git.sesse.net Git - remoteglot/blob - remoteglot.pl

   1 #! /usr/bin/perl
   2
   3 #
   4 # remoteglot - Connects an abitrary UCI-speaking engine to ICS for easier post-game
   5 #              analysis, or for live analysis of relayed games. (Do not use for
   6 #              cheating! Cheating is bad for your karma, and your abuser flag.)
   7 #
   8 # Copyright 2007 Steinar H. Gunderson <sgunderson@bigfoot.com>
   9 # Licensed under the GNU General Public License, version 2.
  10 #
  11
  12 use AnyEvent;
  13 use AnyEvent::Handle;
  14 use AnyEvent::HTTP;
  15 use Chess::PGN::Parse;
  16 use EV;
  17 use Net::Telnet;
  18 use FileHandle;
  19 use IPC::Open2;
  20 use Time::HiRes;
  21 use JSON::XS;
  22 use URI::Escape;
  23 use Tie::Persistent;
  24 require 'Position.pm';
  25 require 'Engine.pm';
  26 require 'config.pm';
  27 use strict;
  28 use warnings;
  29 no warnings qw(once);
  30
  31 # Program starts here
  32 my $latest_update = undef;
  33 my $output_timer = undef;
  34 my $http_timer = undef;
  35 my $stop_pgn_fetch = 0;
  36 my $tb_retry_timer = undef;
  37 my %tb_cache = ();
  38 my $tb_lookup_running = 0;
  39 my $last_written_json = undef;
  40
  41 # Persisted so that we can restart.
  42 tie my %clock_info_for_pos, 'Tie::Persistent', 'clock_info.db', 'rw';
  43 (tied %clock_info_for_pos)->autosync(1);
  44
  45 tie my %json_for_pos, 'Tie::Persistent', 'analysis_info.db', 'rw';
  46 (tied %json_for_pos)->autosync(1);
  47
  48 $| = 1;
  49
  50 open(FICSLOG, ">ficslog.txt")
  51         or die "ficslog.txt: $!";
  52 print FICSLOG "Log starting.\n";
  53 select(FICSLOG);
  54 $| = 1;
  55
  56 open(UCILOG, ">ucilog.txt")
  57         or die "ucilog.txt: $!";
  58 print UCILOG "Log starting.\n";
  59 select(UCILOG);
  60 $| = 1;
  61
  62 open(TBLOG, ">tblog.txt")
  63         or die "tblog.txt: $!";
  64 print TBLOG "Log starting.\n";
  65 select(TBLOG);
  66 $| = 1;
  67
  68 select(STDOUT);
  69
  70 # open the chess engine
  71 my $engine = open_engine($remoteglotconf::engine_cmdline, 'E1', sub { handle_uci(@_, 1); });
  72 my $engine2 = open_engine($remoteglotconf::engine2_cmdline, 'E2', sub { handle_uci(@_, 0); });
  73 my $last_move;
  74 my $last_text = '';
  75 my ($pos_waiting, $pos_calculating, $pos_calculating_second_engine);
  76
  77 uciprint($engine, "setoption name UCI_AnalyseMode value true");
  78 while (my ($key, $value) = each %remoteglotconf::engine_config) {
  79         uciprint($engine, "setoption name $key value $value");
  80 }
  81 uciprint($engine, "ucinewgame");
  82
  83 if (defined($engine2)) {
  84         uciprint($engine2, "setoption name UCI_AnalyseMode value true");
  85         while (my ($key, $value) = each %remoteglotconf::engine2_config) {
  86                 uciprint($engine2, "setoption name $key value $value");
  87         }
  88         uciprint($engine2, "setoption name MultiPV value 500");
  89         uciprint($engine2, "ucinewgame");
  90 }
  91
  92 print "Chess engine ready.\n";
  93
  94 # now talk to FICS
  95 my $t = Net::Telnet->new(Timeout => 10, Prompt => '/fics% /');
  96 $t->input_log(\*FICSLOG);
  97 $t->open($remoteglotconf::server);
  98 $t->print($remoteglotconf::nick);
  99 $t->waitfor('/Press return to enter the server/');
 100 $t->cmd("");
 101
 102 # set some options
 103 $t->cmd("set shout 0");
 104 $t->cmd("set seek 0");
 105 $t->cmd("set style 12");
 106
 107 my $ev1 = AnyEvent->io(
 108         fh => fileno($t),
 109         poll => 'r',
 110         cb => sub {    # what callback to execute
 111                 while (1) {
 112                         my $line = $t->getline(Timeout => 0, errmode => 'return');
 113                         return if (!defined($line));
 114
 115                         chomp $line;
 116                         $line =~ tr/\r//d;
 117                         handle_fics($line);
 118                 }
 119         }
 120 );
 121 if (defined($remoteglotconf::target)) {
 122         if ($remoteglotconf::target =~ /^http:/) {
 123                 fetch_pgn($remoteglotconf::target);
 124         } else {
 125                 $t->cmd("observe $remoteglotconf::target");
 126         }
 127 }
 128 print "FICS ready.\n";
 129
 130 # Engine events have already been set up by Engine.pm.
