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: "http://analysis.sesse.net/analysis.pl?ims=" + ims + "&unique=" + unique
 104                 //url: "http://analysis.sesse.net:5000/analysis.pl?ims=" + ims + "&unique=" + unique
 105         }).done(function(data, textstatus, xhr) {
 106                 ims = xhr.getResponseHeader('X-Remoteglot-Last-Modified');
 107                 var num_viewers = xhr.getResponseHeader('X-Remoteglot-Num-Viewers');
 108                 update_board(data, num_viewers);
 109         }).fail(function() {
 110                 // Wait ten seconds, then try again.
 111                 setTimeout(function() { request_update(); }, 10000);
 112         });
 113 }
 114
 115 var clear_arrows = function() {
 116         for (var i = 0; i < arrows.length; ++i) {
 117                 if (arrows[i].svg) {
 118                         arrows[i].svg.parentElement.removeChild(arrows[i].svg);
 119                         delete arrows[i].svg;
 120                 }
 121         }
 122         arrows = [];
 123
 124         occupied_by_arrows = [];
 125         for (var y = 0; y < 8; ++y) {
 126                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 127         }
 128 }
 129
 130 var redraw_arrows = function() {
 131         for (var i = 0; i < arrows.length; ++i) {
 132                 position_arrow(arrows[i]);
 133         }
 134 }
 135
 136 /** @param {!number} x
 137  * @return {!number}
 138  */
 139 var sign = function(x) {
 140         if (x > 0) {
 141                 return 1;
 142         } else if (x < 0) {
 143                 return -1;
 144         } else {
 145                 return 0;
 146         }
 147 }
 148
 149 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 150  * @param {!string} from The square the arrow is from (e.g. e4).
 151  * @param {!string} to The square the arrow is to (e.g. e4).
 152  * @return {boolean}
 153  */
 154 var interfering_arrow = function(from, to) {
 155         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 156         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 157         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 158         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 159
 160         occupied_by_arrows[from_row][from_col] = true;
 161
 162         // Knight move: Just check that we haven't been at the destination before.
 163         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 164             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 165                 return occupied_by_arrows[to_row][to_col];
 166         }
 167
 168         // Sliding piece: Check if anything except the from-square is seen before.
 169         var dx = sign(to_col - from_col);
 170         var dy = sign(to_row - from_row);
 171         var x = from_col;
 172         var y = from_row;
 173         do {
 174                 x += dx;
 175                 y += dy;
 176                 if (occupied_by_arrows[y][x]) {
 177                         return true;
 178                 }
 179                 occupied_by_arrows[y][x] = true;
 180         } while (x != to_col || y != to_row);
 181
 182         return false;
 183 }
 184
 185 /** Find a point along the coordinate system given by the given line,
 186  * <t> units forward from the start of the line, <u> units to the right of it.
 187  * @param {!number} x1
 188  * @param {!number} x2
 189  * @param {!number} y1
 190  * @param {!number} y2
 191  * @param {!number} t
 192  * @param {!number} u
 193  * @return {!string} The point in "x y" form, suitable for SVG paths.
 194  */
 195 var point_from_start = function(x1, y1, x2, y2, t, u) {
 196         var dx = x2 - x1;
 197         var dy = y2 - y1;
 198
 199         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 200         dx *= norm;
 201         dy *= norm;
 202
 203         var x = x1 + dx * t + dy * u;
 204         var y = y1 + dy * t - dx * u;
 205         return x + " " + y;
 206 }
 207
 208 /** Find a point along the coordinate system given by the given line,
 209  * <t> units forward from the end of the line, <u> units to the right of it.
 210  * @param {!number} x1
 211  * @param {!number} x2
 212  * @param {!number} y1
 213  * @param {!number} y2
 214  * @param {!number} t
 215  * @param {!number} u
 216  * @return {!string} The point in "x y" form, suitable for SVG paths.
