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 File::Slurp;
  19 use IPC::Open2;
  20 use Time::HiRes;
  21 use JSON::XS;
  22 use URI::Escape;
  23 use DBI;
  24 use DBD::Pg;
  25 require 'Position.pm';
  26 require 'Engine.pm';
  27 require 'config.pm';
  28 use strict;
  29 use warnings;
  30 no warnings qw(once);
  31
  32 # Program starts here
  33 my $latest_update = undef;
  34 my $output_timer = undef;
  35 my $http_timer = undef;
  36 my $stop_pgn_fetch = 0;
  37 my $tb_retry_timer = undef;
  38 my %tb_cache = ();
  39 my $tb_lookup_running = 0;
  40 my $last_written_json = undef;
  41
  42 # Persisted so we can restart.
  43 # TODO: Figure out an appropriate way to deal with database restarts
  44 # and/or Postgres going away entirely.
  45 my $dbh = DBI->connect($remoteglotconf::dbistr, $remoteglotconf::dbiuser, $remoteglotconf::dbipass)
  46         or die DBI->errstr;
  47 $dbh->{RaiseError} = 1;
  48
  49 $| = 1;
  50
  51 open(FICSLOG, ">ficslog.txt")
  52         or die "ficslog.txt: $!";
  53 print FICSLOG "Log starting.\n";
  54 select(FICSLOG);
  55 $| = 1;
  56
  57 open(UCILOG, ">ucilog.txt")
  58         or die "ucilog.txt: $!";
  59 print UCILOG "Log starting.\n";
  60 select(UCILOG);
  61 $| = 1;
  62
  63 open(TBLOG, ">tblog.txt")
  64         or die "tblog.txt: $!";
  65 print TBLOG "Log starting.\n";
  66 select(TBLOG);
  67 $| = 1;
  68
  69 select(STDOUT);
  70
  71 # open the chess engine
  72 my $engine = open_engine($remoteglotconf::engine_cmdline, 'E1', sub { handle_uci(@_, 1); });
  73 my $engine2 = open_engine($remoteglotconf::engine2_cmdline, 'E2', sub { handle_uci(@_, 0); });
  74 my $last_move;
  75 my $last_text = '';
  76 my ($pos_waiting, $pos_calculating, $pos_calculating_second_engine);
  77
  78 uciprint($engine, "setoption name UCI_AnalyseMode value true");
  79 while (my ($key, $value) = each %remoteglotconf::engine_config) {
  80         uciprint($engine, "setoption name $key value $value");
  81 }
  82 uciprint($engine, "ucinewgame");
  83
  84 if (defined($engine2)) {
  85         uciprint($engine2, "setoption name UCI_AnalyseMode value true");
  86         while (my ($key, $value) = each %remoteglotconf::engine2_config) {
  87                 uciprint($engine2, "setoption name $key value $value");
  88         }
  89         uciprint($engine2, "setoption name MultiPV value 500");
  90         uciprint($engine2, "ucinewgame");
  91 }
  92
  93 print "Chess engine ready.\n";
  94
  95 # now talk to FICS
  96 my $t = Net::Telnet->new(Timeout => 10, Prompt => '/fics% /');
  97 $t->input_log(\*FICSLOG);
  98 $t->open($remoteglotconf::server);
  99 $t->print($remoteglotconf::nick);
 100 $t->waitfor('/Press return to enter the server/');
 101 $t->cmd("");
 102
 103 # set some options
 104 $t->cmd("set shout 0");
 105 $t->cmd("set seek 0");
 106 $t->cmd("set style 12");
 107
 108 my $ev1 = AnyEvent->io(
 109         fh => fileno($t),
 110         poll => 'r',
 111         cb => sub {    # what callback to execute
 112                 while (1) {
 113                         my $line = $t->getline(Timeout => 0, errmode => 'return');
 114                         return if (!defined($line));
 115
 116                         chomp $line;
 117                         $line =~ tr/\r//d;
 118                         handle_fics($line);
 119                 }
 120         }
 121 );
 122 if (defined($remoteglotconf::target)) {
 123         if ($remoteglotconf::target =~ /^http:/) {
 124                 fetch_pgn($remoteglotconf::target);
 125         } else {
 126                 $t->cmd("observe $remoteglotconf::target");
 127         }
 128 }
 129 print "FICS ready.\n";
 130
 131 # Engine events have already been set up by Engine.pm.
 132 EV::run;
 133
 134 sub handle_uci {
 135         my ($engine, $line, $primary) = @_;
 136
 137         return if $line =~ /(upper|lower)bound/;
 138
 139         $line =~ s/  / /g;  # Sometimes needed for Zappa Mexico
 140         print UCILOG localtime() . " $engine->{'tag'} <= $line\n";
 141         if ($line =~ /^info/) {
 142                 my (@infos) = split / /, $line;
 143                 shift @infos;
 144
 145                 parse_infos($engine, @infos);
 146         }
 147         if ($line =~ /^id/) {
 148                 my (@ids) = split / /, $line;
 149                 shift @ids;
 150
 151                 parse_ids($engine, @ids);
 152         }
 153         if ($line =~ /^bestmove/) {
 154                 if ($primary) {
 155                         return if (!$remoteglotconf::uci_assume_full_compliance);
 156                         if (defined($pos_waiting)) {
 157                                 uciprint($engine, "position fen " . $pos_waiting->fen());
 158                                 uciprint($engine, "go infinite");
 159
 160                                 $pos_calculating = $pos_waiting;
 161                                 $pos_waiting = undef;
 162                         }
 163                 } else {
 164                         $engine2->{'info'} = {};
 165                         my $pos = $pos_waiting // $pos_calculating;
 166                         uciprint($engine2, "position fen " . $pos->fen());
 167                         uciprint($engine2, "go infinite");
 168                         $pos_calculating_second_engine = $pos;
 169                 }
 170         }
 171         output();
 172 }
 173
 174 my $getting_movelist = 0;
 175 my $pos_for_movelist = undef;
 176 my @uci_movelist = ();
 177 my @pretty_movelist = ();
 178
 179 sub handle_fics {
 180         my $line = shift;
 181         if ($line =~ /^<12> /) {
 182                 handle_position(Position->new($line));
 183                 $t->cmd("moves");
 184         }
 185         if ($line =~ /^Movelist for game /) {
 186                 my $pos = $pos_waiting // $pos_calculating;
 187                 if (defined($pos)) {
 188                         @uci_movelist = ();
 189                         @pretty_movelist = ();
 190                         $pos_for_movelist = Position->start_pos($pos->{'player_w'}, $pos->{'player_b'});
 191                         $getting_movelist = 1;
 192                 }
 193         }
 194         if ($getting_movelist &&
 195             $line =~ /^\s* \d+\. \s+                     # move number
 196                        (\S+) \s+ \( [\d:.]+ \) \s*       # first move, then time
 197                        (?: (\S+) \s+ \( [\d:.]+ \) )?    # second move, then time
 198                      /x) {
 199                 eval {
 200                         my $uci_move;
 201                         ($pos_for_movelist, $uci_move) = $pos_for_movelist->make_pretty_move($1);
 202                         push @uci_movelist, $uci_move;
 203                         push @pretty_movelist, $1;
 204
 205                         if (defined($2)) {
 206                                 ($pos_for_movelist, $uci_move) = $pos_for_movelist->make_pretty_move($2);
 207                                 push @uci_movelist, $uci_move;
 208                                 push @pretty_movelist, $2;
 209                         }
 210                 };
 211                 if ($@) {
 212                         warn "Error when getting FICS move history: $@";
 213                         $getting_movelist = 0;
 214                 }
 215         }
 216         if ($getting_movelist &&
 217             $line =~ /^\s+ \{.*\} \s+ (?: \* | 1\/2-1\/2 | 0-1 | 1-0 )/x) {
 218                 # End of movelist.
