the degree we have it.
+       if (!$historic_json_only && exists($pos_calculating->{'history'})) {
+               my %score_history = ();
+
+               my $q = $dbh->prepare('SELECT * FROM scores WHERE id=?');
+               my $pos = Position->start_pos('white', 'black');
+               my $halfmove_num = 0;
+               for my $move (@{$pos_calculating->{'history'}}) {
+                       my $id = id_for_pos($pos, $halfmove_num);
+                       my $ref = $dbh->selectrow_hashref($q, undef, $id);
+                       if (defined($ref)) {
+                               $score_history{$halfmove_num} = [
+                                       $ref->{'score_type'},
+                                       $ref->{'score_value'}
+                               ];
                        }
+                       ++$halfmove_num;
+                       ($pos) = $pos->make_pretty_move($move);
                }
-       }
-
-       return ($wkr, $wkc, $bkr, $bkc);
-}
-
-sub in_mate {
-       my $board = shift;
-       my $check = in_check($board);
-       return 0 if ($check eq 'none');
-
-       # try all possible moves for the side in check
-       for my $row (0..7) {
-               for my $col (0..7) {
-                       my $piece = substr($board->[$row], $col, 1);
-                       next if ($piece eq '-');
-
-                       if ($check eq 'white') {
-                               next if ($piece eq lc($piece));
+               $q->finish;
+
+               # If at any point we are missing 10 consecutive moves,
+               # truncate the history there. This is so we don't get into
+               # a situation where we e.g. start analyzing at move 45,
+               # but we have analysis for 1. e4 from some completely different game
+               # and thus show a huge hole.
+               my $consecutive_missing = 0;
+               my $truncate_until = 0;
+               for (my $i = $halfmove_num; $i --> 0; ) {
+                       if ($consecutive_missing >= 10) {
+                               delete $score_history{$i};
+                               next;
+                       }
+                       if (exists($score_history{$i})) {
+                               $consecutive_missing = 0;
                        } else {
-                               next if ($piece eq uc($piece));
+                               ++$consecutive_missing;
                        }
+               }
 
-                       for my $dest_row (0..7) {
-                               for my $dest_col (0..7) {
-                                       next if ($row == $dest_row && $col == $dest_col);
-                                       next unless (can_reach($board, $piece, $row, $col, $dest_row, $dest_col));
-
-                                       my @nb = @$board;
-                                       substr($nb[$row], $col, 1, '-');
-                                       substr($nb[$dest_row], $dest_col, 1, $piece);
+               $json->{'score_history'} = \%score_history;
+       }
 
-                                       my $new_check = in_check(\@nb);
-                                       return 0 if ($new_check ne $check && $new_check ne 'both');
+       # Give out a list of other games going on. (Empty is fine.)
+       # TODO: Don't bother reading our own file, the data will be stale anyway.
+       if (!$historic_json_only) {
+               my @games = ();
+
+               my $q = $dbh->prepare('SELECT * FROM current_games ORDER BY priority DESC, id');
+               $q->execute;
+               while (my $ref = $q->fetchrow_hashref) {
+                       eval {
+                               my $other_game_contents = File::Slurp::read_file($ref->{'json_path'});
+                               my $other_game_json = JSON::XS::decode_json($other_game_contents);
+
+                               die "Missing position" if (!exists($other_game_json->{'position'}));
+                               my $white = $other_game_json->{'position'}{'player_w'} // die 'Missing white';
+                               my $black = $other_game_json->{'position'}{'player_b'} // die 'Missing black';
+
+                               my $game = {
+                                       id => $ref->{'id'},
+                                       name => "$white–$black",
+                                       url => $ref->{'url'},
+                                       hashurl => $ref->{'hash_url'},
+                               };
+                               if (defined($other_game_json->{'position'}{'result'})) {
+                                       $game->{'result'} = $other_game_json->{'position'}{'result'};
+                               } else {
+                                       $game->{'score'} = $other_game_json->{'score'};
                                }
+                               push @games, $game;
+                       };
+                       if ($@) {
+                               warn "Could not add external game " . $ref->{'json_path'} . ": $@";
                        }
                }
-       }
-
-       # nothing to do; mate
-       return 1;
-}
 