 217  */
 218 var point_from_end = function(x1, y1, x2, y2, t, u) {
 219         var dx = x2 - x1;
 220         var dy = y2 - y1;
 221
 222         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 223         dx *= norm;
 224         dy *= norm;
 225
 226         var x = x2 + dx * t + dy * u;
 227         var y = y2 + dy * t - dx * u;
 228         return x + " " + y;
 229 }
 230
 231 var position_arrow = function(arrow) {
 232         if (arrow.svg) {
 233                 arrow.svg.parentElement.removeChild(arrow.svg);
 234                 delete arrow.svg;
 235         }
 236         if (current_display_line !== null) {
 237                 return;
 238         }
 239
 240         var pos = $(".square-a8").position();
 241
 242         var zoom_factor = $("#board").width() / 400.0;
 243         var line_width = arrow.line_width * zoom_factor;
 244         var arrow_size = arrow.arrow_size * zoom_factor;
 245
 246         var square_width = $(".square-a8").width();
 247         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 248         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 249         var from_x = (arrow.from_col + 0.5)*square_width;
 250         var to_x = (arrow.to_col + 0.5)*square_width;
 251
 252         var SVG_NS = "http://www.w3.org/2000/svg";
 253         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 254         var svg = document.createElementNS(SVG_NS, "svg");
 255         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 256         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 257         svg.setAttribute("style", "position: absolute");
 258         svg.setAttribute("position", "absolute");
 259         svg.setAttribute("version", "1.1");
 260         svg.setAttribute("class", "c1");
 261         svg.setAttribute("xmlns", XHTML_NS);
 262
 263         var x1 = from_x;
 264         var y1 = from_y;
 265         var x2 = to_x;
 266         var y2 = to_y;
 267
 268         // Draw the line.
 269         var outline = document.createElementNS(SVG_NS, "path");
 270         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));
 271         outline.setAttribute("xmlns", XHTML_NS);
 272         outline.setAttribute("stroke", "#666");
 273         outline.setAttribute("stroke-width", line_width + 2);
 274         outline.setAttribute("fill", "none");
 275         svg.appendChild(outline);
 276
 277         var path = document.createElementNS(SVG_NS, "path");
 278         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));
 279         path.setAttribute("xmlns", XHTML_NS);
 280         path.setAttribute("stroke", arrow.fg_color);
 281         path.setAttribute("stroke-width", line_width);
 282         path.setAttribute("fill", "none");
 283         svg.appendChild(path);
 284
 285         // Then the arrow head.
 286         var head = document.createElementNS(SVG_NS, "path");
 287         head.setAttribute("d",
 288                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 289                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 290                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 291                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 292                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 293         head.setAttribute("xmlns", XHTML_NS);
 294         head.setAttribute("stroke", "#000");
 295         head.setAttribute("stroke-width", "1");
 296         head.setAttribute("fill", arrow.fg_color);
 297         svg.appendChild(head);
 298
 299         $(svg).css({ top: pos.top, left: pos.left });
 300         document.body.appendChild(svg);
 301         arrow.svg = svg;
 302 }
 303
 304 /**
 305  * @param {!string} from_square
 306  * @param {!string} to_square
 307  * @param {!string} fg_color
 308  * @param {number} line_width
 309  * @param {number} arrow_size
 310  */
 311 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 312         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 313         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 314         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 315         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 316
 317         // Create arrow.
 318         var arrow = {
 319                 from_col: from_col,
 320                 from_row: from_row,
 321                 to_col: to_col,
 322                 to_row: to_row,
 323                 line_width: line_width,
 324                 arrow_size: arrow_size,
 325                 fg_color: fg_color
 326         };
 327
 328         position_arrow(arrow);
 329         arrows.push(arrow);
 330 }
 331
 332 var compare_by_sort_key = function(refutation_lines, a, b) {
 333         var ska = refutation_lines[a]['sort_key'];
 334         var skb = refutation_lines[b]['sort_key'];
 335         if (ska < skb) return -1;
 336         if (ska > skb) return 1;
 337         return 0;
 338 };
 339
 340 var compare_by_score = function(refutation_lines, a, b) {
 341         var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
 342         var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
 343         return sa - sb;
 344 }
 345
 346 /**
 347  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 348  * sorted by quality, descending.
 349  *
 350  * @param {!Object} data
 351  * @param {number} margin The maximum number of centipawns worse than the
 352  *     best move can be and still be included.
 353  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 354  *     moves, in score order.
