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

   1 (function() {
   2
   3 /**
   4  * Version of this script. If the server returns a version larger than
   5  * this, it is a sign we should reload to upgrade ourselves.
   6  *
   7  * @type {Number}
   8  * @const
   9  * @private */
  10 var SCRIPT_VERSION = 2016032000;
  11
  12 /**
  13  * The current backend URL.
  14  *
  15  * @type {!string}
  16  * @private
  17  */
  18 var backend_url = "/analysis.pl";
  19 var backend_hash_url = "/hash";
  20
  21 /** @type {window.ChessBoard} @private */
  22 var board = null;
  23
  24 /** @type {boolean} @private */
  25 var board_is_animating = false;
  26
  27 /**
  28  * The most recent analysis data we have from the server
  29  * (about the most recent position).
  30  *
  31  * @type {?Object}
  32  * @private */
  33 var current_analysis_data = null;
  34
  35 /**
  36  * If we are displaying previous analysis or from hash, this is non-null,
  37  * and will override most of current_analysis_data.
  38  *
  39  * @type {?Object}
  40  * @private
  41  */
  42 var displayed_analysis_data = null;
  43
  44 /**
  45  * Games currently in progress, if any.
  46  *
  47  * @type {?Array.<{
  48  *      name: string,
  49  *      url: string,
  50  *      id: string,
  51  * }>}
  52  * @private
  53  */
  54 var current_games = null;
  55
  56 /** @type {Array.<{
  57  *      from_col: number,
  58  *      from_row: number,
  59  *      to_col: number,
  60  *      to_row: number,
  61  *      line_width: number,
  62  *      arrow_size: number,
  63  *      fg_color: string
  64  * }>}
  65  * @private
  66  */
  67 var arrows = [];
  68
  69 /** @type {Array.<Array.<boolean>>} */
  70 var occupied_by_arrows = [];
  71
  72 /** Currently displayed refutation lines (on-screen).
  73  * Can either come from the current_analysis_data, displayed_analysis_data,
  74  * or hash_refutation_lines.
  75  */
  76 var refutation_lines = [];
  77
  78 /** Refutation lines from current hash probe.
  79  *
  80  * If non-null, will override refutation lines from the base position.
  81  * Note that these are relative to display_fen, not base_fen.
  82  */
  83 var hash_refutation_lines = null;
  84
  85 /** @type {!number} @private */
  86 var move_num = 1;
  87
  88 /** @type {!string} @private */
  89 var toplay = 'W';
  90
  91 /** @type {number} @private */
  92 var ims = 0;
  93
  94 /** @type {boolean} @private */
  95 var sort_refutation_lines_by_score = true;
  96
  97 /** @type {boolean} @private */
  98 var truncate_display_history = true;
  99
 100 /** @type {!string|undefined} @private */
 101 var highlight_from = undefined;
 102
 103 /** @type {!string|undefined} @private */
 104 var highlight_to = undefined;
 105
 106 /** The HTML object of the move currently being highlighted (in red).
 107  * @type {?jQuery}
 108  * @private */
 109 var highlighted_move = null;
 110
 111 /** Currently suggested/recommended move when dragging.
 112  * @type {?{from: !string, to: !string}}
 113  * @private
 114  */
 115 var recommended_move = null;
 116
 117 /** If reverse-dragging (dragging from the destination square to the
 118  * source square), the destination square.
 119  * @type {?string}
 120  * @private
 121  */
 122 var reverse_dragging_from = null;
 123
 124 /** @type {?number} @private */
 125 var unique = null;
 126
 127 /** @type {boolean} @private */
 128 var enable_sound = false;
 129
 130 /**
 131  * Our best estimate of how many milliseconds we need to add to
 132  * new Date() to get the true UTC time. Calibrated against the
 133  * server clock.
 134  *
 135  * @type {?number}
 136  * @private
 137  */
 138 var client_clock_offset_ms = null;
 139
 140 var clock_timer = null;
 141
 142 /** The current position being analyzed, represented as a FEN string.
 143  * Note that this is not necessarily the same as display_fen.