-sub in_check {
-       my $board = shift;
-       my ($black_check, $white_check) = (0, 0);
-
-       my ($wkr, $wkc, $bkr, $bkc) = find_kings($board);
-
-       # check all pieces for the possibility of threatening the two kings
-       for my $row (0..7) {
-               for my $col (0..7) {
-                       my $piece = substr($board->[$row], $col, 1);
-                       next if ($piece eq '-');
-               
-                       if (uc($piece) eq $piece) {
-                               # white piece
-                               $black_check = 1 if (can_reach($board, $piece, $row, $col, $bkr, $bkc));
-                       } else {
-                               # black piece
-                               $white_check = 1 if (can_reach($board, $piece, $row, $col, $wkr, $wkc));
-                       }
+               if (scalar @games > 0) {
+                       $json->{'games'} = \@games;
                }
        }
 
-       if ($black_check && $white_check) {
-               return 'both';
-       } elsif ($black_check) {
-               return 'black';
-       } elsif ($white_check) {
-               return 'white';
-       } else {
-               return 'none';
+       my $json_enc = JSON::XS->new;
+       $json_enc->canonical(1);
+       my $encoded = $json_enc->encode($json);
+       unless ($historic_json_only || !defined($remoteglotconf::json_output) ||
+               (defined($last_written_json) && $last_written_json eq $encoded)) {
+               atomic_set_contents($remoteglotconf::json_output, $encoded);
+               $last_written_json = $encoded;
        }
-}
-
-sub can_reach {
-       my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
-       
-       # can't eat your own piece
-       my $dest_piece = substr($board->[$to_row], $to_col, 1);
-       if ($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 - $to_col) <= 1);
-       }
-       if (lc($piece) eq 'r') {
-               return 0 unless ($from_row == $to_row || $from_col == $to_col);
-
-               # check that there's a clear passage
-               if ($from_row == $to_row) {
-                       if ($from_col > $to_col) {
-                               ($to_col, $from_col) = ($from_col, $to_col);
-                       }
-
-                       for my $c (($from_col+1)..($to_col-1)) {
-                               my $middle_piece = substr($board->[$to_row], $c, 1);
-                               return 0 if ($middle_piece ne '-');     
-                       }
-
-                       return 1;
-               } else {
-                       if ($from_row > $to_row) {
-                               ($to_row, $from_row) = ($from_row, $to_row);
-                       }
 
-                       for my $r (($from_row+1)..($to_row-1)) {
-                               my $middle_piece = substr($board->[$r], $to_col, 1);
-                               return 0 if ($middle_piece ne '-');     
+       if (exists($pos_calculating->{'history'}) &&
+           defined($remoteglotconf::json_history_dir)) {
+               my $id = id_for_pos($pos_calculating);
+               my $filename = $remoteglotconf::json_history_dir . "/" . $id . ".json";
+
+               # Overwrite old analysis (assuming it exists at all) if we're
+               # using a different engine, or if we've calculated deeper.
+               # nodes is used as a tiebreaker. Don't bother about Multi-PV
+               # data; it's not that important.
+               my ($old_engine, $old_depth, $old_nodes) = get_json_analysis_stats($id);
+               my $new_depth = $json->{'depth'} // 0;
+               my $new_nodes = $json->{'nodes'} // 0;
+               if (!defined($old_engine) ||
+                   $old_engine ne $json->{'engine'}{'name'} ||
+                   $new_depth > $old_depth ||
+                   ($new_depth == $old_depth && $new_nodes >= $old_nodes)) {
+                       atomic_set_contents($filename, $encoded);
+                       if (defined($json->{'score'})) {
+                               $dbh->do('INSERT INTO scores (id, score_type, score_value, engine, depth, nodes) VALUES (?,?,?,?,?,?) ' .
+                                        '    ON CONFLICT (id) DO UPDATE SET ' .
+                                        '        score_type=EXCLUDED.score_type, ' .
+                                        '        score_value=EXCLUDED.score_value, ' .
+                                        '        engine=EXCLUDED.engine, ' .
+                                        '        depth=EXCLUDED.depth, ' .
+                                        '        nodes=EXCLUDED.nodes',
+                                       undef,
+                                       $id, $json->{'score'}[0], $json->{'score'}[1],
+                                       $json->{'engine'}{'name'}, $new_depth, $new_nodes);
                        }
-
-                       return 1;
                }
        }
-       if (lc($piece) eq 'b') {
-               return 0 unless (abs($from_row - $to_row) == abs($from_col - $to_col));
+}
 
-               my $dr = ($to_row - $from_row) / abs($to_row - $from_row);
-               my $dc = ($to_col - $from_col) / abs($to_col - $from_col);
+sub atomic_set_contents {
+       my ($filename, $contents) = @_;
 