 355  */
 356 var find_nonstupid_moves = function(data, margin) {
 357         // First of all, if there are any moves that are more than 0.5 ahead of
 358         // the primary move, the refutation lines are probably bunk, so just
 359         // kill them all.
 360         var best_score = undefined;
 361         var pv_score = undefined;
 362         for (var move in data['refutation_lines']) {
 363                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 364                 if (move == data['pv_uci'][0]) {
 365                         pv_score = score;
 366                 }
 367                 if (best_score === undefined || score > best_score) {
 368                         best_score = score;
 369                 }
 370                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 371                         return [];
 372                 }
 373         }
 374
 375         if (best_score - pv_score > 50) {
 376                 return [];
 377         }
 378
 379         // Now find all moves that are within “margin” of the best score.
 380         // The PV move will always be first.
 381         var moves = [];
 382         for (var move in data['refutation_lines']) {
 383                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 384                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 385                         moves.push(move);
 386                 }
 387         }
 388         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
 389         moves.unshift(data['pv_uci'][0]);
 390
 391         return moves;
 392 }
 393
 394 /**
 395  * @param {number} x
 396  * @return {!string}
 397  */
 398 var thousands = function(x) {
 399         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 400 }
 401
 402 /**
 403  * @param {!string} fen
 404  * @param {Array.<string>} uci_pv
 405  * @param {Array.<string>} pretty_pv
 406  * @param {number} move_num
 407  * @param {!string} toplay
 408  * @param {number=} opt_limit
 409  * @param {boolean=} opt_showlast
 410  */
 411 var add_pv = function(fen, uci_pv, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 412         display_lines.push({
 413                 start_fen: fen,
 414                 uci_pv: uci_pv,
 415                 pretty_pv: pretty_pv,
 416                 line_number: display_lines.length
 417         });
 418         return print_pv(display_lines.length - 1, pretty_pv, move_num, toplay, opt_limit, opt_showlast);
 419 }
 420
 421 /**
 422  * @param {number} line_num
 423  * @param {Array.<string>} pretty_pv
 424  * @param {number} move_num
 425  * @param {!string} toplay
 426  * @param {number=} opt_limit
 427  * @param {boolean=} opt_showlast
 428  */
 429 var print_pv = function(line_num, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 430         var pv = '';
 431         var i = 0;
 432         if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
 433                 // Truncate the PV at the beginning (instead of at the end).
 434                 // We assume here that toplay is 'W'. We also assume that if
 435                 // opt_showlast is set, then it is the history, and thus,
 436                 // the UI should be to expand the history.
 437                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 438                 i = pretty_pv.length - opt_limit;
 439                 if (i % 2 == 1) {
 440                         ++i;
 441                 }
 442                 move_num += i / 2;
 443         } else if (toplay == 'B') {
 444                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 445                 pv = move_num + '. … ' + move;
 446                 toplay = 'W';
 447                 ++i;
 448                 ++move_num;
 449         }
 450         for ( ; i < pretty_pv.length; ++i) {
 451                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 452
 453                 if (toplay == 'W') {
 454                         if (i > opt_limit && !opt_showlast) {
 455                                 return pv + ' (…)';
 456                         }
 457                         if (pv != '') {
 458                                 pv += ' ';
 459                         }
 460                         pv += move_num + '. ' + move;
 461                         ++move_num;
 462                         toplay = 'B';
 463                 } else {
 464                         pv += ' ' + move;
 465                         toplay = 'W';
 466                 }
 467         }
 468         return pv;
 469 }
 470
 471 var update_highlight = function() {
 472         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 473         if (current_display_line === null && highlight_from !== undefined && highlight_to !== undefined) {
 474                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 475                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 476         }
 477 }
 478
 479 var update_history = function() {
 480         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 481                 $("#history").html("No history");