 219                 for my $pos ($pos_waiting, $pos_calculating) {
 220                         next if (!defined($pos));
 221                         if ($pos->fen() eq $pos_for_movelist->fen()) {
 222                                 $pos->{'pretty_history'} = \@pretty_movelist;
 223                         }
 224                 }
 225                 $getting_movelist = 0;
 226         }
 227         if ($line =~ /^([A-Za-z]+)(?:\([A-Z]+\))* tells you: (.*)$/) {
 228                 my ($who, $msg) = ($1, $2);
 229
 230                 next if (grep { $_ eq $who } (@remoteglotconf::masters) == 0);
 231
 232                 if ($msg =~ /^fics (.*?)$/) {
 233                         $t->cmd("tell $who Executing '$1' on FICS.");
 234                         $t->cmd($1);
 235                 } elsif ($msg =~ /^uci (.*?)$/) {
 236                         $t->cmd("tell $who Sending '$1' to the engine.");
 237                         print { $engine->{'write'} } "$1\n";
 238                 } elsif ($msg =~ /^pgn (.*?)$/) {
 239                         my $url = $1;
 240                         $t->cmd("tell $who Starting to poll '$url'.");
 241                         fetch_pgn($url);
 242                 } elsif ($msg =~ /^stoppgn$/) {
 243                         $t->cmd("tell $who Stopping poll.");
 244                         $stop_pgn_fetch = 1;
 245                         $http_timer = undef;
 246                 } elsif ($msg =~ /^quit$/) {
 247                         $t->cmd("tell $who Bye bye.");
 248                         exit;
 249                 } else {
 250                         $t->cmd("tell $who Couldn't understand '$msg', sorry.");
 251                 }
 252         }
 253         #print "FICS: [$line]\n";
 254 }
 255
 256 # Starts periodic fetching of PGNs from the given URL.
 257 sub fetch_pgn {
 258         my ($url) = @_;
 259         AnyEvent::HTTP::http_get($url, sub {
 260                 handle_pgn(@_, $url);
 261         });
 262 }
 263
 264 my ($last_pgn_white, $last_pgn_black);
 265 my @last_pgn_uci_moves = ();
 266 my $pgn_hysteresis_counter = 0;
 267
 268 sub handle_pgn {
 269         my ($body, $header, $url) = @_;
 270
 271         if ($stop_pgn_fetch) {
 272                 $stop_pgn_fetch = 0;
 273                 $http_timer = undef;
 274                 return;
 275         }
 276
 277         my $pgn = Chess::PGN::Parse->new(undef, $body);
 278         if (!defined($pgn) || !$pgn->read_game() || $body !~ /^\[/) {
 279                 warn "Error in parsing PGN from $url\n";
 280         } else {
 281                 eval {
 282                         # Skip to the right game.
 283                         while (defined($remoteglotconf::pgn_filter) &&
 284                                !&$remoteglotconf::pgn_filter($pgn)) {
 285                                 $pgn->read_game() or die "Out of games during filtering";
 286                         }
 287
 288                         $pgn->parse_game({ save_comments => 'yes' });
 289                         my $pos = Position->start_pos($pgn->white, $pgn->black);
 290                         my $moves = $pgn->moves;
 291                         my @uci_moves = ();
 292                         for my $move (@$moves) {
 293                                 my $uci_move;
 294                                 ($pos, $uci_move) = $pos->make_pretty_move($move);
 295                                 push @uci_moves, $uci_move;
 296                         }
 297                         $pos->{'result'} = $pgn->result;
 298                         $pos->{'pretty_history'} = $moves;
 299
 300                         extract_clock($pgn, $pos);
 301
 302                         # Sometimes, PGNs lose a move or two for a short while,
 303                         # or people push out new ones non-atomically.
 304                         # Thus, if we PGN doesn't change names but becomes
 305                         # shorter, we mistrust it for a few seconds.
 306                         my $trust_pgn = 1;
 307                         if (defined($last_pgn_white) && defined($last_pgn_black) &&
 308                             $last_pgn_white eq $pgn->white &&
 309                             $last_pgn_black eq $pgn->black &&
 310                             scalar(@uci_moves) < scalar(@last_pgn_uci_moves)) {
 311                                 if (++$pgn_hysteresis_counter < 3) {
 312                                         $trust_pgn = 0;
 313                                 }
 314                         }
 315                         if ($trust_pgn) {
 316                                 $last_pgn_white = $pgn->white;
 317                                 $last_pgn_black = $pgn->black;
 318                                 @last_pgn_uci_moves = @uci_moves;
 319                                 $pgn_hysteresis_counter = 0;
 320                                 handle_position($pos);
 321                         }
 322                 };
 323                 if ($@) {
 324                         warn "Error in parsing moves from $url: $@\n";
 325                 }
 326         }
 327
 328         $http_timer = AnyEvent->timer(after => 1.0, cb => sub {
 329                 fetch_pgn($url);
 330         });
 331 }
 332
 333 sub handle_position {
 334         my ($pos) = @_;
 335         find_clock_start($pos, $pos_calculating);
 336
 337         # if this is already in the queue, ignore it (just update the result)
 338         if (defined($pos_waiting) && $pos->fen() eq $pos_waiting->fen()) {
 339                 $pos_waiting->{'result'} = $pos->{'result'};
 340                 return;
 341         }
 342
 343         # if we're already chewing on this and there's nothing else in the queue,
 344         # also ignore it
 345         if (!defined($pos_waiting) && defined($pos_calculating) &&
 346             $pos->fen() eq $pos_calculating->fen()) {
 347                 $pos_calculating->{'result'} = $pos->{'result'};
 348                 return;
 349         }
 350
 351         # if we're already thinking on something, stop and wait for the engine
 352         # to approve
 353         if (defined($pos_calculating)) {
 354                 # Store the final data we have for this position in the history,
 355                 # with the precise clock information we just got from the new
 356                 # position. (Historic positions store the clock at the end of
 357                 # the position.)