-               my $r = $from_row + $dr;
-               my $c = $from_col + $dc;
+       open my $fh, ">", $filename . ".tmp"
+               or return;
+       print $fh $contents;
+       close $fh;
+       rename($filename . ".tmp", $filename);
+}
 
-               while ($r != $to_row) {
-                       my $middle_piece = substr($board->[$r], $c, 1);
-                       return 0 if ($middle_piece ne '-');
-                       
-                       $r += $dr;
-                       $c += $dc;
-               }
+sub id_for_pos {
+       my ($pos, $halfmove_num) = @_;
 
-               return 1;
-       }
-       if (lc($piece) eq 'n') {
-               my $diff_r = abs($from_row - $to_row);
-               my $diff_c = abs($from_col - $to_col);
-               return 1 if ($diff_r == 2 && $diff_c == 1);
-               return 1 if ($diff_r == 1 && $diff_c == 2);
-               return 0;
-       }
-       if ($piece eq 'q') {
-               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 'Q') {
-               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));
-       }
+       $halfmove_num //= scalar @{$pos->{'history'}};
+       (my $fen = $pos->fen()) =~ tr,/ ,-_,;
+       return "move$halfmove_num-$fen";
+}
 
-       # TODO: en passant
-       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 $middle_piece = substr($board->[2], $to_col, 1);
-                       return ($dest_piece eq '-' && $middle_piece eq '-');
-               }
-               if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
-                       return ($dest_piece ne '-');
-               }
-               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 $middle_piece = substr($board->[5], $to_col, 1);
-                       return ($dest_piece eq '-' && $middle_piece eq '-');
-               }
-               if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
-                       return ($dest_piece ne '-');
-               }
-               return 0;
+sub get_json_analysis_stats {
+       my $id = shift;
+       my $ref = $dbh->selectrow_hashref('SELECT * FROM scores WHERE id=?', undef, $id);
+       if (defined($ref)) {
+               return ($ref->{'engine'}, $ref->{'depth'}, $ref->{'nodes'});
+       } else {
+               return ('', 0, 0);
        }
-       
-       # unknown piece
-       return 0;
 }
 
 sub uciprint {
        my ($engine, $msg) = @_;
-       print { $engine->{'write'} } "$msg\n";
+       $engine->print($msg);
        print UCILOG localtime() . " $engine->{'tag'} => $msg\n";
 }
 
 sub short_score {
-       my ($info, $pos, $mpv, $invert) = @_;
-
-       $invert //= 0;
-       if ($pos->{'toplay'} eq 'B') {
-               $invert = !$invert;
-       }
+       my ($info, $pos, $mpv) = @_;
 
+       my $invert = ($pos->{'toplay'} eq 'B');
        if (defined($info->{'score_mate' . $mpv})) {
                if ($invert) {
                        return sprintf "M%3d", -$info->{'score_mate' . $mpv};
@@ -1127,7 +1050,11 @@ sub short_score {
                if (exists($info->{'score_cp' . $mpv})) {
                        my $score = $info->{'score_cp' . $mpv} * 0.01;
                        if ($score == 0) {
-                               return " 0.00";
+                               if ($info->{'tablebase'}) {
+                                       return "TB draw";
+                               } else {
+                                       return " 0.00";
+                               }
                        }
                        if ($invert) {
                                $score = -$score;
@@ -1139,22 +1066,28 @@ sub short_score {
        return undef;
 }
 
-sub score_sort_key {
-       my ($info, $pos, $mpv, $invert) = @_;
+# Sufficient for computing long_score, short_score, plot_score and
+# (with side-to-play information) score_sort_key.
+sub score_digest {
+       my ($info, $pos, $mpv) = @_;
 
        if (defined($info->{'score_mate' . $mpv})) {
-               if ($invert) {
-                       return 99999 - $info->{'score_mate' . $mpv};
-               } else {
-                       return -(99999 - $info->{'score_mate' . $mpv});
+               my $mate = $info->{'score_mate' . $mpv};
+               if ($pos->{'toplay'} eq 'B') {
+                       $mate = -$mate;
                }
+               return ['m', $mate];
        } else {
                if (exists($info->{'score_cp' . $mpv})) {
                        my $score = $info->{'score_cp' . $mpv};
-                       if ($invert) {
+                       if ($pos->{'toplay'} eq 'B') {
                                $score = -$score;
                        }
-                       return $score;
+                       if ($score == 0 && $info->{'tablebase'}) {
+                               return ['d', undef];
+                       } else {
+                               return ['cp', $score];
+                       }
                }
        }
 
