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

   1 (function() {
   2
   3 /** @type {window.ChessBoard} @private */
   4 var board = null;
   5
   6 /**
   7  * The most recent analysis data we have from the server
   8  * (about the most recent position).
   9  *
  10  * @type {?Object}
  11  * @private */
  12 var current_analysis_data = null;
  13
  14 /**
  15  * If we are displaying previous analysis, this is non-null,
  16  * and will override most of current_analysis_data.
  17  *
  18  * @type {?Object}
  19  * @private
  20  */
  21 var displayed_analysis_data = null;
  22
  23 /** @type {Array.<{
  24  *      from_col: number,
  25  *      from_row: number,
  26  *      to_col: number,
  27  *      to_row: number,
  28  *      line_width: number,
  29  *      arrow_size: number,
  30  *      fg_color: string
  31  * }>}
  32  * @private
  33  */
  34 var arrows = [];
  35
  36 /** @type {Array.<Array.<boolean>>} */
  37 var occupied_by_arrows = [];
  38
  39 var refutation_lines = [];
  40
  41 /** @type {!number} @private */
  42 var move_num = 1;
  43
  44 /** @type {!string} @private */
  45 var toplay = 'W';
  46
  47 /** @type {number} @private */
  48 var ims = 0;
  49
  50 /** @type {boolean} @private */
  51 var sort_refutation_lines_by_score = true;
  52
  53 /** @type {boolean} @private */
  54 var truncate_display_history = true;
  55
  56 /** @type {!string|undefined} @private */
  57 var highlight_from = undefined;
  58
  59 /** @type {!string|undefined} @private */
  60 var highlight_to = undefined;
  61
  62 /** @type {?jQuery} @private */
  63 var highlighted_move = null;
  64
  65 /** @type {?number} @private */
  66 var unique = null;
  67
  68 /** @type {boolean} @private */
  69 var enable_sound = false;
  70
  71 /**
  72  * Our best estimate of how many milliseconds we need to add to
  73  * new Date() to get the true UTC time. Calibrated against the
  74  * server clock.
  75  *
  76  * @type {?number}
  77  * @private
  78  */
  79 var client_clock_offset_ms = null;
  80
  81 var clock_timer = null;
  82
  83 /** The current position on the board, represented as a FEN string.
  84  * @type {?string}
  85  * @private
  86  */
  87 var fen = null;
  88
  89 /** @typedef {{
  90  *    start_fen: string,
  91  *    uci_pv: Array.<string>,
  92  *    pretty_pv: Array.<string>,
  93  *    line_num: number
  94  * }} DisplayLine
  95  */
  96
  97 /** @type {Array.<DisplayLine>}
  98  * @private
  99  */
 100 var display_lines = [];
 101
 102 /** @type {?DisplayLine} @private */
 103 var current_display_line = null;
 104
 105 /** @type {boolean} @private */
 106 var current_display_line_is_history = false;
 107
 108 /** @type {?number} @private */
 109 var current_display_move = null;
 110
 111 var supports_html5_storage = function() {
 112         try {
 113                 return 'localStorage' in window && window['localStorage'] !== null;
 114         } catch (e) {
 115                 return false;
 116         }
 117 }
 118
 119 // Make the unique token persistent so people refreshing the page won't count twice.
 120 // Of course, you can never fully protect against people deliberately wanting to spam.
 121 var get_unique = function() {
 122         var use_local_storage = supports_html5_storage();
 123         if (use_local_storage && localStorage['unique']) {
 124                 return localStorage['unique'];
 125         }
 126         var unique = Math.random();
 127         if (use_local_storage) {
 128                 localStorage['unique'] = unique;
 129         }
 130         return unique;
 131 }
 132
 133 var request_update = function() {
 134         $.ajax({
 135                 url: "/analysis.pl?ims=" + ims + "&unique=" + unique
 136         }).done(function(data, textstatus, xhr) {
 137                 sync_server_clock(xhr.getResponseHeader('Date'));
 138                 ims = xhr.getResponseHeader('X-Remoteglot-Last-Modified');
 139                 var num_viewers = xhr.getResponseHeader('X-Remoteglot-Num-Viewers');
 140                 possibly_play_sound(current_analysis_data, data);
 141                 current_analysis_data = data;
 142                 update_board(current_analysis_data, displayed_analysis_data);
 143                 update_num_viewers(num_viewers);
 144
 145                 // Next update.
 146                 setTimeout(function() { request_update(); }, 100);
 147         }).fail(function() {
 148                 // Wait ten seconds, then try again.