 144  * @type {?string}
 145  * @private
 146  */
 147 var base_fen = null;
 148
 149 /** The current position on the board, represented as a FEN string.
 150  * Note that board.fen() does not contain e.g. who is to play.
 151  * @type {?string}
 152  * @private
 153  */
 154 var display_fen = null;
 155
 156 /** @typedef {{
 157  *    start_fen: string,
 158  *    pretty_pv: Array.<string>,
 159  *    move_num: number,
 160  *    toplay: string,
 161  *    start_display_move_num: number
 162  * }} DisplayLine
 163  *
 164  * "start_display_move_num" is the (half-)move number to start displaying the PV at.
 165  */
 166
 167 /** All PVs that we currently know of.
 168  *
 169  * Element 0 is history (or null if no history).
 170  * Element 1 is current main PV, or explored line if nowhere else on the screen.
 171  * All remaining elements are refutation lines (multi-PV).
 172  *
 173  * @type {Array.<DisplayLine>}
 174  * @private
 175  */
 176 var display_lines = [];
 177
 178 /** @type {?DisplayLine} @private */
 179 var current_display_line = null;
 180
 181 /** @type {boolean} @private */
 182 var current_display_line_is_history = false;
 183
 184 /** @type {?number} @private */
 185 var current_display_move = null;
 186
 187 /**
 188  * The current backend request to get main analysis (not history), if any,
 189  * so that we can abort it.
 190  *
 191  * @type {?jqXHR}
 192  * @private
 193  */
 194 var current_analysis_xhr = null;
 195
 196 /**
 197  * The current timer to fire off a request to get main analysis (not history),
 198  * if any, so that we can abort it.
 199  *
 200  * @type {?Number}
 201  * @private
 202  */
 203 var current_analysis_request_timer = null;
 204
 205 /**
 206  * The current backend request to get historic data, if any.
 207  *
 208  * @type {?jqXHR}
 209  * @private
 210  */
 211 var current_historic_xhr = null;
 212
 213 /**
 214  * The current backend request to get hash probes, if any, so that we can abort it.
 215  *
 216  * @type {?jqXHR}
 217  * @private
 218  */
 219 var current_hash_xhr = null;
 220
 221 /**
 222  * The current timer to display hash probe information (it could be waiting on the
 223  * board to stop animating), if any, so that we can abort it.
 224  *
 225  * @type {?Number}
 226  * @private
 227  */
 228 var current_hash_display_timer = null;
 229
 230 var supports_html5_storage = function() {
 231         try {
 232                 return 'localStorage' in window && window['localStorage'] !== null;
 233         } catch (e) {
 234                 return false;
 235         }
 236 }
 237
 238 // Make the unique token persistent so people refreshing the page won't count twice.
 239 // Of course, you can never fully protect against people deliberately wanting to spam.
 240 var get_unique = function() {
 241         var use_local_storage = supports_html5_storage();
 242         if (use_local_storage && localStorage['unique']) {
 243                 return localStorage['unique'];
 244         }
 245         var unique = Math.random();
 246         if (use_local_storage) {
 247                 localStorage['unique'] = unique;
 248         }
 249         return unique;
 250 }
 251
 252 var request_update = function() {
 253         current_analysis_request_timer = null;
 254
 255         current_analysis_xhr = $.ajax({
 256                 url: backend_url + "?ims=" + ims + "&unique=" + unique
 257         }).done(function(data, textstatus, xhr) {
 258                 sync_server_clock(xhr.getResponseHeader('Date'));
 259                 ims = xhr.getResponseHeader('X-RGLM');
 260                 var num_viewers = xhr.getResponseHeader('X-RGNV');
 261                 var new_data;
 262                 if (Array.isArray(data)) {
 263                         new_data = JSON.parse(JSON.stringify(current_analysis_data));
 264                         JSON_delta.patch(new_data, data);
 265                 } else {
 266                         new_data = data;
 267                 }
 268
 269                 var minimum_version = xhr.getResponseHeader('X-RGMV');
 270                 if (minimum_version && minimum_version > SCRIPT_VERSION) {
 271                         // Upgrade to latest version with a force-reload.
