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 = Math.random();
  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 request_update = function() {
  80         $.ajax({
  81                 url: "http://analysis.sesse.net/analysis.pl?ims=" + ims + "&unique=" + unique
  82                 //url: "http://analysis.sesse.net:5000/analysis.pl?ims=" + ims + "&unique=" + unique
  83         }).done(function(data, textstatus, xhr) {
  84                 ims = xhr.getResponseHeader('X-Remoteglot-Last-Modified');
  85                 var num_viewers = xhr.getResponseHeader('X-Remoteglot-Num-Viewers');
  86                 update_board(data, num_viewers);
  87         }).fail(function() {
  88                 // Wait ten seconds, then try again.
  89                 setTimeout(function() { request_update(); }, 10000);
  90         });
  91 }
  92
  93 var clear_arrows = function() {
  94         for (var i = 0; i < arrows.length; ++i) {
  95                 if (arrows[i].svg) {
  96                         arrows[i].svg.parentElement.removeChild(arrows[i].svg);
  97                         delete arrows[i].svg;
  98                 }
  99         }
 100         arrows = [];
 101
 102         occupied_by_arrows = [];
 103         for (var y = 0; y < 8; ++y) {
 104                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 105         }
 106 }
 107
 108 var redraw_arrows = function() {
 109         for (var i = 0; i < arrows.length; ++i) {
 110                 position_arrow(arrows[i]);
 111         }
 112 }
 113
 114 /** @param {!number} x
 115  * @return {!number}
 116  */
 117 var sign = function(x) {
 118         if (x > 0) {
 119                 return 1;
 120         } else if (x < 0) {
 121                 return -1;
 122         } else {
 123                 return 0;
 124         }
 125 }
 126
 127 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 128  * @param {!string} from The square the arrow is from (e.g. e4).
 129  * @param {!string} to The square the arrow is to (e.g. e4).
 130  * @return {boolean}
 131  */
 132 var interfering_arrow = function(from, to) {
 133         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 134         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 135         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 136         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 137
 138         occupied_by_arrows[from_row][from_col] = true;
 139
 140         // Knight move: Just check that we haven't been at the destination before.
 141         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 142             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 143                 return occupied_by_arrows[to_row][to_col];
 144         }
 145
 146         // Sliding piece: Check if anything except the from-square is seen before.
 147         var dx = sign(to_col - from_col);
 148         var dy = sign(to_row - from_row);
 149         var x = from_col;
 150         var y = from_row;
 151         do {
 152                 x += dx;
 153                 y += dy;
 154                 if (occupied_by_arrows[y][x]) {
 155                         return true;
 156                 }
 157                 occupied_by_arrows[y][x] = true;
 158         } while (x != to_col || y != to_row);
 159
 160         return false;
 161 }
 162
 163 /** Find a point along the coordinate system given by the given line,
 164  * <t> units forward from the start of the line, <u> units to the right of it.
 165  * @param {!number} x1
 166  * @param {!number} x2
 167  * @param {!number} y1
 168  * @param {!number} y2
 169  * @param {!number} t
 170  * @param {!number} u
 171  * @return {!string} The point in "x y" form, suitable for SVG paths.
 172  */
 173 var point_from_start = function(x1, y1, x2, y2, t, u) {
 174         var dx = x2 - x1;
 175         var dy = y2 - y1;
 176
 177         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 178         dx *= norm;
 179         dy *= norm;
 180
 181         var x = x1 + dx * t + dy * u;
 182         var y = y1 + dy * t - dx * u;
 183         return x + " " + y;
 184 }
 185
 186 /** Find a point along the coordinate system given by the given line,
 187  * <t> units forward from the end of the line, <u> units to the right of it.
 188  * @param {!number} x1
 189  * @param {!number} x2
 190  * @param {!number} y1
 191  * @param {!number} y2
 192  * @param {!number} t
 193  * @param {!number} u
 194  * @return {!string} The point in "x y" form, suitable for SVG paths.