 149                 setTimeout(function() { request_update(); }, 10000);
 150         });
 151 }
 152
 153 var possibly_play_sound = function(old_data, new_data) {
 154         if (!enable_sound) {
 155                 return;
 156         }
 157         if (old_data === null) {
 158                 return;
 159         }
 160         var ding = document.getElementById('ding');
 161         if (ding && ding.play) {
 162                 if (old_data['position'] && old_data['position']['fen'] &&
 163                     new_data['position'] && new_data['position']['fen'] &&
 164                     (old_data['position']['fen'] !== new_data['position']['fen'] ||
 165                      old_data['position']['move_num'] !== new_data['position']['move_num'])) {
 166                         ding.play();
 167                 }
 168         }
 169 }
 170
 171 /**
 172  * @type {!string} server_date_string
 173  */
 174 var sync_server_clock = function(server_date_string) {
 175         var server_time_ms = new Date(server_date_string).getTime();
 176         var client_time_ms = new Date().getTime();
 177         var estimated_offset_ms = server_time_ms - client_time_ms;
 178
 179         // In order not to let the noise move us too much back and forth
 180         // (the server only has one-second resolution anyway), we only
 181         // change an existing skew if we are at least five seconds off.
 182         if (client_clock_offset_ms === null ||
 183             Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
 184                 client_clock_offset_ms = estimated_offset_ms;
 185         }
 186 }
 187
 188 var clear_arrows = function() {
 189         for (var i = 0; i < arrows.length; ++i) {
 190                 if (arrows[i].svg) {
 191                         arrows[i].svg.parentElement.removeChild(arrows[i].svg);
 192                         delete arrows[i].svg;
 193                 }
 194         }
 195         arrows = [];
 196
 197         occupied_by_arrows = [];
 198         for (var y = 0; y < 8; ++y) {
 199                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 200         }
 201 }
 202
 203 var redraw_arrows = function() {
 204         for (var i = 0; i < arrows.length; ++i) {
 205                 position_arrow(arrows[i]);
 206         }
 207 }
 208
 209 /** @param {!number} x
 210  * @return {!number}
 211  */
 212 var sign = function(x) {
 213         if (x > 0) {
 214                 return 1;
 215         } else if (x < 0) {
 216                 return -1;
 217         } else {
 218                 return 0;
 219         }
 220 }
 221
 222 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 223  * @param {!string} from The square the arrow is from (e.g. e4).
 224  * @param {!string} to The square the arrow is to (e.g. e4).
 225  * @return {boolean}
 226  */
 227 var interfering_arrow = function(from, to) {
 228         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 229         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 230         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 231         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 232
 233         occupied_by_arrows[from_row][from_col] = true;
 234
 235         // Knight move: Just check that we haven't been at the destination before.
 236         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 237             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 238                 return occupied_by_arrows[to_row][to_col];
 239         }
 240
 241         // Sliding piece: Check if anything except the from-square is seen before.
 242         var dx = sign(to_col - from_col);
 243         var dy = sign(to_row - from_row);
 244         var x = from_col;
 245         var y = from_row;
 246         do {
 247                 x += dx;
 248                 y += dy;
 249                 if (occupied_by_arrows[y][x]) {
 250                         return true;
 251                 }
 252                 occupied_by_arrows[y][x] = true;
 253         } while (x != to_col || y != to_row);
 254
 255         return false;
 256 }
 257
 258 /** Find a point along the coordinate system given by the given line,
 259  * <t> units forward from the start of the line, <u> units to the right of it.
 260  * @param {!number} x1
 261  * @param {!number} x2
 262  * @param {!number} y1
 263  * @param {!number} y2
 264  * @param {!number} t
 265  * @param {!number} u
 266  * @return {!string} The point in "x y" form, suitable for SVG paths.
 267  */
 268 var point_from_start = function(x1, y1, x2, y2, t, u) {
 269         var dx = x2 - x1;
 270         var dy = y2 - y1;
 271
 272         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 273         dx *= norm;
 274         dy *= norm;
 275
 276         var x = x1 + dx * t + dy * u;
 277         var y = y1 + dy * t - dx * u;
 278         return x + " " + y;
 279 }
 280
 281 /** Find a point along the coordinate system given by the given line,
 282  * <t> units forward from the end of the line, <u> units to the right of it.
 283  * @param {!number} x1
 284  * @param {!number} x2
 285  * @param {!number} y1
 286  * @param {!number} y2
 287  * @param {!number} t
 288  * @param {!number} u
 289  * @return {!string} The point in "x y" form, suitable for SVG paths.