 272                         location.reload(true);
 273                 }
 274
 275                 possibly_play_sound(current_analysis_data, new_data);
 276                 current_analysis_data = new_data;
 277                 update_board();
 278                 update_num_viewers(num_viewers);
 279
 280                 // Next update.
 281                 current_analysis_request_timer = setTimeout(function() { request_update(); }, 100);
 282         }).fail(function(jqXHR, textStatus, errorThrown) {
 283                 if (textStatus === "abort") {
 284                         // Aborted because we are switching backends. Abandon and don't retry,
 285                         // because another one is already started for us.
 286                 } else {
 287                         // Backend error or similar. Wait ten seconds, then try again.
 288                         current_analysis_request_timer = setTimeout(function() { request_update(); }, 10000);
 289                 }
 290         });
 291 }
 292
 293 var possibly_play_sound = function(old_data, new_data) {
 294         if (!enable_sound) {
 295                 return;
 296         }
 297         if (old_data === null) {
 298                 return;
 299         }
 300         var ding = document.getElementById('ding');
 301         if (ding && ding.play) {
 302                 if (old_data['position'] && old_data['position']['fen'] &&
 303                     new_data['position'] && new_data['position']['fen'] &&
 304                     (old_data['position']['fen'] !== new_data['position']['fen'] ||
 305                      old_data['position']['move_num'] !== new_data['position']['move_num'])) {
 306                         ding.play();
 307                 }
 308         }
 309 }
 310
 311 /**
 312  * @type {!string} server_date_string
 313  */
 314 var sync_server_clock = function(server_date_string) {
 315         var server_time_ms = new Date(server_date_string).getTime();
 316         var client_time_ms = new Date().getTime();
 317         var estimated_offset_ms = server_time_ms - client_time_ms;
 318
 319         // In order not to let the noise move us too much back and forth
 320         // (the server only has one-second resolution anyway), we only
 321         // change an existing skew if we are at least five seconds off.
 322         if (client_clock_offset_ms === null ||
 323             Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
 324                 client_clock_offset_ms = estimated_offset_ms;
 325         }
 326 }
 327
 328 var clear_arrows = function() {
 329         for (var i = 0; i < arrows.length; ++i) {
 330                 if (arrows[i].svg) {
 331                         if (arrows[i].svg.parentElement) {
 332                                 arrows[i].svg.parentElement.removeChild(arrows[i].svg);
 333                         }
 334                         delete arrows[i].svg;
 335                 }
 336         }
 337         arrows = [];
 338
 339         occupied_by_arrows = [];
 340         for (var y = 0; y < 8; ++y) {
 341                 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
 342         }
 343 }
 344
 345 var redraw_arrows = function() {
 346         for (var i = 0; i < arrows.length; ++i) {
 347                 position_arrow(arrows[i]);
 348         }
 349 }
 350
 351 /** @param {!number} x
 352  * @return {!number}
 353  */
 354 var sign = function(x) {
 355         if (x > 0) {
 356                 return 1;
 357         } else if (x < 0) {
 358                 return -1;
 359         } else {
 360                 return 0;
 361         }
 362 }
 363
 364 /** See if drawing this arrow on the board would cause unduly amount of confusion.
 365  * @param {!string} from The square the arrow is from (e.g. e4).
 366  * @param {!string} to The square the arrow is to (e.g. e4).
 367  * @return {boolean}
 368  */
 369 var interfering_arrow = function(from, to) {
 370         var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
 371         var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 372         var to_col   = to.charCodeAt(0) - "a1".charCodeAt(0);
 373         var to_row   = to.charCodeAt(1) - "a1".charCodeAt(1);
 374
 375         occupied_by_arrows[from_row][from_col] = true;
 376
 377         // Knight move: Just check that we haven't been at the destination before.
 378         if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
 379             (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
 380                 return occupied_by_arrows[to_row][to_col];
 381         }
 382
 383         // Sliding piece: Check if anything except the from-square is seen before.