 195  */
 196 var point_from_end = function(x1, y1, x2, y2, t, u) {
 197         var dx = x2 - x1;
 198         var dy = y2 - y1;
 199
 200         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 201         dx *= norm;
 202         dy *= norm;
 203
 204         var x = x2 + dx * t + dy * u;
 205         var y = y2 + dy * t - dx * u;
 206         return x + " " + y;
 207 }
 208
 209 var position_arrow = function(arrow) {
 210         if (arrow.svg) {
 211                 arrow.svg.parentElement.removeChild(arrow.svg);
 212                 delete arrow.svg;
 213         }
 214         if (current_display_line !== null) {
 215                 return;
 216         }
 217
 218         var pos = $(".square-a8").position();
 219
 220         var zoom_factor = $("#board").width() / 400.0;
 221         var line_width = arrow.line_width * zoom_factor;
 222         var arrow_size = arrow.arrow_size * zoom_factor;
 223
 224         var square_width = $(".square-a8").width();
 225         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 226         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 227         var from_x = (arrow.from_col + 0.5)*square_width;
 228         var to_x = (arrow.to_col + 0.5)*square_width;
 229
 230         var SVG_NS = "http://www.w3.org/2000/svg";
 231         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 232         var svg = document.createElementNS(SVG_NS, "svg");
 233         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 234         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 235         svg.setAttribute("style", "position: absolute");
 236         svg.setAttribute("position", "absolute");
 237         svg.setAttribute("version", "1.1");
 238         svg.setAttribute("class", "c1");
 239         svg.setAttribute("xmlns", XHTML_NS);
 240
 241         var x1 = from_x;
 242         var y1 = from_y;
 243         var x2 = to_x;
 244         var y2 = to_y;
 245
 246         // Draw the line.
 247         var outline = document.createElementNS(SVG_NS, "path");
 248         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));
 249         outline.setAttribute("xmlns", XHTML_NS);
 250         outline.setAttribute("stroke", "#666");
 251         outline.setAttribute("stroke-width", line_width + 2);
 252         outline.setAttribute("fill", "none");
 253         svg.appendChild(outline);
 254
 255         var path = document.createElementNS(SVG_NS, "path");
 256         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));
 257         path.setAttribute("xmlns", XHTML_NS);
 258         path.setAttribute("stroke", arrow.fg_color);
 259         path.setAttribute("stroke-width", line_width);
 260         path.setAttribute("fill", "none");
 261         svg.appendChild(path);
 262
 263         // Then the arrow head.
 264         var head = document.createElementNS(SVG_NS, "path");
 265         head.setAttribute("d",
 266                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 267                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 268                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 269                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 270                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 271         head.setAttribute("xmlns", XHTML_NS);
 272         head.setAttribute("stroke", "#000");
 273         head.setAttribute("stroke-width", "1");
 274         head.setAttribute("fill", arrow.fg_color);
 275         svg.appendChild(head);
 276
 277         $(svg).css({ top: pos.top, left: pos.left });
 278         document.body.appendChild(svg);
 279         arrow.svg = svg;
 280 }
 281
 282 /**
 283  * @param {!string} from_square
 284  * @param {!string} to_square
 285  * @param {!string} fg_color
 286  * @param {number} line_width
 287  * @param {number} arrow_size
 288  */
 289 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 290         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 291         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 292         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 293         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 294
 295         // Create arrow.
 296         var arrow = {
 297                 from_col: from_col,
 298                 from_row: from_row,
 299                 to_col: to_col,
 300                 to_row: to_row,
 301                 line_width: line_width,
 302                 arrow_size: arrow_size,
 303                 fg_color: fg_color
 304         };
 305
 306         position_arrow(arrow);
 307         arrows.push(arrow);
 308 }
 309
 310 var compare_by_sort_key = function(refutation_lines, a, b) {
 311         var ska = refutation_lines[a]['sort_key'];
 312         var skb = refutation_lines[b]['sort_key'];
 313         if (ska < skb) return -1;
 314         if (ska > skb) return 1;
 315         return 0;
 316 };
 317
 318 var compare_by_score = function(refutation_lines, a, b) {
 319         var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
 320         var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
 321         return sa - sb;
 322 }
 323
 324 /**
 325  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 326  * sorted by quality, descending.
 327  *
 328  * @param {!Object} data
 329  * @param {number} margin The maximum number of centipawns worse than the
 330  *     best move can be and still be included.