 290  */
 291 var point_from_end = function(x1, y1, x2, y2, t, u) {
 292         var dx = x2 - x1;
 293         var dy = y2 - y1;
 294
 295         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 296         dx *= norm;
 297         dy *= norm;
 298
 299         var x = x2 + dx * t + dy * u;
 300         var y = y2 + dy * t - dx * u;
 301         return x + " " + y;
 302 }
 303
 304 var position_arrow = function(arrow) {
 305         if (arrow.svg) {
 306                 arrow.svg.parentElement.removeChild(arrow.svg);
 307                 delete arrow.svg;
 308         }
 309         if (current_display_line !== null && !current_display_line_is_history) {
 310                 return;
 311         }
 312
 313         var pos = $(".square-a8").position();
 314
 315         var zoom_factor = $("#board").width() / 400.0;
 316         var line_width = arrow.line_width * zoom_factor;
 317         var arrow_size = arrow.arrow_size * zoom_factor;
 318
 319         var square_width = $(".square-a8").width();
 320         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 321         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 322         var from_x = (arrow.from_col + 0.5)*square_width;
 323         var to_x = (arrow.to_col + 0.5)*square_width;
 324
 325         var SVG_NS = "http://www.w3.org/2000/svg";
 326         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 327         var svg = document.createElementNS(SVG_NS, "svg");
 328         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 329         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 330         svg.setAttribute("style", "position: absolute");
 331         svg.setAttribute("position", "absolute");
 332         svg.setAttribute("version", "1.1");
 333         svg.setAttribute("class", "c1");
 334         svg.setAttribute("xmlns", XHTML_NS);
 335
 336         var x1 = from_x;
 337         var y1 = from_y;
 338         var x2 = to_x;
 339         var y2 = to_y;
 340
 341         // Draw the line.
 342         var outline = document.createElementNS(SVG_NS, "path");
 343         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));
 344         outline.setAttribute("xmlns", XHTML_NS);
 345         outline.setAttribute("stroke", "#666");
 346         outline.setAttribute("stroke-width", line_width + 2);
 347         outline.setAttribute("fill", "none");
 348         svg.appendChild(outline);
 349
 350         var path = document.createElementNS(SVG_NS, "path");
 351         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));
 352         path.setAttribute("xmlns", XHTML_NS);
 353         path.setAttribute("stroke", arrow.fg_color);
 354         path.setAttribute("stroke-width", line_width);
 355         path.setAttribute("fill", "none");
 356         svg.appendChild(path);
 357
 358         // Then the arrow head.
 359         var head = document.createElementNS(SVG_NS, "path");
 360         head.setAttribute("d",
 361                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 362                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 363                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 364                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 365                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 366         head.setAttribute("xmlns", XHTML_NS);
 367         head.setAttribute("stroke", "#000");
 368         head.setAttribute("stroke-width", "1");
 369         head.setAttribute("fill", arrow.fg_color);
 370         svg.appendChild(head);
 371
 372         $(svg).css({ top: pos.top, left: pos.left });
 373         document.body.appendChild(svg);
 374         arrow.svg = svg;
 375 }
 376
 377 /**
 378  * @param {!string} from_square
 379  * @param {!string} to_square
 380  * @param {!string} fg_color
 381  * @param {number} line_width
 382  * @param {number} arrow_size
 383  */
 384 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 385         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 386         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 387         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 388         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 389
 390         // Create arrow.
 391         var arrow = {
 392                 from_col: from_col,
 393                 from_row: from_row,
 394                 to_col: to_col,
 395                 to_row: to_row,
 396                 line_width: line_width,
 397                 arrow_size: arrow_size,
 398                 fg_color: fg_color
 399         };
 400
 401         position_arrow(arrow);
 402         arrows.push(arrow);
 403 }
 404
 405 var compare_by_sort_key = function(refutation_lines, a, b) {
 406         var ska = refutation_lines[a]['sort_key'];
 407         var skb = refutation_lines[b]['sort_key'];
 408         if (ska < skb) return -1;
 409         if (ska > skb) return 1;
 410         return 0;
 411 };
 412
 413 var compare_by_score = function(refutation_lines, a, b) {
 414         var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
 415         var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
 416         return sa - sb;
 417 }
 418
 419 /**
 420  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 421  * sorted by quality, descending.
 422  *
 423  * @param {!Object} data
 424  * @param {number} margin The maximum number of centipawns worse than the
 425  *     best move can be and still be included.
 426  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 427  *     moves, in score order.
 428  */
 429 var find_nonstupid_moves = function(data, margin) {
 430         // First of all, if there are any moves that are more than 0.5 ahead of
 431         // the primary move, the refutation lines are probably bunk, so just
 432         // kill them all.
