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 = 2016032000;
  11
  12 /**
  13  * The current backend URL.
  14  *
  15  * @type {!string}
  16  * @private
  17  */
  18 var backend_url = "/analysis.pl";
  19 var backend_hash_url = "/hash";
  20
  21 /** @type {window.ChessBoard} @private */
  22 var board = null;
  23
  24 /** @type {boolean} @private */
  25 var board_is_animating = false;
  26
  27 /**
  28  * The most recent analysis data we have from the server
  29  * (about the most recent position).
  30  *
  31  * @type {?Object}
  32  * @private */
  33 var current_analysis_data = null;
  34
  35 /**
  36  * If we are displaying previous analysis or from hash, this is non-null,
  37  * and will override most of current_analysis_data.
  38  *
  39  * @type {?Object}
  40  * @private
  41  */
  42 var displayed_analysis_data = null;
  43
  44 /**
  45  * Games currently in progress, if any.
  46  *
  47  * @type {?Array.<{
  48  *      name: string,
  49  *      url: string,
  50  *      id: string,
  51  * }>}
  52  * @private
  53  */
  54 var current_games = null;
  55
  56 /** @type {Array.<{
  57  *      from_col: number,
  58  *      from_row: number,
  59  *      to_col: number,
  60  *      to_row: number,
  61  *      line_width: number,
  62  *      arrow_size: number,
  63  *      fg_color: string
  64  * }>}
  65  * @private
  66  */
  67 var arrows = [];
  68
  69 /** @type {Array.<Array.<boolean>>} */
  70 var occupied_by_arrows = [];
  71
  72 /** Currently displayed refutation lines (on-screen).
  73  * Can either come from the current_analysis_data, displayed_analysis_data,
  74  * or hash_refutation_lines.
  75  */
  76 var refutation_lines = [];
  77
  78 /** Refutation lines from current hash probe.
  79  *
  80  * If non-null, will override refutation lines from the base position.
  81  * Note that these are relative to display_fen, not base_fen.
  82  */
  83 var hash_refutation_lines = null;
  84
  85 /** @type {!number} @private */
  86 var move_num = 1;
  87
  88 /** @type {!string} @private */
  89 var toplay = 'W';
  90
  91 /** @type {number} @private */
  92 var ims = 0;
  93
  94 /** @type {boolean} @private */
  95 var sort_refutation_lines_by_score = true;
  96
  97 /** @type {boolean} @private */
  98 var truncate_display_history = true;
  99
 100 /** @type {!string|undefined} @private */
 101 var highlight_from = undefined;
 102
 103 /** @type {!string|undefined} @private */
 104 var highlight_to = undefined;
 105
 106 /** The HTML object of the move currently being highlighted (in red).
 107  * @type {?jQuery}
 108  * @private */
 109 var highlighted_move = null;
 110
 111 /** Currently suggested/recommended move when dragging.
 112  * @type {?{from: !string, to: !string}}
 113  * @private
 114  */
 115 var recommended_move = null;
 116
 117 /** If reverse-dragging (dragging from the destination square to the
 118  * source square), the destination square.
 119  * @type {?string}
 120  * @private
 121  */
 122 var reverse_dragging_from = null;
 123
 124 /** @type {?number} @private */
 125 var unique = null;
 126
 127 /** @type {boolean} @private */
 128 var enable_sound = false;
 129
 130 /**
 131  * Our best estimate of how many milliseconds we need to add to
 132  * new Date() to get the true UTC time. Calibrated against the
 133  * server clock.
 134  *
 135  * @type {?number}
 136  * @private
 137  */
 138 var client_clock_offset_ms = null;
 139
 140 var clock_timer = null;
 141
 142 /** The current position being analyzed, represented as a FEN string.
 143  * Note that this is not necessarily the same as display_fen.
 144  * @type {?string}
 145  * @private
 146  */
 147 var base_fen = null;
 148
 149 /** The current position on the board, represented as a FEN string.
 150  * Note that board.fen() does not contain e.g. who is to play.
 151  * @type {?string}
 152  * @private
 153  */
 154 var display_fen = null;
 155
 156 /** @typedef {{
 157  *    start_fen: string,
 158  *    pretty_pv: Array.<string>,
 159  *    move_num: number,
 160  *    toplay: string,
 161  *    start_display_move_num: number
 162  * }} DisplayLine
 163  *
 164  * "start_display_move_num" is the (half-)move number to start displaying the PV at.
 165  */
 166
 167 /** All PVs that we currently know of.
 168  *
 169  * Element 0 is history (or null if no history).
 170  * Element 1 is current main PV, or explored line if nowhere else on the screen.
 171  * All remaining elements are refutation lines (multi-PV).
 172  *
 173  * @type {Array.<DisplayLine>}
 174  * @private
 175  */
 176 var display_lines = [];
 177
 178 /** @type {?DisplayLine} @private */
 179 var current_display_line = null;
 180
 181 /** @type {boolean} @private */
 182 var current_display_line_is_history = false;
 183
 184 /** @type {?number} @private */
 185 var current_display_move = null;
 186
 187 /**
 188  * The current backend request to get main analysis (not history), if any,
 189  * so that we can abort it.
 190  *
 191  * @type {?jqXHR}
 192  * @private
 193  */
 194 var current_analysis_xhr = null;
 195
 196 /**
 197  * The current timer to fire off a request to get main analysis (not history),
 198  * if any, so that we can abort it.
 199  *
 200  * @type {?Number}
 201  * @private
 202  */
 203 var current_analysis_request_timer = null;
 204
 205 /**
 206  * The current backend request to get historic data, if any.
 207  *
 208  * @type {?jqXHR}
 209  * @private
 210  */
 211 var current_historic_xhr = null;
 212
 213 /**
 214  * The current backend request to get hash probes, if any, so that we can abort it.
 215  *
 216  * @type {?jqXHR}
 217  * @private
 218  */
 219 var current_hash_xhr = null;
 220
 221 /**
 222  * The current timer to display hash probe information (it could be waiting on the
 223  * board to stop animating), if any, so that we can abort it.
 224  *
 225  * @type {?Number}
 226  * @private
 227  */
 228 var current_hash_display_timer = null;
 229
 230 var supports_html5_storage = function() {
 231         try {
 232                 return 'localStorage' in window && window['localStorage'] !== null;
 233         } catch (e) {
 234                 return false;
 235         }
 236 }
 237
 238 // Make the unique token persistent so people refreshing the page won't count twice.
 239 // Of course, you can never fully protect against people deliberately wanting to spam.
 240 var get_unique = function() {
 241         var use_local_storage = supports_html5_storage();
 242         if (use_local_storage && localStorage['unique']) {
 243                 return localStorage['unique'];
 244         }
 245         var unique = Math.random();
 246         if (use_local_storage) {
 247                 localStorage['unique'] = unique;
 248         }
 249         return unique;
 250 }
 251
 252 var request_update = function() {
 253         current_analysis_request_timer = null;
 254
 255         current_analysis_xhr = $.ajax({
 256                 url: backend_url + "?ims=" + ims + "&unique=" + unique
 257         }).done(function(data, textstatus, xhr) {
 258                 sync_server_clock(xhr.getResponseHeader('Date'));
 259                 ims = xhr.getResponseHeader('X-RGLM');
 260                 var num_viewers = xhr.getResponseHeader('X-RGNV');
 261                 var new_data;
 262                 if (Array.isArray(data)) {
 263                         new_data = JSON.parse(JSON.stringify(current_analysis_data));
 264                         JSON_delta.patch(new_data, data);
 265                 } else {
 266                         new_data = data;
 267                 }
 268
 269                 var minimum_version = xhr.getResponseHeader('X-RGMV');
 270                 if (minimum_version && minimum_version > SCRIPT_VERSION) {
 271                         // Upgrade to latest version with a force-reload.
 272                         location.reload(true);
 273                 }
 274
 275                 possibly_play_sound(current_analysis_data, new_data);
 276                 current_analysis_data = new_data;
 277                 update_board();
 278                 update_num_viewers(num_viewers);
 279
 280                 // Next update.
 281                 current_analysis_request_timer = setTimeout(function() { request_update(); }, 100);
 282         }).fail(function(jqXHR, textStatus, errorThrown) {
 283                 if (textStatus === "abort") {
 284                         // Aborted because we are switching backends. Abandon and don't retry,
 285                         // because another one is already started for us.
 286                 } else {
 287                         // Backend error or similar. Wait ten seconds, then try again.