 358                 #
 359                 # Do not output anything new to the main analysis; that's
 360                 # going to be obsolete really soon.
 361                 $pos_calculating->{'white_clock'} = $pos->{'white_clock'};
 362                 $pos_calculating->{'black_clock'} = $pos->{'black_clock'};
 363                 delete $pos_calculating->{'white_clock_target'};
 364                 delete $pos_calculating->{'black_clock_target'};
 365                 output_json(1);
 366
 367                 if (!defined($pos_waiting)) {
 368                         uciprint($engine, "stop");
 369                 }
 370                 if ($remoteglotconf::uci_assume_full_compliance) {
 371                         $pos_waiting = $pos;
 372                 } else {
 373                         uciprint($engine, "position fen " . $pos->fen());
 374                         uciprint($engine, "go infinite");
 375                         $pos_calculating = $pos;
 376                 }
 377         } else {
 378                 # it's wrong just to give the FEN (the move history is useful,
 379                 # and per the UCI spec, we should really have sent "ucinewgame"),
 380                 # but it's easier
 381                 uciprint($engine, "position fen " . $pos->fen());
 382                 uciprint($engine, "go infinite");
 383                 $pos_calculating = $pos;
 384         }
 385
 386         if (defined($engine2)) {
 387                 if (defined($pos_calculating_second_engine)) {
 388                         uciprint($engine2, "stop");
 389                 } else {
 390                         uciprint($engine2, "position fen " . $pos->fen());
 391                         uciprint($engine2, "go infinite");
 392                         $pos_calculating_second_engine = $pos;
 393                 }
 394                 $engine2->{'info'} = {};
 395         }
 396
 397         $engine->{'info'} = {};
 398         $last_move = time;
 399
 400         schedule_tb_lookup();
 401
 402         #
 403         # Output a command every move to note that we're
 404         # still paying attention -- this is a good tradeoff,
 405         # since if no move has happened in the last half
 406         # hour, the analysis/relay has most likely stopped
 407         # and we should stop hogging server resources.
 408         #
 409         $t->cmd("date");
 410 }
 411
 412 sub parse_infos {
 413         my ($engine, @x) = @_;
 414         my $mpv = '';
 415
 416         my $info = $engine->{'info'};
 417
 418         # Search for "multipv" first of all, since e.g. Stockfish doesn't put it first.
 419         for my $i (0..$#x - 1) {
 420                 if ($x[$i] eq 'multipv') {
 421                         $mpv = $x[$i + 1];
 422                         next;
 423                 }
 424         }
 425
 426         while (scalar @x > 0) {
 427                 if ($x[0] eq 'multipv') {
 428                         # Dealt with above
 429                         shift @x;
 430                         shift @x;
 431                         next;
 432                 }
 433                 if ($x[0] eq 'currmove' || $x[0] eq 'currmovenumber' || $x[0] eq 'cpuload') {
 434                         my $key = shift @x;
 435                         my $value = shift @x;
 436                         $info->{$key} = $value;
 437                         next;
 438                 }
 439                 if ($x[0] eq 'depth' || $x[0] eq 'seldepth' || $x[0] eq 'hashfull' ||
 440                     $x[0] eq 'time' || $x[0] eq 'nodes' || $x[0] eq 'nps' ||
 441                     $x[0] eq 'tbhits') {
 442                         my $key = shift @x;
 443                         my $value = shift @x;
 444                         $info->{$key . $mpv} = $value;
 445                         next;
 446                 }
 447                 if ($x[0] eq 'score') {
 448                         shift @x;
 449
 450                         delete $info->{'score_cp' . $mpv};
 451                         delete $info->{'score_mate' . $mpv};
 452
 453                         while ($x[0] eq 'cp' || $x[0] eq 'mate') {
 454                                 if ($x[0] eq 'cp') {
 455                                         shift @x;
 456                                         $info->{'score_cp' . $mpv} = shift @x;
 457                                 } elsif ($x[0] eq 'mate') {
 458                                         shift @x;
 459                                         $info->{'score_mate' . $mpv} = shift @x;
 460                                 } else {
 461                                         shift @x;
 462                                 }
 463                         }
 464                         next;
 465                 }
 466                 if ($x[0] eq 'pv') {
 467                         $info->{'pv' . $mpv} = [ @x[1..$#x] ];
 468                         last;
 469                 }
 470                 if ($x[0] eq 'string' || $x[0] eq 'UCI_AnalyseMode' || $x[0] eq 'setting' || $x[0] eq 'contempt') {
 471                         last;
 472                 }
 473
 474                 #print "unknown info '$x[0]', trying to recover...\n";
 475                 #shift @x;
 476                 die "Unknown info '" . join(',', @x) . "'";
 477
 478         }
 479 }
 480
 481 sub parse_ids {
 482         my ($engine, @x) = @_;
 483
 484         while (scalar @x > 0) {
 485                 if ($x[0] =~ /^(name|author)$/) {
 486                         my $key = shift @x;
 487                         my $value = join(' ', @x);
 488                         $engine->{'id'}{$key} = $value;
 489                         last;
 490                 }
 491
 492                 # unknown
 493                 shift @x;
 494         }
 495 }
 496
 497 sub prettyprint_pv_no_cache {
 498         my ($board, @pvs) = @_;
 499
 500         if (scalar @pvs == 0 || !defined($pvs[0])) {
 501                 return ();
 502         }
 503
 504         my $pv = shift @pvs;
 505         my ($from_col, $from_row, $to_col, $to_row, $promo) = parse_uci_move($pv);
 506         my ($pretty, $nb) = $board->prettyprint_move($from_row, $from_col, $to_row, $to_col, $promo);
 507         return ( $pretty, prettyprint_pv_no_cache($nb, @pvs) );
 508 }
 509
 510 sub prettyprint_pv {
 511         my ($pos, @pvs) = @_;
 512
 513         my $cachekey = join('', @pvs);
 514         if (exists($pos->{'prettyprint_cache'}{$cachekey})) {
 515                 return @{$pos->{'prettyprint_cache'}{$cachekey}};
 516         } else {
 517                 my @res = prettyprint_pv_no_cache($pos->{'board'}, @pvs);
 518                 $pos->{'prettyprint_cache'}{$cachekey} = \@res;
 519                 return @res;
 520         }
 521 }
 522
 523 sub output {
 524         #return;
 525
 526         return if (!defined($pos_calculating));
 527
 528         # Don't update too often.