 384         var dx = sign(to_col - from_col);
 385         var dy = sign(to_row - from_row);
 386         var x = from_col;
 387         var y = from_row;
 388         do {
 389                 x += dx;
 390                 y += dy;
 391                 if (occupied_by_arrows[y][x]) {
 392                         return true;
 393                 }
 394                 occupied_by_arrows[y][x] = true;
 395         } while (x != to_col || y != to_row);
 396
 397         return false;
 398 }
 399
 400 /** Find a point along the coordinate system given by the given line,
 401  * <t> units forward from the start of the line, <u> units to the right of it.
 402  * @param {!number} x1
 403  * @param {!number} x2
 404  * @param {!number} y1
 405  * @param {!number} y2
 406  * @param {!number} t
 407  * @param {!number} u
 408  * @return {!string} The point in "x y" form, suitable for SVG paths.
 409  */
 410 var point_from_start = function(x1, y1, x2, y2, t, u) {
 411         var dx = x2 - x1;
 412         var dy = y2 - y1;
 413
 414         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 415         dx *= norm;
 416         dy *= norm;
 417
 418         var x = x1 + dx * t + dy * u;
 419         var y = y1 + dy * t - dx * u;
 420         return x + " " + y;
 421 }
 422
 423 /** Find a point along the coordinate system given by the given line,
 424  * <t> units forward from the end of the line, <u> units to the right of it.
 425  * @param {!number} x1
 426  * @param {!number} x2
 427  * @param {!number} y1
 428  * @param {!number} y2
 429  * @param {!number} t
 430  * @param {!number} u
 431  * @return {!string} The point in "x y" form, suitable for SVG paths.
 432  */
 433 var point_from_end = function(x1, y1, x2, y2, t, u) {
 434         var dx = x2 - x1;
 435         var dy = y2 - y1;
 436
 437         var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
 438         dx *= norm;
 439         dy *= norm;
 440
 441         var x = x2 + dx * t + dy * u;
 442         var y = y2 + dy * t - dx * u;
 443         return x + " " + y;
 444 }
 445
 446 var position_arrow = function(arrow) {
 447         if (arrow.svg) {
 448                 if (arrow.svg.parentElement) {
 449                         arrow.svg.parentElement.removeChild(arrow.svg);
 450                 }
 451                 delete arrow.svg;
 452         }
 453         if (current_display_line !== null && !current_display_line_is_history) {
 454                 return;
 455         }
 456
 457         var pos = $(".square-a8").position();
 458
 459         var zoom_factor = $("#board").width() / 400.0;
 460         var line_width = arrow.line_width * zoom_factor;
 461         var arrow_size = arrow.arrow_size * zoom_factor;
 462
 463         var square_width = $(".square-a8").width();
 464         var from_y = (7 - arrow.from_row + 0.5)*square_width;
 465         var to_y = (7 - arrow.to_row + 0.5)*square_width;
 466         var from_x = (arrow.from_col + 0.5)*square_width;
 467         var to_x = (arrow.to_col + 0.5)*square_width;
 468
 469         var SVG_NS = "http://www.w3.org/2000/svg";
 470         var XHTML_NS = "http://www.w3.org/1999/xhtml";
 471         var svg = document.createElementNS(SVG_NS, "svg");
 472         svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
 473         svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
 474         svg.setAttribute("style", "position: absolute");
 475         svg.setAttribute("position", "absolute");
 476         svg.setAttribute("version", "1.1");
 477         svg.setAttribute("class", "c1");
 478         svg.setAttribute("xmlns", XHTML_NS);
 479
 480         var x1 = from_x;
 481         var y1 = from_y;
 482         var x2 = to_x;
 483         var y2 = to_y;
 484
 485         // Draw the line.
 486         var outline = document.createElementNS(SVG_NS, "path");
 487         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));
 488         outline.setAttribute("xmlns", XHTML_NS);
 489         outline.setAttribute("stroke", "#666");
 490         outline.setAttribute("stroke-width", line_width + 2);
 491         outline.setAttribute("fill", "none");
 492         svg.appendChild(outline);
 493
 494         var path = document.createElementNS(SVG_NS, "path");
 495         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));
 496         path.setAttribute("xmlns", XHTML_NS);
 497         path.setAttribute("stroke", arrow.fg_color);
 498         path.setAttribute("stroke-width", line_width);
 499         path.setAttribute("fill", "none");
 500         svg.appendChild(path);
 501
 502         // Then the arrow head.