 288                         current_analysis_request_timer = setTimeout(function() { request_update(); }, 10000);
 289                 }
 290         });
 291 }
 292
 293 var possibly_play_sound = function(old_data, new_data) {
 294         if (!enable_sound) {
 295                 return;
 296         }
 297         if (old_data === null) {
 298                 return;
 299         }
 300         var ding = document.getElementById('ding');
 301         if (ding && ding.play) {
 302                 if (old_data['position'] && old_data['position']['fen'] &&
 303                     new_data['position'] && new_data['position']['fen'] &&
 304                     (old_data['position']['fen'] !== new_data['position']['fen'] ||
 305                      old_data['position']['move_num'] !== new_data['position']['move_num'])) {
 306                         ding.play();
 307                 }
 308         }
 309 }
 310
 311 /**
 312  * @type {!string} server_date_string
 313  */
 314 var sync_server_clock = function(server_date_string) {
 315         var server_time_ms = new Date(server_date_string).getTime();
 316         var client_time_ms = new Date().getTime();
 317         var estimated_offset_ms = server_time_ms - client_time_ms;
 318
 319         // In order not to let the noise move us too much back and forth
 320         // (the server only has one-second resolution anyway), we only
 321         // change an existing skew if we are at least five seconds off.
 322         if (client_clock_offset_ms === null ||
 323             Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
 324                 client_clock_offset_ms = estimated_offset_ms;
 325         }
 326 }
 327
 328 var clear_arrows = function() {
 329         for (var i = 0; i < arrows.length; ++i) {
 330                 if (arrows[i].svg) {
 331                         if (arrows[i].svg.parentElement) {
 332                                 arrows[i].svg.parentElement.removeChild(arrows[i].svg);
 333                         }
 334                         delete arrows[i].svg;
 335                 }
 336         }
 337         arrows = [];
 338
 339         occupied_by_arrows = [];
 340         for (var y = 0; y < 8; ++y) {
 341                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 342         }
 343 }
 344
 345 var redraw_arrows = function() {
 346         for (var i = 0; i < arrows.length; ++i) {
 347                 position_arrow(arrows[i]);
 348         }
 349 }
 350
 351 /** @param {!number} x
 352  * @return {!number}
 353  */
 354 var sign = function(x) {
 355         if (x > 0) {
 356                 return 1;
 357         } else if (x < 0) {
 358                 return -1;
 359         } else {
 360                 return 0;
 361         }
 362 }
 363
 364 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 365  * @param {!string} from The square the arrow is from (e.g. e4).
 366  * @param {!string} to The square the arrow is to (e.g. e4).
 367  * @return {boolean}
 368  */
 369 var interfering_arrow = function(from, to) {
 370         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 371         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 372         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 373         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 374
 375         occupied_by_arrows[from_row][from_col] = true;
 376
 377         // Knight move: Just check that we haven't been at the destination before.
 378         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 379             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 380                 return occupied_by_arrows[to_row][to_col];
 381         }
 382
 383         // Sliding piece: Check if anything except the from-square is seen before.
 384         var dx = sign(to_col - from_col);
 385         var dy = sign(to_row - from_row);
 386         var x = from_col;
 387         var y = from_row;
 388         do {
 389                 x += dx;
 390                 y += dy;
 391                 if (occupied_by_arrows[y][x]) {
 392                         return true;
 393                 }
 394                 occupied_by_arrows[y][x] = true;
 395         } while (x != to_col || y != to_row);
 396
 397         return false;
 398 }
 399
 400 /** Find a point along the coordinate system given by the given line,
 401  * <t> units forward from the start of the line, <u> units to the right of it.
 402  * @param {!number} x1
 403  * @param {!number} x2
 404  * @param {!number} y1
 405  * @param {!number} y2
 406  * @param {!number} t
 407  * @param {!number} u
 408  * @return {!string} The point in "x y" form, suitable for SVG paths.
 409  */
 410 var point_from_start = function(x1, y1, x2, y2, t, u) {
 411         var dx = x2 - x1;
 412         var dy = y2 - y1;
 413
 414         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 415         dx *= norm;
 416         dy *= norm;
 417
 418         var x = x1 + dx * t + dy * u;
 419         var y = y1 + dy * t - dx * u;
 420         return x + " " + y;
 421 }
 422
 423 /** Find a point along the coordinate system given by the given line,
 424  * <t> units forward from the end of the line, <u> units to the right of it.
 425  * @param {!number} x1
 426  * @param {!number} x2
 427  * @param {!number} y1
 428  * @param {!number} y2
 429  * @param {!number} t
 430  * @param {!number} u
 431  * @return {!string} The point in "x y" form, suitable for SVG paths.
 432  */
 433 var point_from_end = function(x1, y1, x2, y2, t, u) {
 434         var dx = x2 - x1;
 435         var dy = y2 - y1;
 436
 437         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 438         dx *= norm;
 439         dy *= norm;
 440
 441         var x = x2 + dx * t + dy * u;
 442         var y = y2 + dy * t - dx * u;
 443         return x + " " + y;
 444 }
 445
 446 var position_arrow = function(arrow) {
 447         if (arrow.svg) {
 448                 if (arrow.svg.parentElement) {
 449                         arrow.svg.parentElement.removeChild(arrow.svg);
 450                 }
 451                 delete arrow.svg;
 452         }
 453         if (current_display_line !== null && !current_display_line_is_history) {
 454                 return;
 455         }
 456
 457         var pos = $(".square-a8").position();
 458
 459         var zoom_factor = $("#board").width() / 400.0;
 460         var line_width = arrow.line_width * zoom_factor;
 461         var arrow_size = arrow.arrow_size * zoom_factor;
 462
 463         var square_width = $(".square-a8").width();
 464         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 465         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 466         var from_x = (arrow.from_col + 0.5)*square_width;
 467         var to_x = (arrow.to_col + 0.5)*square_width;
 468
 469         var SVG_NS = "http://www.w3.org/2000/svg";
 470         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 471         var svg = document.createElementNS(SVG_NS, "svg");
 472         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 473         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 474         svg.setAttribute("style", "position: absolute");
 475         svg.setAttribute("position", "absolute");
 476         svg.setAttribute("version", "1.1");
 477         svg.setAttribute("class", "c1");
 478         svg.setAttribute("xmlns", XHTML_NS);
 479
 480         var x1 = from_x;
 481         var y1 = from_y;
 482         var x2 = to_x;
 483         var y2 = to_y;
 484
 485         // Draw the line.
 486         var outline = document.createElementNS(SVG_NS, "path");
 487         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));
 488         outline.setAttribute("xmlns", XHTML_NS);
 489         outline.setAttribute("stroke", "#666");
 490         outline.setAttribute("stroke-width", line_width + 2);
 491         outline.setAttribute("fill", "none");
 492         svg.appendChild(outline);
 493
 494         var path = document.createElementNS(SVG_NS, "path");
 495         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));
 496         path.setAttribute("xmlns", XHTML_NS);
 497         path.setAttribute("stroke", arrow.fg_color);
 498         path.setAttribute("stroke-width", line_width);
 499         path.setAttribute("fill", "none");
 500         svg.appendChild(path);
 501
 502         // Then the arrow head.
 503         var head = document.createElementNS(SVG_NS, "path");
 504         head.setAttribute("d",
 505                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 506                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 507                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 508                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 509                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 510         head.setAttribute("xmlns", XHTML_NS);
 511         head.setAttribute("stroke", "#000");
 512         head.setAttribute("stroke-width", "1");
 513         head.setAttribute("fill", arrow.fg_color);
 514         svg.appendChild(head);
 515
 516         $(svg).css({ top: pos.top, left: pos.left, 'pointer-events': 'none' });
 517         document.body.appendChild(svg);
 518         arrow.svg = svg;
 519 }
 520
 521 /**
 522  * @param {!string} from_square
 523  * @param {!string} to_square
 524  * @param {!string} fg_color
 525  * @param {number} line_width
 526  * @param {number} arrow_size
 527  */
 528 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 529         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 530         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 531         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 532         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 533
 534         // Create arrow.
 535         var arrow = {
 536                 from_col: from_col,
 537                 from_row: from_row,
 538                 to_col: to_col,
 539                 to_row: to_row,
 540                 line_width: line_width,
 541                 arrow_size: arrow_size,
 542                 fg_color: fg_color
 543         };
 544
 545         position_arrow(arrow);
 546         arrows.push(arrow);
 547 }
 548
 549 // Note: invert is ignored.
 550 var compare_by_sort_key = function(refutation_lines, invert, a, b) {
 551         var ska = refutation_lines[a]['sort_key'];
 552         var skb = refutation_lines[b]['sort_key'];
 553         if (ska < skb) return -1;
 554         if (ska > skb) return 1;
 555         return 0;
 556 };
 557
 558 var compare_by_score = function(refutation_lines, invert, a, b) {
 559         var sa = compute_score_sort_key(refutation_lines[b]['score'], invert);
 560         var sb = compute_score_sort_key(refutation_lines[a]['score'], invert);
 561         return sa - sb;
 562 }
 563
 564 /**
 565  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 566  * sorted by quality, descending.
