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

   1 (function() {
   2
   3 /** @type {window.ChessBoard} @private */
   4 var board = null;
   5
   6 /** @type {window.ChessBoard} @private */
   7 var hiddenboard = null;
   8
   9 /** @type {Array.<{
  10  *      from_col: number,
  11  *      from_row: number,
  12  *      to_col: number,
  13  *      to_row: number,
  14  *      line_width: number,
  15  *      arrow_size: number,
  16  *      fg_color: string
  17  * }>}
  18  * @private
  19  */
  20 var arrows = [];
  21
  22 /** @type {Array.<Array.<boolean>>} */
  23 var occupied_by_arrows = [];
  24
  25 var refutation_lines = [];
  26
  27 /** @type {!number} @private */
  28 var move_num = 1;
  29
  30 /** @type {!string} @private */
  31 var toplay = 'W';
  32
  33 /** @type {number} @private */
  34 var ims = 0;
  35
  36 /** @type {boolean} @private */
  37 var sort_refutation_lines_by_score = true;
  38
  39 /** @type {boolean} @private */
  40 var truncate_display_history = true;
  41
  42 /** @type {!string|undefined} @private */
  43 var highlight_from = undefined;
  44
  45 /** @type {!string|undefined} @private */
  46 var highlight_to = undefined;
  47
  48 /** @type {?jQuery} @private */
  49 var highlighted_move = null;
  50
  51 /** @type {?number} @private */
  52 var unique = null;
  53
  54 /** The current position on the board, represented as a FEN string.
  55  * @type {?string}
  56  * @private
  57  */
  58 var fen = null;
  59
  60 /** @typedef {{
  61  *    start_fen: string,
  62  *    uci_pv: Array.<string>,
  63  *    pretty_pv: Array.<string>,
  64  *    line_num: number
  65  * }} DisplayLine
  66  */
  67
  68 /** @type {Array.<DisplayLine>}
  69  * @private
  70  */
  71 var display_lines = [];
  72
  73 /** @type {?DisplayLine} @private */
  74 var current_display_line = null;
  75
  76 /** @type {?number} @private */
  77 var current_display_move = null;
  78
  79 var supports_html5_storage = function() {
  80         try {
  81                 return 'localStorage' in window && window['localStorage'] !== null;
  82         } catch (e) {
  83                 return false;
  84         }
  85 }
  86
  87 // Make the unique token persistent so people refreshing the page won't count twice.
  88 // Of course, you can never fully protect against people deliberately wanting to spam.
  89 var get_unique = function() {
  90         var use_local_storage = supports_html5_storage();
  91         if (use_local_storage && localStorage['unique']) {
  92                 return localStorage['unique'];
  93         }
  94         var unique = Math.random();
  95         if (use_local_storage) {
  96                 localStorage['unique'] = unique;
  97         }
  98         return unique;
  99 }
 100
 101 var request_update = function() {
 102         $.ajax({
 103                 url: "/analysis.pl?ims=" + ims + "&unique=" + unique
 104         }).done(function(data, textstatus, xhr) {
 105                 ims = xhr.getResponseHeader('X-Remoteglot-Last-Modified');
 106                 var num_viewers = xhr.getResponseHeader('X-Remoteglot-Num-Viewers');
 107                 update_board(data, num_viewers);
 108         }).fail(function() {
 109                 // Wait ten seconds, then try again.
 110                 setTimeout(function() { request_update(); }, 10000);
 111         });
 112 }
 113
 114 var clear_arrows = function() {
 115         for (var i = 0; i < arrows.length; ++i) {
 116                 if (arrows[i].svg) {
 117                         arrows[i].svg.parentElement.removeChild(arrows[i].svg);
 118                         delete arrows[i].svg;
 119                 }
 120         }
 121         arrows = [];
 122
 123         occupied_by_arrows = [];
 124         for (var y = 0; y < 8; ++y) {
 125                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 126         }
 127 }
 128
 129 var redraw_arrows = function() {
 130         for (var i = 0; i < arrows.length; ++i) {
 131                 position_arrow(arrows[i]);
 132         }
 133 }
 134
 135 /** @param {!number} x
 136  * @return {!number}
 137  */
 138 var sign = function(x) {
 139         if (x > 0) {
 140                 return 1;
 141         } else if (x < 0) {
 142                 return -1;
 143         } else {
 144                 return 0;
 145         }
 146 }
 147
 148 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 149  * @param {!string} from The square the arrow is from (e.g. e4).