 503         var head = document.createElementNS(SVG_NS, "path");
 504         head.setAttribute("d",
 505                 "M " +  point_from_end(x1, y1, x2, y2, 0, 0) +
 506                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
 507                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
 508                 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
 509                 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
 510         head.setAttribute("xmlns", XHTML_NS);
 511         head.setAttribute("stroke", "#000");
 512         head.setAttribute("stroke-width", "1");
 513         head.setAttribute("fill", arrow.fg_color);
 514         svg.appendChild(head);
 515
 516         $(svg).css({ top: pos.top, left: pos.left, 'pointer-events': 'none' });
 517         document.body.appendChild(svg);
 518         arrow.svg = svg;
 519 }
 520
 521 /**
 522  * @param {!string} from_square
 523  * @param {!string} to_square
 524  * @param {!string} fg_color
 525  * @param {number} line_width
 526  * @param {number} arrow_size
 527  */
 528 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
 529         var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
 530         var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 531         var to_col   = to_square.charCodeAt(0) - "a1".charCodeAt(0);
 532         var to_row   = to_square.charCodeAt(1) - "a1".charCodeAt(1);
 533
 534         // Create arrow.
 535         var arrow = {
 536                 from_col: from_col,
 537                 from_row: from_row,
 538                 to_col: to_col,
 539                 to_row: to_row,
 540                 line_width: line_width,
 541                 arrow_size: arrow_size,
 542                 fg_color: fg_color
 543         };
 544
 545         position_arrow(arrow);
 546         arrows.push(arrow);
 547 }
 548
 549 var compare_by_sort_key = function(refutation_lines, a, b) {
 550         var ska = refutation_lines[a]['sort_key'];
 551         var skb = refutation_lines[b]['sort_key'];
 552         if (ska < skb) return -1;
 553         if (ska > skb) return 1;
 554         return 0;
 555 };
 556
 557 var compare_by_score = function(refutation_lines, a, b) {
 558         var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
 559         var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
 560         return sa - sb;
 561 }
 562
 563 /**
 564  * Fake multi-PV using the refutation lines. Find all “relevant” moves,
 565  * sorted by quality, descending.
 566  *
 567  * @param {!Object} data
 568  * @param {number} margin The maximum number of centipawns worse than the
 569  *     best move can be and still be included.
 570  * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
 571  *     moves, in score order.
 572  */
 573 var find_nonstupid_moves = function(data, margin) {
 574         // First of all, if there are any moves that are more than 0.5 ahead of
 575         // the primary move, the refutation lines are probably bunk, so just
 576         // kill them all.
 577         var best_score = undefined;
 578         var pv_score = undefined;
 579         for (var move in data['refutation_lines']) {
 580                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 581                 if (move == data['pv_uci'][0]) {
 582                         pv_score = score;
 583                 }
 584                 if (best_score === undefined || score > best_score) {
 585                         best_score = score;
 586                 }
 587                 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
 588                         return [];
 589                 }
 590         }
 591
 592         if (best_score - pv_score > 50) {
 593                 return [];
 594         }
 595
 596         // Now find all moves that are within “margin” of the best score.
 597         // The PV move will always be first.
 598         var moves = [];
 599         for (var move in data['refutation_lines']) {
 600                 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
 601                 if (move != data['pv_uci'][0] && best_score - score <= margin) {
 602                         moves.push(move);
 603                 }
 604         }
 605         moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
 606         moves.unshift(data['pv_uci'][0]);
 607
 608         return moves;
 609 }
 610
 611 /**
 612  * @param {number} x
 613  * @return {!string}
 614  */
 615 var thousands = function(x) {
 616         return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 617 }
 618
 619 /**
 620  * @param {!string} start_fen
 621  * @param {Array.<string>} pretty_pv
 622  * @param {number} move_num
 623  * @param {!string} toplay
 624  * @param {number} start_display_move_num
 625  * @param {number=} opt_limit
 626  * @param {boolean=} opt_showlast
 627  */
 628 var add_pv = function(start_fen, pretty_pv, move_num, toplay, start_display_move_num, opt_limit, opt_showlast) {
 629         display_lines.push({
 630                 start_fen: start_fen,
 631                 pretty_pv: pretty_pv,
 632                 move_num: parseInt(move_num),
 633                 toplay: toplay,
 634                 start_display_move_num: start_display_move_num,
 635         });
 636         return print_pv(display_lines.length - 1, opt_limit, opt_showlast);
 637 }
 638
 639 /**
 640  * @param {number} line_num
 641  * @param {number=} opt_limit
 642  * @param {boolean=} opt_showlast
 643  */
 644 var print_pv = function(line_num, opt_limit, opt_showlast) {
 645         var display_line = display_lines[line_num];
 646         var pretty_pv = display_line.pretty_pv;
 647         var move_num = display_line.move_num;
 648         var toplay = display_line.toplay;
 649
 650         // Truncate PV at the start if needed.
