git.sesse.net Git - remoteglot/blob - www/js/remoteglot.js

   1 (function() {
   2
   3 /**
   4  * Version of this script. If the server returns a version larger than
   5  * this, it is a sign we should reload to upgrade ourselves.
   6  *
   7  * @type {Number}
   8  * @const
   9  * @private */
  10 var SCRIPT_VERSION = 2015062103;
  11
  12 /** @type {window.ChessBoard} @private */
  13 var board = null;
  14
  15 /**
  16  * The most recent analysis data we have from the server
  17  * (about the most recent position).
  18  *
  19  * @type {?Object}
  20  * @private */
  21 var current_analysis_data = null;
  22
  23 /**
  24  * If we are displaying previous analysis, this is non-null,
  25  * and will override most of current_analysis_data.
  26  *
  27  * @type {?Object}
  28  * @private
  29  */
  30 var displayed_analysis_data = null;
  31
  32 /** @type {Array.<{
  33  *      from_col: number,
  34  *      from_row: number,
  35  *      to_col: number,
  36  *      to_row: number,
  37  *      line_width: number,
  38  *      arrow_size: number,
  39  *      fg_color: string
  40  * }>}
  41  * @private
  42  */
  43 var arrows = [];
  44
  45 /** @type {Array.<Array.<boolean>>} */
  46 var occupied_by_arrows = [];
  47
  48 var refutation_lines = [];
  49
  50 /** @type {!number} @private */
  51 var move_num = 1;
  52
  53 /** @type {!string} @private */
  54 var toplay = 'W';
  55
  56 /** @type {number} @private */
  57 var ims = 0;
  58
  59 /** @type {boolean} @private */
  60 var sort_refutation_lines_by_score = true;
  61
  62 /** @type {boolean} @private */
  63 var truncate_display_history = true;
  64
  65 /** @type {!string|undefined} @private */
  66 var highlight_from = undefined;
  67
  68 /** @type {!string|undefined} @private */
  69 var highlight_to = undefined;
  70
  71 /** @type {?jQuery} @private */
  72 var highlighted_move = null;
  73
  74 /** @type {?number} @private */
  75 var unique = null;
  76
  77 /** @type {boolean} @private */
  78 var enable_sound = false;
  79
  80 /**
  81  * Our best estimate of how many milliseconds we need to add to
  82  * new Date() to get the true UTC time. Calibrated against the
  83  * server clock.
  84  *
  85  * @type {?number}
  86  * @private
  87  */
  88 var client_clock_offset_ms = null;
  89
  90 var clock_timer = null;
  91
  92 /** The current position on the board, represented as a FEN string.
  93  * @type {?string}
  94  * @private
  95  */
  96 var fen = null;
  97
  98 /** @typedef {{
  99  *    start_fen: string,
 100  *    uci_pv: Array.<string>,
 101  *    pretty_pv: Array.<string>,
 102  *    line_num: number
 103  * }} DisplayLine
 104  */
 105
 106 /** @type {Array.<DisplayLine>}
 107  * @private
 108  */
 109 var display_lines = [];
 110
 111 /** @type {?DisplayLine} @private */
 112 var current_display_line = null;
 113
 114 /** @type {boolean} @private */
 115 var current_display_line_is_history = false;
 116
 117 /** @type {?number} @private */
 118 var current_display_move = null;
 119
 120 var supports_html5_storage = function() {
 121         try {
 122                 return 'localStorage' in window && window['localStorage'] !== null;
 123         } catch (e) {
 124                 return false;
 125         }
 126 }
 127
 128 // Make the unique token persistent so people refreshing the page won't count twice.
 129 // Of course, you can never fully protect against people deliberately wanting to spam.
 130 var get_unique = function() {
 131         var use_local_storage = supports_html5_storage();
 132         if (use_local_storage && localStorage['unique']) {
 133                 return localStorage['unique'];
 134         }
 135         var unique = Math.random();
 136         if (use_local_storage) {
 137                 localStorage['unique'] = unique;
 138         }
 139         return unique;
 140 }
 141
 142 var request_update = function() {
 143         $.ajax({
 144                 url: "/analysis.pl?ims=" + ims + "&unique=" + unique
 145         }).done(function(data, textstatus, xhr) {
 146                 sync_server_clock(xhr.getResponseHeader('Date'));
 147                 ims = xhr.getResponseHeader('X-RGLM');
 148                 var num_viewers = xhr.getResponseHeader('X-RGNV');
 149                 var new_data;
 150                 if (Array.isArray(data)) {
 151                         new_data = JSON.parse(JSON.stringify(current_analysis_data));
 152                         JSON_delta.patch(new_data, data);
 153                 } else {
 154                         new_data = data;
 155                 }
 156
 157                 var minimum_version = xhr.getResponseHeader('X-RGMV');
 158                 if (minimum_version && minimum_version > SCRIPT_VERSION) {
 159                         // Upgrade to latest version with a force-reload.
 160                         location.reload(true);
 161                 }
 162
 163                 possibly_play_sound(current_analysis_data, new_data);
 164                 current_analysis_data = new_data;
 165                 update_board(current_analysis_data, displayed_analysis_data);
 166                 update_num_viewers(num_viewers);
 167
 168                 // Next update.
 169                 setTimeout(function() { request_update(); }, 100);
 170         }).fail(function() {
 171                 // Wait ten seconds, then try again.