 433         var best_score = undefined;
 434         var pv_score = undefined;
 435         for (var move in data['refutation_lines']) {
 436                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 437                 if (move == data['pv_uci'][0]) {
 438                         pv_score = score;
 439                 }
 440                 if (best_score === undefined || score > best_score) {
 441                         best_score = score;
 442                 }
 443                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 444                         return [];
 445                 }
 446         }
 447
 448         if (best_score - pv_score > 50) {
 449                 return [];
 450         }
 451
 452         // Now find all moves that are within “margin” of the best score.
 453         // The PV move will always be first.
 454         var moves = [];
 455         for (var move in data['refutation_lines']) {
 456                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 457                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 458                         moves.push(move);
 459                 }
 460         }
 461         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
 462         moves.unshift(data['pv_uci'][0]);
 463
 464         return moves;
 465 }
 466
 467 /**
 468  * @param {number} x
 469  * @return {!string}
 470  */
 471 var thousands = function(x) {
 472         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 473 }
 474
 475 /**
 476  * @param {!string} fen
 477  * @param {Array.<string>} pretty_pv
 478  * @param {number} move_num
 479  * @param {!string} toplay
 480  * @param {number=} opt_limit
 481  * @param {boolean=} opt_showlast
 482  */
 483 var add_pv = function(fen, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 484         display_lines.push({
 485                 start_fen: fen,
 486                 pretty_pv: pretty_pv,
 487                 line_number: display_lines.length
 488         });
 489         return print_pv(display_lines.length - 1, pretty_pv, move_num, toplay, opt_limit, opt_showlast);
 490 }
 491
 492 /**
 493  * @param {number} line_num
 494  * @param {Array.<string>} pretty_pv
 495  * @param {number} move_num
 496  * @param {!string} toplay
 497  * @param {number=} opt_limit
 498  * @param {boolean=} opt_showlast
 499  */
 500 var print_pv = function(line_num, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {
 501         var pv = '';
 502         var i = 0;
 503         if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
 504                 // Truncate the PV at the beginning (instead of at the end).
 505                 // We assume here that toplay is 'W'. We also assume that if
 506                 // opt_showlast is set, then it is the history, and thus,
 507                 // the UI should be to expand the history.
 508                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 509                 i = pretty_pv.length - opt_limit;
 510                 if (i % 2 == 1) {
 511                         ++i;
 512                 }
 513                 move_num += i / 2;
 514         } else if (toplay == 'B' && pretty_pv.length > 0) {
 515                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 516                 pv = move_num + '. … ' + move;
 517                 toplay = 'W';
 518                 ++i;
 519                 ++move_num;
 520         }
 521         for ( ; i < pretty_pv.length; ++i) {
 522                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 523
 524                 if (toplay == 'W') {
 525                         if (i > opt_limit && !opt_showlast) {
 526                                 return pv + ' (…)';
 527                         }
 528                         if (pv != '') {
 529                                 pv += ' ';
 530                         }
 531                         pv += move_num + '. ' + move;
 532                         ++move_num;
 533                         toplay = 'B';
 534                 } else {
 535                         pv += ' ' + move;
 536                         toplay = 'W';
 537                 }
 538         }
 539         return pv;
 540 }
 541
 542 var update_highlight = function() {
 543         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 544         if ((current_display_line === null || current_display_line_is_history) &&
 545             highlight_from !== undefined && highlight_to !== undefined) {
 546                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 547                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 548         }
 549 }
 550
 551 var update_history = function() {
 552         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 553                 $("#history").html("No history");
 554         } else if (truncate_display_history) {
 555                 $("#history").html(print_pv(0, display_lines[0].pretty_pv, 1, 'W', 8, true));
 556         } else {
 557                 $("#history").html(
 558                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 559                         print_pv(0, display_lines[0].pretty_pv, 1, 'W'));
 560         }
 561 }
 562
 563 /**
 564  * @param {!boolean} truncate_history
 565  */
 566 var collapse_history = function(truncate_history) {
 567         truncate_display_history = truncate_history;
 568         update_history();
 569 }
 570 window['collapse_history'] = collapse_history;
 571
 572 var update_refutation_lines = function() {
 573         if (fen === null) {
 574                 return;
 575         }
 576         if (display_lines.length > 2) {
 577                 display_lines = [ display_lines[0], display_lines[1] ];
 578         }
 579
 580         var tbl = $("#refutationlines");
 581         tbl.empty();
 582
 583         var moves = [];
 584         for (var move in refutation_lines) {
 585                 moves.push(move);
 586         }
 587         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 588         moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
 589         for (var i = 0; i < moves.length; ++i) {
 590                 var line = refutation_lines[moves[i]];
 591
 592                 var tr = document.createElement("tr");
 593
 594                 var move_td = document.createElement("td");
 595                 tr.appendChild(move_td);
 596                 $(move_td).addClass("move");
 597                 if (line['pv_pretty'].length == 0) {
 598                         $(move_td).text(line['pretty_move']);
 599                 } else {
 600                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 601                         $(move_td).html(move);
 602                 }
 603
 604                 var score_td = document.createElement("td");
 605                 tr.appendChild(score_td);
 606                 $(score_td).addClass("score");
 607                 $(score_td).text(line['pretty_score']);
 608
 609                 var depth_td = document.createElement("td");
 610                 tr.appendChild(depth_td);
 611                 $(depth_td).addClass("depth");
 612                 $(depth_td).text("d" + line['depth']);
 613
 614                 var pv_td = document.createElement("td");
 615                 tr.appendChild(pv_td);
 616                 $(pv_td).addClass("pv");
 617                 $(pv_td).html(add_pv(fen, line['pv_pretty'], move_num, toplay, 10));
 618
 619                 tbl.append(tr);
 620         }
 621
 622         // Make one of the links clickable and the other nonclickable.