 567  *
 568  * @param {!Object} data
 569  * @param {number} margin The maximum number of centipawns worse than the
 570  *     best move can be and still be included.
 571  * @param {boolean} margin Whether black is to play.
 572  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 573  *     moves, in score order.
 574  */
 575 var find_nonstupid_moves = function(data, margin, invert) {
 576         // First of all, if there are any moves that are more than 0.5 ahead of
 577         // the primary move, the refutation lines are probably bunk, so just
 578         // kill them all.
 579         var best_score = undefined;
 580         var pv_score = undefined;
 581         for (var move in data['refutation_lines']) {
 582                 var score = compute_score_sort_key(data['refutation_lines'][move]['score'], invert);
 583                 if (move == data['pv_uci'][0]) {
 584                         pv_score = score;
 585                 }
 586                 if (best_score === undefined || score > best_score) {
 587                         best_score = score;
 588                 }
 589                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 590                         return [];
 591                 }
 592         }
 593
 594         if (best_score - pv_score > 50) {
 595                 return [];
 596         }
 597
 598         // Now find all moves that are within “margin” of the best score.
 599         // The PV move will always be first.
 600         var moves = [];
 601         for (var move in data['refutation_lines']) {
 602                 var score = compute_score_sort_key(data['refutation_lines'][move]['score'], invert);
 603                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 604                         moves.push(move);
 605                 }
 606         }
 607         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], data['position']['toplay'] === 'B', a, b) });
 608         moves.unshift(data['pv_uci'][0]);
 609
 610         return moves;
 611 }
 612
 613 /**
 614  * @param {number} x
 615  * @return {!string}
 616  */
 617 var thousands = function(x) {
 618         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 619 }
 620
 621 /**
 622  * @param {!string} start_fen
 623  * @param {Array.<string>} pretty_pv
 624  * @param {number} move_num
 625  * @param {!string} toplay
 626  * @param {number} start_display_move_num
 627  * @param {number=} opt_limit
 628  * @param {boolean=} opt_showlast
 629  */
 630 var add_pv = function(start_fen, pretty_pv, move_num, toplay, start_display_move_num, opt_limit, opt_showlast) {
 631         display_lines.push({
 632                 start_fen: start_fen,
 633                 pretty_pv: pretty_pv,
 634                 move_num: parseInt(move_num),
 635                 toplay: toplay,
 636                 start_display_move_num: start_display_move_num,
 637         });
 638         return print_pv(display_lines.length - 1, opt_limit, opt_showlast);
 639 }
 640
 641 /**
 642  * @param {number} line_num
 643  * @param {number=} opt_limit
 644  * @param {boolean=} opt_showlast
 645  */
 646 var print_pv = function(line_num, opt_limit, opt_showlast) {
 647         var display_line = display_lines[line_num];
 648         var pretty_pv = display_line.pretty_pv;
 649         var move_num = display_line.move_num;
 650         var toplay = display_line.toplay;
 651
 652         // Truncate PV at the start if needed.
 653         var start_display_move_num = display_line.start_display_move_num;
 654         if (start_display_move_num > 0) {
 655                 pretty_pv = pretty_pv.slice(start_display_move_num);
 656                 var to_add = start_display_move_num;
 657                 if (toplay === 'B') {
 658                         ++move_num;
 659                         toplay = 'W';
 660                         --to_add;
 661                 }
 662                 if (to_add % 2 == 1) {
 663                         toplay = 'B';
 664                         --to_add;
 665                 }
 666                 move_num += to_add / 2;
 667         }
 668
 669         var pv = '';
 670         var i = 0;
 671         if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
 672                 // Truncate the PV at the beginning (instead of at the end).
 673                 // We assume here that toplay is 'W'. We also assume that if
 674                 // opt_showlast is set, then it is the history, and thus,
 675                 // the UI should be to expand the history.
 676                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 677                 i = pretty_pv.length - opt_limit;
 678                 if (i % 2 == 1) {
 679                         ++i;
 680                 }
 681                 move_num += i / 2;
 682         } else if (toplay == 'B' && pretty_pv.length > 0) {
 683                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 684                 pv = move_num + '. … ' + move;
 685                 toplay = 'W';
 686                 ++i;
 687                 ++move_num;
 688         }
 689         for ( ; i < pretty_pv.length; ++i) {
 690                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 691
 692                 if (toplay == 'W') {
 693                         if (i > opt_limit && !opt_showlast) {
 694                                 return pv + ' (…)';
 695                         }
 696                         if (pv != '') {
 697                                 pv += ' ';
 698                         }
 699                         pv += move_num + '. ' + move;
 700                         ++move_num;
 701                         toplay = 'B';
 702                 } else {
 703                         pv += ' ' + move;
 704                         toplay = 'W';
 705                 }
 706         }
 707         return pv;
 708 }
 709
 710 /** Update the highlighted to/from squares on the board.
 711  * Based on the global "highlight_from" and "highlight_to" variables.
 712  */
 713 var update_board_highlight = function() {
 714         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 715         if ((current_display_line === null || current_display_line_is_history) &&
 716             highlight_from !== undefined && highlight_to !== undefined) {
 717                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 718                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 719         }
 720 }
 721
 722 var update_history = function() {
 723         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 724                 $("#history").html("No history");
 725         } else if (truncate_display_history) {
 726                 $("#history").html(print_pv(0, 8, true));
 727         } else {
 728                 $("#history").html(
 729                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 730                         print_pv(0, 1, 'W'));
 731         }
 732 }
 733
 734 /**
 735  * @param {!boolean} truncate_history
 736  */
 737 var collapse_history = function(truncate_history) {
 738         truncate_display_history = truncate_history;
 739         update_history();
 740 }
 741 window['collapse_history'] = collapse_history;
 742
 743 /** Update the HTML display of multi-PV from the global "refutation_lines".
 744  *
 745  * Also recreates the global "display_lines".
 746  */
 747 var update_refutation_lines = function() {
 748         if (base_fen === null) {
 749                 return;
 750         }
 751         if (display_lines.length > 2) {
 752                 // Truncate so that only the history and PV is left.
 753                 display_lines = [ display_lines[0], display_lines[1] ];
 754         }
 755         var tbl = $("#refutationlines");
 756         tbl.empty();
 757
 758         // Find out where the lines start from.
 759         var base_line = [];
 760         var start_display_move_num = 0;
 761         if (hash_refutation_lines) {
 762                 base_line = current_display_line.pretty_pv.slice(0, current_display_move + 1);
 763                 start_display_move_num = base_line.length;
 764         }
 765
 766         var moves = [];
 767         for (var move in refutation_lines) {
 768                 moves.push(move);
 769         }
 770
 771         var invert = (toplay === 'B');
 772         if (current_display_line && current_display_move % 2 == 0) {
 773                 invert = !invert;
 774         }
 775         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 776         moves = moves.sort(function(a, b) { return compare(refutation_lines, invert, a, b) });
 777         for (var i = 0; i < moves.length; ++i) {
 778                 var line = refutation_lines[moves[i]];
 779
 780                 var tr = document.createElement("tr");
 781
 782                 var move_td = document.createElement("td");
 783                 tr.appendChild(move_td);
 784                 $(move_td).addClass("move");
 785
 786                 if (line['pv_pretty'].length == 0) {
 787                         // Not found, so just make a one-move PV.
 788                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 789                         $(move_td).html(move);
 790                         var score_td = document.createElement("td");
 791
 792                         $(score_td).addClass("score");
 793                         $(score_td).text("—");
 794                         tr.appendChild(score_td);
 795
 796                         var depth_td = document.createElement("td");
 797                         tr.appendChild(depth_td);
 798                         $(depth_td).addClass("depth");
 799                         $(depth_td).text("—");
 800
 801                         var pv_td = document.createElement("td");
 802                         tr.appendChild(pv_td);
 803                         $(pv_td).addClass("pv");
 804                         $(pv_td).html(add_pv(base_fen, base_line.concat([ line['pretty_move'] ]), move_num, toplay, start_display_move_num));
 805
 806                         tbl.append(tr);
 807                         continue;
 808                 }
 809
 810                 var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 811                 $(move_td).html(move);
 812
 813                 var score_td = document.createElement("td");
 814                 tr.appendChild(score_td);
 815                 $(score_td).addClass("score");
 816                 $(score_td).text(format_short_score(line['score']));
 817
 818                 var depth_td = document.createElement("td");
 819                 tr.appendChild(depth_td);
 820                 $(depth_td).addClass("depth");
 821                 $(depth_td).text("d" + line['depth']);
 822
 823                 var pv_td = document.createElement("td");
 824                 tr.appendChild(pv_td);
 825                 $(pv_td).addClass("pv");
 826                 $(pv_td).html(add_pv(base_fen, base_line.concat(line['pv_pretty']), move_num, toplay, start_display_move_num, 10));
 827
 828                 tbl.append(tr);
 829         }
 830
 831         // Make one of the links clickable and the other nonclickable.