 131 EV::run;
 132
 133 sub handle_uci {
 134         my ($engine, $line, $primary) = @_;
 135
 136         return if $line =~ /(upper|lower)bound/;
 137
 138         $line =~ s/  / /g;  # Sometimes needed for Zappa Mexico
 139         print UCILOG localtime() . " $engine->{'tag'} <= $line\n";
 140         if ($line =~ /^info/) {
 141                 my (@infos) = split / /, $line;
 142                 shift @infos;
 143
 144                 parse_infos($engine, @infos);
 145         }
 146         if ($line =~ /^id/) {
 147                 my (@ids) = split / /, $line;
 148                 shift @ids;
 149
 150                 parse_ids($engine, @ids);
 151         }
 152         if ($line =~ /^bestmove/) {
 153                 if ($primary) {
 154                         return if (!$remoteglotconf::uci_assume_full_compliance);
 155                         if (defined($pos_waiting)) {
 156                                 uciprint($engine, "position fen " . $pos_waiting->fen());
 157                                 uciprint($engine, "go infinite");
 158
 159                                 $pos_calculating = $pos_waiting;
 160                                 $pos_waiting = undef;
 161                         }
 162                 } else {
 163                         $engine2->{'info'} = {};
 164                         my $pos = $pos_waiting // $pos_calculating;
 165                         uciprint($engine2, "position fen " . $pos->fen());
 166                         uciprint($engine2, "go infinite");
 167                         $pos_calculating_second_engine = $pos;
 168                 }
 169         }
 170         output();
 171 }
 172
 173 my $getting_movelist = 0;
 174 my $pos_for_movelist = undef;
 175 my @uci_movelist = ();
 176 my @pretty_movelist = ();
 177
 178 sub handle_fics {
 179         my $line = shift;
 180         if ($line =~ /^<12> /) {
 181                 handle_position(Position->new($line));
 182                 $t->cmd("moves");
 183         }
 184         if ($line =~ /^Movelist for game /) {
 185                 my $pos = $pos_waiting // $pos_calculating;
 186                 if (defined($pos)) {
 187                         @uci_movelist = ();
 188                         @pretty_movelist = ();
 189                         $pos_for_movelist = Position->start_pos($pos->{'player_w'}, $pos->{'player_b'});
 190                         $getting_movelist = 1;
 191                 }
 192         }
 193         if ($getting_movelist &&
 194             $line =~ /^\s* \d+\. \s+                     # move number
 195                        (\S+) \s+ \( [\d:.]+ \) \s*       # first move, then time
 196                        (?: (\S+) \s+ \( [\d:.]+ \) )?    # second move, then time
 197                      /x) {
 198                 eval {
 199                         my $uci_move;
 200                         ($pos_for_movelist, $uci_move) = $pos_for_movelist->make_pretty_move($1);
 201                         push @uci_movelist, $uci_move;
 202                         push @pretty_movelist, $1;
 203
 204                         if (defined($2)) {
 205                                 ($pos_for_movelist, $uci_move) = $pos_for_movelist->make_pretty_move($2);
 206                                 push @uci_movelist, $uci_move;
 207                                 push @pretty_movelist, $2;
 208                         }
 209                 };
 210                 if ($@) {
 211                         warn "Error when getting FICS move history: $@";
 212                         $getting_movelist = 0;
 213                 }
 214         }
 215         if ($getting_movelist &&
 216             $line =~ /^\s+ \{.*\} \s+ (?: \* | 1\/2-1\/2 | 0-1 | 1-0 )/x) {
 217                 # End of movelist.
 218                 for my $pos ($pos_waiting, $pos_calculating) {
 219                         next if (!defined($pos));
 220                         if ($pos->fen() eq $pos_for_movelist->fen()) {
 221                                 $pos->{'pretty_history'} = \@pretty_movelist;
 222                         }
 223                 }
 224                 $getting_movelist = 0;
 225         }
 226         if ($line =~ /^([A-Za-z]+)(?:\([A-Z]+\))* tells you: (.*)$/) {
 227                 my ($who, $msg) = ($1, $2);
 228
 229                 next if (grep { $_ eq $who } (@remoteglotconf::masters) == 0);
 230
 231                 if ($msg =~ /^fics (.*?)$/) {
 232                         $t->cmd("tell $who Executing '$1' on FICS.");
 233                         $t->cmd($1);
 234                 } elsif ($msg =~ /^uci (.*?)$/) {
 235                         $t->cmd("tell $who Sending '$1' to the engine.");
 236                         print { $engine->{'write'} } "$1\n";
 237                 } elsif ($msg =~ /^pgn (.*?)$/) {
 238                         my $url = $1;
 239                         $t->cmd("tell $who Starting to poll '$url'.");
 240                         fetch_pgn($url);
 241                 } elsif ($msg =~ /^stoppgn$/) {
 242                         $t->cmd("tell $who Stopping poll.");
 243                         $stop_pgn_fetch = 1;
 244                         $http_timer = undef;
 245                 } elsif ($msg =~ /^quit$/) {
 246                         $t->cmd("tell $who Bye bye.");
 247                         exit;
 248                 } else {
 249                         $t->cmd("tell $who Couldn't understand '$msg', sorry.");
 250                 }
 251         }
 252         #print "FICS: [$line]\n";
 253 }
 254
 255 # Starts periodic fetching of PGNs from the given URL.
 256 sub fetch_pgn {
 257         my ($url) = @_;
 258         AnyEvent::HTTP::http_get($url, sub {
 259                 handle_pgn(@_, $url);
 260         });
 261 }
 262
 263 my ($last_pgn_white, $last_pgn_black);
 264 my @last_pgn_uci_moves = ();
 265 my $pgn_hysteresis_counter = 0;
 266
 267 sub handle_pgn {
 268         my ($body, $header, $url) = @_;
 269
 270         if ($stop_pgn_fetch) {
 271                 $stop_pgn_fetch = 0;
 272                 $http_timer = undef;
 273                 return;
 274         }
 275
 276         my $pgn = Chess::PGN::Parse->new(undef, $body);
 277         if (!defined($pgn) || !$pgn->read_game() || $body !~ /^\[/) {
 278                 warn "Error in parsing PGN from $url\n";
 279         } else {
 280                 eval {
 281                         # Skip to the right game.
 282                         while (defined($remoteglotconf::pgn_filter) &&
 283                                !&$remoteglotconf::pgn_filter($pgn)) {
 284                                 $pgn->read_game() or die "Out of games during filtering";
 285                         }
 286
 287                         $pgn->parse_game({ save_comments => 'yes' });
 288                         my $pos = Position->start_pos($pgn->white, $pgn->black);
 289                         my $moves = $pgn->moves;
 290                         my @uci_moves = ();
 291                         for my $move (@$moves) {
 292                                 my $uci_move;
 293                                 ($pos, $uci_move) = $pos->make_pretty_move($move);
 294                                 push @uci_moves, $uci_move;
 295                         }
 296                         $pos->{'result'} = $pgn->result;
 297                         $pos->{'pretty_history'} = $moves;
 298
 299                         extract_clock($pgn, $pos);
 300
 301                         # Sometimes, PGNs lose a move or two for a short while,
 302                         # or people push out new ones non-atomically.
 303                         # Thus, if we PGN doesn't change names but becomes
 304                         # shorter, we mistrust it for a few seconds.