 623         if (sort_refutation_lines_by_score) {
 624                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 625                 $("#sortbyscore1").html("<strong>Score</strong>");
 626         } else {
 627                 $("#sortbyscore0").html("<strong>Move</strong>");
 628                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 629         }
 630 }
 631
 632 /**
 633  * @param {Object} data
 634  * @param {?Object} display_data
 635  */
 636 var update_board = function(current_data, display_data) {
 637         var data = display_data || current_data;
 638
 639         display_lines = [];
 640
 641         // Print the history. This is pretty much the only thing that's
 642         // unconditionally taken from current_data (we're not interested in
 643         // historic history).
 644         if (current_data['position']['pretty_history']) {
 645                 add_pv('start', current_data['position']['pretty_history'], 1, 'W', 8, true);
 646         } else {
 647                 display_lines.push(null);
 648         }
 649         update_history();
 650
 651         // The headline. Names are always fetched from current_data;
 652         // the rest can depend a bit.
 653         var headline;
 654         if (current_data &&
 655             current_data['position']['player_w'] && current_data['position']['player_b']) {
 656                 headline = current_data['position']['player_w'] + '–' +
 657                         current_data['position']['player_b'] + ', analysis';
 658         } else {
 659                 headline = 'Analysis';
 660         }
 661
 662         var last_move;
 663         if (display_data) {
 664                 // Displaying some non-current position, pick out the last move
 665                 // from the history. This will work even if the fetch failed.
 666                 last_move = format_move_with_number(
 667                         current_display_line.pretty_pv[current_display_move],
 668                         Math.floor((current_display_move + 1) / 2) + 1,
 669                         (current_display_move % 2 == 1));
 670                 headline += ' after ' + last_move;
 671         } else if (data['position']['last_move'] !== 'none') {
 672                 last_move = format_move_with_number(
 673                         data['position']['last_move'],
 674                         data['position']['move_num'],
 675                         data['position']['toplay'] == 'W');
 676                 headline += ' after ' + last_move;
 677         } else {
 678                 last_move = null;
 679         }
 680         $("#headline").text(headline);
 681
 682         // The <title> contains a very brief headline.
 683         var title_elems = [];
 684         if (data['short_score'] !== undefined && data['short_score'] !== null) {
 685                 title_elems.push(data['short_score'].replace(/^ /, ""));
 686         }
 687         if (last_move !== null) {
 688                 title_elems.push(last_move);
 689         }
 690
 691         if (title_elems.length != 0) {
 692                 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
 693         } else {
 694                 document.title = 'analysis.sesse.net';
 695         }
 696
 697         // The last move (shown by highlighting the from and to squares).
 698         if (data['position'] && data['position']['last_move_uci']) {
 699                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
 700                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
 701         } else if (current_display_line_is_history && current_display_move >= 0) {
 702                 // We don't have historic analysis for this position, but we
 703                 // can reconstruct what the last move was by just replaying
 704                 // from the start.