 482         } else if (truncate_display_history) {
 483                 $("#history").html(print_pv(0, display_lines[0].pretty_pv, 1, 'W', 8, true));
 484         } else {
 485                 $("#history").html(
 486                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 487                         print_pv(0, display_lines[0].pretty_pv, 1, 'W'));
 488         }
 489 }
 490
 491 /**
 492  * @param {!boolean} truncate_history
 493  */
 494 var collapse_history = function(truncate_history) {
 495         truncate_display_history = truncate_history;
 496         update_history();
 497 }
 498 window['collapse_history'] = collapse_history;
 499
 500 var update_refutation_lines = function() {
 501         if (fen === null) {
 502                 return;
 503         }
 504         if (display_lines.length > 2) {
 505                 display_lines = [ display_lines[0], display_lines[1] ];
 506         }
 507
 508         var tbl = $("#refutationlines");
 509         tbl.empty();
 510
 511         var moves = [];
 512         for (var move in refutation_lines) {
 513                 moves.push(move);
 514         }
 515         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 516         moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
 517         for (var i = 0; i < moves.length; ++i) {
 518                 var line = refutation_lines[moves[i]];
 519
 520                 var tr = document.createElement("tr");
 521
 522                 var move_td = document.createElement("td");
 523                 tr.appendChild(move_td);
 524                 $(move_td).addClass("move");
 525                 if (line['pv_uci'].length == 0) {
 526                         $(move_td).text(line['pretty_move']);
 527                 } else {
 528                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 529                         $(move_td).html(move);
 530                 }
 531
 532                 var score_td = document.createElement("td");
 533                 tr.appendChild(score_td);
 534                 $(score_td).addClass("score");
 535                 $(score_td).text(line['pretty_score']);
 536
 537                 var depth_td = document.createElement("td");
 538                 tr.appendChild(depth_td);
 539                 $(depth_td).addClass("depth");
 540                 $(depth_td).text("d" + line['depth']);
 541
 542                 var pv_td = document.createElement("td");
 543                 tr.appendChild(pv_td);
 544                 $(pv_td).addClass("pv");
 545                 $(pv_td).html(add_pv(fen, line['pv_uci'], line['pv_pretty'], move_num, toplay, 10));
 546
 547                 tbl.append(tr);
 548         }
 549
 550         // Make one of the links clickable and the other nonclickable.
 551         if (sort_refutation_lines_by_score) {
 552                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 553                 $("#sortbyscore1").html("<strong>Score</strong>");
 554         } else {
 555                 $("#sortbyscore0").html("<strong>Move</strong>");
 556                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 557         }
 558 }
 559
 560 /**
 561  * @param {Object} data
 562  * @param {number} num_viewers
 563  */
 564 var update_board = function(data, num_viewers) {
 565         display_lines = [];
 566
 567         // The headline.
 568         var headline;
 569         if (data['position']['player_w'] && data['position']['player_b']) {
 570                 headline = data['position']['player_w'] + '–' +
 571                         data['position']['player_b'] + ', analysis';
 572         } else {
 573                 headline = 'Analysis';
 574         }
 575         if (data['position']['last_move'] !== 'none') {
 576                 headline += ' after '
 577                 if (data['position']['toplay'] == 'W') {
 578                         headline += (data['position']['move_num']-1) + '… ';
 579                 } else {
 580                         headline += data['position']['move_num'] + '. ';
 581                 }
 582                 headline += data['position']['last_move'];
 583         }
 584
 585         $("#headline").text(headline);
 586
 587         if (num_viewers === null) {
 588                 $("#numviewers").text("");
 589         } else if (num_viewers == 1) {
 590                 $("#numviewers").text("You are the only current viewer");
 591         } else {
 592                 $("#numviewers").text(num_viewers + " current viewers");
 593         }
 594
 595         // The engine id.
 596         if (data['id'] && data['id']['name'] !== null) {
 597                 $("#engineid").text(data['id']['name']);
 598         }
 599
 600         // The score.
 601         if (data['score'] !== null) {
 602                 $("#score").text(data['score']);
 603         }
 604         if (data['short_score'] !== undefined) {
 605                 document.title = '(' + data['short_score'] + ') analysis.sesse.net';
 606         } else {
 607                 document.title = 'analysis.sesse.net';
 608         }
 609
 610         // The search stats.