@@ -1177,6 +1110,13 @@ sub long_score {
        } else {
                if (exists($info->{'score_cp' . $mpv})) {
                        my $score = $info->{'score_cp' . $mpv} * 0.01;
+                       if ($score == 0) {
+                               if ($info->{'tablebase'}) {
+                                       return "Theoretical draw";
+                               } else {
+                                       return "Score:  0.00";
+                               }
+                       }
                        if ($pos->{'toplay'} eq 'B') {
                                $score = -$score;
                        }
@@ -1187,6 +1127,36 @@ sub long_score {
        return undef;
 }
 
+# For graphs; a single number in centipawns, capped at +/- 500.
+sub plot_score {
+       my ($info, $pos, $mpv) = @_;
+
+       my $invert = ($pos->{'toplay'} eq 'B');
+       if (defined($info->{'score_mate' . $mpv})) {
+               my $mate = $info->{'score_mate' . $mpv};
+               if ($invert) {
+                       $mate = -$mate;
+               }
+               if ($mate > 0) {
+                       return 500;
+               } else {
+                       return -500;
+               }
+       } else {
+               if (exists($info->{'score_cp' . $mpv})) {
+                       my $score = $info->{'score_cp' . $mpv};
+                       if ($invert) {
+                               $score = -$score;
+                       }
+                       $score = 500 if ($score > 500);
+                       $score = -500 if ($score < -500);
+                       return int($score);
+               }
+       }
+
+       return undef;
+}
+
 my %book_cache = ();
 sub book_info {
        my ($fen, $board, $toplay) = @_;
@@ -1207,7 +1177,7 @@ sub book_info {
                if ($move eq '')  {
                        $pmove = '(current)';
                } else {
-                       ($pmove) = prettyprint_pv($board, $move);
+                       ($pmove) = prettyprint_pv_no_cache($board, $move);
                        $pmove .= $annotation;
                }
 
@@ -1239,62 +1209,206 @@ sub book_info {
        return $text;
 }
 
-sub open_engine {
-       my ($cmdline, $tag) = @_;
-       my ($uciread, $uciwrite);
-       my $pid = IPC::Open2::open2($uciread, $uciwrite, $cmdline);
-
-       my $engine = {
-               pid => $pid,
-               read => $uciread,
-               readbuf => '',
-               write => $uciwrite,
-               info => {},
-               ids => {},
-               tag => $tag,
-       };
+sub extract_clock {
+       my ($pgn, $pos) = @_;
 
-       uciprint($engine, "uci");
+       # Look for extended PGN clock tags.
+       my $tags = $pgn->tags;
+       if (exists($tags->{'WhiteClock'}) && exists($tags->{'BlackClock'})) {
+               $pos->{'white_clock'} = hms_to_sec($tags->{'WhiteClock'});
+               $pos->{'black_clock'} = hms_to_sec($tags->{'BlackClock'});
+               return;
+       }
 
-       # gobble the options
-       while (<$uciread>) {
-               /uciok/ && last;
-               handle_uci($engine, $_);
+       # Look for TCEC-style time comments.
+       my $moves = $pgn->moves;
+       my $comments = $pgn->comments;
+       my $last_black_move = int((scalar @$moves) / 2);
+       my $last_white_move = int((1 + scalar @$moves) / 2);
+
+       my $black_key = $last_black_move . "b";
+       my $white_key = $last_white_move . "w";
+
+       if (exists($comments->{$white_key}) &&
+           exists($comments->{$black_key}) &&
+           $comments->{$white_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/ &&
+           $comments->{$black_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/) {
+               $comments->{$white_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/;
+               $pos->{'white_clock'} = hms_to_sec($1);
+               $comments->{$black_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/;
+               $pos->{'black_clock'} = hms_to_sec($1);
+               return;
        }
-       
-       return $engine;
+
+       delete $pos->{'white_clock'};
+       delete $pos->{'black_clock'};
 }
 
-sub read_lines {
-       my $engine = shift;
+sub hms_to_sec {
+       my $hms = shift;
+       return undef if (!defined($hms));
+       $hms =~ /(\d+):(\d+):(\d+)/;
+       return $1 * 3600 + $2 * 60 + $3;
+}
 