 150  * @param {!string} to The square the arrow is to (e.g. e4).
 151  * @return {boolean}
 152  */
 153 var interfering_arrow = function(from, to) {
 154         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 155         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 156         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 157         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 158
 159         occupied_by_arrows[from_row][from_col] = true;
 160
 161         // Knight move: Just check that we haven't been at the destination before.
 162         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 163             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 164                 return occupied_by_arrows[to_row][to_col];
 165         }
 166
 167         // Sliding piece: Check if anything except the from-square is seen before.
 168         var dx = sign(to_col - from_col);
 169         var dy = sign(to_row - from_row);
 170         var x = from_col;
 171         var y = from_row;
 172         do {
 173                 x += dx;
 174                 y += dy;
 175                 if (occupied_by_arrows[y][x]) {
 176                         return true;
 177                 }
 178                 occupied_by_arrows[y][x] = true;
 179         } while (x != to_col || y != to_row);
 180
 181         return false;
 182 }
 183
 184 /** Find a point along the coordinate system given by the given line,
 185  * <t> units forward from the start of the line, <u> units to the right of it.
 186  * @param {!number} x1
 187  * @param {!number} x2
 188  * @param {!number} y1
 189  * @param {!number} y2
 190  * @param {!number} t
 191  * @param {!number} u
 192  * @return {!string} The point in "x y" form, suitable for SVG paths.
 193  */
 194 var point_from_start = function(x1, y1, x2, y2, t, u) {
 195         var dx = x2 - x1;
 196         var dy = y2 - y1;
 197
 198         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 199         dx *= norm;
 200         dy *= norm;
 201
 202         var x = x1 + dx * t + dy * u;
 203         var y = y1 + dy * t - dx * u;
 204         return x + " " + y;
 205 }
 206
 207 /** Find a point along the coordinate system given by the given line,
 208  * <t> units forward from the end of the line, <u> units to the right of it.
 209  * @param {!number} x1
 210  * @param {!number} x2
 211  * @param {!number} y1
 212  * @param {!number} y2
 213  * @param {!number} t
 214  * @param {!number} u
 215  * @return {!string} The point in "x y" form, suitable for SVG paths.
 216  */
 217 var point_from_end = function(x1, y1, x2, y2, t, u) {
 218         var dx = x2 - x1;
 219         var dy = y2 - y1;
 220
 221         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 222         dx *= norm;
 223         dy *= norm;
 224
 225         var x = x2 + dx * t + dy * u;
 226         var y = y2 + dy * t - dx * u;
 227         return x + " " + y;
 228 }
 229
 230 var position_arrow = function(arrow) {
 231         if (arrow.svg) {
 232                 arrow.svg.parentElement.removeChild(arrow.svg);
 233                 delete arrow.svg;
 234         }
 235         if (current_display_line !== null) {
 236                 return;
 237         }
 238
 239         var pos = $(".square-a8").position();
 240
 241         var zoom_factor = $("#board").width() / 400.0;
 242         var line_width = arrow.line_width * zoom_factor;
 243         var arrow_size = arrow.arrow_size * zoom_factor;
 244
 245         var square_width = $(".square-a8").width();
 246         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 247         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 248         var from_x = (arrow.from_col + 0.5)*square_width;
 249         var to_x = (arrow.to_col + 0.5)*square_width;
 250
 251         var SVG_NS = "http://www.w3.org/2000/svg";
 252         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 253         var svg = document.createElementNS(SVG_NS, "svg");
 254         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 255         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 256         svg.setAttribute("style", "position: absolute");
 257         svg.setAttribute("position", "absolute");
 258         svg.setAttribute("version", "1.1");
 259         svg.setAttribute("class", "c1");
 260         svg.setAttribute("xmlns", XHTML_NS);
 261
 262         var x1 = from_x;
 263         var y1 = from_y;
 264         var x2 = to_x;
 265         var y2 = to_y;
 266
 267         // Draw the line.