 705                 var hiddenboard = new Chess();
 706                 for (var i = 0; i <= current_display_move; ++i) {
 707                         hiddenboard.move(current_display_line.pretty_pv[i]);
 708                 }
 709                 var moves = hiddenboard.history({ verbose: true });
 710                 var last_move = moves.pop();
 711                 highlight_from = last_move.from;
 712                 highlight_to = last_move.to;
 713         } else {
 714                 highlight_from = highlight_to = undefined;
 715         }
 716         update_highlight();
 717
 718         if (data['failed']) {
 719                 $("#score").text("No analysis for this move");
 720                 $("#pv").empty();
 721                 $("#searchstats").html("&nbsp;");
 722                 $("#refutationlines").empty();
 723                 $("#whiteclock").empty();
 724                 $("#blackclock").empty();
 725                 refutation_lines = [];
 726                 update_refutation_lines();
 727                 clear_arrows();
 728                 update_displayed_line();
 729                 return;
 730         }
 731
 732         update_clock();
 733
 734         // The engine id.
 735         if (data['id'] && data['id']['name'] !== null) {
 736                 $("#engineid").text(data['id']['name']);
 737         }
 738
 739         // The score.
 740         if (data['score'] !== null) {
 741                 $("#score").text(data['score']);
 742         }
 743
 744         // The search stats.
 745         if (data['tablebase'] == 1) {
 746                 $("#searchstats").text("Tablebase result");
 747         } else if (data['nodes'] && data['nps'] && data['depth']) {
 748                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
 749                 if (data['seldepth']) {
 750                         stats += ' (' + data['seldepth'] + ' selective)';
 751                 }
 752                 if (data['tbhits'] && data['tbhits'] > 0) {
 753                         if (data['tbhits'] == 1) {
 754                                 stats += ', one Syzygy hit';
 755                         } else {
 756                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
 757                         }
 758                 }
 759
 760                 $("#searchstats").text(stats);
 761         } else {
 762                 $("#searchstats").text("");
 763         }
 764
 765         // Update the board itself.
 766         fen = data['position']['fen'];
 767         update_displayed_line();
 768
 769         // Print the PV.
 770         $("#pv").html(add_pv(data['position']['fen'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));
 771
 772         // Update the PV arrow.
 773         clear_arrows();
 774         if (data['pv_uci'].length >= 1) {
 775                 // draw a continuation arrow as long as it's the same piece
 776                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
 777                         var from = data['pv_uci'][i].substr(0, 2);
 778                         var to = data['pv_uci'][i].substr(2,4);
 779                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
 780                              interfering_arrow(from, to)) {
 781                                 break;
 782                         }
 783                         create_arrow(from, to, '#f66', 6, 20);
 784                 }
 785
 786                 var alt_moves = find_nonstupid_moves(data, 30);
 787                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
 788                         create_arrow(alt_moves[i].substr(0, 2),
 789                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
 790                 }
 791         }
 792
 793         // See if all semi-reasonable moves have only one possible response.
 794         if (data['pv_uci'].length >= 2) {
 795                 var nonstupid_moves = find_nonstupid_moves(data, 300);
 796                 var response = data['pv_uci'][1];
 797                 for (var i = 0; i < nonstupid_moves.length; ++i) {
 798                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
 799                                 // ignore the PV move for refutation lines.
 800                                 continue;
 801                         }
 802                         if (!data['refutation_lines'] ||
 803                             !data['refutation_lines'][nonstupid_moves[i]] ||
 804                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
 805                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
 806                                 // Incomplete PV, abort.
 807                                 response = undefined;
 808                                 break;
 809                         }
 810                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
 811                         if (response !== this_response) {
 812                                 // Different response depending on lines, abort.
 813                                 response = undefined;
 814                                 break;
 815                         }
 816                 }
 817
 818                 if (nonstupid_moves.length > 0 && response !== undefined) {
 819                         create_arrow(response.substr(0, 2),
 820                                      response.substr(2, 2), '#66f', 6, 20);
 821                 }
 822         }
 823
 824         // Update the refutation lines.
 825         fen = data['position']['fen'];
 826         move_num = data['position']['move_num'];
 827         toplay = data['position']['toplay'];
 828         refutation_lines = data['refutation_lines'];
 829         update_refutation_lines();
 830 }
 831
 832 /**
 833  * @param {number} num_viewers
 834  */
 835 var update_num_viewers = function(num_viewers) {
 836         if (num_viewers === null) {
 837                 $("#numviewers").text("");
 838         } else if (num_viewers == 1) {
 839                 $("#numviewers").text("You are the only current viewer");
 840         } else {
 841                 $("#numviewers").text(num_viewers + " current viewers");
 842         }
 843 }
 844
 845 var update_clock = function() {
 846         clearTimeout(clock_timer);
 847
 848         var data = displayed_analysis_data || current_analysis_data;
 849         if (data['position']) {
 850                 var result = data['position']['result'];
 851                 if (result === '1-0') {
 852                         $("#whiteclock").text("1");
 853                         $("#blackclock").text("0");
 854                         return;
 855                 }
 856                 if (result === '1/2-1/2') {
 857                         $("#whiteclock").text("1/2");
 858                         $("#blackclock").text("1/2");
 859                         return;
 860                 }
 861                 if (result === '0-1') {
 862                         $("#whiteclock").text("0");
 863                         $("#blackclock").text("1");
 864                         return;
 865                 }
 866         }
 867
 868         var white_clock = "";
 869         var black_clock = "";
 870
 871         // Static clocks.