 529         my $age = Time::HiRes::tv_interval($latest_update);
 530         if ($age < $remoteglotconf::update_max_interval) {
 531                 my $wait = $remoteglotconf::update_max_interval + 0.01 - $age;
 532                 $output_timer = AnyEvent->timer(after => $wait, cb => \&output);
 533                 return;
 534         }
 535
 536         my $info = $engine->{'info'};
 537
 538         #
 539         # If we have tablebase data from a previous lookup, replace the
 540         # engine data with the data from the tablebase.
 541         #
 542         my $fen = $pos_calculating->fen();
 543         if (exists($tb_cache{$fen})) {
 544                 for my $key (qw(pv score_cp score_mate nodes nps depth seldepth tbhits)) {
 545                         delete $info->{$key . '1'};
 546                         delete $info->{$key};
 547                 }
 548                 $info->{'nodes'} = 0;
 549                 $info->{'nps'} = 0;
 550                 $info->{'depth'} = 0;
 551                 $info->{'seldepth'} = 0;
 552                 $info->{'tbhits'} = 0;
 553
 554                 my $t = $tb_cache{$fen};
 555                 my $pv = $t->{'pv'};
 556                 my $matelen = int((1 + $t->{'score'}) / 2);
 557                 if ($t->{'result'} eq '1/2-1/2') {
 558                         $info->{'score_cp'} = 0;
 559                 } elsif ($t->{'result'} eq '1-0') {
 560                         if ($pos_calculating->{'toplay'} eq 'B') {
 561                                 $info->{'score_mate'} = -$matelen;
 562                         } else {
 563                                 $info->{'score_mate'} = $matelen;
 564                         }
 565                 } else {
 566                         if ($pos_calculating->{'toplay'} eq 'B') {
 567                                 $info->{'score_mate'} = $matelen;
 568                         } else {
 569                                 $info->{'score_mate'} = -$matelen;
 570                         }
 571                 }
 572                 $info->{'pv'} = $pv;
 573                 $info->{'tablebase'} = 1;
 574         } else {
 575                 $info->{'tablebase'} = 0;
 576         }
 577
 578         #
 579         # Some programs _always_ report MultiPV, even with only one PV.
 580         # In this case, we simply use that data as if MultiPV was never
 581         # specified.
 582         #
 583         if (exists($info->{'pv1'}) && !exists($info->{'pv2'})) {
 584                 for my $key (qw(pv score_cp score_mate nodes nps depth seldepth tbhits)) {
 585                         if (exists($info->{$key . '1'})) {
 586                                 $info->{$key} = $info->{$key . '1'};
 587                         }
 588                 }
 589         }
 590
 591         #
 592         # Check the PVs first. if they're invalid, just wait, as our data
 593         # is most likely out of sync. This isn't a very good solution, as
 594         # it can frequently miss stuff, but it's good enough for most users.
 595         #
 596         eval {
 597                 my $dummy;
 598                 if (exists($info->{'pv'})) {
 599                         $dummy = prettyprint_pv($pos_calculating, @{$info->{'pv'}});
 600                 }
 601
 602                 my $mpv = 1;
 603                 while (exists($info->{'pv' . $mpv})) {
 604                         $dummy = prettyprint_pv($pos_calculating, @{$info->{'pv' . $mpv}});
 605                         ++$mpv;
 606                 }
 607         };
 608         if ($@) {
 609                 $engine->{'info'} = {};
 610                 return;
 611         }
 612
 613         output_screen();
 614         output_json(0);
 615         $latest_update = [Time::HiRes::gettimeofday];
 616 }
 617
 618 sub output_screen {
 619         my $info = $engine->{'info'};
 620         my $id = $engine->{'id'};
 621
 622         my $text = 'Analysis';
 623         if ($pos_calculating->{'last_move'} ne 'none') {
 624                 if ($pos_calculating->{'toplay'} eq 'W') {
 625                         $text .= sprintf ' after %u. ... %s', ($pos_calculating->{'move_num'}-1), $pos_calculating->{'last_move'};
 626                 } else {
 627                         $text .= sprintf ' after %u. %s', $pos_calculating->{'move_num'}, $pos_calculating->{'last_move'};
 628                 }
 629                 if (exists($id->{'name'})) {
 630                         $text .= ',';
 631                 }
 632         }
 633
 634         if (exists($id->{'name'})) {
 635                 $text .= " by $id->{'name'}:\n\n";
 636         } else {
 637                 $text .= ":\n\n";
 638         }
 639
 640         return unless (exists($pos_calculating->{'board'}));
 641
 642         if (exists($info->{'pv1'}) && exists($info->{'pv2'})) {
 643                 # multi-PV
 644                 my $mpv = 1;
 645                 while (exists($info->{'pv' . $mpv})) {
 646                         $text .= sprintf "  PV%2u", $mpv;
 647                         my $score = short_score($info, $pos_calculating, $mpv);
 648                         $text .= "  ($score)" if (defined($score));
 649
 650                         my $tbhits = '';
 651                         if (exists($info->{'tbhits' . $mpv}) && $info->{'tbhits' . $mpv} > 0) {
 652                                 if ($info->{'tbhits' . $mpv} == 1) {
 653                                         $tbhits = ", 1 tbhit";
 654                                 } else {
 655                                         $tbhits = sprintf ", %u tbhits", $info->{'tbhits' . $mpv};
 656                                 }
 657                         }
 658
 659                         if (exists($info->{'nodes' . $mpv}) && exists($info->{'nps' . $mpv}) && exists($info->{'depth' . $mpv})) {
 660                                 $text .= sprintf " (%5u kn, %3u kn/s, %2u ply$tbhits)",
 661                                         $info->{'nodes' . $mpv} / 1000, $info->{'nps' . $mpv} / 1000, $info->{'depth' . $mpv};
 662                         }
 663
 664                         $text .= ":\n";
 665                         $text .= "  " . join(', ', prettyprint_pv($pos_calculating, @{$info->{'pv' . $mpv}})) . "\n";
 666                         $text .= "\n";
 667                         ++$mpv;
 668                 }
 669         } else {
 670                 # single-PV
 671                 my $score = long_score($info, $pos_calculating, '');
 672                 $text .= "  $score\n" if defined($score);
 673                 $text .=  "  PV: " . join(', ', prettyprint_pv($pos_calculating, @{$info->{'pv'}}));
 674                 $text .=  "\n";
 675
 676                 if (exists($info->{'nodes'}) && exists($info->{'nps'}) && exists($info->{'depth'})) {
 677                         $text .= sprintf "  %u nodes, %7u nodes/sec, depth %u ply",
 678                                 $info->{'nodes'}, $info->{'nps'}, $info->{'depth'};
 679                 }
 680                 if (exists($info->{'seldepth'})) {
 681                         $text .= sprintf " (%u selective)", $info->{'seldepth'};
 682                 }
 683                 if (exists($info->{'tbhits'}) && $info->{'tbhits'} > 0) {