 832         if (sort_refutation_lines_by_score) {
 833                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 834                 $("#sortbyscore1").html("<strong>Score</strong>");
 835         } else {
 836                 $("#sortbyscore0").html("<strong>Move</strong>");
 837                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 838         }
 839
 840         // Update the move highlight, as we've rewritten all the HTML.
 841         update_move_highlight();
 842 }
 843
 844 /**
 845  * Create a Chess.js board object, containing the given position plus the given moves,
 846  * up to the given limit.
 847  *
 848  * @param {?string} fen
 849  * @param {Array.<string>} moves
 850  * @param {number} last_move
 851  */
 852 var chess_from = function(fen, moves, last_move) {
 853         var hiddenboard = new Chess();
 854         if (fen !== null) {
 855                 hiddenboard.load(fen);
 856         }
 857         for (var i = 0; i <= last_move; ++i) {
 858                 if (moves[i] === '0-0') {
 859                         hiddenboard.move('O-O');
 860                 } else if (moves[i] === '0-0-0') {
 861                         hiddenboard.move('O-O-O');
 862                 } else {
 863                         hiddenboard.move(moves[i]);
 864                 }
 865         }
 866         return hiddenboard;
 867 }
 868
 869 var update_game_list = function(games) {
 870         $("#games").text("");
 871         if (games === null) {
 872                 return;
 873         }
 874
 875         var games_div = document.getElementById('games');
 876         for (var game_num = 0; game_num < games.length; ++game_num) {
 877                 var game = games[game_num];
 878                 var game_span = document.createElement("span");
 879                 game_span.setAttribute("class", "game");
 880
 881                 var game_name = document.createTextNode(game['name']);
 882                 if (game['url'] === backend_url) {
 883                         game_span.appendChild(game_name);
 884                 } else {
 885                         var game_a = document.createElement("a");
 886                         game_a.setAttribute("href", "#" + game['id']);
 887                         game_a.appendChild(game_name);
 888                         game_span.appendChild(game_a);
 889                 }
 890                 games_div.appendChild(game_span);
 891         }
 892 }
 893
 894 /**
 895  * Try to find a running game that matches with the current hash,
 896  * and switch to it if we're not already displaying it.
 897  */
 898 var possibly_switch_game_from_hash = function() {
 899         if (current_games === null) {
 900                 return;
 901         }
 902
 903         var hash = window.location.hash.replace(/^#/,'');
 904         for (var i = 0; i < current_games.length; ++i) {
 905                 if (current_games[i]['id'] === hash) {
 906                         if (backend_url !== current_games[i]['url']) {
 907                                 switch_backend(current_games[i]['url']);
 908                         }
 909                         return;
 910                 }
 911         }
 912 }
 913
 914 /** Update all the HTML on the page, based on current global state.
 915  */
 916 var update_board = function() {
 917         var data = displayed_analysis_data || current_analysis_data;
 918         var current_data = current_analysis_data;  // Convenience alias.
 919
 920         display_lines = [];
 921
 922         // Print the history. This is pretty much the only thing that's
 923         // unconditionally taken from current_data (we're not interested in
 924         // historic history).
 925         if (current_data['position']['pretty_history']) {
 926                 add_pv('start', current_data['position']['pretty_history'], 1, 'W', 0, 8, true);
 927         } else {
 928                 display_lines.push(null);
 929         }
 930         update_history();
 931
 932         // Games currently in progress, if any.
 933         if (current_data['games']) {
 934                 current_games = current_data['games'];
 935                 possibly_switch_game_from_hash();
 936                 update_game_list(current_data['games']);
 937         } else {
 938                 current_games = null;
 939                 update_game_list(null);
 940         }
 941
 942         // The headline. Names are always fetched from current_data;
 943         // the rest can depend a bit.
 944         var headline;
 945         if (current_data &&
 946             current_data['position']['player_w'] && current_data['position']['player_b']) {
 947                 headline = current_data['position']['player_w'] + '–' +
 948                         current_data['position']['player_b'] + ', analysis';
 949         } else {
 950                 headline = 'Analysis';
 951         }
 952
 953         // Credits, where applicable. Note that we don't want the footer to change a lot
 954         // when e.g. viewing history, so if any of these changed during the game,
 955         // use the current one still.
 956         if (current_data['using_lomonosov']) {
 957                 $("#lomonosov").show();
 958         } else {
 959                 $("#lomonosov").hide();
 960         }
 961
 962         // Credits: The engine name/version.
 963         if (current_data['engine'] && current_data['engine']['name'] !== null) {
 964                 $("#engineid").text(current_data['engine']['name']);
 965         }
 966
 967         // Credits: The engine URL.
 968         if (current_data['engine'] && current_data['engine']['url']) {
 969                 $("#engineid").attr("href", current_data['engine']['url']);
 970         } else {
 971                 $("#engineid").removeAttr("href");
 972         }
 973
 974         // Credits: Engine details.
 975         if (current_data['engine'] && current_data['engine']['details']) {
 976                 $("#enginedetails").text(" (" + current_data['engine']['details'] + ")");
 977         } else {
 978                 $("#enginedetails").text("");
 979         }
 980
 981         // Credits: Move source, possibly with URL.
 982         if (current_data['move_source'] && current_data['move_source_url']) {
 983                 $("#movesource").text("Moves provided by ");
 984                 var movesource_a = document.createElement("a");
 985                 movesource_a.setAttribute("href", current_data['move_source_url']);
 986                 var movesource_text = document.createTextNode(current_data['move_source']);
 987                 movesource_a.appendChild(movesource_text);
 988                 var movesource_period = document.createTextNode(".");
 989                 document.getElementById("movesource").appendChild(movesource_a);
 990                 document.getElementById("movesource").appendChild(movesource_period);
 991         } else if (current_data['move_source']) {
 992                 $("#movesource").text("Moves provided by " + current_data['move_source'] + ".");
 993         } else {
 994                 $("#movesource").text("");
 995         }
 996
 997         var last_move;
 998         if (displayed_analysis_data) {
 999                 // Displaying some non-current position, pick out the last move
1000                 // from the history. This will work even if the fetch failed.
1001                 last_move = format_halfmove_with_number(
1002                         current_display_line.pretty_pv[current_display_move],
1003                         current_display_move + 1);
1004                 headline += ' after ' + last_move;
1005         } else if (data['position']['last_move'] !== 'none') {
1006                 last_move = format_move_with_number(
1007                         data['position']['last_move'],
1008                         data['position']['move_num'],
1009                         data['position']['toplay'] == 'W');
1010                 headline += ' after ' + last_move;
1011         } else {
1012                 last_move = null;
1013         }
1014         $("#headline").text(headline);
1015
1016         // The <title> contains a very brief headline.
1017         var title_elems = [];
1018         if (data['score']) {
1019                 title_elems.push(format_short_score(data['score']).replace(/^ /, ""));
1020         }
1021         if (last_move !== null) {
1022                 title_elems.push(last_move);
1023         }
1024
1025         if (title_elems.length != 0) {
1026                 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
1027         } else {
1028                 document.title = 'analysis.sesse.net';
1029         }
1030
1031         // The last move (shown by highlighting the from and to squares).
1032         if (data['position'] && data['position']['last_move_uci']) {
1033                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
1034                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
1035         } else if (current_display_line_is_history && current_display_move >= 0) {
1036                 // We don't have historic analysis for this position, but we
1037                 // can reconstruct what the last move was by just replaying
1038                 // from the start.
1039                 var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1040                 var moves = hiddenboard.history({ verbose: true });
1041                 var last_move = moves.pop();
1042                 highlight_from = last_move.from;
1043                 highlight_to = last_move.to;
1044         } else {
1045                 highlight_from = highlight_to = undefined;
1046         }
1047         update_board_highlight();
1048
1049         if (data['failed']) {
1050                 $("#score").text("No analysis for this move");
1051                 $("#pvtitle").text("PV:");
1052                 $("#pv").empty();
1053                 $("#searchstats").html("&nbsp;");
1054                 $("#refutationlines").empty();
1055                 $("#whiteclock").empty();
1056                 $("#blackclock").empty();
1057                 refutation_lines = [];
1058                 update_refutation_lines();
1059                 clear_arrows();
1060                 update_displayed_line();
1061                 update_move_highlight();
1062                 return;
1063         }
1064
1065         update_clock();
1066
1067         // The score.