 172                 setTimeout(function() { request_update(); }, 10000);
 173         });
 174 }
 175
 176 var possibly_play_sound = function(old_data, new_data) {
 177         if (!enable_sound) {
 178                 return;
 179         }
 180         if (old_data === null) {
 181                 return;
 182         }
 183         var ding = document.getElementById('ding');
 184         if (ding && ding.play) {
 185                 if (old_data['position'] && old_data['position']['fen'] &&
 186                     new_data['position'] && new_data['position']['fen'] &&
 187                     (old_data['position']['fen'] !== new_data['position']['fen'] ||
 188                      old_data['position']['move_num'] !== new_data['position']['move_num'])) {
 189                         ding.play();
 190                 }
 191         }
 192 }
 193
 194 /**
 195  * @type {!string} server_date_string
 196  */
 197 var sync_server_clock = function(server_date_string) {
 198         var server_time_ms = new Date(server_date_string).getTime();
 199         var client_time_ms = new Date().getTime();
 200         var estimated_offset_ms = server_time_ms - client_time_ms;
 201
 202         // In order not to let the noise move us too much back and forth
 203         // (the server only has one-second resolution anyway), we only
 204         // change an existing skew if we are at least five seconds off.
 205         if (client_clock_offset_ms === null ||
 206             Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
 207                 client_clock_offset_ms = estimated_offset_ms;
 208         }
 209 }
 210
 211 var clear_arrows = function() {
 212         for (var i = 0; i < arrows.length; ++i) {
 213                 if (arrows[i].svg) {
 214                         arrows[i].svg.parentElement.removeChild(arrows[i].svg);
 215                         delete arrows[i].svg;
 216                 }
 217         }
 218         arrows = [];
 219
 220         occupied_by_arrows = [];
 221         for (var y = 0; y < 8; ++y) {
 222                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 223         }
 224 }
 225
 226 var redraw_arrows = function() {
 227         for (var i = 0; i < arrows.length; ++i) {
 228                 position_arrow(arrows[i]);
 229         }
 230 }
 231
 232 /** @param {!number} x
 233  * @return {!number}
 234  */
 235 var sign = function(x) {
 236         if (x > 0) {
 237                 return 1;
 238         } else if (x < 0) {
 239                 return -1;
 240         } else {
 241                 return 0;
 242         }
 243 }
 244
 245 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 246  * @param {!string} from The square the arrow is from (e.g. e4).
 247  * @param {!string} to The square the arrow is to (e.g. e4).
 248  * @return {boolean}
 249  */
 250 var interfering_arrow = function(from, to) {
 251         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 252         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 253         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 254         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 255
 256         occupied_by_arrows[from_row][from_col] = true;
 257
 258         // Knight move: Just check that we haven't been at the destination before.
 259         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 260             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 261                 return occupied_by_arrows[to_row][to_col];
 262         }
 263
 264         // Sliding piece: Check if anything except the from-square is seen before.
 265         var dx = sign(to_col - from_col);
 266         var dy = sign(to_row - from_row);
 267         var x = from_col;
 268         var y = from_row;
 269         do {
 270                 x += dx;
 271                 y += dy;
 272                 if (occupied_by_arrows[y][x]) {
 273                         return true;
 274                 }
 275                 occupied_by_arrows[y][x] = true;
 276         } while (x != to_col || y != to_row);
 277
 278         return false;
 279 }
 280
 281 /** Find a point along the coordinate system given by the given line,
 282  * <t> units forward from the start of the line, <u> units to the right of it.
 283  * @param {!number} x1
 284  * @param {!number} x2
 285  * @param {!number} y1
 286  * @param {!number} y2
 287  * @param {!number} t
 288  * @param {!number} u
 289  * @return {!string} The point in "x y" form, suitable for SVG paths.
 290  */
 291 var point_from_start = function(x1, y1, x2, y2, t, u) {
 292         var dx = x2 - x1;
 293         var dy = y2 - y1;
 294
 295         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 296         dx *= norm;
 297         dy *= norm;
 298
 299         var x = x1 + dx * t + dy * u;
 300         var y = y1 + dy * t - dx * u;
 301         return x + " " + y;
 302 }
 303
 304 /** Find a point along the coordinate system given by the given line,
 305  * <t> units forward from the end of the line, <u> units to the right of it.
 306  * @param {!number} x1
 307  * @param {!number} x2
 308  * @param {!number} y1
 309  * @param {!number} y2
 310  * @param {!number} t
 311  * @param {!number} u
 312  * @return {!string} The point in "x y" form, suitable for SVG paths.
 313  */
 314 var point_from_end = function(x1, y1, x2, y2, t, u) {
 315         var dx = x2 - x1;
 316         var dy = y2 - y1;
 317
 318         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 319         dx *= norm;
 320         dy *= norm;
 321
 322         var x = x2 + dx * t + dy * u;
 323         var y = y2 + dy * t - dx * u;
 324         return x + " " + y;
 325 }
 326
 327 var position_arrow = function(arrow) {
 328         if (arrow.svg) {
 329                 arrow.svg.parentElement.removeChild(arrow.svg);
 330                 delete arrow.svg;
 331         }
 332         if (current_display_line !== null && !current_display_line_is_history) {
 333                 return;
 334         }
 335
 336         var pos = $(".square-a8").position();
 337
 338         var zoom_factor = $("#board").width() / 400.0;
 339         var line_width = arrow.line_width * zoom_factor;
 340         var arrow_size = arrow.arrow_size * zoom_factor;
 341
 342         var square_width = $(".square-a8").width();
 343         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 344         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 345         var from_x = (arrow.from_col + 0.5)*square_width;
 346         var to_x = (arrow.to_col + 0.5)*square_width;
 347
 348         var SVG_NS = "http://www.w3.org/2000/svg";
 349         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 350         var svg = document.createElementNS(SVG_NS, "svg");
 351         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 352         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 353         svg.setAttribute("style", "position: absolute");
 354         svg.setAttribute("position", "absolute");
 355         svg.setAttribute("version", "1.1");
 356         svg.setAttribute("class", "c1");
 357         svg.setAttribute("xmlns", XHTML_NS);
 358
 359         var x1 = from_x;
 360         var y1 = from_y;
 361         var x2 = to_x;
 362         var y2 = to_y;
 363
 364         // Draw the line.