 684                         if ($info->{'tbhits'} == 1) {
 685                                 $text .= ", one Syzygy hit";
 686                         } else {
 687                                 $text .= sprintf ", %u Syzygy hits", $info->{'tbhits'};
 688                         }
 689                 }
 690                 $text .= "\n\n";
 691         }
 692
 693         #$text .= book_info($pos_calculating->fen(), $pos_calculating->{'board'}, $pos_calculating->{'toplay'});
 694
 695         my @refutation_lines = ();
 696         if (defined($engine2)) {
 697                 for (my $mpv = 1; $mpv < 500; ++$mpv) {
 698                         my $info = $engine2->{'info'};
 699                         last if (!exists($info->{'pv' . $mpv}));
 700                         eval {
 701                                 my $pv = $info->{'pv' . $mpv};
 702
 703                                 my $pretty_move = join('', prettyprint_pv($pos_calculating_second_engine, $pv->[0]));
 704                                 my @pretty_pv = prettyprint_pv($pos_calculating_second_engine, @$pv);
 705                                 if (scalar @pretty_pv > 5) {
 706                                         @pretty_pv = @pretty_pv[0..4];
 707                                         push @pretty_pv, "...";
 708                                 }
 709                                 my $key = $pretty_move;
 710                                 my $line = sprintf("  %-6s %6s %3s  %s",
 711                                         $pretty_move,
 712                                         short_score($info, $pos_calculating_second_engine, $mpv),
 713                                         "d" . $info->{'depth' . $mpv},
 714                                         join(', ', @pretty_pv));
 715                                 push @refutation_lines, [ $key, $line ];
 716                         };
 717                 }
 718         }
 719
 720         if ($#refutation_lines >= 0) {
 721                 $text .= "Shallow search of all legal moves:\n\n";
 722                 for my $line (sort { $a->[0] cmp $b->[0] } @refutation_lines) {
 723                         $text .= $line->[1] . "\n";
 724                 }
 725                 $text .= "\n\n";
 726         }
 727
 728         if ($last_text ne $text) {
 729                 print "\e[H\e[2J"; # clear the screen
 730                 print $text;
 731                 $last_text = $text;
 732         }
 733 }
 734
 735 sub output_json {
 736         my $historic_json_only = shift;
 737         my $info = $engine->{'info'};
 738
 739         my $json = {};
 740         $json->{'position'} = $pos_calculating->to_json_hash();
 741         $json->{'id'} = $engine->{'id'};
 742         $json->{'score'} = long_score($info, $pos_calculating, '');
 743         $json->{'short_score'} = short_score($info, $pos_calculating, '');
 744         $json->{'plot_score'} = plot_score($info, $pos_calculating, '');
 745
 746         $json->{'nodes'} = $info->{'nodes'};
 747         $json->{'nps'} = $info->{'nps'};
 748         $json->{'depth'} = $info->{'depth'};
 749         $json->{'tbhits'} = $info->{'tbhits'};
 750         $json->{'seldepth'} = $info->{'seldepth'};
 751         $json->{'tablebase'} = $info->{'tablebase'};
 752
 753         $json->{'pv_uci'} = $info->{'pv'};  # Still needs to be there for the JS to calculate arrows; only for the primary PV, though!
 754         $json->{'pv_pretty'} = [ prettyprint_pv($pos_calculating, @{$info->{'pv'}}) ];
 755
 756         my %refutation_lines = ();
 757         my @refutation_lines = ();
 758         if (defined($engine2)) {
 759                 for (my $mpv = 1; $mpv < 500; ++$mpv) {
 760                         my $info = $engine2->{'info'};
 761                         my $pretty_move = "";
 762                         my @pretty_pv = ();
 763                         last if (!exists($info->{'pv' . $mpv}));
 764
 765                         eval {
 766                                 my $pv = $info->{'pv' . $mpv};
 767                                 my $pretty_move = join('', prettyprint_pv($pos_calculating, $pv->[0]));
 768                                 my @pretty_pv = prettyprint_pv($pos_calculating, @$pv);
 769                                 $refutation_lines{$pv->[0]} = {
 770                                         sort_key => $pretty_move,
 771                                         depth => $info->{'depth' . $mpv},
 772                                         score_sort_key => score_sort_key($info, $pos_calculating, $mpv, 0),
 773                                         pretty_score => short_score($info, $pos_calculating, $mpv),
 774                                         pretty_move => $pretty_move,
 775                                         pv_pretty => \@pretty_pv,
 776                                 };
 777                         };
 778                 }
 779         }
 780         $json->{'refutation_lines'} = \%refutation_lines;
 781
 782         # Piece together historic score information, to the degree we have it.
 783         if (!$historic_json_only && exists($pos_calculating->{'pretty_history'})) {
 784                 my %score_history = ();
 785
 786                 my $q = $dbh->prepare('SELECT * FROM scores WHERE id=?');
 787                 my $pos = Position->start_pos('white', 'black');
 788                 my $halfmove_num = 0;
 789                 for my $move (@{$pos_calculating->{'pretty_history'}}) {
 790                         my $id = id_for_pos($pos, $halfmove_num);
 791                         my $ref = $dbh->selectrow_hashref($q, undef, $id);
 792                         if (defined($ref)) {
 793                                 $score_history{$halfmove_num} = [
 794                                         $ref->{'plot_score'},
 795                                         $ref->{'short_score'}
 796                                 ];
 797                         }
 798                         ++$halfmove_num;
 799                         ($pos) = $pos->make_pretty_move($move);
 800                 }
 801                 $q->finish;
 802
 803                 # If at any point we are missing 10 consecutive moves,
 804                 # truncate the history there. This is so we don't get into
 805                 # a situation where we e.g. start analyzing at move 45,
 806                 # but we have analysis for 1. e4 from some completely different game
 807                 # and thus show a huge hole.
 808                 my $consecutive_missing = 0;
 809                 my $truncate_until = 0;
 810                 for (my $i = $halfmove_num; $i --> 0; ) {
 811                         if ($consecutive_missing >= 10) {
 812                                 delete $score_history{$i};
 813                                 next;
 814                         }
 815                         if (exists($score_history{$i})) {
 816                                 $consecutive_missing = 0;
 817                         } else {
 818                                 ++$consecutive_missing;
 819                         }
 820                 }
 821
 822                 $json->{'score_history'} = \%score_history;
 823         }
 824
 825         # Give out a list of other games going on. (Empty is fine.)