 305                         my $trust_pgn = 1;
 306                         if (defined($last_pgn_white) && defined($last_pgn_black) &&
 307                             $last_pgn_white eq $pgn->white &&
 308                             $last_pgn_black eq $pgn->black &&
 309                             scalar(@uci_moves) < scalar(@last_pgn_uci_moves)) {
 310                                 if (++$pgn_hysteresis_counter < 3) {
 311                                         $trust_pgn = 0;
 312                                 }
 313                         }
 314                         if ($trust_pgn) {
 315                                 $last_pgn_white = $pgn->white;
 316                                 $last_pgn_black = $pgn->black;
 317                                 @last_pgn_uci_moves = @uci_moves;
 318                                 $pgn_hysteresis_counter = 0;
 319                                 handle_position($pos);
 320                         }
 321                 };
 322                 if ($@) {
 323                         warn "Error in parsing moves from $url: $@\n";
 324                 }
 325         }
 326
 327         $http_timer = AnyEvent->timer(after => 1.0, cb => sub {
 328                 fetch_pgn($url);
 329         });
 330 }
 331
 332 sub handle_position {
 333         my ($pos) = @_;
 334         find_clock_start($pos, $pos_calculating);
 335
 336         # if this is already in the queue, ignore it (just update the result)
 337         if (defined($pos_waiting) && $pos->fen() eq $pos_waiting->fen()) {
 338                 $pos_waiting->{'result'} = $pos->{'result'};
 339                 return;
 340         }
 341
 342         # if we're already chewing on this and there's nothing else in the queue,
 343         # also ignore it
 344         if (!defined($pos_waiting) && defined($pos_calculating) &&
 345             $pos->fen() eq $pos_calculating->fen()) {
 346                 $pos_calculating->{'result'} = $pos->{'result'};
 347                 return;
 348         }
 349
 350         # if we're already thinking on something, stop and wait for the engine
 351         # to approve
 352         if (defined($pos_calculating)) {
 353                 # Store the final data we have for this position in the history,
 354                 # with the precise clock information we just got from the new
 355                 # position. (Historic positions store the clock at the end of
 356                 # the position.)
 357                 #
 358                 # Do not output anything new to the main analysis; that's
 359                 # going to be obsolete really soon.
 360                 $pos_calculating->{'white_clock'} = $pos->{'white_clock'};
 361                 $pos_calculating->{'black_clock'} = $pos->{'black_clock'};
 362                 delete $pos_calculating->{'white_clock_target'};
 363                 delete $pos_calculating->{'black_clock_target'};
 364                 output_json(1);
 365
 366                 if (!defined($pos_waiting)) {
 367                         uciprint($engine, "stop");
 368                 }
 369                 if ($remoteglotconf::uci_assume_full_compliance) {
 370                         $pos_waiting = $pos;
 371                 } else {
 372                         uciprint($engine, "position fen " . $pos->fen());
 373                         uciprint($engine, "go infinite");
 374                         $pos_calculating = $pos;
 375                 }
 376         } else {
 377                 # it's wrong just to give the FEN (the move history is useful,
 378                 # and per the UCI spec, we should really have sent "ucinewgame"),
 379                 # but it's easier
 380                 uciprint($engine, "position fen " . $pos->fen());
 381                 uciprint($engine, "go infinite");
 382                 $pos_calculating = $pos;
 383         }
 384
 385         if (defined($engine2)) {
 386                 if (defined($pos_calculating_second_engine)) {
 387                         uciprint($engine2, "stop");
 388                 } else {
 389                         uciprint($engine2, "position fen " . $pos->fen());
 390                         uciprint($engine2, "go infinite");
 391                         $pos_calculating_second_engine = $pos;
 392                 }
 393                 $engine2->{'info'} = {};
 394         }
 395
 396         $engine->{'info'} = {};
 397         $last_move = time;
 398
 399         schedule_tb_lookup();
 400
 401         #
 402         # Output a command every move to note that we're
 403         # still paying attention -- this is a good tradeoff,
 404         # since if no move has happened in the last half
 405         # hour, the analysis/relay has most likely stopped
 406         # and we should stop hogging server resources.
 407         #
 408         $t->cmd("date");
 409 }
 410
 411 sub parse_infos {
 412         my ($engine, @x) = @_;
 413         my $mpv = '';
 414
 415         my $info = $engine->{'info'};
 416
 417         # Search for "multipv" first of all, since e.g. Stockfish doesn't put it first.
 418         for my $i (0..$#x - 1) {
 419                 if ($x[$i] eq 'multipv') {
 420                         $mpv = $x[$i + 1];
 421                         next;
 422                 }
 423         }
 424
 425         while (scalar @x > 0) {
 426                 if ($x[0] eq 'multipv') {
 427                         # Dealt with above
 428                         shift @x;
 429                         shift @x;
 430                         next;
 431                 }
 432                 if ($x[0] eq 'currmove' || $x[0] eq 'currmovenumber' || $x[0] eq 'cpuload') {
 433                         my $key = shift @x;
 434                         my $value = shift @x;
 435                         $info->{$key} = $value;
 436                         next;
 437                 }
 438                 if ($x[0] eq 'depth' || $x[0] eq 'seldepth' || $x[0] eq 'hashfull' ||
 439                     $x[0] eq 'time' || $x[0] eq 'nodes' || $x[0] eq 'nps' ||
 440                     $x[0] eq 'tbhits') {
 441                         my $key = shift @x;
 442                         my $value = shift @x;
 443                         $info->{$key . $mpv} = $value;
 444                         next;
 445                 }
 446                 if ($x[0] eq 'score') {
 447                         shift @x;
 448
 449                         delete $info->{'score_cp' . $mpv};
 450                         delete $info->{'score_mate' . $mpv};
 451
 452                         while ($x[0] eq 'cp' || $x[0] eq 'mate') {
 453                                 if ($x[0] eq 'cp') {
 454                                         shift @x;
 455                                         $info->{'score_cp' . $mpv} = shift @x;
 456                                 } elsif ($x[0] eq 'mate') {
 457                                         shift @x;
 458                                         $info->{'score_mate' . $mpv} = shift @x;
 459                                 } else {
 460                                         shift @x;
 461                                 }
 462                         }
 463                         next;
 464                 }
 465                 if ($x[0] eq 'pv') {
 466                         $info->{'pv' . $mpv} = [ @x[1..$#x] ];
 467                         last;
 468                 }
 469                 if ($x[0] eq 'string' || $x[0] eq 'UCI_AnalyseMode' || $x[0] eq 'setting' || $x[0] eq 'contempt') {
 470                         last;
 471                 }
 472
 473                 #print "unknown info '$x[0]', trying to recover...\n";
 474                 #shift @x;
 475                 die "Unknown info '" . join(',', @x) . "'";
 476
 477         }
 478 }
 479
 480 sub parse_ids {
 481         my ($engine, @x) = @_;
 482
 483         while (scalar @x > 0) {
 484                 if ($x[0] =~ /^(name|author)$/) {
 485                         my $key = shift @x;
 486                         my $value = join(' ', @x);
 487                         $engine->{'id'}{$key} = $value;
 488                         last;
 489                 }
 490
 491                 # unknown
 492                 shift @x;
 493         }
 494 }
 495
 496 sub prettyprint_pv_no_cache {
 497         my ($board, @pvs) = @_;
 498
 499         if (scalar @pvs == 0 || !defined($pvs[0])) {
 500                 return ();
 501         }
 502
 503         my $pv = shift @pvs;
 504         my ($from_col, $from_row, $to_col, $to_row, $promo) = parse_uci_move($pv);
 505         my ($pretty, $nb) = $board->prettyprint_move($from_row, $from_col, $to_row, $to_col, $promo);
 506         return ( $pretty, prettyprint_pv_no_cache($nb, @pvs) );
 507 }
 508
 509 sub prettyprint_pv {
 510         my ($pos, @pvs) = @_;
 511
 512         my $cachekey = join('', @pvs);
 513         if (exists($pos->{'prettyprint_cache'}{$cachekey})) {
 514                 return @{$pos->{'prettyprint_cache'}{$cachekey}};
 515         } else {
 516                 my @res = prettyprint_pv_no_cache($pos->{'board'}, @pvs);
 517                 $pos->{'prettyprint_cache'}{$cachekey} = \@res;
 518                 return @res;
 519         }
 520 }
 521
 522 sub output {
 523         #return;
 524
 525         return if (!defined($pos_calculating));
 526
 527         # Don't update too often.