 365         var outline = document.createElementNS(SVG_NS, "path");
 366         outline.setAttribute("d", "M " + point_from_start(x1, y1, x2, y2, arrow_size / 2, 0) + " L " + point_from_end(x1, y1, x2, y2, -arrow_size / 2, 0));
 367         outline.setAttribute("xmlns", XHTML_NS);
 368         outline.setAttribute("stroke", "#666");
 369         outline.setAttribute("stroke-width", line_width + 2);
 370         outline.setAttribute("fill", "none");
 371         svg.appendChild(outline);
 372
 373         var path = document.createElementNS(SVG_NS, "path");
 374         path.setAttribute("d", "M " + point_from_start(x1, y1, x2, y2, arrow_size / 2, 0) + " L " + point_from_end(x1, y1, x2, y2, -arrow_size / 2, 0));
 375         path.setAttribute("xmlns", XHTML_NS);
 376         path.setAttribute("stroke", arrow.fg_color);
 377         path.setAttribute("stroke-width", line_width);
 378         path.setAttribute("fill", "none");
 379         svg.appendChild(path);
 380
 381         // Then the arrow head.
 382         var head = document.createElementNS(SVG_NS, "path");
 383         head.setAttribute("d",
 384                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 385                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 386                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 387                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 388                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 389         head.setAttribute("xmlns", XHTML_NS);
 390         head.setAttribute("stroke", "#000");
 391         head.setAttribute("stroke-width", "1");
 392         head.setAttribute("fill", arrow.fg_color);
 393         svg.appendChild(head);
 394
 395         $(svg).css({ top: pos.top, left: pos.left });
 396         document.body.appendChild(svg);
 397         arrow.svg = svg;
 398 }
 399
 400 /**
 401  * @param {!string} from_square
 402  * @param {!string} to_square
 403  * @param {!string} fg_color
 404  * @param {number} line_width
 405  * @param {number} arrow_size
 406  */
 407 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 408         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 409         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 410         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 411         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 412
 413         // Create arrow.
 414         var arrow = {
 415                 from_col: from_col,
 416                 from_row: from_row,
 417                 to_col: to_col,
 418                 to_row: to_row,
 419                 line_width: line_width,
 420                 arrow_size: arrow_size,
 421                 fg_color: fg_color
 422         };
 423
 424         position_arrow(arrow);
 425         arrows.push(arrow);
 426 }
 427
 428 var compare_by_sort_key = function(refutation_lines, a, b) {
 429         var ska = refutation_lines[a]['sort_key'];
 430         var skb = refutation_lines[b]['sort_key'];
 431         if (ska < skb) return -1;
 432         if (ska > skb) return 1;
 433         return 0;
 434 };
 435
 436 var compare_by_score = function(refutation_lines, a, b) {
 437         var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
 438         var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
 439         return sa - sb;
 440 }
 441
 442 /**
 443  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 444  * sorted by quality, descending.
 445  *
 446  * @param {!Object} data
 447  * @param {number} margin The maximum number of centipawns worse than the
 448  *     best move can be and still be included.
 449  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 450  *     moves, in score order.
 451  */
 452 var find_nonstupid_moves = function(data, margin) {
 453         // First of all, if there are any moves that are more than 0.5 ahead of
 454         // the primary move, the refutation lines are probably bunk, so just
 455         // kill them all.
 456         var best_score = undefined;
 457         var pv_score = undefined;
 458         for (var move in data['refutation_lines']) {
 459                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 460                 if (move == data['pv_uci'][0]) {
 461                         pv_score = score;
 462                 }
 463                 if (best_score === undefined || score > best_score) {
 464                         best_score = score;
 465                 }
 466                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 467                         return [];
 468                 }
 469         }
 470
 471         if (best_score - pv_score > 50) {
 472                 return [];
 473         }
 474
 475         // Now find all moves that are within “margin” of the best score.
 476         // The PV move will always be first.
 477         var moves = [];
 478         for (var move in data['refutation_lines']) {
 479                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 480                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 481                         moves.push(move);
 482                 }
 483         }
 484         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
 485         moves.unshift(data['pv_uci'][0]);
 486
 487         return moves;
 488 }
 489
 490 /**
 491  * @param {number} x
 492  * @return {!string}
 493  */
 494 var thousands = function(x) {
 495         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 496 }
 497
 498 /**
 499  * @param {!string} fen
 500  * @param {Array.<string>} pretty_pv
 501  * @param {number} move_num
 502  * @param {!string} toplay
 503  * @param {number=} opt_limit
 504  * @param {boolean=} opt_showlast
 505  */
 506 var add_pv = function(fen, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 507         display_lines.push({
 508                 start_fen: fen,
 509                 pretty_pv: pretty_pv,
 510                 line_number: display_lines.length
 511         });
 512         return print_pv(display_lines.length - 1, pretty_pv, move_num, toplay, opt_limit, opt_showlast);
 513 }
 514
 515 /**
 516  * @param {number} line_num
 517  * @param {Array.<string>} pretty_pv
 518  * @param {number} move_num
 519  * @param {!string} toplay
 520  * @param {number=} opt_limit
 521  * @param {boolean=} opt_showlast
 522  */
 523 var print_pv = function(line_num, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 524         var pv = '';
 525         var i = 0;
 526         if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
 527                 // Truncate the PV at the beginning (instead of at the end).