1068         if (data['score']) {
1069                 $("#score").text(format_long_score(data['score']));
1070         }
1071
1072         // The search stats.
1073         if (data['searchstats']) {
1074                 $("#searchstats").html(data['searchstats']);
1075         } else if (data['tablebase'] == 1) {
1076                 $("#searchstats").text("Tablebase result");
1077         } else if (data['nodes'] && data['nps'] && data['depth']) {
1078                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
1079                 if (data['seldepth']) {
1080                         stats += ' (' + data['seldepth'] + ' selective)';
1081                 }
1082                 if (data['tbhits'] && data['tbhits'] > 0) {
1083                         if (data['tbhits'] == 1) {
1084                                 stats += ', one Syzygy hit';
1085                         } else {
1086                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
1087                         }
1088                 }
1089
1090                 $("#searchstats").text(stats);
1091         } else {
1092                 $("#searchstats").text("");
1093         }
1094
1095         // Update the board itself.
1096         base_fen = data['position']['fen'];
1097         update_displayed_line();
1098
1099         // Print the PV.
1100         $("#pvtitle").text("PV:");
1101         $("#pv").html(add_pv(data['position']['fen'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay'], 0));
1102
1103         // Update the PV arrow.
1104         clear_arrows();
1105         if (data['pv_uci'].length >= 1) {
1106                 // draw a continuation arrow as long as it's the same piece
1107                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
1108                         var from = data['pv_uci'][i].substr(0, 2);
1109                         var to = data['pv_uci'][i].substr(2,4);
1110                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
1111                              interfering_arrow(from, to)) {
1112                                 break;
1113                         }
1114                         create_arrow(from, to, '#f66', 6, 20);
1115                 }
1116
1117                 var alt_moves = find_nonstupid_moves(data, 30, data['position']['toplay'] === 'B');
1118                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
1119                         create_arrow(alt_moves[i].substr(0, 2),
1120                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
1121                 }
1122         }
1123
1124         // See if all semi-reasonable moves have only one possible response.
1125         if (data['pv_uci'].length >= 2) {
1126                 var nonstupid_moves = find_nonstupid_moves(data, 300, data['position']['toplay'] === 'B');
1127                 var response = data['pv_uci'][1];
1128                 for (var i = 0; i < nonstupid_moves.length; ++i) {
1129                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
1130                                 // ignore the PV move for refutation lines.
1131                                 continue;
1132                         }
1133                         if (!data['refutation_lines'] ||
1134                             !data['refutation_lines'][nonstupid_moves[i]] ||
1135                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
1136                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
1137                                 // Incomplete PV, abort.
1138                                 response = undefined;
1139                                 break;
1140                         }
1141                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
1142                         if (response !== this_response) {
1143                                 // Different response depending on lines, abort.
1144                                 response = undefined;
1145                                 break;
1146                         }
1147                 }
1148
1149                 if (nonstupid_moves.length > 0 && response !== undefined) {
1150                         create_arrow(response.substr(0, 2),
1151                                      response.substr(2, 2), '#66f', 6, 20);
1152                 }
1153         }
1154
1155         // Update the refutation lines.
1156         base_fen = data['position']['fen'];
1157         move_num = parseInt(data['position']['move_num']);
1158         toplay = data['position']['toplay'];
1159         refutation_lines = hash_refutation_lines || data['refutation_lines'];
1160         update_refutation_lines();
1161
1162         // Update the sparkline last, since its size depends on how everything else reflowed.
1163         update_sparkline(data);
1164 }
1165
1166 var update_sparkline = function(data) {
1167         if (data && data['score_history']) {
1168                 var first_move_num = undefined;
1169                 for (var halfmove_num in data['score_history']) {
1170                         halfmove_num = parseInt(halfmove_num);
1171                         if (first_move_num === undefined || halfmove_num < first_move_num) {
1172                                 first_move_num = halfmove_num;
1173                         }
1174                 }
1175                 if (first_move_num !== undefined) {
1176                         var last_move_num = data['position']['move_num'] * 2 - 3;
1177                         if (data['position']['toplay'] === 'B') {
1178                                 ++last_move_num;
1179                         }
1180
1181                         // Possibly truncate some moves if we don't have enough width.
1182                         // FIXME: Sometimes width() for #scorecontainer (and by extent,
1183                         // #scoresparkcontainer) on Chrome for mobile seems to start off
1184                         // at something very small, and then suddenly snap back into place.
1185                         // Figure out why.
1186                         var max_moves = Math.floor($("#scoresparkcontainer").width() / 5) - 5;
1187                         if (last_move_num - first_move_num > max_moves) {
1188                                 first_move_num = last_move_num - max_moves;
1189                         }
1190
1191                         var min_score = -100;
1192                         var max_score = 100;
1193                         var last_score = null;
1194                         var scores = [];
1195                         for (var halfmove_num = first_move_num; halfmove_num <= last_move_num; ++halfmove_num) {
1196                                 if (data['score_history'][halfmove_num]) {
1197                                         var score = compute_plot_score(data['score_history'][halfmove_num]);
1198                                         last_score = score;
1199                                         if (score < min_score) min_score = score;
1200                                         if (score > max_score) max_score = score;
1201                                 }
1202                                 scores.push(last_score);
1203                         }
1204                         if (data['score']) {
1205                                 scores.push(compute_plot_score(data['score']));
1206                         }
1207                         // FIXME: at some widths, calling sparkline() seems to push
1208                         // #scorecontainer under the board.
1209                         $("#scorespark").sparkline(scores, {
1210                                 type: 'bar',
1211                                 zeroColor: 'gray',
1212                                 chartRangeMin: min_score,
1213                                 chartRangeMax: max_score,
1214                                 tooltipFormatter: function(sparkline, options, fields) {
1215                                         return format_tooltip(data, fields[0].offset + first_move_num);
1216                                 }
1217                         });
1218                 } else {
1219                         $("#scorespark").text("");
1220                 }
1221         } else {
1222                 $("#scorespark").text("");
1223         }
1224 }
1225
1226 /**
1227  * @param {number} num_viewers
1228  */
1229 var update_num_viewers = function(num_viewers) {
1230         if (num_viewers === null) {
1231                 $("#numviewers").text("");
1232         } else if (num_viewers == 1) {
1233                 $("#numviewers").text("You are the only current viewer");
1234         } else {
1235                 $("#numviewers").text(num_viewers + " current viewers");
1236         }
1237 }
1238
1239 var update_clock = function() {
1240         clearTimeout(clock_timer);
1241
1242         var data = displayed_analysis_data || current_analysis_data;
1243         if (data['position']) {
1244                 var result = data['position']['result'];
1245                 if (result === '1-0') {
1246                         $("#whiteclock").text("1");
1247                         $("#blackclock").text("0");
1248                         $("#whiteclock").removeClass("running-clock");
1249                         $("#blackclock").removeClass("running-clock");
1250                         return;
1251                 }
1252                 if (result === '1/2-1/2') {
1253                         $("#whiteclock").text("1/2");
1254                         $("#blackclock").text("1/2");
1255                         $("#whiteclock").removeClass("running-clock");
1256                         $("#blackclock").removeClass("running-clock");
1257                         return;
1258                 }
1259                 if (result === '0-1') {
1260                         $("#whiteclock").text("0");
1261                         $("#blackclock").text("1");
1262                         $("#whiteclock").removeClass("running-clock");
1263                         $("#blackclock").removeClass("running-clock");
1264                         return;
1265                 }
1266         }
1267
1268         var white_clock_ms = null;
1269         var black_clock_ms = null;
1270         var show_seconds = false;
1271
1272         // Static clocks.
1273         if (data['position'] &&
1274             data['position']['white_clock'] &&
1275             data['position']['black_clock']) {
1276                 white_clock_ms = data['position']['white_clock'] * 1000;
1277                 black_clock_ms = data['position']['black_clock'] * 1000;
1278         }
1279
1280         // Dynamic clock (only one, obviously).
1281         var color;
1282         if (data['position']['white_clock_target']) {
1283                 color = "white";
1284                 $("#whiteclock").addClass("running-clock");
1285                 $("#blackclock").removeClass("running-clock");
1286         } else if (data['position']['black_clock_target']) {
1287                 color = "black";
1288                 $("#whiteclock").removeClass("running-clock");
1289                 $("#blackclock").addClass("running-clock");
1290         } else {
1291                 $("#whiteclock").removeClass("running-clock");
1292                 $("#blackclock").removeClass("running-clock");
1293         }
1294         var remaining_ms;
1295         if (color) {
1296                 var now = new Date().getTime() + client_clock_offset_ms;
1297                 remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
1298                 if (color === "white") {
1299                         white_clock_ms = remaining_ms;
1300                 } else {
1301                         black_clock_ms = remaining_ms;
1302                 }
1303         }
1304
1305         if (white_clock_ms === null || black_clock_ms === null) {
1306                 $("#whiteclock").empty();
1307                 $("#blackclock").empty();
1308                 return;
1309         }
1310
1311         // If either player has ten minutes or less left, add the second counters.