 528         my $age = Time::HiRes::tv_interval($latest_update);
 529         if ($age < $remoteglotconf::update_max_interval) {
 530                 my $wait = $remoteglotconf::update_max_interval + 0.01 - $age;
 531                 $output_timer = AnyEvent->timer(after => $wait, cb => \&output);
 532                 return;
 533         }
 534
 535         my $info = $engine->{'info'};
 536
 537         #
 538         # If we have tablebase data from a previous lookup, replace the
 539         # engine data with the data from the tablebase.
 540         #
 541         my $fen = $pos_calculating->fen();
 542         if (exists($tb_cache{$fen})) {
 543                 for my $key (qw(pv score_cp score_mate nodes nps depth seldepth tbhits)) {
 544                         delete $info->{$key . '1'};
 545                         delete $info->{$key};
 546                 }
 547                 $info->{'nodes'} = 0;
 548                 $info->{'nps'} = 0;
 549                 $info->{'depth'} = 0;
 550                 $info->{'seldepth'} = 0;
 551                 $info->{'tbhits'} = 0;
 552
 553                 my $t = $tb_cache{$fen};
 554                 my $pv = $t->{'pv'};
 555                 my $matelen = int((1 + $t->{'score'}) / 2);
 556                 if ($t->{'result'} eq '1/2-1/2') {
 557                         $info->{'score_cp'} = 0;
 558                 } elsif ($t->{'result'} eq '1-0') {
 559                         if ($pos_calculating->{'toplay'} eq 'B') {
 560                                 $info->{'score_mate'} = -$matelen;
 561                         } else {
 562                                 $info->{'score_mate'} = $matelen;
 563                         }
 564                 } else {
 565                         if ($pos_calculating->{'toplay'} eq 'B') {
 566                                 $info->{'score_mate'} = $matelen;
 567                         } else {
 568                                 $info->{'score_mate'} = -$matelen;
 569                         }
 570                 }
 571                 $info->{'pv'} = $pv;
 572                 $info->{'tablebase'} = 1;
 573         } else {
 574                 $info->{'tablebase'} = 0;
 575         }
 576
 577         #
 578         # Some programs _always_ report MultiPV, even with only one PV.
 579         # In this case, we simply use that data as if MultiPV was never
 580         # specified.
 581         #
 582         if (exists($info->{'pv1'}) && !exists($info->{'pv2'})) {
 583                 for my $key (qw(pv score_cp score_mate nodes nps depth seldepth tbhits)) {
 584                         if (exists($info->{$key . '1'})) {
 585                                 $info->{$key} = $info->{$key . '1'};
 586                         }
 587                 }
 588         }
 589
 590         #
 591         # Check the PVs first. if they're invalid, just wait, as our data
 592         # is most likely out of sync. This isn't a very good solution, as
 593         # it can frequently miss stuff, but it's good enough for most users.
 594         #
 595         eval {
 596                 my $dummy;
 597                 if (exists($info->{'pv'})) {
 598                         $dummy = prettyprint_pv($pos_calculating, @{$info->{'pv'}});
 599                 }
 600
 601                 my $mpv = 1;
 602                 while (exists($info->{'pv' . $mpv})) {
 603                         $dummy = prettyprint_pv($pos_calculating, @{$info->{'pv' . $mpv}});
 604                         ++$mpv;
 605                 }
 606         };
 607         if ($@) {
 608                 $engine->{'info'} = {};
 609                 return;
 610         }
 611
 612         output_screen();
 613         output_json(0);
 614         $latest_update = [Time::HiRes::gettimeofday];
 615 }
 616
 617 sub output_screen {
 618         my $info = $engine->{'info'};
 619         my $id = $engine->{'id'};
 620
 621         my $text = 'Analysis';
 622         if ($pos_calculating->{'last_move'} ne 'none') {
 623                 if ($pos_calculating->{'toplay'} eq 'W') {
 624                         $text .= sprintf ' after %u. ... %s', ($pos_calculating->{'move_num'}-1), $pos_calculating->{'last_move'};
 625                 } else {
 626                         $text .= sprintf ' after %u. %s', $pos_calculating->{'move_num'}, $pos_calculating->{'last_move'};
 627                 }
 628                 if (exists($id->{'name'})) {
 629                         $text .= ',';
 630                 }
 631         }
 632
 633         if (exists($id->{'name'})) {
 634                 $text .= " by $id->{'name'}:\n\n";
 635         } else {
 636                 $text .= ":\n\n";
 637         }
 638
 639         return unless (exists($pos_calculating->{'board'}));
 640
 641         if (exists($info->{'pv1'}) && exists($info->{'pv2'})) {
 642                 # multi-PV
 643                 my $mpv = 1;
 644                 while (exists($info->{'pv' . $mpv})) {
 645                         $text .= sprintf "  PV%2u", $mpv;
 646                         my $score = short_score($info, $pos_calculating, $mpv);
 647                         $text .= "  ($score)" if (defined($score));
 648
 649                         my $tbhits = '';
 650                         if (exists($info->{'tbhits' . $mpv}) && $info->{'tbhits' . $mpv} > 0) {
 651                                 if ($info->{'tbhits' . $mpv} == 1) {
 652                                         $tbhits = ", 1 tbhit";
 653                                 } else {
 654                                         $tbhits = sprintf ", %u tbhits", $info->{'tbhits' . $mpv};
 655                                 }
 656                         }
 657
 658                         if (exists($info->{'nodes' . $mpv}) && exists($info->{'nps' . $mpv}) && exists($info->{'depth' . $mpv})) {
 659                                 $text .= sprintf " (%5u kn, %3u kn/s, %2u ply$tbhits)",
 660                                         $info->{'nodes' . $mpv} / 1000, $info->{'nps' . $mpv} / 1000, $info->{'depth' . $mpv};
 661                         }
 662
 663                         $text .= ":\n";