 528                 // We assume here that toplay is 'W'. We also assume that if
 529                 // opt_showlast is set, then it is the history, and thus,
 530                 // the UI should be to expand the history.
 531                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 532                 i = pretty_pv.length - opt_limit;
 533                 if (i % 2 == 1) {
 534                         ++i;
 535                 }
 536                 move_num += i / 2;
 537         } else if (toplay == 'B' && pretty_pv.length > 0) {
 538                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 539                 pv = move_num + '. … ' + move;
 540                 toplay = 'W';
 541                 ++i;
 542                 ++move_num;
 543         }
 544         for ( ; i < pretty_pv.length; ++i) {
 545                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 546
 547                 if (toplay == 'W') {
 548                         if (i > opt_limit && !opt_showlast) {
 549                                 return pv + ' (…)';
 550                         }
 551                         if (pv != '') {
 552                                 pv += ' ';
 553                         }
 554                         pv += move_num + '. ' + move;
 555                         ++move_num;
 556                         toplay = 'B';
 557                 } else {
 558                         pv += ' ' + move;
 559                         toplay = 'W';
 560                 }
 561         }
 562         return pv;
 563 }
 564
 565 var update_highlight = function() {
 566         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 567         if ((current_display_line === null || current_display_line_is_history) &&
 568             highlight_from !== undefined && highlight_to !== undefined) {
 569                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 570                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 571         }
 572 }
 573
 574 var update_history = function() {
 575         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 576                 $("#history").html("No history");
 577         } else if (truncate_display_history) {
 578                 $("#history").html(print_pv(0, display_lines[0].pretty_pv, 1, 'W', 8, true));
 579         } else {
 580                 $("#history").html(
 581                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 582                         print_pv(0, display_lines[0].pretty_pv, 1, 'W'));
 583         }
 584 }
 585
 586 /**
 587  * @param {!boolean} truncate_history
 588  */
 589 var collapse_history = function(truncate_history) {
 590         truncate_display_history = truncate_history;
 591         update_history();
 592 }
 593 window['collapse_history'] = collapse_history;
 594
 595 var update_refutation_lines = function() {
 596         if (fen === null) {
 597                 return;
 598         }
 599         if (display_lines.length > 2) {
 600                 display_lines = [ display_lines[0], display_lines[1] ];
 601         }
 602
 603         var tbl = $("#refutationlines");
 604         tbl.empty();
 605
 606         var moves = [];
 607         for (var move in refutation_lines) {
 608                 moves.push(move);
 609         }
 610         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 611         moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
 612         for (var i = 0; i < moves.length; ++i) {
 613                 var line = refutation_lines[moves[i]];
 614
 615                 var tr = document.createElement("tr");
 616
 617                 var move_td = document.createElement("td");
 618                 tr.appendChild(move_td);
 619                 $(move_td).addClass("move");
 620                 if (line['pv_pretty'].length == 0) {
 621                         $(move_td).text(line['pretty_move']);
 622                 } else {
 623                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 624                         $(move_td).html(move);
 625                 }
 626
 627                 var score_td = document.createElement("td");
 628                 tr.appendChild(score_td);
 629                 $(score_td).addClass("score");
 630                 $(score_td).text(line['pretty_score']);
 631
 632                 var depth_td = document.createElement("td");
 633                 tr.appendChild(depth_td);
 634                 $(depth_td).addClass("depth");
 635                 $(depth_td).text("d" + line['depth']);
 636
 637                 var pv_td = document.createElement("td");
 638                 tr.appendChild(pv_td);
 639                 $(pv_td).addClass("pv");
 640                 $(pv_td).html(add_pv(fen, line['pv_pretty'], move_num, toplay, 10));
 641
 642                 tbl.append(tr);
 643         }
 644
 645         // Make one of the links clickable and the other nonclickable.
 646         if (sort_refutation_lines_by_score) {
 647                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 648                 $("#sortbyscore1").html("<strong>Score</strong>");
 649         } else {
 650                 $("#sortbyscore0").html("<strong>Move</strong>");
 651                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 652         }
 653 }
 654
 655 /**
 656  * @param {?string} fen
 657  * @param {Array.<string>} moves
 658  * @param {number} last_move
 659  */
 660 var chess_from = function(fen, moves, last_move) {
 661         var hiddenboard = new Chess();
 662         if (fen !== null) {
 663                 hiddenboard.load(fen);
 664         }
 665         for (var i = 0; i <= last_move; ++i) {
 666                 if (moves[i] === '0-0') {
 667                         hiddenboard.move('O-O');
 668                 } else if (moves[i] === '0-0-0') {
 669                         hiddenboard.move('O-O-O');
 670                 } else {
 671                         hiddenboard.move(moves[i]);
 672                 }
 673         }
 674         return hiddenboard;
 675 }
 676
 677 /**
 678  * @param {Object} data
 679  * @param {?Object} display_data
 680  */
 681 var update_board = function(current_data, display_data) {
 682         var data = display_data || current_data;
 683
 684         display_lines = [];
 685
 686         // Print the history. This is pretty much the only thing that's
 687         // unconditionally taken from current_data (we're not interested in
 688         // historic history).
 689         if (current_data['position']['pretty_history']) {
 690                 add_pv('start', current_data['position']['pretty_history'], 1, 'W', 8, true);
 691         } else {
 692                 display_lines.push(null);
 693         }
 694         update_history();
 695
 696         // The headline. Names are always fetched from current_data;
 697         // the rest can depend a bit.
 698         var headline;
 699         if (current_data &&
 700             current_data['position']['player_w'] && current_data['position']['player_b']) {
 701                 headline = current_data['position']['player_w'] + '–' +
 702                         current_data['position']['player_b'] + ', analysis';
 703         } else {
 704                 headline = 'Analysis';
 705         }
 706
 707         var last_move;
 708         if (display_data) {
 709                 // Displaying some non-current position, pick out the last move
 710                 // from the history. This will work even if the fetch failed.
