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