 331  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 332  *     moves, in score order.
 333  */
 334 var find_nonstupid_moves = function(data, margin) {
 335         // First of all, if there are any moves that are more than 0.5 ahead of
 336         // the primary move, the refutation lines are probably bunk, so just
 337         // kill them all.
 338         var best_score = undefined;
 339         var pv_score = undefined;
 340         for (var move in data['refutation_lines']) {
 341                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 342                 if (move == data['pv_uci'][0]) {
 343                         pv_score = score;
 344                 }
 345                 if (best_score === undefined || score > best_score) {
 346                         best_score = score;
 347                 }
 348                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 349                         return [];
 350                 }
 351         }
 352
 353         if (best_score - pv_score > 50) {
 354                 return [];
 355         }
 356
 357         // Now find all moves that are within “margin” of the best score.
 358         // The PV move will always be first.
 359         var moves = [];
 360         for (var move in data['refutation_lines']) {
 361                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 362                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 363                         moves.push(move);
 364                 }
 365         }
 366         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
 367         moves.unshift(data['pv_uci'][0]);
 368
 369         return moves;
 370 }
 371
 372 /**
 373  * @param {number} x
 374  * @return {!string}
 375  */
 376 var thousands = function(x) {
 377         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 378 }
 379
 380 /**
 381  * @param {!string} fen
 382  * @param {Array.<string>} uci_pv
 383  * @param {Array.<string>} pretty_pv
 384  * @param {number} move_num
 385  * @param {!string} toplay
 386  * @param {number=} opt_limit
 387  * @param {boolean=} opt_showlast
 388  */
 389 var add_pv = function(fen, uci_pv, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 390         display_lines.push({
 391                 start_fen: fen,
 392                 uci_pv: uci_pv,
 393                 pretty_pv: pretty_pv,
 394                 line_number: display_lines.length
 395         });
 396         return print_pv(display_lines.length - 1, pretty_pv, move_num, toplay, opt_limit, opt_showlast);
 397 }
 398
 399 /**
 400  * @param {number} line_num
 401  * @param {Array.<string>} pretty_pv
 402  * @param {number} move_num
 403  * @param {!string} toplay
 404  * @param {number=} opt_limit
 405  * @param {boolean=} opt_showlast
 406  */
 407 var print_pv = function(line_num, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 408         var pv = '';
 409         var i = 0;
 410         if (opt_limit && opt_showlast) {
 411                 // Truncate the PV at the beginning (instead of at the end).
 412                 // We assume here that toplay is 'W'. We also assume that if
 413                 // opt_showlast is set, then it is the history, and thus,
 414                 // the UI should be to expand the history.
 415                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 416                 i = pretty_pv.length - opt_limit;
 417                 if (i < 0) {
 418                         i = 0;
 419                 }
 420                 if (i % 2 == 1) {
 421                         ++i;
 422                 }
 423                 move_num += i / 2;
 424         } else if (toplay == 'B') {
 425                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 426                 pv = move_num + '. … ' + move;
 427                 toplay = 'W';
 428                 ++i;
 429                 ++move_num;
 430         }
 431         for ( ; i < pretty_pv.length; ++i) {
 432                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 433
 434                 if (toplay == 'W') {
 435                         if (i > opt_limit && !opt_showlast) {
 436                                 return pv + ' (…)';
 437                         }
 438                         if (pv != '') {
 439                                 pv += ' ';
 440                         }
 441                         pv += move_num + '. ' + move;
 442                         ++move_num;
 443                         toplay = 'B';
 444                 } else {
 445                         pv += ' ' + move;
 446                         toplay = 'W';
 447                 }
 448         }
 449         return pv;
 450 }
 451
 452 var update_highlight = function() {
 453         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 454         if (current_display_line === null && highlight_from !== undefined && highlight_to !== undefined) {
 455                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 456                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 457         }