 268         var outline = document.createElementNS(SVG_NS, "path");
 269         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));
 270         outline.setAttribute("xmlns", XHTML_NS);
 271         outline.setAttribute("stroke", "#666");
 272         outline.setAttribute("stroke-width", line_width + 2);
 273         outline.setAttribute("fill", "none");
 274         svg.appendChild(outline);
 275
 276         var path = document.createElementNS(SVG_NS, "path");
 277         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));
 278         path.setAttribute("xmlns", XHTML_NS);
 279         path.setAttribute("stroke", arrow.fg_color);
 280         path.setAttribute("stroke-width", line_width);
 281         path.setAttribute("fill", "none");
 282         svg.appendChild(path);
 283
 284         // Then the arrow head.
 285         var head = document.createElementNS(SVG_NS, "path");
 286         head.setAttribute("d",
 287                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 288                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 289                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 290                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 291                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 292         head.setAttribute("xmlns", XHTML_NS);
 293         head.setAttribute("stroke", "#000");
 294         head.setAttribute("stroke-width", "1");
 295         head.setAttribute("fill", arrow.fg_color);
 296         svg.appendChild(head);
 297
 298         $(svg).css({ top: pos.top, left: pos.left });
 299         document.body.appendChild(svg);
 300         arrow.svg = svg;
 301 }
 302
 303 /**
 304  * @param {!string} from_square
 305  * @param {!string} to_square
 306  * @param {!string} fg_color
 307  * @param {number} line_width
 308  * @param {number} arrow_size
 309  */
 310 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 311         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 312         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 313         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 314         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 315
 316         // Create arrow.
 317         var arrow = {
 318                 from_col: from_col,
 319                 from_row: from_row,
 320                 to_col: to_col,
 321                 to_row: to_row,
 322                 line_width: line_width,
 323                 arrow_size: arrow_size,
 324                 fg_color: fg_color
 325         };
 326
 327         position_arrow(arrow);
 328         arrows.push(arrow);
 329 }
 330
 331 var compare_by_sort_key = function(refutation_lines, a, b) {
 332         var ska = refutation_lines[a]['sort_key'];
 333         var skb = refutation_lines[b]['sort_key'];
 334         if (ska < skb) return -1;
 335         if (ska > skb) return 1;
 336         return 0;
 337 };
 338
 339 var compare_by_score = function(refutation_lines, a, b) {
 340         var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
 341         var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
 342         return sa - sb;
 343 }
 344
 345 /**
 346  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 347  * sorted by quality, descending.
 348  *
 349  * @param {!Object} data
 350  * @param {number} margin The maximum number of centipawns worse than the
 351  *     best move can be and still be included.
 352  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 353  *     moves, in score order.
 354  */
 355 var find_nonstupid_moves = function(data, margin) {
 356         // First of all, if there are any moves that are more than 0.5 ahead of
 357         // the primary move, the refutation lines are probably bunk, so just
 358         // kill them all.
 359         var best_score = undefined;
 360         var pv_score = undefined;
 361         for (var move in data['refutation_lines']) {
 362                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 363                 if (move == data['pv_uci'][0]) {
 364                         pv_score = score;
 365                 }
 366                 if (best_score === undefined || score > best_score) {
 367                         best_score = score;
 368                 }
 369                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 370                         return [];
 371                 }
 372         }
 373
 374         if (best_score - pv_score > 50) {
 375                 return [];
 376         }
 377
 378         // Now find all moves that are within “margin” of the best score.
 379         // The PV move will always be first.