-       # 
-       # Read until we've got a full line -- if the engine sends part of
-       # a line and then stops we're pretty much hosed, but that should
-       # never happen.
-       #
-       while ($engine->{'readbuf'} !~ /\n/) {
-               my $tmp;
-               my $ret = sysread $engine->{'read'}, $tmp, 4096;
-
-               if (!defined($ret)) {
-                       next if ($!{EINTR});
-                       die "error in reading from the UCI engine: $!";
-               } elsif ($ret == 0) {
-                       die "EOF from UCI engine";
+sub find_clock_start {
+       my ($pos, $prev_pos) = @_;
+
+       # If the game is over, the clock is stopped.
+       if (exists($pos->{'result'}) &&
+           ($pos->{'result'} eq '1-0' ||
+            $pos->{'result'} eq '1/2-1/2' ||
+            $pos->{'result'} eq '0-1')) {
+               return;
+       }
+
+       # When we don't have any moves, we assume the clock hasn't started yet.
+       if ($pos->{'move_num'} == 1 && $pos->{'toplay'} eq 'W') {
+               if (defined($remoteglotconf::adjust_clocks_before_move)) {
+                       &$remoteglotconf::adjust_clocks_before_move(\$pos->{'white_clock'}, \$pos->{'black_clock'}, 1, 'W');
                }
+               return;
+       }
+
+       # TODO(sesse): Maybe we can get the number of moves somehow else for FICS games.
+       # The history is needed for id_for_pos.
+       if (!exists($pos->{'history'})) {
+               return;
+       }
 
-               $engine->{'readbuf'} .= $tmp;
+       my $id = id_for_pos($pos);
+       my $clock_info = $dbh->selectrow_hashref('SELECT * FROM clock_info WHERE id=?', undef, $id);
+       if (defined($clock_info)) {
+               $pos->{'white_clock'} //= $clock_info->{'white_clock'};
+               $pos->{'black_clock'} //= $clock_info->{'black_clock'};
+               if ($pos->{'toplay'} eq 'W') {
+                       $pos->{'white_clock_target'} = $clock_info->{'white_clock_target'};
+               } else {
+                       $pos->{'black_clock_target'} = $clock_info->{'black_clock_target'};
+               }
+               return;
        }
 