 711                 last_move = format_halfmove_with_number(
 712                         current_display_line.pretty_pv[current_display_move],
 713                         current_display_move + 1);
 714                 headline += ' after ' + last_move;
 715         } else if (data['position']['last_move'] !== 'none') {
 716                 last_move = format_move_with_number(
 717                         data['position']['last_move'],
 718                         data['position']['move_num'],
 719                         data['position']['toplay'] == 'W');
 720                 headline += ' after ' + last_move;
 721         } else {
 722                 last_move = null;
 723         }
 724         $("#headline").text(headline);
 725
 726         // The <title> contains a very brief headline.
 727         var title_elems = [];
 728         if (data['short_score'] !== undefined && data['short_score'] !== null) {
 729                 title_elems.push(data['short_score'].replace(/^ /, ""));
 730         }
 731         if (last_move !== null) {
 732                 title_elems.push(last_move);
 733         }
 734
 735         if (title_elems.length != 0) {
 736                 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
 737         } else {
 738                 document.title = 'analysis.sesse.net';
 739         }
 740
 741         // The last move (shown by highlighting the from and to squares).
 742         if (data['position'] && data['position']['last_move_uci']) {
 743                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
 744                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
 745         } else if (current_display_line_is_history && current_display_move >= 0) {
 746                 // We don't have historic analysis for this position, but we
 747                 // can reconstruct what the last move was by just replaying
 748                 // from the start.
 749                 var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
 750                 var moves = hiddenboard.history({ verbose: true });
 751                 var last_move = moves.pop();
 752                 highlight_from = last_move.from;
 753                 highlight_to = last_move.to;
 754         } else {
 755                 highlight_from = highlight_to = undefined;
 756         }
 757         update_highlight();
 758
 759         if (data['failed']) {
 760                 $("#score").text("No analysis for this move");
 761                 $("#pv").empty();
 762                 $("#searchstats").html("&nbsp;");
 763                 $("#refutationlines").empty();
 764                 $("#whiteclock").empty();
 765                 $("#blackclock").empty();
 766                 refutation_lines = [];
 767                 update_refutation_lines();
 768                 clear_arrows();
 769                 update_displayed_line();
 770                 return;
 771         }
 772
 773         update_clock();
 774
 775         // The engine id.
 776         if (data['id'] && data['id']['name'] !== null) {
 777                 $("#engineid").text(data['id']['name']);
 778         }
 779
 780         // The score.
 781         if (data['score'] !== null) {
 782                 $("#score").text(data['score']);
 783         }
 784
 785         // The search stats.
 786         if (data['tablebase'] == 1) {
 787                 $("#searchstats").text("Tablebase result");
 788         } else if (data['nodes'] && data['nps'] && data['depth']) {
 789                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
 790                 if (data['seldepth']) {
 791                         stats += ' (' + data['seldepth'] + ' selective)';
 792                 }
 793                 if (data['tbhits'] && data['tbhits'] > 0) {
 794                         if (data['tbhits'] == 1) {
 795                                 stats += ', one Syzygy hit';
 796                         } else {
 797                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
 798                         }
 799                 }
 800
 801                 $("#searchstats").text(stats);
 802         } else {
 803                 $("#searchstats").text("");
 804         }
 805
 806         // Update the board itself.
 807         fen = data['position']['fen'];
 808         update_displayed_line();
 809
 810         // Print the PV.
 811         $("#pv").html(add_pv(data['position']['fen'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));
 812
 813         // Update the PV arrow.
 814         clear_arrows();
 815         if (data['pv_uci'].length >= 1) {
 816                 // draw a continuation arrow as long as it's the same piece
 817                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
 818                         var from = data['pv_uci'][i].substr(0, 2);
 819                         var to = data['pv_uci'][i].substr(2,4);
 820                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
 821                              interfering_arrow(from, to)) {
 822                                 break;
 823                         }
 824                         create_arrow(from, to, '#f66', 6, 20);
 825                 }
 826
 827                 var alt_moves = find_nonstupid_moves(data, 30);
 828                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
 829                         create_arrow(alt_moves[i].substr(0, 2),
 830                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
 831                 }
 832         }
 833
 834         // See if all semi-reasonable moves have only one possible response.
 835         if (data['pv_uci'].length >= 2) {
 836                 var nonstupid_moves = find_nonstupid_moves(data, 300);
 837                 var response = data['pv_uci'][1];
 838                 for (var i = 0; i < nonstupid_moves.length; ++i) {
 839                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
 840                                 // ignore the PV move for refutation lines.
 841                                 continue;
 842                         }
 843                         if (!data['refutation_lines'] ||
 844                             !data['refutation_lines'][nonstupid_moves[i]] ||
 845                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
 846                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
 847                                 // Incomplete PV, abort.
 848                                 response = undefined;
 849                                 break;
 850                         }
 851                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
 852                         if (response !== this_response) {
 853                                 // Different response depending on lines, abort.
 854                                 response = undefined;
 855                                 break;
 856                         }
 857                 }
 858
 859                 if (nonstupid_moves.length > 0 && response !== undefined) {
 860                         create_arrow(response.substr(0, 2),
 861                                      response.substr(2, 2), '#66f', 6, 20);
 862                 }
 863         }
 864
 865         // Update the refutation lines.
 866         fen = data['position']['fen'];
 867         move_num = data['position']['move_num'];
 868         toplay = data['position']['toplay'];
 869         refutation_lines = data['refutation_lines'];
 870         update_refutation_lines();
 871
 872         // Update the sparkline last, since its size depends on how everything else reflowed.