 380         var moves = [];
 381         for (var move in data['refutation_lines']) {
 382                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 383                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 384                         moves.push(move);
 385                 }
 386         }
 387         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
 388         moves.unshift(data['pv_uci'][0]);
 389
 390         return moves;
 391 }
 392
 393 /**
 394  * @param {number} x
 395  * @return {!string}
 396  */
 397 var thousands = function(x) {
 398         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 399 }
 400
 401 /**
 402  * @param {!string} fen
 403  * @param {Array.<string>} uci_pv
 404  * @param {Array.<string>} pretty_pv
 405  * @param {number} move_num
 406  * @param {!string} toplay
 407  * @param {number=} opt_limit
 408  * @param {boolean=} opt_showlast
 409  */
 410 var add_pv = function(fen, uci_pv, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 411         display_lines.push({
 412                 start_fen: fen,
 413                 uci_pv: uci_pv,
 414                 pretty_pv: pretty_pv,
 415                 line_number: display_lines.length
 416         });
 417         return print_pv(display_lines.length - 1, pretty_pv, move_num, toplay, opt_limit, opt_showlast);
 418 }
 419
 420 /**
 421  * @param {number} line_num
 422  * @param {Array.<string>} pretty_pv
 423  * @param {number} move_num
 424  * @param {!string} toplay
 425  * @param {number=} opt_limit
 426  * @param {boolean=} opt_showlast
 427  */
 428 var print_pv = function(line_num, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 429         var pv = '';
 430         var i = 0;
 431         if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
 432                 // Truncate the PV at the beginning (instead of at the end).
 433                 // We assume here that toplay is 'W'. We also assume that if
 434                 // opt_showlast is set, then it is the history, and thus,
 435                 // the UI should be to expand the history.
 436                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 437                 i = pretty_pv.length - opt_limit;
 438                 if (i % 2 == 1) {
 439                         ++i;
 440                 }
 441                 move_num += i / 2;
 442         } else if (toplay == 'B' && pretty_pv.length > 0) {
 443                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 444                 pv = move_num + '. … ' + move;
 445                 toplay = 'W';
 446                 ++i;
 447                 ++move_num;
 448         }
 449         for ( ; i < pretty_pv.length; ++i) {
 450                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 451
 452                 if (toplay == 'W') {
 453                         if (i > opt_limit && !opt_showlast) {
 454                                 return pv + ' (…)';
 455                         }
 456                         if (pv != '') {
 457                                 pv += ' ';
 458                         }
 459                         pv += move_num + '. ' + move;
 460                         ++move_num;
 461                         toplay = 'B';
 462                 } else {
 463                         pv += ' ' + move;
 464                         toplay = 'W';
 465                 }
 466         }
 467         return pv;
 468 }
 469
 470 var update_highlight = function() {
 471         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 472         if (current_display_line === null && highlight_from !== undefined && highlight_to !== undefined) {
 473                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 474                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 475         }
 476 }
 477
 478 var update_history = function() {
 479         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 480                 $("#history").html("No history");
 481         } else if (truncate_display_history) {
 482                 $("#history").html(print_pv(0, display_lines[0].pretty_pv, 1, 'W', 8, true));
 483         } else {
 484                 $("#history").html(
 485                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 486                         print_pv(0, display_lines[0].pretty_pv, 1, 'W'));
 487         }
 488 }
 489
 490 /**
 491  * @param {!boolean} truncate_history
 492  */
 493 var collapse_history = function(truncate_history) {
 494         truncate_display_history = truncate_history;
 495         update_history();
 496 }
 497 window['collapse_history'] = collapse_history;
 498
 499 var update_refutation_lines = function() {
 500         if (fen === null) {
 501                 return;
 502         }
 503         if (display_lines.length > 2) {
 504                 display_lines = [ display_lines[0], display_lines[1] ];
 505         }
 506
 507         var tbl = $("#refutationlines");
 508         tbl.empty();
 509
 510         var moves = [];
 511         for (var move in refutation_lines) {
 512                 moves.push(move);
 513         }
 514         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 515         moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
 516         for (var i = 0; i < moves.length; ++i) {
 517                 var line = refutation_lines[moves[i]];
 518
 519                 var tr = document.createElement("tr");
 520
 521                 var move_td = document.createElement("td");
 522                 tr.appendChild(move_td);
 523                 $(move_td).addClass("move");
 524                 if (line['pv_uci'].length == 0) {
 525                         $(move_td).text(line['pretty_move']);
 526                 } else {
 527                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 528                         $(move_td).html(move);
 529                 }
 530
 531                 var score_td = document.createElement("td");
 532                 tr.appendChild(score_td);
 533                 $(score_td).addClass("score");
 534                 $(score_td).text(line['pretty_score']);
 535
 536                 var depth_td = document.createElement("td");
 537                 tr.appendChild(depth_td);
 538                 $(depth_td).addClass("depth");
 539                 $(depth_td).text("d" + line['depth']);
 540
 541                 var pv_td = document.createElement("td");
 542                 tr.appendChild(pv_td);
 543                 $(pv_td).addClass("pv");
 544                 $(pv_td).html(add_pv(fen, line['pv_uci'], line['pv_pretty'], move_num, toplay, 10));
 545
 546                 tbl.append(tr);
 547         }
 548
 549         // Make one of the links clickable and the other nonclickable.