 826         if (!$historic_json_only) {
 827                 my @games = ();
 828
 829                 my $q = $dbh->prepare('SELECT * FROM current_games ORDER BY priority DESC, id');
 830                 $q->execute;
 831                 while (my $ref = $q->fetchrow_hashref) {
 832                         eval {
 833                                 my $other_game_contents = File::Slurp::read_file($ref->{'json_path'});
 834                                 my $other_game_json = JSON::XS::decode_json($other_game_contents);
 835
 836                                 die "Missing position" if (!exists($other_game_json->{'position'}));
 837                                 my $white = $other_game_json->{'position'}{'player_w'} // die 'Missing white';
 838                                 my $black = $other_game_json->{'position'}{'player_b'} // die 'Missing black';
 839
 840                                 push @games, {
 841                                         id => $ref->{'id'},
 842                                         name => "$white–$black",
 843                                         url => $ref->{'url'}
 844                                 };
 845                         };
 846                         if ($@) {
 847                                 warn "Could not add external game " . $ref->{'json_path'} . ": $@";
 848                         }
 849                 }
 850
 851                 if (scalar @games > 0) {
 852                         $json->{'games'} = \@games;
 853                 }
 854         }
 855
 856         my $json_enc = JSON::XS->new;
 857         $json_enc->canonical(1);
 858         my $encoded = $json_enc->encode($json);
 859         unless ($historic_json_only || !defined($remoteglotconf::json_output) ||
 860                 (defined($last_written_json) && $last_written_json eq $encoded)) {
 861                 atomic_set_contents($remoteglotconf::json_output, $encoded);
 862                 $last_written_json = $encoded;
 863         }
 864
 865         if (exists($pos_calculating->{'pretty_history'}) &&
 866             defined($remoteglotconf::json_history_dir)) {
 867                 my $id = id_for_pos($pos_calculating);
 868                 my $filename = $remoteglotconf::json_history_dir . "/" . $id . ".json";
 869
 870                 # Overwrite old analysis (assuming it exists at all) if we're
 871                 # using a different engine, or if we've calculated deeper.
 872                 # nodes is used as a tiebreaker. Don't bother about Multi-PV
 873                 # data; it's not that important.
 874                 my ($old_engine, $old_depth, $old_nodes) = get_json_analysis_stats($id);
 875                 my $new_depth = $json->{'depth'} // 0;
 876                 my $new_nodes = $json->{'nodes'} // 0;
 877                 if (!defined($old_engine) ||
 878                     $old_engine ne $json->{'id'}{'name'} ||
 879                     $new_depth > $old_depth ||
 880                     ($new_depth == $old_depth && $new_nodes >= $old_nodes)) {
 881                         atomic_set_contents($filename, $encoded);
 882                         if (defined($json->{'plot_score'})) {
 883                                 local $dbh->{AutoCommit} = 0;
 884                                 $dbh->do('DELETE FROM scores WHERE id=?', undef, $id);
 885                                 $dbh->do('INSERT INTO scores (id, plot_score, short_score, engine, depth, nodes) VALUES (?,?,?,?,?,?)', undef,
 886                                         $id, $json->{'plot_score'}, $json->{'short_score'},
 887                                         $json->{'id'}{'name'}, $new_depth, $new_nodes);
 888                                 $dbh->commit;
 889                         }
 890                 }
 891         }
 892 }
 893
 894 sub atomic_set_contents {
 895         my ($filename, $contents) = @_;
 896
 897         open my $fh, ">", $filename . ".tmp"
 898                 or return;
 899         print $fh $contents;
 900         close $fh;
 901         rename($filename . ".tmp", $filename);
 902 }
 903
 904 sub id_for_pos {
 905         my ($pos, $halfmove_num) = @_;
 906
 907         $halfmove_num //= scalar @{$pos->{'pretty_history'}};
 908         (my $fen = $pos->fen()) =~ tr,/ ,-_,;
 909         return "move$halfmove_num-$fen";
 910 }
 911
 912 sub get_json_analysis_stats {
 913         my $id = shift;
 914         my $ref = $dbh->selectrow_hashref('SELECT * FROM scores WHERE id=?', undef, $id);
 915         if (defined($ref)) {
 916                 return ($ref->{'engine'}, $ref->{'depth'}, $ref->{'nodes'});
 917         } else {
 918                 return ('', 0, 0);
 919         }
 920 }
 921
 922 sub uciprint {
 923         my ($engine, $msg) = @_;
 924         $engine->print($msg);
 925         print UCILOG localtime() . " $engine->{'tag'} => $msg\n";
 926 }
 927
 928 sub short_score {
 929         my ($info, $pos, $mpv) = @_;
 930
 931         my $invert = ($pos->{'toplay'} eq 'B');
 932         if (defined($info->{'score_mate' . $mpv})) {
 933                 if ($invert) {
 934                         return sprintf "M%3d", -$info->{'score_mate' . $mpv};
 935                 } else {
 936                         return sprintf "M%3d", $info->{'score_mate' . $mpv};
 937                 }
 938         } else {
 939                 if (exists($info->{'score_cp' . $mpv})) {
 940                         my $score = $info->{'score_cp' . $mpv} * 0.01;
 941                         if ($score == 0) {
 942                                 if ($info->{'tablebase'}) {
 943                                         return "TB draw";
 944                                 } else {
 945                                         return " 0.00";
 946                                 }
 947                         }
 948                         if ($invert) {
 949                                 $score = -$score;
 950                         }
 951                         return sprintf "%+5.2f", $score;
 952                 }
 953         }
 954
 955         return undef;
 956 }
 957
 958 sub score_sort_key {
 959         my ($info, $pos, $mpv, $invert) = @_;
 960
 961         if (defined($info->{'score_mate' . $mpv})) {
 962                 my $mate = $info->{'score_mate' . $mpv};
 963                 my $score;
 964                 if ($mate > 0) {
 965                         # Side to move mates
 966                         $score = 99999 - $mate;
 967                 } else {
 968                         # Side to move is getting mated (note the double negative for $mate)
 969                         $score = -99999 - $mate;
 970                 }
 971                 if ($invert) {
 972                         $score = -$score;
 973                 }
 974                 return $score;
 975         } else {
 976                 if (exists($info->{'score_cp' . $mpv})) {
 977                         my $score = $info->{'score_cp' . $mpv};
 978                         if ($invert) {
 979                                 $score = -$score;
 980                         }
 981                         return $score;
 982                 }
 983         }
 984
 985         return undef;
 986 }
 987
 988 sub long_score {
 989         my ($info, $pos, $mpv) = @_;
 990
 991         if (defined($info->{'score_mate' . $mpv})) {
 992                 my $mate = $info->{'score_mate' . $mpv};
 993                 if ($pos->{'toplay'} eq 'B') {
 994                         $mate = -$mate;
 995                 }
 996                 if ($mate > 0) {
 997                         return sprintf "White mates in %u", $mate;
 998                 } else {
 999                         return sprintf "Black mates in %u", -$mate;
1000                 }
1001         } else {
1002                 if (exists($info->{'score_cp' . $mpv})) {
1003                         my $score = $info->{'score_cp' . $mpv} * 0.01;
1004                         if ($score == 0) {
1005                                 if ($info->{'tablebase'}) {
1006                                         return "Theoretical draw";
1007                                 } else {
1008                                         return "Score:  0.00";
1009                                 }
1010                         }
1011                         if ($pos->{'toplay'} eq 'B') {
1012                                 $score = -$score;
1013                         }
1014                         return sprintf "Score: %+5.2f", $score;
1015                 }
1016         }
1017
1018         return undef;
1019 }
1020
1021 # For graphs; a single number in centipawns, capped at +/- 500.