 458 }
 459
 460 var update_history = function() {
 461         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 462                 $("#history").html("No history");
 463         } else if (truncate_display_history) {
 464                 $("#history").html(print_pv(0, display_lines[0].pretty_pv, 1, 'W', 8, true));
 465         } else {
 466                 $("#history").html(
 467                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 468                         print_pv(0, display_lines[0].pretty_pv, 1, 'W'));
 469         }
 470 }
 471
 472 /**
 473  * @param {!boolean} truncate_history
 474  */
 475 var collapse_history = function(truncate_history) {
 476         truncate_display_history = truncate_history;
 477         update_history();
 478 }
 479 window['collapse_history'] = collapse_history;
 480
 481 var update_refutation_lines = function() {
 482         if (fen === null) {
 483                 return;
 484         }
 485         if (display_lines.length > 2) {
 486                 display_lines = [ display_lines[0], display_lines[1] ];
 487         }
 488
 489         var tbl = $("#refutationlines");
 490         tbl.empty();
 491
 492         var moves = [];
 493         for (var move in refutation_lines) {
 494                 moves.push(move);
 495         }
 496         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 497         moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
 498         for (var i = 0; i < moves.length; ++i) {
 499                 var line = refutation_lines[moves[i]];
 500
 501                 var tr = document.createElement("tr");
 502
 503                 var move_td = document.createElement("td");
 504                 tr.appendChild(move_td);
 505                 $(move_td).addClass("move");
 506                 if (line['pv_uci'].length == 0) {
 507                         $(move_td).text(line['pretty_move']);
 508                 } else {
 509                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 510                         $(move_td).html(move);
 511                 }
 512
 513                 var score_td = document.createElement("td");
 514                 tr.appendChild(score_td);
 515                 $(score_td).addClass("score");
 516                 $(score_td).text(line['pretty_score']);
 517
 518                 var depth_td = document.createElement("td");
 519                 tr.appendChild(depth_td);
 520                 $(depth_td).addClass("depth");
 521                 $(depth_td).text("d" + line['depth']);
 522
 523                 var pv_td = document.createElement("td");
 524                 tr.appendChild(pv_td);
 525                 $(pv_td).addClass("pv");
 526                 $(pv_td).html(add_pv(fen, line['pv_uci'], line['pv_pretty'], move_num, toplay, 10));
 527
 528                 tbl.append(tr);
 529         }
 530
 531         // Make one of the links clickable and the other nonclickable.
 532         if (sort_refutation_lines_by_score) {
 533                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 534                 $("#sortbyscore1").html("<strong>Score</strong>");
 535         } else {
 536                 $("#sortbyscore0").html("<strong>Move</strong>");
 537                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 538         }
 539 }
 540
 541 /**
 542  * @param {Object} data
 543  * @param {number} num_viewers
 544  */
 545 var update_board = function(data, num_viewers) {
 546         display_lines = [];
 547
 548         // The headline.
 549         var headline;
 550         if (data['position']['player_w'] && data['position']['player_b']) {
 551                 headline = data['position']['player_w'] + '–' +
 552                         data['position']['player_b'] + ', analysis';
 553         } else {
 554                 headline = 'Analysis';
 555         }
 556         if (data['position']['last_move'] !== 'none') {
 557                 headline += ' after '
 558                 if (data['position']['toplay'] == 'W') {
 559                         headline += (data['position']['move_num']-1) + '… ';
 560                 } else {
 561                         headline += data['position']['move_num'] + '. ';
 562                 }
 563                 headline += data['position']['last_move'];
 564         }
 565
 566         $("#headline").text(headline);
 567
 568         if (num_viewers === null) {
 569                 $("#numviewers").text("");
 570         } else if (num_viewers == 1) {
 571                 $("#numviewers").text("You are the only current viewer");
 572         } else {
 573                 $("#numviewers").text(num_viewers + " current viewers");
 574         }
 575
 576         // The engine id.
 577         if (data['id'] && data['id']['name'] !== null) {
 578                 $("#engineid").text(data['id']['name']);
 579         }
 580
 581         // The score.
 582         if (data['score'] !== null) {
 583                 $("#score").text(data['score']);
 584         }
 585
 586         // The search stats.