 550         if (sort_refutation_lines_by_score) {
 551                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 552                 $("#sortbyscore1").html("<strong>Score</strong>");
 553         } else {
 554                 $("#sortbyscore0").html("<strong>Move</strong>");
 555                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 556         }
 557 }
 558
 559 /**
 560  * @param {Object} data
 561  * @param {number} num_viewers
 562  */
 563 var update_board = function(data, num_viewers) {
 564         display_lines = [];
 565
 566         // The headline.
 567         var headline;
 568         if (data['position']['player_w'] && data['position']['player_b']) {
 569                 headline = data['position']['player_w'] + '–' +
 570                         data['position']['player_b'] + ', analysis';
 571         } else {
 572                 headline = 'Analysis';
 573         }
 574         var last_move;
 575         if (data['position']['last_move'] !== 'none') {
 576                 if (data['position']['toplay'] == 'W') {
 577                         last_move = (data['position']['move_num']-1) + '… ';
 578                 } else {
 579                         last_move = data['position']['move_num'] + '. ';
 580                 }
 581                 last_move += data['position']['last_move'];
 582
 583                 headline += ' after ' + last_move;
 584         } else {
 585                 last_move = null;
 586         }
 587
 588         $("#headline").text(headline);
 589
 590         if (num_viewers === null) {
 591                 $("#numviewers").text("");
 592         } else if (num_viewers == 1) {
 593                 $("#numviewers").text("You are the only current viewer");
 594         } else {
 595                 $("#numviewers").text(num_viewers + " current viewers");
 596         }
 597
 598         // The engine id.
 599         if (data['id'] && data['id']['name'] !== null) {
 600                 $("#engineid").text(data['id']['name']);
 601         }
 602
 603         // The score.
 604         if (data['score'] !== null) {
 605                 $("#score").text(data['score']);
 606         }
 607
 608         var title_elems = [];
 609         if (data['short_score'] !== undefined && data['short_score'] !== null) {
 610                 title_elems.push(data['short_score']);
 611         }
 612         if (last_move !== null) {
 613                 title_elems.push(last_move);
 614         }
 615
 616         if (title_elems.length != 0) {
 617                 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
 618         } else {
 619                 document.title = 'analysis.sesse.net';
 620         }
 621
 622         // The search stats.
 623         if (data['tablebase'] == 1) {
 624                 $("#searchstats").text("Tablebase result");
 625         } else if (data['nodes'] && data['nps'] && data['depth']) {
 626                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
 627                 if (data['seldepth']) {
 628                         stats += ' (' + data['seldepth'] + ' selective)';
 629                 }
 630                 if (data['tbhits'] && data['tbhits'] > 0) {
 631                         if (data['tbhits'] == 1) {
 632                                 stats += ', one Syzygy hit';
 633                         } else {
 634                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
 635                         }
 636                 }
 637
 638                 $("#searchstats").text(stats);
 639         } else {
 640                 $("#searchstats").text("");
 641         }
 642
 643         // Update the board itself.