1022 sub plot_score {
1023         my ($info, $pos, $mpv) = @_;
1024
1025         my $invert = ($pos->{'toplay'} eq 'B');
1026         if (defined($info->{'score_mate' . $mpv})) {
1027                 my $mate = $info->{'score_mate' . $mpv};
1028                 if ($invert) {
1029                         $mate = -$mate;
1030                 }
1031                 if ($mate > 0) {
1032                         return 500;
1033                 } else {
1034                         return -500;
1035                 }
1036         } else {
1037                 if (exists($info->{'score_cp' . $mpv})) {
1038                         my $score = $info->{'score_cp' . $mpv};
1039                         if ($invert) {
1040                                 $score = -$score;
1041                         }
1042                         $score = 500 if ($score > 500);
1043                         $score = -500 if ($score < -500);
1044                         return int($score);
1045                 }
1046         }
1047
1048         return undef;
1049 }
1050
1051 my %book_cache = ();
1052 sub book_info {
1053         my ($fen, $board, $toplay) = @_;
1054
1055         if (exists($book_cache{$fen})) {
1056                 return $book_cache{$fen};
1057         }
1058
1059         my $ret = `./booklook $fen`;
1060         return "" if ($ret =~ /Not found/ || $ret eq '');
1061
1062         my @moves = ();
1063
1064         for my $m (split /\n/, $ret) {
1065                 my ($move, $annotation, $win, $draw, $lose, $rating, $rating_div) = split /,/, $m;
1066
1067                 my $pmove;
1068                 if ($move eq '')  {
1069                         $pmove = '(current)';
1070                 } else {
1071                         ($pmove) = prettyprint_pv_no_cache($board, $move);
1072                         $pmove .= $annotation;
1073                 }
1074
1075                 my $score;
1076                 if ($toplay eq 'W') {
1077                         $score = 1.0 * $win + 0.5 * $draw + 0.0 * $lose;
1078                 } else {
1079                         $score = 0.0 * $win + 0.5 * $draw + 1.0 * $lose;
1080                 }
1081                 my $n = $win + $draw + $lose;
1082
1083                 my $percent;
1084                 if ($n == 0) {
1085                         $percent = "     ";
1086                 } else {
1087                         $percent = sprintf "%4u%%", int(100.0 * $score / $n + 0.5);
1088                 }
1089
1090                 push @moves, [ $pmove, $n, $percent, $rating ];
1091         }
1092
1093         @moves[1..$#moves] = sort { $b->[2] cmp $a->[2] } @moves[1..$#moves];
1094
1095         my $text = "Book moves:\n\n              Perf.     N     Rating\n\n";
1096         for my $m (@moves) {
1097                 $text .= sprintf "  %-10s %s   %6u    %4s\n", $m->[0], $m->[2], $m->[1], $m->[3]
1098         }
1099
1100         return $text;
1101 }
1102
1103 sub extract_clock {
1104         my ($pgn, $pos) = @_;
1105
1106         # Look for extended PGN clock tags.
1107         my $tags = $pgn->tags;
1108         if (exists($tags->{'WhiteClock'}) && exists($tags->{'BlackClock'})) {
1109                 $pos->{'white_clock'} = hms_to_sec($tags->{'WhiteClock'});
1110                 $pos->{'black_clock'} = hms_to_sec($tags->{'BlackClock'});
1111                 return;
1112         }
1113
1114         # Look for TCEC-style time comments.
1115         my $moves = $pgn->moves;
1116         my $comments = $pgn->comments;
1117         my $last_black_move = int((scalar @$moves) / 2);
1118         my $last_white_move = int((1 + scalar @$moves) / 2);
1119
1120         my $black_key = $last_black_move . "b";
1121         my $white_key = $last_white_move . "w";
1122
1123         if (exists($comments->{$white_key}) &&
1124             exists($comments->{$black_key}) &&
1125             $comments->{$white_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/ &&
1126             $comments->{$black_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/) {
1127                 $comments->{$white_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/;
1128                 $pos->{'white_clock'} = hms_to_sec($1);
1129                 $comments->{$black_key} =~ /(?:tl=|clk )(\d+:\d+:\d+)/;
1130                 $pos->{'black_clock'} = hms_to_sec($1);
1131                 return;
1132         }
1133
1134         delete $pos->{'white_clock'};
1135         delete $pos->{'black_clock'};
1136 }
1137
1138 sub hms_to_sec {
1139         my $hms = shift;
1140         return undef if (!defined($hms));
1141         $hms =~ /(\d+):(\d+):(\d+)/;
1142         return $1 * 3600 + $2 * 60 + $3;
1143 }
1144
1145 sub find_clock_start {
1146         my ($pos, $prev_pos) = @_;
1147
1148         # If the game is over, the clock is stopped.
1149         if (exists($pos->{'result'}) &&
1150             ($pos->{'result'} eq '1-0' ||
1151              $pos->{'result'} eq '1/2-1/2' ||
1152              $pos->{'result'} eq '0-1')) {
1153                 return;
1154         }
1155
1156         # When we don't have any moves, we assume the clock hasn't started yet.
1157         if ($pos->{'move_num'} == 1 && $pos->{'toplay'} eq 'W') {
1158                 if (defined($remoteglotconf::adjust_clocks_before_move)) {
1159                         &$remoteglotconf::adjust_clocks_before_move(\$pos->{'white_clock'}, \$pos->{'black_clock'}, 1, 'W');
1160                 }
1161                 return;
1162         }
1163
1164         # TODO(sesse): Maybe we can get the number of moves somehow else for FICS games.
1165         # The history is needed for id_for_pos.
1166         if (!exists($pos->{'pretty_history'})) {
1167                 return;
1168         }
1169
1170         my $id = id_for_pos($pos);
1171         my $clock_info = $dbh->selectrow_hashref('SELECT * FROM clock_info WHERE id=?', undef, $id);
1172         if (defined($clock_info)) {
1173                 $pos->{'white_clock'} //= $clock_info->{'white_clock'};
1174                 $pos->{'black_clock'} //= $clock_info->{'black_clock'};
1175                 if ($pos->{'toplay'} eq 'W') {
1176                         $pos->{'white_clock_target'} = $clock_info->{'white_clock_target'};
1177                 } else {
1178                         $pos->{'black_clock_target'} = $clock_info->{'black_clock_target'};
1179                 }
1180                 return;
1181         }
1182
1183         # OK, we haven't seen this position before, so we assume the move
1184         # happened right now.