 873         update_sparkline(data);
 874 }
 875
 876 var update_sparkline = function(data) {
 877         if (data && data['score_history']) {
 878                 var first_move_num = undefined;
 879                 for (var halfmove_num in data['score_history']) {
 880                         halfmove_num = parseInt(halfmove_num);
 881                         if (first_move_num === undefined || halfmove_num < first_move_num) {
 882                                 first_move_num = halfmove_num;
 883                         }
 884                 }
 885                 if (first_move_num !== undefined) {
 886                         var last_move_num = data['position']['move_num'] * 2 - 3;
 887                         if (data['position']['toplay'] === 'B') {
 888                                 ++last_move_num;
 889                         }
 890
 891                         // Possibly truncate some moves if we don't have enough width.
 892                         // FIXME: Sometimes width() for #scorecontainer (and by extent,
 893                         // #scoresparkcontainer) on Chrome for mobile seems to start off
 894                         // at something very small, and then suddenly snap back into place.
 895                         // Figure out why.
 896                         var max_moves = Math.floor($("#scoresparkcontainer").width() / 5) - 5;
 897                         if (last_move_num - first_move_num > max_moves) {
 898                                 first_move_num = last_move_num - max_moves;
 899                         }
 900
 901                         var min_score = -100;
 902                         var max_score = 100;
 903                         var last_score = null;
 904                         var scores = [];
 905                         for (var halfmove_num = first_move_num; halfmove_num <= last_move_num; ++halfmove_num) {
 906                                 if (data['score_history'][halfmove_num]) {
 907                                         var score = data['score_history'][halfmove_num][0];
 908                                         if (score < min_score) min_score = score;
 909                                         if (score > max_score) max_score = score;
 910                                         last_score = data['score_history'][halfmove_num][0];
 911                                 }
 912                                 scores.push(last_score);
 913                         }
 914                         if (data['plot_score']) {
 915                                 scores.push(data['plot_score']);
 916                         }
 917                         // FIXME: at some widths, calling sparkline() seems to push
 918                         // #scorecontainer under the board.
 919                         $("#scorespark").sparkline(scores, {
 920                                 type: 'bar',
 921                                 zeroColor: 'gray',
 922                                 chartRangeMin: min_score,
 923                                 chartRangeMax: max_score,
 924                                 tooltipFormatter: function(sparkline, options, fields) {
 925                                         return format_tooltip(data, fields[0].offset + first_move_num);
 926                                 }
 927                         });
 928                 } else {
 929                         $("#scorespark").text("");
 930                 }
 931         } else {
 932                 $("#scorespark").text("");
 933         }
 934 }
 935
 936 /**
 937  * @param {number} num_viewers
 938  */
 939 var update_num_viewers = function(num_viewers) {
 940         if (num_viewers === null) {
 941                 $("#numviewers").text("");
 942         } else if (num_viewers == 1) {
 943                 $("#numviewers").text("You are the only current viewer");
 944         } else {
 945                 $("#numviewers").text(num_viewers + " current viewers");
 946         }
 947 }
 948
 949 var update_clock = function() {
 950         clearTimeout(clock_timer);
 951
 952         var data = displayed_analysis_data || current_analysis_data;
 953         if (data['position']) {
 954                 var result = data['position']['result'];
 955                 if (result === '1-0') {
 956                         $("#whiteclock").text("1");
 957                         $("#blackclock").text("0");
 958                         $("#whiteclock").removeClass("running-clock");
 959                         $("#blackclock").removeClass("running-clock");
 960                         return;
 961                 }
 962                 if (result === '1/2-1/2') {
 963                         $("#whiteclock").text("1/2");
 964                         $("#blackclock").text("1/2");
 965                         $("#whiteclock").removeClass("running-clock");
 966                         $("#blackclock").removeClass("running-clock");
 967                         return;
 968                 }
 969                 if (result === '0-1') {
 970                         $("#whiteclock").text("0");
 971                         $("#blackclock").text("1");
 972                         $("#whiteclock").removeClass("running-clock");
 973                         $("#blackclock").removeClass("running-clock");
 974                         return;
 975                 }
 976         }
 977
 978         var white_clock_ms = null;
 979         var black_clock_ms = null;
 980         var show_seconds = false;
 981
 982         // Static clocks.
 983         if (data['position'] &&
 984             data['position']['white_clock'] &&
 985             data['position']['black_clock']) {
 986                 white_clock_ms = data['position']['white_clock'] * 1000;
 987                 black_clock_ms = data['position']['black_clock'] * 1000;
 988         }
 989
 990         // Dynamic clock (only one, obviously).
 991         var color;
 992         if (data['position']['white_clock_target']) {
 993                 color = "white";
 994                 $("#whiteclock").addClass("running-clock");
 995                 $("#blackclock").removeClass("running-clock");
 996         } else if (data['position']['black_clock_target']) {
 997                 color = "black";
 998                 $("#whiteclock").removeClass("running-clock");
 999                 $("#blackclock").addClass("running-clock");
1000         } else {
1001                 $("#whiteclock").removeClass("running-clock");
1002                 $("#blackclock").removeClass("running-clock");
1003         }
1004         var remaining_ms;
1005         if (color) {
1006                 var now = new Date().getTime() + client_clock_offset_ms;
1007                 remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
1008                 if (color === "white") {
1009                         white_clock_ms = remaining_ms;
1010                 } else {
1011                         black_clock_ms = remaining_ms;
1012                 }
1013         }
1014
1015         if (white_clock_ms === null || black_clock_ms === null) {
1016                 $("#whiteclock").empty();
1017                 $("#blackclock").empty();
1018                 return;
1019         }
1020
1021         // If either player has ten minutes or less left, add the second counters.