1312         var show_seconds = (white_clock_ms < 60 * 10 * 1000 || black_clock_ms < 60 * 10 * 1000);
1313
1314         if (color) {
1315                 // See when the clock will change next, and update right after that.
1316                 var next_update_ms;
1317                 if (show_seconds) {
1318                         next_update_ms = remaining_ms % 1000 + 100;
1319                 } else {
1320                         next_update_ms = remaining_ms % 60000 + 100;
1321                 }
1322                 clock_timer = setTimeout(update_clock, next_update_ms);
1323         }
1324
1325         $("#whiteclock").text(format_clock(white_clock_ms, show_seconds));
1326         $("#blackclock").text(format_clock(black_clock_ms, show_seconds));
1327 }
1328
1329 /**
1330  * @param {Number} remaining_ms
1331  * @param {boolean} show_seconds
1332  */
1333 var format_clock = function(remaining_ms, show_seconds) {
1334         if (remaining_ms <= 0) {
1335                 if (show_seconds) {
1336                         return "00:00:00";
1337                 } else {
1338                         return "00:00";
1339                 }
1340         }
1341
1342         var remaining = Math.floor(remaining_ms / 1000);
1343         var seconds = remaining % 60;
1344         remaining = (remaining - seconds) / 60;
1345         var minutes = remaining % 60;
1346         remaining = (remaining - minutes) / 60;
1347         var hours = remaining;
1348         if (show_seconds) {
1349                 return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
1350         } else {
1351                 return format_2d(hours) + ":" + format_2d(minutes);
1352         }
1353 }
1354
1355 /**
1356  * @param {Number} x
1357  */
1358 var format_2d = function(x) {
1359         if (x >= 10) {
1360                 return x;
1361         } else {
1362                 return "0" + x;
1363         }
1364 }
1365
1366 /**
1367  * @param {string} move
1368  * @param {Number} move_num
1369  * @param {boolean} white_to_play
1370  */
1371 var format_move_with_number = function(move, move_num, white_to_play) {
1372         var ret;
1373         if (white_to_play) {
1374                 ret = (move_num - 1) + '… ';
1375         } else {
1376                 ret = move_num + '. ';
1377         }
1378         ret += move;
1379         return ret;
1380 }
1381
1382 /**
1383  * @param {string} move
1384  * @param {Number} halfmove_num
1385  */
1386 var format_halfmove_with_number = function(move, halfmove_num) {
1387         return format_move_with_number(
1388                 move,
1389                 Math.floor(halfmove_num / 2) + 1,
1390                 halfmove_num % 2 == 0);
1391 }
1392
1393 /**
1394  * @param {Object} data
1395  * @param {Number} halfmove_num
1396  */
1397 var format_tooltip = function(data, halfmove_num) {
1398         if (data['score_history'][halfmove_num] ||
1399             halfmove_num === data['position']['pretty_history'].length) {
1400                 var move;
1401                 var short_score;
1402                 if (halfmove_num === data['position']['pretty_history'].length) {
1403                         move = data['position']['last_move'];
1404                         short_score = format_short_score(data['score']);
1405                 } else {
1406                         move = data['position']['pretty_history'][halfmove_num];
1407                         short_score = format_short_score(data['score_history'][halfmove_num]);
1408                 }
1409                 var move_with_number = format_halfmove_with_number(move, halfmove_num);
1410
1411                 return "After " + move_with_number + ": " + short_score;
1412         } else {
1413                 for (var i = halfmove_num; i --> 0; ) {
1414                         if (data['score_history'][i]) {
1415                                 var move = data['position']['pretty_history'][i];
1416                                 return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
1417                         }
1418                 }
1419         }
1420 }
1421
1422 /**
1423  * @param {boolean} sort_by_score
1424  */
1425 var resort_refutation_lines = function(sort_by_score) {
1426         sort_refutation_lines_by_score = sort_by_score;
1427         if (supports_html5_storage()) {
1428                 localStorage['sort_refutation_lines_by_score'] = sort_by_score ? 1 : 0;
1429         }
1430         update_refutation_lines();
1431 }
1432 window['resort_refutation_lines'] = resort_refutation_lines;
1433
1434 /**
1435  * @param {boolean} truncate_history
1436  */
1437 var set_truncate_history = function(truncate_history) {
1438         truncate_display_history = truncate_history;
1439         update_refutation_lines();
1440 }
1441 window['set_truncate_history'] = set_truncate_history;
1442
1443 /**
1444  * @param {number} line_num
1445  * @param {number} move_num
1446  */
1447 var show_line = function(line_num, move_num) {
1448         if (line_num == -1) {
1449                 current_display_line = null;
1450                 current_display_move = null;
1451                 hash_refutation_lines = null;
1452                 if (displayed_analysis_data) {
1453                         // TODO: Support exiting to history position if we are in an
1454                         // analysis line of a history position.
1455                         displayed_analysis_data = null;
1456                 }
1457                 update_board();
1458                 return;
1459         } else {
1460                 current_display_line = jQuery.extend({}, display_lines[line_num]);  // Shallow clone.
1461                 current_display_move = move_num + current_display_line.start_display_move_num;
1462         }
1463         current_display_line_is_history = (line_num == 0);
1464
1465         update_historic_analysis();
1466         update_displayed_line();
1467         update_board_highlight();
1468         update_move_highlight();
1469         redraw_arrows();
1470 }
1471 window['show_line'] = show_line;
1472
1473 var prev_move = function() {
1474         if (current_display_line &&
1475             current_display_move >= current_display_line.start_display_move_num) {
1476                 --current_display_move;
1477         }
1478         update_historic_analysis();
1479         update_displayed_line();
1480         update_move_highlight();
1481 }
1482 window['prev_move'] = prev_move;
1483
1484 var next_move = function() {
1485         if (current_display_line &&
1486             current_display_move < current_display_line.pretty_pv.length - 1) {
1487                 ++current_display_move;
1488         }
1489         update_historic_analysis();
1490         update_displayed_line();
1491         update_move_highlight();
1492 }
1493 window['next_move'] = next_move;
1494
1495 var update_historic_analysis = function() {
1496         if (!current_display_line_is_history) {
1497                 return;
1498         }
1499         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1500                 displayed_analysis_data = null;
1501                 update_board();
1502         }
1503
1504         // Fetch old analysis for this line if it exists.
1505         var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1506         var filename = "/history/move" + (current_display_move + 1) + "-" +
1507                 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1508
1509         current_historic_xhr = $.ajax({
1510                 url: filename
1511         }).done(function(data, textstatus, xhr) {
1512                 displayed_analysis_data = data;
1513                 update_board();
1514         }).fail(function(jqXHR, textStatus, errorThrown) {
1515                 if (textStatus === "abort") {
1516                         // Aborted because we are switching backends. Don't do anything;
1517                         // we will already have been cleared.
1518                 } else {
1519                         displayed_analysis_data = {'failed': true};
1520                         update_board();
1521                 }
1522         });
1523 }
1524
1525 /**
1526  * @param {string} fen
1527  */
1528 var update_imbalance = function(fen) {
1529         var hiddenboard = new Chess(fen);
1530         var imbalance = {'k': 0, 'q': 0, 'r': 0, 'b': 0, 'n': 0, 'p': 0};
1531         for (var row = 0; row < 8; ++row) {
1532                 for (var col = 0; col < 8; ++col) {
1533                         var col_text = String.fromCharCode('a1'.charCodeAt(0) + col);
1534                         var row_text = String.fromCharCode('a1'.charCodeAt(1) + row);
1535                         var square = col_text + row_text;
1536                         var contents = hiddenboard.get(square);
1537                         if (contents !== null) {
1538                                 if (contents.color === 'w') {
1539                                         ++imbalance[contents.type];
1540                                 } else {
1541                                         --imbalance[contents.type];
1542                                 }
1543                         }
1544                 }
1545         }
1546         var white_imbalance = '';
1547         var black_imbalance = '';
1548         for (var piece in imbalance) {
1549                 for (var i = 0; i < imbalance[piece]; ++i) {
1550                         white_imbalance += '<img src="img/chesspieces/wikipedia/w' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1551                 }
1552                 for (var i = 0; i < -imbalance[piece]; ++i) {
1553                         black_imbalance += '<img src="img/chesspieces/wikipedia/b' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1554                 }
1555         }
1556         $('#whiteimbalance').html(white_imbalance);
1557         $('#blackimbalance').html(black_imbalance);
1558 }
1559
1560 /** Mark the currently selected move in red.