1185
1186         # See if we should do our own clock management (ie., clock information
1187         # is spurious or non-existent).
1188         if (defined($remoteglotconf::adjust_clocks_before_move)) {
1189                 my $wc = $pos->{'white_clock'} // $prev_pos->{'white_clock'};
1190                 my $bc = $pos->{'black_clock'} // $prev_pos->{'black_clock'};
1191                 if (defined($prev_pos->{'white_clock_target'})) {
1192                         $wc = $prev_pos->{'white_clock_target'} - time;
1193                 }
1194                 if (defined($prev_pos->{'black_clock_target'})) {
1195                         $bc = $prev_pos->{'black_clock_target'} - time;
1196                 }
1197                 &$remoteglotconf::adjust_clocks_before_move(\$wc, \$bc, $pos->{'move_num'}, $pos->{'toplay'});
1198                 $pos->{'white_clock'} = $wc;
1199                 $pos->{'black_clock'} = $bc;
1200         }
1201
1202         my $key = ($pos->{'toplay'} eq 'W') ? 'white_clock' : 'black_clock';
1203         if (!exists($pos->{$key})) {
1204                 # No clock information.
1205                 return;
1206         }
1207         my $time_left = $pos->{$key};
1208         my ($white_clock_target, $black_clock_target);
1209         if ($pos->{'toplay'} eq 'W') {
1210                 $white_clock_target = $pos->{'white_clock_target'} = time + $time_left;
1211         } else {
1212                 $black_clock_target = $pos->{'black_clock_target'} = time + $time_left;
1213         }
1214         local $dbh->{AutoCommit} = 0;
1215         $dbh->do('DELETE FROM clock_info WHERE id=?', undef, $id);
1216         $dbh->do('INSERT INTO clock_info (id, white_clock, black_clock, white_clock_target, black_clock_target) VALUES (?, ?, ?, ?, ?)', undef,
1217                 $id, $pos->{'white_clock'}, $pos->{'black_clock'}, $white_clock_target, $black_clock_target);
1218         $dbh->commit;
1219 }
1220
1221 sub schedule_tb_lookup {
1222         return if (!defined($remoteglotconf::tb_serial_key));
1223         my $pos = $pos_waiting // $pos_calculating;
1224         return if (exists($tb_cache{$pos->fen()}));
1225
1226         # If there's more than seven pieces, there's not going to be an answer,
1227         # so don't bother.
1228         return if ($pos->num_pieces() > 7);
1229
1230         # Max one at a time. If it's still relevant when it returns,
1231         # schedule_tb_lookup() will be called again.
1232         return if ($tb_lookup_running);
1233
1234         $tb_lookup_running = 1;
1235         my $url = 'http://158.250.18.203:6904/tasks/addtask?auth.login=' .
1236                 $remoteglotconf::tb_serial_key .
1237                 '&auth.password=aquarium&type=0&fen=' .
1238                 URI::Escape::uri_escape($pos->fen());
1239         print TBLOG "Downloading $url...\n";
1240         AnyEvent::HTTP::http_get($url, sub {
1241                 handle_tb_lookup_return(@_, $pos, $pos->fen());
1242         });
1243 }
1244
1245 sub handle_tb_lookup_return {
1246         my ($body, $header, $pos, $fen) = @_;
1247         print TBLOG "Response for [$fen]:\n";
1248         print TBLOG $header . "\n\n";
1249         print TBLOG $body . "\n\n";
1250         eval {
1251                 my $response = JSON::XS::decode_json($body);
1252                 if ($response->{'ErrorCode'} != 0) {
1253                         die "Unknown tablebase server error: " . $response->{'ErrorDesc'};
1254                 }
1255                 my $state = $response->{'Response'}{'StateString'};
1256                 if ($state eq 'COMPLETE') {
1257                         my $pgn = Chess::PGN::Parse->new(undef, $response->{'Response'}{'Moves'});
1258                         if (!defined($pgn) || !$pgn->read_game()) {
1259                                 warn "Error in parsing PGN\n";
1260                         } else {
1261                                 $pgn->quick_parse_game;
1262                                 my $pvpos = $pos;
1263                                 my $moves = $pgn->moves;
1264                                 my @uci_moves = ();
1265                                 for my $move (@$moves) {
1266                                         my $uci_move;
1267                                         ($pvpos, $uci_move) = $pvpos->make_pretty_move($move);
1268                                         push @uci_moves, $uci_move;
1269                                 }
1270                                 $tb_cache{$fen} = {
1271                                         result => $pgn->result,
1272                                         pv => \@uci_moves,
1273                                         score => $response->{'Response'}{'Score'},
1274                                 };
1275                                 output();
1276                         }
1277                 } elsif ($state =~ /QUEUED/ || $state =~ /PROCESSING/) {
1278                         # Try again in a second. Note that if we have changed
1279                         # position in the meantime, we might query a completely
1280                         # different position! But that's fine.
1281                 } else {
1282                         die "Unknown response state " . $state;
1283                 }
1284
1285                 # Wait a second before we schedule another one.
1286                 $tb_retry_timer = AnyEvent->timer(after => 1.0, cb => sub {
1287                         $tb_lookup_running = 0;
1288                         schedule_tb_lookup();
1289                 });
1290         };
1291         if ($@) {
1292                 warn "Error in tablebase lookup: $@";
1293
1294                 # Don't try this one again, but don't block new lookups either.
1295                 $tb_lookup_running = 0;
1296         }
1297 }
1298
1299 sub open_engine {
1300         my ($cmdline, $tag, $cb) = @_;
1301         return undef if (!defined($cmdline));
1302         return Engine->open($cmdline, $tag, $cb);
1303 }
1304
1305 sub col_letter_to_num {
1306         return ord(shift) - ord('a');
1307 }
1308
1309 sub row_letter_to_num {
1310         return 7 - (ord(shift) - ord('1'));
1311 }
1312
1313 sub parse_uci_move {
1314         my $move = shift;
1315         my $from_col = col_letter_to_num(substr($move, 0, 1));
1316         my $from_row = row_letter_to_num(substr($move, 1, 1));
1317         my $to_col   = col_letter_to_num(substr($move, 2, 1));
1318         my $to_row   = row_letter_to_num(substr($move, 3, 1));
1319         my $promo    = substr($move, 4, 1);
1320         return ($from_col, $from_row, $to_col, $to_row, $promo);
1321 }