1022         var show_seconds = (white_clock_ms < 60 * 10 * 1000 || black_clock_ms < 60 * 10 * 1000);
1023
1024         if (color) {
1025                 // See when the clock will change next, and update right after that.
1026                 var next_update_ms;
1027                 if (show_seconds) {
1028                         next_update_ms = remaining_ms % 1000 + 100;
1029                 } else {
1030                         next_update_ms = remaining_ms % 60000 + 100;
1031                 }
1032                 clock_timer = setTimeout(update_clock, next_update_ms);
1033         }
1034
1035         $("#whiteclock").text(format_clock(white_clock_ms, show_seconds));
1036         $("#blackclock").text(format_clock(black_clock_ms, show_seconds));
1037 }
1038
1039 /**
1040  * @param {Number} remaining_ms
1041  * @param {boolean} show_seconds
1042  */
1043 var format_clock = function(remaining_ms, show_seconds) {
1044         if (remaining_ms <= 0) {
1045                 if (show_seconds) {
1046                         return "00:00:00";
1047                 } else {
1048                         return "00:00";
1049                 }
1050         }
1051
1052         var remaining = Math.floor(remaining_ms / 1000);
1053         var seconds = remaining % 60;
1054         remaining = (remaining - seconds) / 60;
1055         var minutes = remaining % 60;
1056         remaining = (remaining - minutes) / 60;
1057         var hours = remaining;
1058         if (show_seconds) {
1059                 return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
1060         } else {
1061                 return format_2d(hours) + ":" + format_2d(minutes);
1062         }
1063 }
1064
1065 /**
1066  * @param {Number} x
1067  */
1068 var format_2d = function(x) {
1069         if (x >= 10) {
1070                 return x;
1071         } else {
1072                 return "0" + x;
1073         }
1074 }
1075
1076 /**
1077  * @param {string} move
1078  * @param {Number} move_num
1079  * @param {boolean} white_to_play
1080  */
1081 var format_move_with_number = function(move, move_num, white_to_play) {
1082         var ret;
1083         if (white_to_play) {
1084                 ret = (move_num - 1) + '… ';
1085         } else {
1086                 ret = move_num + '. ';
1087         }
1088         ret += move;
1089         return ret;
1090 }
1091
1092 /**
1093  * @param {string} move
1094  * @param {Number} halfmove_num
1095  */
1096 var format_halfmove_with_number = function(move, halfmove_num) {
1097         return format_move_with_number(
1098                 move,
1099                 Math.floor(halfmove_num / 2) + 1,
1100                 halfmove_num % 2 == 0);
1101 }
1102
1103 /**
1104  * @param {Object} data
1105  * @param {Number} halfmove_num
1106  */
1107 var format_tooltip = function(data, halfmove_num) {
1108         if (data['score_history'][halfmove_num] ||
1109             halfmove_num === data['position']['pretty_history'].length) {
1110                 var move;
1111                 var short_score;
1112                 if (halfmove_num === data['position']['pretty_history'].length) {
1113                         move = data['position']['last_move'];
1114                         short_score = data['short_score'];
1115                 } else {
1116                         move = data['position']['pretty_history'][halfmove_num];
1117                         short_score = data['score_history'][halfmove_num][1];
1118                 }
1119                 var move_with_number = format_halfmove_with_number(move, halfmove_num);
1120
1121                 return "After " + move_with_number + ": " + short_score;
1122         } else {
1123                 for (var i = halfmove_num; i --> 0; ) {
1124                         if (data['score_history'][i]) {
1125                                 var move = data['position']['pretty_history'][i];
1126                                 return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
1127                         }
1128                 }
1129         }
1130 }
1131
1132 /**
1133  * @param {boolean} sort_by_score
1134  */
1135 var resort_refutation_lines = function(sort_by_score) {
1136         sort_refutation_lines_by_score = sort_by_score;
1137         if (supports_html5_storage()) {
1138                 localStorage['sort_refutation_lines_by_score'] = sort_by_score ? 1 : 0;
1139         }
1140         update_refutation_lines();
1141 }
1142 window['resort_refutation_lines'] = resort_refutation_lines;
1143
1144 /**
1145  * @param {boolean} truncate_history
1146  */
1147 var set_truncate_history = function(truncate_history) {
1148         truncate_display_history = truncate_history;
1149         update_refutation_lines();
1150 }
1151 window['set_truncate_history'] = set_truncate_history;
1152
1153 /**
1154  * @param {number} line_num
1155  * @param {number} move_num
1156  */
1157 var show_line = function(line_num, move_num) {
1158         if (line_num == -1) {
1159                 current_display_line = null;
1160                 current_display_move = null;
1161                 if (displayed_analysis_data) {
1162                         // TODO: Support exiting to history position if we are in an
1163                         // analysis line of a history position.
1164                         displayed_analysis_data = null;
1165                         update_board(current_analysis_data, displayed_analysis_data);
1166                 }
1167         } else {
1168                 current_display_line = display_lines[line_num];
1169                 current_display_move = move_num;
1170         }
1171         current_display_line_is_history = (line_num == 0);
1172
1173         update_historic_analysis();
1174         update_displayed_line();
1175         update_highlight();
1176         redraw_arrows();
1177 }
1178 window['show_line'] = show_line;
1179
1180 var prev_move = function() {
1181         if (current_display_move > -1) {
1182                 --current_display_move;
1183         }
1184         update_historic_analysis();
1185         update_displayed_line();
1186 }
1187 window['prev_move'] = prev_move;
1188
1189 var next_move = function() {
1190         if (current_display_line && current_display_move < current_display_line.pretty_pv.length - 1) {
1191                 ++current_display_move;
1192         }
1193         update_historic_analysis();
1194         update_displayed_line();
1195 }
1196 window['next_move'] = next_move;
1197
1198 var update_historic_analysis = function() {
1199         if (!current_display_line_is_history) {
1200                 return;
1201         }
1202         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1203                 displayed_analysis_data = null;
1204                 update_board(current_analysis_data, displayed_analysis_data);
1205         }
1206
1207         // Fetch old analysis for this line if it exists.