 872         if (data['position'] &&
 873             data['position']['white_clock'] &&
 874             data['position']['black_clock']) {
 875                 white_clock = data['position']['white_clock'];
 876                 black_clock = data['position']['black_clock'];
 877         }
 878
 879         // Dynamic clock (only one, obviously).
 880         var color;
 881         if (data['position']['white_clock_target']) {
 882                 color = "white";
 883         } else if (data['position']['black_clock_target']) {
 884                 color = "black";
 885         }
 886         if (color) {
 887                 var now = new Date().getTime() + client_clock_offset_ms;
 888                 var remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
 889                 if (color === "white") {
 890                         white_clock = format_clock(remaining_ms);
 891                 } else {
 892                         black_clock = format_clock(remaining_ms);
 893                 }
 894
 895                 // See when the clock will change next, and update right after that.
 896                 var next_update_ms = remaining_ms % 1000 + 100;
 897                 clock_timer = setTimeout(update_clock, next_update_ms);
 898         }
 899
 900         $("#whiteclock").text(white_clock);
 901         $("#blackclock").text(black_clock);
 902 }
 903
 904 /**
 905  * @param {Number} remaining_ms
 906  */
 907 var format_clock = function(remaining_ms) {
 908         if (remaining_ms <= 0) {
 909                 return "00:00:00";
 910         }
 911
 912         var remaining = Math.floor(remaining_ms / 1000);
 913         var seconds = remaining % 60;
 914         remaining = (remaining - seconds) / 60;
 915         var minutes = remaining % 60;
 916         remaining = (remaining - minutes) / 60;
 917         var hours = remaining;
 918         return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
 919 }
 920
 921 /**
 922  * @param {Number} x
 923  */
 924 var format_2d = function(x) {
 925         if (x >= 10) {
 926                 return x;
 927         } else {
 928                 return "0" + x;
 929         }
 930 }
 931
 932 /**
 933  * @param {string} move
 934  * @param {Number} move_num
 935  * @param {boolean} white_to_play
 936  */
 937 var format_move_with_number = function(move, move_num, white_to_play) {
 938         var ret;
 939         if (white_to_play) {
 940                 ret = (move_num - 1) + '… ';
 941         } else {
 942                 ret = move_num + '. ';
 943         }
 944         ret += move;
 945         return ret;
 946 }
 947
 948 /**
 949  * @param {boolean} sort_by_score
 950  */
 951 var resort_refutation_lines = function(sort_by_score) {
 952         sort_refutation_lines_by_score = sort_by_score;
 953         if (supports_html5_storage()) {
 954                 localStorage['sort_refutation_lines_by_score'] = sort_by_score ? 1 : 0;
 955         }
 956         update_refutation_lines();
 957 }
 958 window['resort_refutation_lines'] = resort_refutation_lines;
 959
 960 /**
 961  * @param {boolean} truncate_history
 962  */
 963 var set_truncate_history = function(truncate_history) {
 964         truncate_display_history = truncate_history;
 965         update_refutation_lines();
 966 }
 967 window['set_truncate_history'] = set_truncate_history;
 968
 969 /**
 970  * @param {number} line_num
 971  * @param {number} move_num
 972  */
 973 var show_line = function(line_num, move_num) {
 974         if (line_num == -1) {
 975                 current_display_line = null;
 976                 current_display_move = null;
 977                 if (displayed_analysis_data) {
 978                         // TODO: Support exiting to history position if we are in an
 979                         // analysis line of a history position.