-       # Blah.
-       my @lines = ();
-       while ($engine->{'readbuf'} =~ s/^([^\n]*)\n//) {
-               my $line = $1;
-               $line =~ tr/\r\n//d;
-               push @lines, $line;
+       # OK, we haven't seen this position before, so we assume the move
+       # happened right now.
+
+       # See if we should do our own clock management (ie., clock information
+       # is spurious or non-existent).
+       if (defined($remoteglotconf::adjust_clocks_before_move)) {
+               my $wc = $pos->{'white_clock'} // $prev_pos->{'white_clock'};
+               my $bc = $pos->{'black_clock'} // $prev_pos->{'black_clock'};
+               if (defined($prev_pos->{'white_clock_target'})) {
+                       $wc = $prev_pos->{'white_clock_target'} - time;
+               }
+               if (defined($prev_pos->{'black_clock_target'})) {
+                       $bc = $prev_pos->{'black_clock_target'} - time;
+               }
+               &$remoteglotconf::adjust_clocks_before_move(\$wc, \$bc, $pos->{'move_num'}, $pos->{'toplay'});
+               $pos->{'white_clock'} = $wc;
+               $pos->{'black_clock'} = $bc;
        }
-       return @lines;
+
+       my $key = ($pos->{'toplay'} eq 'W') ? 'white_clock' : 'black_clock';
+       if (!exists($pos->{$key})) {
+               # No clock information.
+               return;
+       }
+       my $time_left = $pos->{$key};
+       my ($white_clock_target, $black_clock_target);
+       if ($pos->{'toplay'} eq 'W') {
+               $white_clock_target = $pos->{'white_clock_target'} = time + $time_left;
+       } else {
+               $black_clock_target = $pos->{'black_clock_target'} = time + $time_left;
+       }
+       local $dbh->{AutoCommit} = 0;
+       $dbh->do('DELETE FROM clock_info WHERE id=?', undef, $id);
+       $dbh->do('INSERT INTO clock_info (id, white_clock, black_clock, white_clock_target, black_clock_target) VALUES (?, ?, ?, ?, ?)', undef,
+               $id, $pos->{'white_clock'}, $pos->{'black_clock'}, $white_clock_target, $black_clock_target);
+       $dbh->commit;
+}
+
+sub schedule_tb_lookup {
+       return if (!defined($remoteglotconf::tb_serial_key));
+       my $pos = $pos_waiting // $pos_calculating;
+       return if (exists($tb_cache{$pos->fen()}));
+
+       # If there's more than seven pieces, there's not going to be an answer,
+       # so don't bother.
+       return if ($pos->num_pieces() > 7);
+
+       # Max one at a time. If it's still relevant when it returns,
+       # schedule_tb_lookup() will be called again.
+       return if ($tb_lookup_running);
+
+       $tb_lookup_running = 1;
+       my $url = 'http://158.250.18.203:6904/tasks/addtask?auth.login=' .
+               $remoteglotconf::tb_serial_key .
+               '&auth.password=aquarium&type=0&fen=' . 
+               URI::Escape::uri_escape($pos->fen());
+       print TBLOG "Downloading $url...\n";
+       AnyEvent::HTTP::http_get($url, sub {
+               handle_tb_lookup_return(@_, $pos, $pos->fen());
+       });
+}
+
+sub handle_tb_lookup_return {
+       my ($body, $header, $pos, $fen) = @_;
+       print TBLOG "Response for [$fen]:\n";
+       print TBLOG $header . "\n\n";
+       print TBLOG $body . "\n\n";
+       eval {
+               my $response = JSON::XS::decode_json($body);
+               if ($response->{'ErrorCode'} != 0) {
+                       die "Unknown tablebase server error: " . $response->{'ErrorDesc'};
+               }
+               my $state = $response->{'Response'}{'StateString'};
+               if ($state eq 'COMPLETE') {
+                       my $pgn = Chess::PGN::Parse->new(undef, $response->{'Response'}{'Moves'});
+                       if (!defined($pgn) || !$pgn->read_game()) {
+                               warn "Error in parsing PGN\n";
+                       } else {
+                               $pgn->quick_parse_game;
+                               my $pvpos = $pos;
+                               my $moves = $pgn->moves;
+                               my @uci_moves = ();
+                               for my $move (@$moves) {
+                                       my $uci_move;
+                                       ($pvpos, $uci_move) = $pvpos->make_pretty_move($move);
+                                       push @uci_moves, $uci_move;
+                               }
+                               $tb_cache{$fen} = {
+                                       result => $pgn->result,
+                                       pv => \@uci_moves,
+                                       score => $response->{'Response'}{'Score'},
+                               };
+                               output();
+                       }
+               } elsif ($state =~ /QUEUED/ || $state =~ /PROCESSING/) {
+                       # Try again in a second. Note that if we have changed
+                       # position in the meantime, we might query a completely
+                       # different position! But that's fine.
+               } else {
+                       die "Unknown response state " . $state;
+               }
+
+               # Wait a second before we schedule another one.
+               $tb_retry_timer = AnyEvent->timer(after => 1.0, cb => sub {
+                       $tb_lookup_running = 0;
+                       schedule_tb_lookup();
+               });
+       };
+       if ($@) {
+               warn "Error in tablebase lookup: $@";
+
+               # Don't try this one again, but don't block new lookups either.
+               $tb_lookup_running = 0;
+       }
+}
+
+sub open_engine {
+       my ($cmdline, $tag, $cb) = @_;
+       return undef if (!defined($cmdline));
+       return Engine->open($cmdline, $tag, $cb);
 }
 
 sub col_letter_to_num {
@@ -1305,8 +1419,12 @@ sub row_letter_to_num {
        return 7 - (ord(shift) - ord('1'));
 }
 
-sub move_to_uci_notation {
-       my ($from_row, $from_col, $to_row, $to_col, $promo) = @_;
-       $promo //= "";
-       return sprintf("%c%d%c%d%s", ord('a') + $from_col, 8 - $from_row, ord('a') + $to_col, 8 - $to_row, $promo);
+sub parse_uci_move {
+       my $move = shift;
+       my $from_col = col_letter_to_num(substr($move, 0, 1));
+       my $from_row = row_letter_to_num(substr($move, 1, 1));
+       my $to_col   = col_letter_to_num(substr($move, 2, 1));
+       my $to_row   = row_letter_to_num(substr($move, 3, 1));
+       my $promo    = substr($move, 4, 1);
+       return ($from_row, $from_col, $to_row, $to_col, $promo);
 }