1208         var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1209         var filename = "/history/move" + (current_display_move + 1) + "-" +
1210                 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1211
1212         $.ajax({
1213                 url: filename
1214         }).done(function(data, textstatus, xhr) {
1215                 displayed_analysis_data = data;
1216                 update_board(current_analysis_data, displayed_analysis_data);
1217         }).fail(function() {
1218                 displayed_analysis_data = {'failed': true};
1219                 update_board(current_analysis_data, displayed_analysis_data);
1220         });
1221 }
1222
1223 /**
1224  * @param {string} fen
1225  */
1226 var update_imbalance = function(fen) {
1227         var hiddenboard = new Chess(fen);
1228         var imbalance = {'k': 0, 'q': 0, 'r': 0, 'b': 0, 'n': 0, 'p': 0};
1229         for (var row = 0; row < 8; ++row) {
1230                 for (var col = 0; col < 8; ++col) {
1231                         var col_text = String.fromCharCode('a1'.charCodeAt(0) + col);
1232                         var row_text = String.fromCharCode('a1'.charCodeAt(1) + row);
1233                         var square = col_text + row_text;
1234                         var contents = hiddenboard.get(square);
1235                         if (contents !== null) {
1236                                 if (contents.color === 'w') {
1237                                         ++imbalance[contents.type];
1238                                 } else {
1239                                         --imbalance[contents.type];
1240                                 }
1241                         }
1242                 }
1243         }
1244         var white_imbalance = '';
1245         var black_imbalance = '';
1246         for (var piece in imbalance) {
1247                 for (var i = 0; i < imbalance[piece]; ++i) {
1248                         white_imbalance += '<img src="img/chesspieces/wikipedia/w' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1249                 }
1250                 for (var i = 0; i < -imbalance[piece]; ++i) {
1251                         black_imbalance += '<img src="img/chesspieces/wikipedia/b' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1252                 }
1253         }
1254         $('#whiteimbalance').html(white_imbalance);
1255         $('#blackimbalance').html(black_imbalance);
1256 }
1257
1258 var update_displayed_line = function() {
1259         if (highlighted_move !== null) {
1260                 highlighted_move.removeClass('highlight');
1261         }
1262         if (current_display_line === null) {
1263                 $("#linenav").hide();
1264                 $("#linemsg").show();
1265                 board.position(fen);
1266                 update_imbalance(fen);
1267                 return;
1268         }
1269
1270         $("#linenav").show();
1271         $("#linemsg").hide();
1272
1273         if (current_display_move <= 0) {
1274                 $("#prevmove").html("Previous");
1275         } else {
1276                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
1277         }
1278         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1279                 $("#nextmove").html("Next");
1280         } else {
1281                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
1282         }
1283
1284         highlighted_move = $("#automove" + current_display_line.line_number + "-" + current_display_move);
1285         highlighted_move.addClass('highlight');
1286
1287         var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pretty_pv, current_display_move);
1288         board.position(hiddenboard.fen());
1289         update_imbalance(hiddenboard.fen());
1290 }
1291
1292 /**
1293  * @param {boolean} param_enable_sound
1294  */
1295 var set_sound = function(param_enable_sound) {
1296         enable_sound = param_enable_sound;
1297         if (enable_sound) {
1298                 $("#soundon").html("<strong>On</strong>");
1299                 $("#soundoff").html("<a href=\"javascript:set_sound(false)\">Off</a>");
1300
1301                 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1302                 // and also preload the file since the user has selected audio.
1303                 var ding = document.getElementById('ding');
1304                 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1305                         ding.src = 'ding.opus';
1306                         ding.load();
1307                 }
1308         } else {
1309                 $("#soundon").html("<a href=\"javascript:set_sound(true)\">On</a>");
1310                 $("#soundoff").html("<strong>Off</strong>");
1311         }
1312         if (supports_html5_storage()) {
1313                 localStorage['enable_sound'] = enable_sound ? 1 : 0;
1314         }
1315 }
1316 window['set_sound'] = set_sound;
1317
1318 var init = function() {
1319         unique = get_unique();
1320
1321         // Load settings from HTML5 local storage if available.
1322         if (supports_html5_storage() && localStorage['enable_sound']) {
1323                 set_sound(parseInt(localStorage['enable_sound']));
1324         } else {
1325                 set_sound(false);
1326         }
1327         if (supports_html5_storage() && localStorage['sort_refutation_lines_by_score']) {
1328                 sort_refutation_lines_by_score = parseInt(localStorage['sort_refutation_lines_by_score']);
1329         } else {
1330                 sort_refutation_lines_by_score = true;
1331         }
1332
1333         // Create board.
1334         board = new window.ChessBoard('board', 'start');
1335
1336         request_update();
1337         $(window).resize(function() {
1338                 board.resize();
1339                 update_sparkline(displayed_analysis_data || current_analysis_data);
1340                 update_highlight();
1341                 redraw_arrows();
1342         });
1343         $(window).keyup(function(event) {
1344                 if (event.which == 39) {
1345                         next_move();
1346                 } else if (event.which == 37) {
1347                         prev_move();
1348                 }
1349         });
1350 };
1351 $(document).ready(init);
1352
1353 })();