 980                         displayed_analysis_data = null;
 981                         update_board(current_analysis_data, displayed_analysis_data);
 982                 }
 983         } else {
 984                 current_display_line = display_lines[line_num];
 985                 current_display_move = move_num;
 986         }
 987         current_display_line_is_history = (line_num == 0);
 988
 989         update_historic_analysis();
 990         update_displayed_line();
 991         update_highlight();
 992         redraw_arrows();
 993 }
 994 window['show_line'] = show_line;
 995
 996 var prev_move = function() {
 997         if (current_display_move > -1) {
 998                 --current_display_move;
 999         }
1000         update_historic_analysis();
1001         update_displayed_line();
1002 }
1003 window['prev_move'] = prev_move;
1004
1005 var next_move = function() {
1006         if (current_display_line && current_display_move < current_display_line.pretty_pv.length - 1) {
1007                 ++current_display_move;
1008         }
1009         update_historic_analysis();
1010         update_displayed_line();
1011 }
1012 window['next_move'] = next_move;
1013
1014 var update_historic_analysis = function() {
1015         if (!current_display_line_is_history) {
1016                 return;
1017         }
1018         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1019                 displayed_analysis_data = null;
1020                 update_board(current_analysis_data, displayed_analysis_data);
1021         }
1022
1023         // Fetch old analysis for this line if it exists.
1024         var hiddenboard = new Chess();
1025         for (var i = 0; i <= current_display_move; ++i) {
1026                 hiddenboard.move(current_display_line.pretty_pv[i]);
1027         }
1028         var filename = "/history/move" + (current_display_move + 1) + "-" +
1029                 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1030
1031         $.ajax({
1032                 url: filename
1033         }).done(function(data, textstatus, xhr) {
1034                 displayed_analysis_data = data;
1035                 update_board(current_analysis_data, displayed_analysis_data);
1036         }).fail(function() {
1037                 displayed_analysis_data = {'failed': true};
1038                 update_board(current_analysis_data, displayed_analysis_data);
1039         });
1040 }
1041
1042 var update_displayed_line = function() {
1043         if (highlighted_move !== null) {
1044                 highlighted_move.removeClass('highlight');
1045         }
1046         if (current_display_line === null) {
1047                 $("#linenav").hide();
1048                 $("#linemsg").show();
1049                 board.position(fen);
1050                 return;
1051         }
1052
1053         $("#linenav").show();
1054         $("#linemsg").hide();
1055
1056         if (current_display_move <= 0) {
1057                 $("#prevmove").html("Previous");
1058         } else {
1059                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
1060         }
1061         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1062                 $("#nextmove").html("Next");
1063         } else {
1064                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
1065         }
1066
1067         var hiddenboard = new Chess();
1068         hiddenboard.load(current_display_line.start_fen);
1069         for (var i = 0; i <= current_display_move; ++i) {
1070                 hiddenboard.move(current_display_line.pretty_pv[i]);
1071         }
1072
1073         highlighted_move = $("#automove" + current_display_line.line_number + "-" + current_display_move);
1074         highlighted_move.addClass('highlight');
1075
1076         board.position(hiddenboard.fen());
1077 }
1078
1079 /**
1080  * @param {boolean} param_enable_sound
1081  */
1082 var set_sound = function(param_enable_sound) {
1083         enable_sound = param_enable_sound;
1084         if (enable_sound) {
1085                 $("#soundon").html("<strong>On</strong>");
1086                 $("#soundoff").html("<a href=\"javascript:set_sound(false)\">Off</a>");
1087
1088                 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1089                 // and also preload the file since the user has selected audio.
1090                 var ding = document.getElementById('ding');
1091                 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1092                         ding.src = 'ding.opus';
1093                         ding.load();
1094                 }
1095         } else {
1096                 $("#soundon").html("<a href=\"javascript:set_sound(true)\">On</a>");
1097                 $("#soundoff").html("<strong>Off</strong>");
1098         }
1099         if (supports_html5_storage()) {
1100                 localStorage['enable_sound'] = enable_sound ? 1 : 0;
1101         }
1102 }
1103 window['set_sound'] = set_sound;
1104
1105 var init = function() {
1106         unique = get_unique();
1107
1108         // Load settings from HTML5 local storage if available.
1109         if (supports_html5_storage() && localStorage['enable_sound']) {
1110                 set_sound(parseInt(localStorage['enable_sound']));
1111         } else {
1112                 set_sound(false);
1113         }
1114         if (supports_html5_storage() && localStorage['sort_refutation_lines_by_score']) {
1115                 sort_refutation_lines_by_score = parseInt(localStorage['sort_refutation_lines_by_score']);
1116         } else {
1117                 sort_refutation_lines_by_score = true;
1118         }
1119
1120         // Create board.
1121         board = new window.ChessBoard('board', 'start');
1122
1123         request_update();
1124         $(window).resize(function() {
1125                 board.resize();
1126                 update_highlight();
1127                 redraw_arrows();
1128         });
1129         $(window).keyup(function(event) {
1130                 if (event.which == 39) {
1131                         next_move();
1132                 } else if (event.which == 37) {
1133                         prev_move();
1134                 }
1135         });
1136 };
1137 $(document).ready(init);
1138
1139 })();