 611         if (data['tablebase'] == 1) {
 612                 $("#searchstats").text("Tablebase result");
 613         } else if (data['nodes'] && data['nps'] && data['depth']) {
 614                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
 615                 if (data['seldepth']) {
 616                         stats += ' (' + data['seldepth'] + ' selective)';
 617                 }
 618                 if (data['tbhits'] && data['tbhits'] > 0) {
 619                         if (data['tbhits'] == 1) {
 620                                 stats += ', one Syzygy hit';
 621                         } else {
 622                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
 623                         }
 624                 }
 625
 626                 $("#searchstats").text(stats);
 627         } else {
 628                 $("#searchstats").text("");
 629         }
 630
 631         // Update the board itself.
 632         fen = data['position']['fen'];
 633         update_displayed_line();
 634
 635         if (data['position']['last_move_uci']) {
 636                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
 637                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
 638         } else {
 639                 highlight_from = highlight_to = undefined;
 640         }
 641         update_highlight();
 642
 643         // Print the history.
 644         if (data['position']['history']) {
 645                 add_pv('start', data['position']['history'], data['position']['pretty_history'], 1, 'W', 8, true);
 646         } else {
 647                 display_lines.push(null);
 648         }
 649         update_history();
 650
 651         // Print the PV.
 652         $("#pv").html(add_pv(data['position']['fen'], data['pv_uci'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));
 653
 654         // Update the PV arrow.
 655         clear_arrows();
 656         if (data['pv_uci'].length >= 1) {
 657                 // draw a continuation arrow as long as it's the same piece
 658                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
 659                         var from = data['pv_uci'][i].substr(0, 2);
 660                         var to = data['pv_uci'][i].substr(2,4);
 661                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
 662                              interfering_arrow(from, to)) {
 663                                 break;
 664                         }
 665                         create_arrow(from, to, '#f66', 6, 20);
 666                 }
 667
 668                 var alt_moves = find_nonstupid_moves(data, 30);
 669                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
 670                         create_arrow(alt_moves[i].substr(0, 2),
 671                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
 672                 }
 673         }
 674
 675         // See if all semi-reasonable moves have only one possible response.
 676         if (data['pv_uci'].length >= 2) {
 677                 var nonstupid_moves = find_nonstupid_moves(data, 300);
 678                 var response = data['pv_uci'][1];
 679                 for (var i = 0; i < nonstupid_moves.length; ++i) {
 680                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
 681                                 // ignore the PV move for refutation lines.
 682                                 continue;
 683                         }
 684                         if (!data['refutation_lines'] ||
 685                             !data['refutation_lines'][nonstupid_moves[i]] ||
 686                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
 687                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
 688                                 // Incomplete PV, abort.
 689                                 response = undefined;
 690                                 break;
 691                         }
 692                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
 693                         if (response !== this_response) {
 694                                 // Different response depending on lines, abort.
 695                                 response = undefined;
 696                                 break;
 697                         }
 698                 }
 699
 700                 if (nonstupid_moves.length > 0 && response !== undefined) {
 701                         create_arrow(response.substr(0, 2),
 702                                      response.substr(2, 2), '#66f', 6, 20);
 703                 }
 704         }
 705
 706         // Update the refutation lines.
 707         fen = data['position']['fen'];
 708         move_num = data['position']['move_num'];
 709         toplay = data['position']['toplay'];
 710         refutation_lines = data['refutation_lines'];
 711         update_refutation_lines();
 712
 713         // Next update.