 664                         $text .= "  " . join(', ', prettyprint_pv($pos_calculating, @{$info->{'pv' . $mpv}})) . "\n";
 665                         $text .= "\n";
 666                         ++$mpv;
 667                 }
 668         } else {
 669                 # single-PV
 670                 my $score = long_score($info, $pos_calculating, '');
 671                 $text .= "  $score\n" if defined($score);
 672                 $text .=  "  PV: " . join(', ', prettyprint_pv($pos_calculating, @{$info->{'pv'}}));
 673                 $text .=  "\n";
 674
 675                 if (exists($info->{'nodes'}) && exists($info->{'nps'}) && exists($info->{'depth'})) {
 676                         $text .= sprintf "  %u nodes, %7u nodes/sec, depth %u ply",
 677                                 $info->{'nodes'}, $info->{'nps'}, $info->{'depth'};
 678                 }
 679                 if (exists($info->{'seldepth'})) {
 680                         $text .= sprintf " (%u selective)", $info->{'seldepth'};
 681                 }
 682                 if (exists($info->{'tbhits'}) && $info->{'tbhits'} > 0) {
 683                         if ($info->{'tbhits'} == 1) {
 684                                 $text .= ", one Syzygy hit";
 685                         } else {
 686                                 $text .= sprintf ", %u Syzygy hits", $info->{'tbhits'};
 687                         }
 688                 }
 689                 $text .= "\n\n";
 690         }
 691
 692         #$text .= book_info($pos_calculating->fen(), $pos_calculating->{'board'}, $pos_calculating->{'toplay'});
 693
 694         my @refutation_lines = ();
 695         if (defined($engine2)) {
 696                 for (my $mpv = 1; $mpv < 500; ++$mpv) {
 697                         my $info = $engine2->{'info'};
 698                         last if (!exists($info->{'pv' . $mpv}));
 699                         eval {
 700                                 my $pv = $info->{'pv' . $mpv};
 701
 702                                 my $pretty_move = join('', prettyprint_pv($pos_calculating_second_engine, $pv->[0]));
 703                                 my @pretty_pv = prettyprint_pv($pos_calculating_second_engine, @$pv);
 704                                 if (scalar @pretty_pv > 5) {
 705                                         @pretty_pv = @pretty_pv[0..4];
 706                                         push @pretty_pv, "...";
 707                                 }
 708                                 my $key = $pretty_move;
 709                                 my $line = sprintf("  %-6s %6s %3s  %s",
 710                                         $pretty_move,
 711                                         short_score($info, $pos_calculating_second_engine, $mpv),
 712                                         "d" . $info->{'depth' . $mpv},
 713                                         join(', ', @pretty_pv));
 714                                 push @refutation_lines, [ $key, $line ];
 715                         };
 716                 }
 717         }
 718
 719         if ($#refutation_lines >= 0) {
 720                 $text .= "Shallow search of all legal moves:\n\n";
 721                 for my $line (sort { $a->[0] cmp $b->[0] } @refutation_lines) {
 722                         $text .= $line->[1] . "\n";
 723                 }
 724                 $text .= "\n\n";
 725         }
 726
 727         if ($last_text ne $text) {
 728                 print "\e[H\e[2J"; # clear the screen
 729                 print $text;
 730                 $last_text = $text;
 731         }
 732 }
 733
 734 sub output_json {
 735         my $historic_json_only = shift;
 736         my $info = $engine->{'info'};
 737
 738         my $json = {};
 739         $json->{'position'} = $pos_calculating->to_json_hash();
 740         $json->{'id'} = $engine->{'id'};
 741         $json->{'score'} = long_score($info, $pos_calculating, '');
 742         $json->{'short_score'} = short_score($info, $pos_calculating, '');
 743         $json->{'plot_score'} = plot_score($info, $pos_calculating, '');
 744
 745         $json->{'nodes'} = $info->{'nodes'};
 746         $json->{'nps'} = $info->{'nps'};
 747         $json->{'depth'} = $info->{'depth'};
 748         $json->{'tbhits'} = $info->{'tbhits'};
 749         $json->{'seldepth'} = $info->{'seldepth'};
 750         $json->{'tablebase'} = $info->{'tablebase'};
 751
 752         $json->{'pv_uci'} = $info->{'pv'};  # Still needs to be there for the JS to calculate arrows; only for the primary PV, though!
 753         $json->{'pv_pretty'} = [ prettyprint_pv($pos_calculating, @{$info->{'pv'}}) ];
 754
 755         my %refutation_lines = ();
 756         my @refutation_lines = ();
 757         if (defined($engine2)) {
 758                 for (my $mpv = 1; $mpv < 500; ++$mpv) {
 759                         my $info = $engine2->{'info'};
 760                         my $pretty_move = "";
 761                         my @pretty_pv = ();
 762                         last if (!exists($info->{'pv' . $mpv}));
 763
 764                         eval {
 765                                 my $pv = $info->{'pv' . $mpv};
 766                                 my $pretty_move = join('', prettyprint_pv($pos_calculating, $pv->[0]));
 767                                 my @pretty_pv = prettyprint_pv($pos_calculating, @$pv);
 768                                 $refutation_lines{$pv->[0]} = {
 769                                         sort_key => $pretty_move,
 770                                         depth => $info->{'depth' . $mpv},
 771                                         score_sort_key => score_sort_key($info, $pos_calculating, $mpv, 0),
 772                                         pretty_score => short_score($info, $pos_calculating, $mpv),
 773                                         pretty_move => $pretty_move,
 774                                         pv_pretty => \@pretty_pv,
 775                                 };
 776                         };
 777                 }
 778         }
 779         $json->{'refutation_lines'} = \%refutation_lines;
 780
 781         # Piece together historic score information, to the degree we have it.