1561  * Also replaces the PV with the current displayed line if it's not shown
1562  * anywhere else on the screen.
1563  */
1564 var update_move_highlight = function() {
1565         if (highlighted_move !== null) {
1566                 highlighted_move.removeClass('highlight');
1567         }
1568         if (current_display_line) {
1569                 var display_line_num = find_display_line_matching_num();
1570                 if (display_line_num === null) {
1571                         // Replace the PV with the (complete) line.
1572                         $("#pvtitle").text("Exploring:");
1573                         current_display_line.start_display_move_num = 0;
1574                         display_lines.push(current_display_line);
1575                         $("#pv").html(print_pv(display_lines.length - 1));
1576                         display_line_num = display_lines.length - 1;
1577                 }
1578
1579                 highlighted_move = $("#automove" + display_line_num + "-" + (current_display_move - current_display_line.start_display_move_num));
1580                 highlighted_move.addClass('highlight');
1581         }
1582 }
1583
1584 /**
1585  * See if the current displayed line is identical to any of the ones
1586  * we have on screen. (It might not be if e.g. the analysis reloaded
1587  * since we started looking.)
1588  *
1589  * @return {?number}
1590  */
1591 var find_display_line_matching_num = function() {
1592         for (var i = 0; i < display_lines.length; ++i) {
1593                 var line = display_lines[i];
1594                 if (line.start_display_move_num > 0) continue;
1595                 if (current_display_line.start_fen !== line.start_fen) continue;
1596                 if (current_display_line.pretty_pv.length !== line.pretty_pv.length) continue;
1597                 var ok = true;
1598                 for (var j = 0; j < line.pretty_pv.length; ++j) {
1599                         if (current_display_line.pretty_pv[j] !== line.pretty_pv[j]) {
1600                                 ok = false;
1601                                 break;
1602                         }
1603                 }
1604                 if (ok) {
1605                         return i;
1606                 }
1607         }
1608         return null;
1609 }
1610
1611 var update_displayed_line = function() {
1612         if (current_display_line === null) {
1613                 $("#linenav").hide();
1614                 $("#linemsg").show();
1615                 display_fen = base_fen;
1616                 board.position(base_fen);
1617                 update_imbalance(base_fen);
1618                 return;
1619         }
1620
1621         $("#linenav").show();
1622         $("#linemsg").hide();
1623
1624         if (current_display_move <= 0) {
1625                 $("#prevmove").html("Previous");
1626         } else {
1627                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
1628         }
1629         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1630                 $("#nextmove").html("Next");
1631         } else {
1632                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
1633         }
1634
1635         var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pretty_pv, current_display_move);
1636         display_fen = hiddenboard.fen();
1637         board_is_animating = true;
1638         var old_fen = board.fen();
1639         board.position(hiddenboard.fen());
1640         if (board.fen() === old_fen) {
1641                 board_is_animating = false;
1642         } else if (!current_display_line_is_history) {
1643                 // Fire off a hash request, since we're now off the main position
1644                 // and it just changed.
1645                 explore_hash(display_fen);
1646         }
1647         update_imbalance(hiddenboard.fen());
1648 }
1649
1650 /**
1651  * @param {boolean} param_enable_sound
1652  */
1653 var set_sound = function(param_enable_sound) {
1654         enable_sound = param_enable_sound;
1655         if (enable_sound) {
1656                 $("#soundon").html("<strong>On</strong>");
1657                 $("#soundoff").html("<a href=\"javascript:set_sound(false)\">Off</a>");
1658
1659                 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1660                 // and also preload the file since the user has selected audio.
1661                 var ding = document.getElementById('ding');
1662                 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1663                         ding.src = 'ding.opus';
1664                         ding.load();
1665                 }
1666         } else {
1667                 $("#soundon").html("<a href=\"javascript:set_sound(true)\">On</a>");
1668                 $("#soundoff").html("<strong>Off</strong>");
1669         }
1670         if (supports_html5_storage()) {
1671                 localStorage['enable_sound'] = enable_sound ? 1 : 0;
1672         }
1673 }
1674 window['set_sound'] = set_sound;
1675
1676 /** Send off a hash probe request to the backend.
1677  * @param {string} fen
1678  */
1679 var explore_hash = function(fen) {
1680         // If we already have a backend response going, abort it.
1681         if (current_hash_xhr) {
1682                 current_hash_xhr.abort();
1683         }
1684         if (current_hash_display_timer) {
1685                 clearTimeout(current_hash_display_timer);
1686                 current_hash_display_timer = null;
1687         }
1688         $("#refutationlines").empty();
1689         current_hash_xhr = $.ajax({
1690                 url: backend_hash_url + "?fen=" + fen
1691         }).done(function(data, textstatus, xhr) {
1692                 show_explore_hash_results(data, fen);
1693         });
1694 }
1695
1696 /** Process the JSON response from a hash probe request.
1697  * @param {!Object} data
1698  * @param {string} fen
1699  */
1700 var show_explore_hash_results = function(data, fen) {
1701         if (board_is_animating) {
1702                 // Updating while the animation is still going causes
1703                 // the animation to jerk. This is pretty crude, but it will do.
1704                 current_hash_display_timer = setTimeout(function() { show_explore_hash_results(data, fen); }, 100);
1705                 return;
1706         }
1707         current_hash_display_timer = null;
1708         hash_refutation_lines = data['lines'];
1709         update_board();
1710 }
1711
1712 // almost all of this stuff comes from the chessboard.js example page
1713 var onDragStart = function(source, piece, position, orientation) {
1714         var pseudogame = new Chess(display_fen);
1715         if (pseudogame.game_over() === true ||
1716             (pseudogame.turn() === 'w' && piece.search(/^b/) !== -1) ||
1717             (pseudogame.turn() === 'b' && piece.search(/^w/) !== -1)) {
1718                 return false;
1719         }
1720
1721         recommended_move = get_best_move(pseudogame, source, null, pseudogame.turn() === 'b');
1722         if (recommended_move) {
1723                 var squareEl = $('#board .square-' + recommended_move.to);
1724                 squareEl.addClass('highlight1-32417');
1725         }
1726         return true;
1727 }
1728
1729 var mousedownSquare = function(e) {
1730         reverse_dragging_from = null;
1731         var square = $(this).attr('data-square');
1732
1733         var pseudogame = new Chess(display_fen);
1734         if (pseudogame.game_over() === true) {
1735                 return;
1736         }
1737
1738         // If the square is empty, or has a piece of the side not to move,
1739         // we handle it. If not, normal piece dragging will take it.
1740         var position = board.position();
1741         if (!position.hasOwnProperty(square) ||
1742             (pseudogame.turn() === 'w' && position[square].search(/^b/) !== -1) ||
1743             (pseudogame.turn() === 'b' && position[square].search(/^w/) !== -1)) {
1744                 reverse_dragging_from = square;
1745                 recommended_move = get_best_move(pseudogame, null, square, pseudogame.turn() === 'b');
1746                 if (recommended_move) {
1747                         var squareEl = $('#board .square-' + recommended_move.from);
1748                         squareEl.addClass('highlight1-32417');
1749                         squareEl = $('#board .square-' + recommended_move.to);
1750                         squareEl.addClass('highlight1-32417');
1751                 }
1752         }
1753 }
1754
1755 var mouseupSquare = function(e) {
1756         if (reverse_dragging_from === null) {
1757                 return;
1758         }
1759         var source = $(this).attr('data-square');
1760         var target = reverse_dragging_from;
1761         reverse_dragging_from = null;
1762         if (onDrop(source, target) !== 'snapback') {
1763                 onSnapEnd(source, target);
1764         }
1765         $("#board").find('.square-55d63').removeClass('highlight1-32417');
1766 }
1767
1768 var get_best_move = function(game, source, target, invert) {
1769         var moves = game.moves({ verbose: true });
1770         if (source !== null) {
1771                 moves = moves.filter(function(move) { return move.from == source; });
1772         }
1773         if (target !== null) {
1774                 moves = moves.filter(function(move) { return move.to == target; });
1775         }
1776         if (moves.length == 0) {
1777                 return null;
1778         }
1779         if (moves.length == 1) {
1780                 return moves[0];
1781         }
1782
1783         // More than one move. Use the display lines (if we have them)
1784         // to disambiguate; otherwise, we have no information.
1785         var move_hash = {};
1786         for (var i = 0; i < moves.length; ++i) {
1787                 move_hash[moves[i].san] = moves[i];
1788         }
1789
1790         // History and PV take priority over the display lines.