 644         fen = data['position']['fen'];
 645         update_displayed_line();
 646
 647         if (data['position']['last_move_uci']) {
 648                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
 649                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
 650         } else {
 651                 highlight_from = highlight_to = undefined;
 652         }
 653         update_highlight();
 654
 655         // Print the history.
 656         if (data['position']['history']) {
 657                 add_pv('start', data['position']['history'], data['position']['pretty_history'], 1, 'W', 8, true);
 658         } else {
 659                 display_lines.push(null);
 660         }
 661         update_history();
 662
 663         // Print the PV.
 664         $("#pv").html(add_pv(data['position']['fen'], data['pv_uci'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));
 665
 666         // Update the PV arrow.
 667         clear_arrows();
 668         if (data['pv_uci'].length >= 1) {
 669                 // draw a continuation arrow as long as it's the same piece
 670                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
 671                         var from = data['pv_uci'][i].substr(0, 2);
 672                         var to = data['pv_uci'][i].substr(2,4);
 673                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
 674                              interfering_arrow(from, to)) {
 675                                 break;
 676                         }
 677                         create_arrow(from, to, '#f66', 6, 20);
 678                 }
 679
 680                 var alt_moves = find_nonstupid_moves(data, 30);
 681                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
 682                         create_arrow(alt_moves[i].substr(0, 2),
 683                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
 684                 }
 685         }
 686
 687         // See if all semi-reasonable moves have only one possible response.
 688         if (data['pv_uci'].length >= 2) {
 689                 var nonstupid_moves = find_nonstupid_moves(data, 300);
 690                 var response = data['pv_uci'][1];
 691                 for (var i = 0; i < nonstupid_moves.length; ++i) {
 692                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
 693                                 // ignore the PV move for refutation lines.
 694                                 continue;
 695                         }
 696                         if (!data['refutation_lines'] ||
 697                             !data['refutation_lines'][nonstupid_moves[i]] ||
 698                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
 699                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
 700                                 // Incomplete PV, abort.
 701                                 response = undefined;
 702                                 break;
 703                         }
 704                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
 705                         if (response !== this_response) {
 706                                 // Different response depending on lines, abort.
 707                                 response = undefined;
 708                                 break;
 709                         }
 710                 }
 711
 712                 if (nonstupid_moves.length > 0 && response !== undefined) {
 713                         create_arrow(response.substr(0, 2),
 714                                      response.substr(2, 2), '#66f', 6, 20);
 715                 }
 716         }
 717
 718         // Update the refutation lines.
 719         fen = data['position']['fen'];
 720         move_num = data['position']['move_num'];
 721         toplay = data['position']['toplay'];
 722         refutation_lines = data['refutation_lines'];
 723         update_refutation_lines();
 724
 725         // Next update.
 726         setTimeout(function() { request_update(); }, 100);
 727 }
 728
 729 /**
 730  * @param {boolean} sort_by_score
 731  */
 732 var resort_refutation_lines = function(sort_by_score) {
 733         sort_refutation_lines_by_score = sort_by_score;
 734         update_refutation_lines();
 735 }
 736 window['resort_refutation_lines'] = resort_refutation_lines;
 737
 738 /**
 739  * @param {boolean} truncate_history
 740  */
 741 var set_truncate_history = function(truncate_history) {
 742         truncate_display_history = truncate_history;
 743         update_refutation_lines();
 744 }
 745 window['set_truncate_history'] = set_truncate_history;
 746
 747 /**
 748  * @param {number} line_num
 749  * @param {number} move_num
 750  */
 751 var show_line = function(line_num, move_num) {
 752         if (line_num == -1) {
 753                 current_display_line = null;
 754                 current_display_move = null;
 755         } else {
 756                 current_display_line = display_lines[line_num];