 782         if (!$historic_json_only && exists($pos_calculating->{'pretty_history'})) {
 783                 my %score_history = ();
 784
 785                 my $pos = Position->start_pos('white', 'black');
 786                 my $halfmove_num = 0;
 787                 for my $move (@{$pos_calculating->{'pretty_history'}}) {
 788                         my $id = id_for_pos($pos, $halfmove_num);
 789                         if (exists($json_for_pos{$id}) && defined($json_for_pos{$id}->{'plot_score'})) {
 790                                 $score_history{$halfmove_num} = [
 791                                         $json_for_pos{$id}->{'plot_score'},
 792                                         $json_for_pos{$id}->{'short_score'}
 793                                 ];
 794                         }
 795                         ++$halfmove_num;
 796                         ($pos) = $pos->make_pretty_move($move);
 797                 }
 798
 799                 # If at any point we are missing 10 consecutive moves,
 800                 # truncate the history there. This is so we don't get into
 801                 # a situation where we e.g. start analyzing at move 45,
 802                 # but we have analysis for 1. e4 from some completely different game
 803                 # and thus show a huge hole.
 804                 my $consecutive_missing = 0;
 805                 my $truncate_until = 0;
 806                 for (my $i = $halfmove_num; $i --> 0; ) {
 807                         if ($consecutive_missing >= 10) {
 808                                 delete $score_history{$i};
 809                                 next;
 810                         }
 811                         if (exists($score_history{$i})) {
 812                                 $consecutive_missing = 0;
 813                         } else {
 814                                 ++$consecutive_missing;
 815                         }
 816                 }
 817
 818                 $json->{'score_history'} = \%score_history;
 819         }
 820
 821         my $json_enc = JSON::XS->new;
 822         $json_enc->canonical(1);
 823         my $encoded = $json_enc->encode($json);
 824         unless ($historic_json_only || !defined($remoteglotconf::json_output) ||
 825                 (defined($last_written_json) && $last_written_json eq $encoded)) {
 826                 atomic_set_contents($remoteglotconf::json_output, $encoded);
 827                 $last_written_json = $encoded;
 828         }
 829
 830         if (exists($pos_calculating->{'pretty_history'}) &&
 831             defined($remoteglotconf::json_history_dir)) {
 832                 my $id = id_for_pos($pos_calculating);
 833                 my $filename = $remoteglotconf::json_history_dir . "/" . $id . ".json";
 834
 835                 # Overwrite old analysis (assuming it exists at all) if we're
 836                 # using a different engine, or if we've calculated deeper.
 837                 # nodes is used as a tiebreaker. Don't bother about Multi-PV
 838                 # data; it's not that important.
 839                 my ($old_engine, $old_depth, $old_nodes) = get_json_analysis_stats($filename);
 840                 my $new_depth = $json->{'depth'} // 0;
 841                 my $new_nodes = $json->{'nodes'} // 0;
 842                 if (!defined($old_engine) ||
 843                     $old_engine ne $json->{'id'}{'name'} ||
 844                     $new_depth > $old_depth ||
 845                     ($new_depth == $old_depth && $new_nodes >= $old_nodes)) {
 846                         atomic_set_contents($filename, $encoded);
 847                         $json_for_pos{$id} = $json;
 848                 }
 849         }
 850 }
 851
 852 sub atomic_set_contents {
 853         my ($filename, $contents) = @_;
 854
 855         open my $fh, ">", $filename . ".tmp"
 856                 or return;
 857         print $fh $contents;
 858         close $fh;
 859         rename($filename . ".tmp", $filename);
 860 }
 861
 862 sub id_for_pos {
 863         my ($pos, $halfmove_num) = @_;
 864
 865         $halfmove_num //= scalar @{$pos->{'pretty_history'}};
 866         (my $fen = $pos->fen()) =~ tr,/ ,-_,;
 867         return "move$halfmove_num-$fen";
 868 }
 869
 870 sub get_json_analysis_stats {
 871         my $filename = shift;
 872
 873         my ($engine, $depth, $nodes);
 874
 875         open my $fh, "<", $filename
 876                 or return undef;
 877         local $/ = undef;
 878         eval {
 879                 my $json = JSON::XS::decode_json(<$fh>);
 880                 $engine = $json->{'id'}{'name'} // die;
 881                 $depth = $json->{'depth'} // 0;
 882                 $nodes = $json->{'nodes'} // 0;
 883         };
 884         close $fh;
 885         if ($@) {
 886                 warn "Error in decoding $filename: $@";
 887                 return undef;
 888         }
 889         return ($engine, $depth, $nodes);
 890 }
 891
 892 sub uciprint {
 893         my ($engine, $msg) = @_;
 894         $engine->print($msg);
 895         print UCILOG localtime() . " $engine->{'tag'} => $msg\n";
 896 }
 897
 898 sub short_score {
 899         my ($info, $pos, $mpv) = @_;
 900
 901         my $invert = ($pos->{'toplay'} eq 'B');
 902         if (defined($info->{'score_mate' . $mpv})) {
 903                 if ($invert) {
 904                         return sprintf "M%3d", -$info->{'score_mate' . $mpv};
 905                 } else {
 906                         return sprintf "M%3d", $info->{'score_mate' . $mpv};
 907                 }
 908         } else {
 909                 if (exists($info->{'score_cp' . $mpv})) {
 910                         my $score = $info->{'score_cp' . $mpv} * 0.01;
 911                         if ($score == 0) {
 912                                 if ($info->{'tablebase'}) {
 913                                         return "TB draw";
 914                                 } else {
 915                                         return " 0.00";
 916                                 }
 917                         }
 918                         if ($invert) {
 919                                 $score = -$score;
 920                         }
 921                         return sprintf "%+5.2f", $score;
 922                 }
 923         }
 924
 925         return undef;
 926 }
 927
 928 sub score_sort_key {
 929         my ($info, $pos, $mpv, $invert) = @_;
 930
 931         if (defined($info->{'score_mate' . $mpv})) {
 932                 my $mate = $info->{'score_mate' . $mpv};
 933                 my $score;
 934                 if ($mate > 0) {
 935                         # Side to move mates
 936                         $score = 99999 - $mate;
 937                 } else {
 938                         # Side to move is getting mated (note the double negative for $mate)
 939                         $score = -99999 - $mate;
 940                 }
 941                 if ($invert) {
 942                         $score = -$score;
 943                 }
 944                 return $score;
 945         } else {
 946                 if (exists($info->{'score_cp' . $mpv})) {
 947                         my $score = $info->{'score_cp' . $mpv};
 948                         if ($invert) {
 949                                 $score = -$score;
 950                         }
 951                         return $score;
 952                 }
 953         }
 954
 955         return undef;
 956 }
 957
 958 sub long_score {
 959         my ($info, $pos, $mpv) = @_;
 960
 961         if (defined($info->{'score_mate' . $mpv})) {
 962                 my $mate = $info->{'score_mate' . $mpv};
 963                 if ($pos->{'toplay'} eq 'B') {
 964                         $mate = -$mate;
 965                 }
 966                 if ($mate > 0) {
 967                         return sprintf "White mates in %u", $mate;
 968                 } else {
 969                         return sprintf "Black mates in %u", -$mate;
 970                 }
 971         } else {
 972                 if (exists($info->{'score_cp' . $mpv})) {
 973                         my $score = $info->{'score_cp' . $mpv} * 0.01;
 974                         if ($score == 0) {
 975                                 if ($info->{'tablebase'}) {
 976                                         return "Theoretical draw";
 977                                 } else {
 978                                         return "Score:  0.00";
 979                                 }
 980                         }
 981                         if ($pos->{'toplay'} eq 'B') {
 982                                 $score = -$score;
 983                         }
 984                         return sprintf "Score: %+5.2f", $score;
 985                 }
 986         }
 987
 988         return undef;
 989 }
 990
 991 # For graphs; a single number in centipawns, capped at +/- 500.