1791         for (var i = 0; i < 2; ++i) {
1792                 var line = display_lines[i];
1793                 var first_move = line.pretty_pv[line.start_display_move_num];
1794                 if (move_hash[first_move]) {
1795                         return move_hash[first_move];
1796                 }
1797         }
1798
1799         var best_move = null;
1800         var best_move_score = null;
1801
1802         for (var move in refutation_lines) {
1803                 var line = refutation_lines[move];
1804                 if (!line['score']) {
1805                         continue;
1806                 }
1807                 var first_move = line['pv_pretty'][0];
1808                 if (move_hash[first_move]) {
1809                         var score = compute_score_sort_key(line['score'], invert);
1810                         if (best_move_score === null || score > best_move_score) {
1811                                 best_move = move_hash[first_move];
1812                                 best_move_score = score;
1813                         }
1814                 }
1815         }
1816         return best_move;
1817 }
1818
1819 var onDrop = function(source, target) {
1820         if (source === target) {
1821                 if (recommended_move === null) {
1822                         return 'snapback';
1823                 } else {
1824                         // Accept the move. It will be changed in onSnapEnd.
1825                         return;
1826                 }
1827         } else {
1828                 // Suggestion not asked for.
1829                 recommended_move = null;
1830         }
1831
1832         // see if the move is legal
1833         var pseudogame = new Chess(display_fen);
1834         var move = pseudogame.move({
1835                 from: source,
1836                 to: target,
1837                 promotion: 'q' // NOTE: always promote to a queen for example simplicity
1838         });
1839
1840         // illegal move
1841         if (move === null) return 'snapback';
1842 }
1843
1844 var onSnapEnd = function(source, target) {
1845         if (source === target && recommended_move !== null) {
1846                 source = recommended_move.from;
1847                 target = recommended_move.to;
1848         }
1849         recommended_move = null;
1850         var pseudogame = new Chess(display_fen);
1851         var move = pseudogame.move({
1852                 from: source,
1853                 to: target,
1854                 promotion: 'q' // NOTE: always promote to a queen for example simplicity
1855         });
1856
1857         if (current_display_line &&
1858             current_display_move < current_display_line.pretty_pv.length - 1 &&
1859             current_display_line.pretty_pv[current_display_move] === move.san) {
1860                 next_move();
1861                 return;
1862         }
1863
1864         // Walk down the displayed lines until we find one that starts with
1865         // this move, then select that. Note that this gives us a good priority
1866         // order (history first, then PV, then multi-PV lines).
1867         for (var i = 0; i < display_lines.length; ++i) {
1868                 var line = display_lines[i];
1869                 if (line.pretty_pv[line.start_display_move_num] === move.san) {
1870                         show_line(i, 0);
1871                         return;
1872                 }
1873         }
1874
1875         // Shouldn't really be here if we have hash probes, but there's really
1876         // nothing we can do.
1877 }
1878 // End of dragging-related code.
1879
1880 var pad = function(val, num_digits) {
1881         var s = val.toString();
1882         while (s.length < num_digits) {
1883                 s = " " + s;
1884         }
1885         return s;
1886 }
1887
1888 var fmt_cp = function(v) {
1889         if (v === 0) {
1890                 return "0.00";
1891         } else if (v > 0) {
1892                 return "+" + (v / 100).toFixed(2);
1893         } else {
1894                 v = -v;
1895                 return "-" + (v / 100).toFixed(2);
1896         }
1897 }
1898
1899 var format_short_score = function(score) {
1900         if (score[0] === 'm') {
1901                 if (score[2]) {  // Is a bound.
1902                         return score[2] + "\u00a0M" + pad(score[1], 3);
1903                 } else {
1904                         return "M" + pad(score[1], 3);
1905                 }
1906         } else if (score[0] === 'd') {
1907                 return "TB draw";
1908         } else if (score[0] === 'cp') {
1909                 if (score[2]) {  // Is a bound.
1910                         return score[2] + "\u00a0" + fmt_cp(score[1]);
1911                 } else {
1912                         return pad(fmt_cp(score[1]), 5);
1913                 }
1914         }
1915         return null;
1916 }
1917
1918 var format_long_score = function(score) {
1919         if (score[0] === 'm') {
1920                 if (score[1] > 0) {
1921                         return "White mates in " + score[1];
1922                 } else {
1923                         return "Black mates in " + (-score[1]);
1924                 }
1925         } else if (score[0] === 'd') {
1926                 return "Theoretical draw";
1927         } else if (score[0] === 'cp') {
1928                 return "Score: " + format_short_score(score);
1929         }
1930         return null;
1931 }
1932
1933 var compute_plot_score = function(score) {
1934         if (score[0] === 'm') {
1935                 if (score[1] > 0) {
1936                         return 500;
1937                 } else {
1938                         return -500;
1939                 }
1940         } else if (score[0] === 'd') {
1941                 return 0;
1942         } else if (score[0] === 'cp') {
1943                 if (score[1] > 500) {
1944                         return 500;
1945                 } else if (score[1] < -500) {
1946                         return -500;
1947                 } else {
1948                         return score[1];
1949                 }
1950         }
1951         return null;
1952 }
1953
1954 /**
1955  * @param score The score digest tuple.
1956  * @param {boolean} invert Whether black is to play.
1957  * @return {number}
1958  */
1959 var compute_score_sort_key = function(score, invert) {
1960         var s;
1961         if (!score) {
1962                 return -10000000;
1963         }
1964         if (score[0] === 'm') {
1965                 if (score[1] > 0) {
1966                         // White mates.
1967                         s = 99999 - score[1];
1968                 } else {
1969                         // Black mates (note the double negative for score[1]).
1970                         s = -99999 - score[1];
1971                 }
1972                 if (invert) s = -s;
1973                 return s;
1974         } else if (score[0] === 'd') {
1975                 return 0;
1976         } else if (score[0] === 'cp') {
1977                 return invert ? -score[1] : score[1];
1978         }
1979         return null;
1980 }
1981
1982 /**
1983  * @param {string} new_backend_url
1984  */
1985 var switch_backend = function(new_backend_url) {
1986         // Stop looking at historic data.
1987         current_display_line = null;
1988         current_display_move = null;
1989         displayed_analysis_data = null;
1990         if (current_historic_xhr) {
1991                 current_historic_xhr.abort();
1992         }
1993
1994         // If we already have a backend response going, abort it.
1995         if (current_analysis_xhr) {
1996                 current_analysis_xhr.abort();
1997         }
1998         if (current_hash_xhr) {
1999                 current_hash_xhr.abort();
2000         }
2001
2002         // Otherwise, we should have a timer going to start a new one.
2003         // Kill that, too.
2004         if (current_analysis_request_timer) {
2005                 clearTimeout(current_analysis_request_timer);
2006                 current_analysis_request_timer = null;
2007         }
2008         if (current_hash_display_timer) {
2009                 clearTimeout(current_hash_display_timer);
2010                 current_hash_display_timer = null;
2011         }
2012
2013         // Request an immediate fetch with the new backend.
2014         backend_url = new_backend_url;
2015         current_analysis_data = null;
2016         ims = 0;
2017         request_update();
2018 }
2019 window['switch_backend'] = switch_backend;
2020
2021 var init = function() {
2022         unique = get_unique();
2023
2024         // Load settings from HTML5 local storage if available.
2025         if (supports_html5_storage() && localStorage['enable_sound']) {
2026                 set_sound(parseInt(localStorage['enable_sound']));
2027         } else {
2028                 set_sound(false);
2029         }
2030         if (supports_html5_storage() && localStorage['sort_refutation_lines_by_score']) {
2031                 sort_refutation_lines_by_score = parseInt(localStorage['sort_refutation_lines_by_score']);
2032         } else {
2033                 sort_refutation_lines_by_score = true;
2034         }
2035
2036         // Create board.
2037         board = new window.ChessBoard('board', {
2038                 onMoveEnd: function() { board_is_animating = false; },
2039
2040                 draggable: true,
2041                 onDragStart: onDragStart,
2042                 onDrop: onDrop,
2043                 onSnapEnd: onSnapEnd
2044         });
2045         $("#board").on('mousedown', '.square-55d63', mousedownSquare);
2046         $("#board").on('mouseup', '.square-55d63', mouseupSquare);
2047
2048         request_update();
2049         $(window).resize(function() {
2050                 board.resize();
2051                 update_sparkline(displayed_analysis_data || current_analysis_data);
2052                 update_board_highlight();
2053                 redraw_arrows();
2054         });
2055         $(window).keyup(function(event) {
2056                 if (event.which == 39) {
2057                         next_move();
2058                 } else if (event.which == 37) {
2059                         prev_move();
2060                 }
2061         });
2062         window.addEventListener('hashchange', possibly_switch_game_from_hash, false);
2063 };
2064 $(document).ready(init);
2065
2066 })();