 714         setTimeout(function() { request_update(); }, 100);
 715 }
 716
 717 /**
 718  * @param {boolean} sort_by_score
 719  */
 720 var resort_refutation_lines = function(sort_by_score) {
 721         sort_refutation_lines_by_score = sort_by_score;
 722         update_refutation_lines();
 723 }
 724 window['resort_refutation_lines'] = resort_refutation_lines;
 725
 726 /**
 727  * @param {boolean} truncate_history
 728  */
 729 var set_truncate_history = function(truncate_history) {
 730         truncate_display_history = truncate_history;
 731         update_refutation_lines();
 732 }
 733 window['set_truncate_history'] = set_truncate_history;
 734
 735 /**
 736  * @param {number} line_num
 737  * @param {number} move_num
 738  */
 739 var show_line = function(line_num, move_num) {
 740         if (line_num == -1) {
 741                 current_display_line = null;
 742                 current_display_move = null;
 743         } else {
 744                 current_display_line = display_lines[line_num];
 745                 current_display_move = move_num;
 746         }
 747         update_displayed_line();
 748         update_highlight();
 749         redraw_arrows();
 750 }
 751 window['show_line'] = show_line;
 752
 753 var prev_move = function() {
 754         if (current_display_move > -1) {
 755                 --current_display_move;
 756         }
 757         update_displayed_line();
 758 }
 759 window['prev_move'] = prev_move;
 760
 761 var next_move = function() {
 762         if (current_display_line && current_display_move < current_display_line.pretty_pv.length - 1) {
 763                 ++current_display_move;
 764         }
 765         update_displayed_line();
 766 }
 767 window['next_move'] = next_move;
 768
 769 var update_displayed_line = function() {
 770         if (highlighted_move !== null) {
 771                 highlighted_move.removeClass('highlight');
 772         }
 773         if (current_display_line === null) {
 774                 $("#linenav").hide();
 775                 $("#linemsg").show();
 776                 board.position(fen);
 777                 return;
 778         }
 779
 780         $("#linenav").show();
 781         $("#linemsg").hide();
 782
 783         if (current_display_move <= 0) {
 784                 $("#prevmove").html("Previous");
 785         } else {
 786                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
 787         }
 788         if (current_display_move == current_display_line.uci_pv.length - 1) {
 789                 $("#nextmove").html("Next");
 790         } else {
 791                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
 792         }
 793
 794         hiddenboard.position(current_display_line.start_fen, false);
 795         for (var i = 0; i <= current_display_move; ++i) {
 796                 var pos = hiddenboard.position();
 797                 var move = current_display_line.uci_pv[i];
 798                 var source = move.substr(0, 2);
 799                 var target = move.substr(2, 2);
 800                 var promo = move.substr(4, 1);
 801
 802                 // Check if we need to do en passant.
 803                 var piece = pos[source];
 804                 if (piece == "wP" || piece == "bP") {
 805                         if (source.substr(0, 1) != target.substr(0, 1) &&
 806                             pos[target] === undefined) {
 807                                 var ep_square = target.substr(0, 1) + source.substr(1, 1);
 808                                 delete pos[ep_square];
 809                                 hiddenboard.position(pos, false);
 810                         }
 811                 }
 812
 813                 move = source + "-" + target;
 814                 hiddenboard.move(move, false);
 815                 pos = hiddenboard.position();
 816
 817                 // Do promotion if needed.
 818                 if (promo != "") {
 819                         pos[target] = pos[target].substr(0, 1) + promo.toUpperCase();
 820                         hiddenboard.position(pos, false);
 821                 }
 822
 823                 // chessboard.js does not automatically move the rook on castling
 824                 // (issue #51; marked as won't fix), so update it ourselves.
 825                 if (move == "e1-g1" && hiddenboard.position().g1 == "wK") {  // white O-O
 826                         hiddenboard.move("h1-f1", false);
 827                 } else if (move == "e1-c1" && hiddenboard.position().c1 == "wK") {  // white O-O-O
 828                         hiddenboard.move("a1-d1", false);
 829                 } else if (move == "e8-g8" && hiddenboard.position().g8 == "bK") {  // black O-O
 830                         hiddenboard.move("h8-f8", false);
 831                 } else if (move == "e8-c8" && hiddenboard.position().c8 == "bK") {  // black O-O-O
 832                         hiddenboard.move("a8-d8", false);
 833                 }
 834         }
 835
 836         highlighted_move = $("#automove" + current_display_line.line_number + "-" + current_display_move);
 837         highlighted_move.addClass('highlight');
 838
 839         board.position(hiddenboard.position());
 840 }
 841
 842 var init = function() {
 843         unique = get_unique();
 844
 845         // Create board.
 846         board = new window.ChessBoard('board', 'start');
 847         hiddenboard = new window.ChessBoard('hiddenboard', 'start');
 848
 849         request_update();
 850         $(window).resize(function() {
 851                 board.resize();
 852                 update_highlight();
 853                 redraw_arrows();
 854         });
 855         $(window).keyup(function(event) {
 856                 if (event.which == 39) {
 857                         next_move();
 858                 } else if (event.which == 37) {
 859                         prev_move();
 860                 }
 861         });
 862 };
 863 $(document).ready(init);
 864
 865 })();