 587         if (data['nodes'] && data['nps'] && data['depth']) {
 588                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
 589                 if (data['seldepth']) {
 590                         stats += ' (' + data['seldepth'] + ' selective)';
 591                 }
 592                 if (data['tbhits'] && data['tbhits'] > 0) {
 593                         if (data['tbhits'] == 1) {
 594                                 stats += ', one Syzygy hit';
 595                         } else {
 596                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
 597                         }
 598                 }
 599
 600                 $("#searchstats").text(stats);
 601         }
 602
 603         // Update the board itself.
 604         fen = data['position']['fen'];
 605         update_displayed_line();
 606
 607         if (data['position']['last_move_uci']) {
 608                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
 609                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
 610         } else {
 611                 highlight_from = highlight_to = undefined;
 612         }
 613         update_highlight();
 614
 615         // Print the history.
 616         if (data['position']['history']) {
 617                 add_pv('start', data['position']['history'], data['position']['pretty_history'], 1, 'W', 8, true);
 618         } else {
 619                 display_lines.push(null);
 620         }
 621         update_history();
 622
 623         // Print the PV.
 624         $("#pv").html(add_pv(data['position']['fen'], data['pv_uci'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));
 625
 626         // Update the PV arrow.
 627         clear_arrows();
 628         if (data['pv_uci'].length >= 1) {
 629                 // draw a continuation arrow as long as it's the same piece
 630                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
 631                         var from = data['pv_uci'][i].substr(0, 2);
 632                         var to = data['pv_uci'][i].substr(2,4);
 633                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
 634                              interfering_arrow(from, to)) {
 635                                 break;
 636                         }
 637                         create_arrow(from, to, '#f66', 6, 20);
 638                 }
 639
 640                 var alt_moves = find_nonstupid_moves(data, 30);
 641                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
 642                         create_arrow(alt_moves[i].substr(0, 2),
 643                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
 644                 }
 645         }
 646
 647         // See if all semi-reasonable moves have only one possible response.
 648         if (data['pv_uci'].length >= 2) {
 649                 var nonstupid_moves = find_nonstupid_moves(data, 300);
 650                 var response = data['pv_uci'][1];
 651                 for (var i = 0; i < nonstupid_moves.length; ++i) {
 652                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
 653                                 // ignore the PV move for refutation lines.
 654                                 continue;
 655                         }
 656                         if (!data['refutation_lines'] ||
 657                             !data['refutation_lines'][nonstupid_moves[i]] ||
 658                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
 659                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
 660                                 // Incomplete PV, abort.
 661                                 response = undefined;
 662                                 break;
 663                         }
 664                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
 665                         if (response !== this_response) {
 666                                 // Different response depending on lines, abort.
 667                                 response = undefined;
 668                                 break;
 669                         }
 670                 }
 671
 672                 if (nonstupid_moves.length > 0 && response !== undefined) {
 673                         create_arrow(response.substr(0, 2),
 674                                      response.substr(2, 2), '#66f', 6, 20);
 675                 }
 676         }
 677
 678         // Update the refutation lines.
 679         fen = data['position']['fen'];
 680         move_num = data['position']['move_num'];
 681         toplay = data['position']['toplay'];
 682         refutation_lines = data['refutation_lines'];
 683         update_refutation_lines();
 684
 685         // Next update.