 992 sub plot_score {
 993         my ($info, $pos, $mpv) = @_;
 994
 995         my $invert = ($pos->{'toplay'} eq 'B');
 996         if (defined($info->{'score_mate' . $mpv})) {
 997                 my $mate = $info->{'score_mate' . $mpv};
 998                 if ($invert) {
 999                         $mate = -$mate;
1000                 }
1001                 if ($mate > 0) {
1002                         return 500;
1003                 } else {
1004                         return -500;
1005                 }
1006         } else {
1007                 if (exists($info->{'score_cp' . $mpv})) {
1008                         my $score = $info->{'score_cp' . $mpv};
1009                         if ($invert) {
1010                                 $score = -$score;
1011                         }
1012                         $score = 500 if ($score > 500);
1013                         $score = -500 if ($score < -500);
1014                         return int($score);
1015                 }
1016         }
1017
1018         return undef;
1019 }
1020
1021 my %book_cache = ();
1022 sub book_info {
1023         my ($fen, $board, $toplay) = @_;
1024
1025         if (exists($book_cache{$fen})) {
1026                 return $book_cache{$fen};
1027         }
1028
1029         my $ret = `./booklook $fen`;
1030         return "" if ($ret =~ /Not found/ || $ret eq '');
1031
1032         my @moves = ();
1033
1034         for my $m (split /\n/, $ret) {
1035                 my ($move, $annotation, $win, $draw, $lose, $rating, $rating_div) = split /,/, $m;
1036
1037                 my $pmove;
1038                 if ($move eq '')  {
1039                         $pmove = '(current)';
1040                 } else {
1041                         ($pmove) = prettyprint_pv_no_cache($board, $move);
1042                         $pmove .= $annotation;
1043                 }
1044
1045                 my $score;
1046                 if ($toplay eq 'W') {
1047                         $score = 1.0 * $win + 0.5 * $draw + 0.0 * $lose;
1048                 } else {
1049                         $score = 0.0 * $win + 0.5 * $draw + 1.0 * $lose;
1050                 }
1051                 my $n = $win + $draw + $lose;
1052
1053                 my $percent;
1054                 if ($n == 0) {
1055                         $percent = "     ";
1056                 } else {
1057                         $percent = sprintf "%4u%%", int(100.0 * $score / $n + 0.5);
1058                 }
1059
1060                 push @moves, [ $pmove, $n, $percent, $rating ];
1061         }
1062
1063         @moves[1..$#moves] = sort { $b->[2] cmp $a->[2] } @moves[1..$#moves];
1064
1065         my $text = "Book moves:\n\n              Perf.     N     Rating\n\n";
1066         for my $m (@moves) {
1067                 $text .= sprintf "  %-10s %s   %6u    %4s\n", $m->[0], $m->[2], $m->[1], $m->[3]
1068         }
1069
1070         return $text;
1071 }
1072
1073 sub extract_clock {
1074         my ($pgn, $pos) = @_;
1075
1076         # Look for extended PGN clock tags.
1077         my $tags = $pgn->tags;
1078         if (exists($tags->{'WhiteClock'}) && exists($tags->{'BlackClock'})) {
1079                 $pos->{'white_clock'} = hms_to_sec($tags->{'WhiteClock'});
1080                 $pos->{'black_clock'} = hms_to_sec($tags->{'BlackClock'});
1081                 return;
1082         }
1083
1084         # Look for TCEC-style time comments.
1085         my $moves = $pgn->moves;
1086         my $comments = $pgn->comments;
1087         my $last_black_move = int((scalar @$moves) / 2);
1088         my $last_white_move = int((1 + scalar @$moves) / 2);
1089
1090         my $black_key = $last_black_move . "b";
1091         my $white_key = $last_white_move . "w";
1092
1093         if (exists($comments->{$white_key}) &&
1094             exists($comments->{$black_key}) &&
1095             $comments->{$white_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/ &&
1096             $comments->{$black_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/) {
1097                 $comments->{$white_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/;
1098                 $pos->{'white_clock'} = hms_to_sec($1);
1099                 $comments->{$black_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/;
1100                 $pos->{'black_clock'} = hms_to_sec($1);
1101                 return;
1102         }
1103
1104         delete $pos->{'white_clock'};
1105         delete $pos->{'black_clock'};
1106 }
1107
1108 sub hms_to_sec {
1109         my $hms = shift;
1110         return undef if (!defined($hms));
1111         $hms =~ /(\d+):(\d+):(\d+)/;
1112         return $1 * 3600 + $2 * 60 + $3;
1113 }
1114
1115 sub find_clock_start {
1116         my ($pos, $prev_pos) = @_;
1117
1118         # If the game is over, the clock is stopped.
1119         if (exists($pos->{'result'}) &&
1120             ($pos->{'result'} eq '1-0' ||
1121              $pos->{'result'} eq '1/2-1/2' ||
1122              $pos->{'result'} eq '0-1')) {
1123                 return;
1124         }
1125
1126         # When we don't have any moves, we assume the clock hasn't started yet.
1127         if ($pos->{'move_num'} == 1 && $pos->{'toplay'} eq 'W') {
1128                 if (defined($remoteglotconf::adjust_clocks_before_move)) {
1129                         &$remoteglotconf::adjust_clocks_before_move(\$pos->{'white_clock'}, \$pos->{'black_clock'}, 1, 'W');
1130                 }
1131                 return;
1132         }
1133
1134         # TODO(sesse): Maybe we can get the number of moves somehow else for FICS games.
1135         # The history is needed for id_for_pos.