 757                 current_display_move = move_num;
 758         }
 759         update_displayed_line();
 760         update_highlight();
 761         redraw_arrows();
 762 }
 763 window['show_line'] = show_line;
 764
 765 var prev_move = function() {
 766         if (current_display_move > -1) {
 767                 --current_display_move;
 768         }
 769         update_displayed_line();
 770 }
 771 window['prev_move'] = prev_move;
 772
 773 var next_move = function() {
 774         if (current_display_line && current_display_move < current_display_line.pretty_pv.length - 1) {
 775                 ++current_display_move;
 776         }
 777         update_displayed_line();
 778 }
 779 window['next_move'] = next_move;
 780
 781 var update_displayed_line = function() {
 782         if (highlighted_move !== null) {
 783                 highlighted_move.removeClass('highlight');
 784         }
 785         if (current_display_line === null) {
 786                 $("#linenav").hide();
 787                 $("#linemsg").show();
 788                 board.position(fen);
 789                 return;
 790         }
 791
 792         $("#linenav").show();
 793         $("#linemsg").hide();
 794
 795         if (current_display_move <= 0) {
 796                 $("#prevmove").html("Previous");
 797         } else {
 798                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
 799         }
 800         if (current_display_move == current_display_line.uci_pv.length - 1) {
 801                 $("#nextmove").html("Next");
 802         } else {
 803                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
 804         }
 805
 806         hiddenboard.position(current_display_line.start_fen, false);
 807         for (var i = 0; i <= current_display_move; ++i) {
 808                 var pos = hiddenboard.position();
 809                 var move = current_display_line.uci_pv[i];
 810                 var source = move.substr(0, 2);
 811                 var target = move.substr(2, 2);
 812                 var promo = move.substr(4, 1);
 813
 814                 // Check if we need to do en passant.
 815                 var piece = pos[source];
 816                 if (piece == "wP" || piece == "bP") {
 817                         if (source.substr(0, 1) != target.substr(0, 1) &&
 818                             pos[target] === undefined) {
 819                                 var ep_square = target.substr(0, 1) + source.substr(1, 1);
 820                                 delete pos[ep_square];
 821                                 hiddenboard.position(pos, false);
 822                         }
 823                 }
 824
 825                 move = source + "-" + target;
 826                 hiddenboard.move(move, false);
 827                 pos = hiddenboard.position();
 828
 829                 // Do promotion if needed.
 830                 if (promo != "") {
 831                         pos[target] = pos[target].substr(0, 1) + promo.toUpperCase();
 832                         hiddenboard.position(pos, false);
 833                 }
 834
 835                 // chessboard.js does not automatically move the rook on castling
 836                 // (issue #51; marked as won't fix), so update it ourselves.
 837                 if (move == "e1-g1" && hiddenboard.position().g1 == "wK") {  // white O-O
 838                         hiddenboard.move("h1-f1", false);
 839                 } else if (move == "e1-c1" && hiddenboard.position().c1 == "wK") {  // white O-O-O
 840                         hiddenboard.move("a1-d1", false);
 841                 } else if (move == "e8-g8" && hiddenboard.position().g8 == "bK") {  // black O-O
 842                         hiddenboard.move("h8-f8", false);
 843                 } else if (move == "e8-c8" && hiddenboard.position().c8 == "bK") {  // black O-O-O
 844                         hiddenboard.move("a8-d8", false);
 845                 }
 846         }
 847
 848         highlighted_move = $("#automove" + current_display_line.line_number + "-" + current_display_move);
 849         highlighted_move.addClass('highlight');
 850
 851         board.position(hiddenboard.position());
 852 }
 853
 854 var init = function() {
 855         unique = get_unique();
 856
 857         // Create board.
 858         board = new window.ChessBoard('board', 'start');
 859         hiddenboard = new window.ChessBoard('hiddenboard', 'start');
 860
 861         request_update();
 862         $(window).resize(function() {
 863                 board.resize();
 864                 update_highlight();
 865                 redraw_arrows();
 866         });
 867         $(window).keyup(function(event) {
 868                 if (event.which == 39) {
 869                         next_move();
 870                 } else if (event.which == 37) {
 871                         prev_move();
 872                 }
 873         });
 874 };
 875 $(document).ready(init);
 876
 877 })();