 686         setTimeout(function() { request_update(); }, 100);
 687 }
 688
 689 /**
 690  * @param {boolean} sort_by_score
 691  */
 692 var resort_refutation_lines = function(sort_by_score) {
 693         sort_refutation_lines_by_score = sort_by_score;
 694         update_refutation_lines();
 695 }
 696 window['resort_refutation_lines'] = resort_refutation_lines;
 697
 698 /**
 699  * @param {boolean} truncate_history
 700  */
 701 var set_truncate_history = function(truncate_history) {
 702         truncate_display_history = truncate_history;
 703         update_refutation_lines();
 704 }
 705 window['set_truncate_history'] = set_truncate_history;
 706
 707 /**
 708  * @param {number} line_num
 709  * @param {number} move_num
 710  */
 711 var show_line = function(line_num, move_num) {
 712         if (line_num == -1) {
 713                 current_display_line = null;
 714                 current_display_move = null;
 715         } else {
 716                 current_display_line = display_lines[line_num];
 717                 current_display_move = move_num;
 718         }
 719         update_displayed_line();
 720         update_highlight();
 721         redraw_arrows();
 722 }
 723 window['show_line'] = show_line;
 724
 725 var prev_move = function() {
 726         if (current_display_move > -1) {
 727                 --current_display_move;
 728         }
 729         update_displayed_line();
 730 }
 731 window['prev_move'] = prev_move;
 732
 733 var next_move = function() {
 734         if (current_display_line && current_display_move < current_display_line.pretty_pv.length - 1) {
 735                 ++current_display_move;
 736         }
 737         update_displayed_line();
 738 }
 739 window['next_move'] = next_move;
 740
 741 var update_displayed_line = function() {
 742         if (highlighted_move !== null) {
 743                 highlighted_move.removeClass('highlight');
 744         }
 745         if (current_display_line === null) {
 746                 $("#linenav").hide();
 747                 $("#linemsg").show();
 748                 board.position(fen);
 749                 return;
 750         }
 751
 752         $("#linenav").show();
 753         $("#linemsg").hide();
 754
 755         if (current_display_move <= 0) {
 756                 $("#prevmove").html("Previous");
 757         } else {
 758                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
 759         }
 760         if (current_display_move == current_display_line.uci_pv.length - 1) {
 761                 $("#nextmove").html("Next");
 762         } else {
 763                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
 764         }
 765
 766         hiddenboard.position(current_display_line.start_fen, false);
 767         for (var i = 0; i <= current_display_move; ++i) {
 768                 var pos = hiddenboard.position();
 769                 var move = current_display_line.uci_pv[i];
 770                 var source = move.substr(0, 2);
 771                 var target = move.substr(2, 2);
 772                 var promo = move.substr(4, 1);
 773
 774                 // Check if we need to do en passant.
 775                 var piece = pos[source];
 776                 if (piece == "wP" || piece == "bP") {
 777                         if (source.substr(0, 1) != target.substr(0, 1) &&
 778                             pos[target] === undefined) {
 779                                 var ep_square = target.substr(0, 1) + source.substr(1, 1);
 780                                 delete pos[ep_square];
 781                                 hiddenboard.position(pos, false);
 782                         }
 783                 }
 784
 785                 move = source + "-" + target;
 786                 hiddenboard.move(move, false);
 787                 pos = hiddenboard.position();
 788
 789                 // Do promotion if needed.
 790                 if (promo != "") {
 791                         pos[target] = pos[target].substr(0, 1) + promo.toUpperCase();
 792                         hiddenboard.position(pos, false);
 793                 }
 794
 795                 // chessboard.js does not automatically move the rook on castling
 796                 // (issue #51; marked as won't fix), so update it ourselves.
 797                 if (move == "e1-g1" && hiddenboard.position().g1 == "wK") {  // white O-O
 798                         hiddenboard.move("h1-f1", false);
 799                 } else if (move == "e1-c1" && hiddenboard.position().c1 == "wK") {  // white O-O-O
 800                         hiddenboard.move("a1-d1", false);
 801                 } else if (move == "e8-g8" && hiddenboard.position().g8 == "bK") {  // black O-O
 802                         hiddenboard.move("h8-f8", false);
 803                 } else if (move == "e8-c8" && hiddenboard.position().c8 == "bK") {  // black O-O-O
 804                         hiddenboard.move("a8-d8", false);
 805                 }
 806         }
 807
 808         highlighted_move = $("#automove" + current_display_line.line_number + "-" + current_display_move);
 809         highlighted_move.addClass('highlight');
 810
 811         board.position(hiddenboard.position());
 812 }
 813
 814 var init = function() {
 815         // Create board.
 816         board = new window.ChessBoard('board', 'start');
 817         hiddenboard = new window.ChessBoard('hiddenboard', 'start');
 818
 819         request_update();
 820         $(window).resize(function() {
 821                 board.resize();
 822                 update_highlight();
 823                 redraw_arrows();
 824         });
 825         $(window).keyup(function(event) {
 826                 if (event.which == 39) {
 827                         next_move();
 828                 } else if (event.which == 37) {
 829                         prev_move();
 830                 }
 831         });
 832 };
 833 $(document).ready(init);
 834
 835 })();