1136         if (!exists($pos->{'pretty_history'})) {
1137                 return;
1138         }
1139
1140         my $id = id_for_pos($pos);
1141         if (exists($clock_info_for_pos{$id})) {
1142                 $pos->{'white_clock'} //= $clock_info_for_pos{$id}{'white_clock'};
1143                 $pos->{'black_clock'} //= $clock_info_for_pos{$id}{'black_clock'};
1144                 if ($pos->{'toplay'} eq 'W') {
1145                         $pos->{'white_clock_target'} = $clock_info_for_pos{$id}->{'white_clock_target'};
1146                 } else {
1147                         $pos->{'black_clock_target'} = $clock_info_for_pos{$id}->{'black_clock_target'};
1148                 }
1149                 return;
1150         }
1151
1152         # OK, we haven't seen this position before, so we assume the move
1153         # happened right now.
1154
1155         # See if we should do our own clock management (ie., clock information
1156         # is spurious or non-existent).
1157         if (defined($remoteglotconf::adjust_clocks_before_move)) {
1158                 my $wc = $pos->{'white_clock'} // $prev_pos->{'white_clock'};
1159                 my $bc = $pos->{'black_clock'} // $prev_pos->{'black_clock'};
1160                 if (defined($prev_pos->{'white_clock_target'})) {
1161                         $wc = $prev_pos->{'white_clock_target'} - time;
1162                 }
1163                 if (defined($prev_pos->{'black_clock_target'})) {
1164                         $bc = $prev_pos->{'black_clock_target'} - time;
1165                 }
1166                 &$remoteglotconf::adjust_clocks_before_move(\$wc, \$bc, $pos->{'move_num'}, $pos->{'toplay'});
1167                 $pos->{'white_clock'} = $wc;
1168                 $pos->{'black_clock'} = $bc;
1169         }
1170
1171         my $key = ($pos->{'toplay'} eq 'W') ? 'white_clock' : 'black_clock';
1172         if (!exists($pos->{$key})) {
1173                 # No clock information.
1174                 return;
1175         }
1176         my $time_left = $pos->{$key};
1177         my $clock_info = {
1178                 white_clock => $pos->{'white_clock'},
1179                 black_clock => $pos->{'black_clock'}
1180         };
1181         if ($pos->{'toplay'} eq 'W') {
1182                 $clock_info->{'white_clock_target'} = $pos->{'white_clock_target'} = time + $time_left;
1183         } else {
1184                 $clock_info->{'black_clock_target'} = $pos->{'black_clock_target'} = time + $time_left;
1185         }
1186         $clock_info_for_pos{$id} = $clock_info;
1187 }
1188
1189 sub schedule_tb_lookup {
1190         return if (!defined($remoteglotconf::tb_serial_key));
1191         my $pos = $pos_waiting // $pos_calculating;
1192         return if (exists($tb_cache{$pos->fen()}));
1193
1194         # If there's more than seven pieces, there's not going to be an answer,
1195         # so don't bother.
1196         return if ($pos->num_pieces() > 7);
1197
1198         # Max one at a time. If it's still relevant when it returns,
1199         # schedule_tb_lookup() will be called again.
1200         return if ($tb_lookup_running);
1201
1202         $tb_lookup_running = 1;
1203         my $url = 'http://158.250.18.203:6904/tasks/addtask?auth.login=' .
1204                 $remoteglotconf::tb_serial_key .
1205                 '&auth.password=aquarium&type=0&fen=' .
1206                 URI::Escape::uri_escape($pos->fen());
1207         print TBLOG "Downloading $url...\n";
1208         AnyEvent::HTTP::http_get($url, sub {
1209                 handle_tb_lookup_return(@_, $pos, $pos->fen());
1210         });
1211 }
1212
1213 sub handle_tb_lookup_return {
1214         my ($body, $header, $pos, $fen) = @_;
1215         print TBLOG "Response for [$fen]:\n";
1216         print TBLOG $header . "\n\n";
1217         print TBLOG $body . "\n\n";
1218         eval {
1219                 my $response = JSON::XS::decode_json($body);
1220                 if ($response->{'ErrorCode'} != 0) {
1221                         die "Unknown tablebase server error: " . $response->{'ErrorDesc'};
1222                 }
1223                 my $state = $response->{'Response'}{'StateString'};
1224                 if ($state eq 'COMPLETE') {
1225                         my $pgn = Chess::PGN::Parse->new(undef, $response->{'Response'}{'Moves'});
1226                         if (!defined($pgn) || !$pgn->read_game()) {
1227                                 warn "Error in parsing PGN\n";
1228                         } else {
1229                                 $pgn->quick_parse_game;
1230                                 my $pvpos = $pos;
1231                                 my $moves = $pgn->moves;
1232                                 my @uci_moves = ();
1233                                 for my $move (@$moves) {
1234                                         my $uci_move;
1235                                         ($pvpos, $uci_move) = $pvpos->make_pretty_move($move);
1236                                         push @uci_moves, $uci_move;
1237                                 }
1238                                 $tb_cache{$fen} = {
1239                                         result => $pgn->result,
1240                                         pv => \@uci_moves,
1241                                         score => $response->{'Response'}{'Score'},
1242                                 };
1243                                 output();
1244                         }
1245                 } elsif ($state =~ /QUEUED/ || $state =~ /PROCESSING/) {
1246                         # Try again in a second. Note that if we have changed
1247                         # position in the meantime, we might query a completely
1248                         # different position! But that's fine.
1249                 } else {
1250                         die "Unknown response state " . $state;
1251                 }
1252
1253                 # Wait a second before we schedule another one.
1254                 $tb_retry_timer = AnyEvent->timer(after => 1.0, cb => sub {
1255                         $tb_lookup_running = 0;
1256                         schedule_tb_lookup();
1257                 });
1258         };
1259         if ($@) {
1260                 warn "Error in tablebase lookup: $@";
1261
1262                 # Don't try this one again, but don't block new lookups either.
1263                 $tb_lookup_running = 0;
1264         }
1265 }
1266
1267 sub open_engine {
1268         my ($cmdline, $tag, $cb) = @_;
1269         return undef if (!defined($cmdline));
1270         return Engine->open($cmdline, $tag, $cb);
1271 }
1272
1273 sub col_letter_to_num {
1274         return ord(shift) - ord('a');
1275 }
1276
1277 sub row_letter_to_num {
1278         return 7 - (ord(shift) - ord('1'));
1279 }
1280
1281 sub parse_uci_move {
1282         my $move = shift;
1283         my $from_col = col_letter_to_num(substr($move, 0, 1));
1284         my $from_row = row_letter_to_num(substr($move, 1, 1));
1285         my $to_col   = col_letter_to_num(substr($move, 2, 1));
1286         my $to_row   = row_letter_to_num(substr($move, 3, 1));
1287         my $promo    = substr($move, 4, 1);
1288         return ($from_col, $from_row, $to_col, $to_row, $promo);
1289 }