 651         var start_display_move_num = display_line.start_display_move_num;
 652         if (start_display_move_num > 0) {
 653                 pretty_pv = pretty_pv.slice(start_display_move_num);
 654                 var to_add = start_display_move_num;
 655                 if (toplay === 'B') {
 656                         ++move_num;
 657                         toplay = 'W';
 658                         --to_add;
 659                 }
 660                 if (to_add % 2 == 1) {
 661                         toplay = 'B';
 662                         --to_add;
 663                 }
 664                 move_num += to_add / 2;
 665         }
 666
 667         var pv = '';
 668         var i = 0;
 669         if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
 670                 // Truncate the PV at the beginning (instead of at the end).
 671                 // We assume here that toplay is 'W'. We also assume that if
 672                 // opt_showlast is set, then it is the history, and thus,
 673                 // the UI should be to expand the history.
 674                 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
 675                 i = pretty_pv.length - opt_limit;
 676                 if (i % 2 == 1) {
 677                         ++i;
 678                 }
 679                 move_num += i / 2;
 680         } else if (toplay == 'B' && pretty_pv.length > 0) {
 681                 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
 682                 pv = move_num + '. … ' + move;
 683                 toplay = 'W';
 684                 ++i;
 685                 ++move_num;
 686         }
 687         for ( ; i < pretty_pv.length; ++i) {
 688                 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
 689
 690                 if (toplay == 'W') {
 691                         if (i > opt_limit && !opt_showlast) {
 692                                 return pv + ' (…)';
 693                         }
 694                         if (pv != '') {
 695                                 pv += ' ';
 696                         }
 697                         pv += move_num + '. ' + move;
 698                         ++move_num;
 699                         toplay = 'B';
 700                 } else {
 701                         pv += ' ' + move;
 702                         toplay = 'W';
 703                 }
 704         }
 705         return pv;
 706 }
 707
 708 /** Update the highlighted to/from squares on the board.
 709  * Based on the global "highlight_from" and "highlight_to" variables.
 710  */
 711 var update_board_highlight = function() {
 712         $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
 713         if ((current_display_line === null || current_display_line_is_history) &&
 714             highlight_from !== undefined && highlight_to !== undefined) {
 715                 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
 716                 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
 717         }
 718 }
 719
 720 var update_history = function() {
 721         if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
 722                 $("#history").html("No history");
 723         } else if (truncate_display_history) {
 724                 $("#history").html(print_pv(0, 8, true));
 725         } else {
 726                 $("#history").html(
 727                         '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
 728                         print_pv(0, 1, 'W'));
 729         }
 730 }
 731
 732 /**
 733  * @param {!boolean} truncate_history
 734  */
 735 var collapse_history = function(truncate_history) {
 736         truncate_display_history = truncate_history;
 737         update_history();
 738 }
 739 window['collapse_history'] = collapse_history;
 740
 741 /** Update the HTML display of multi-PV from the global "refutation_lines".
 742  *
 743  * Also recreates the global "display_lines".
 744  */
 745 var update_refutation_lines = function() {
 746         if (base_fen === null) {
 747                 return;
 748         }
 749         if (display_lines.length > 2) {
 750                 // Truncate so that only the history and PV is left.
 751                 display_lines = [ display_lines[0], display_lines[1] ];
 752         }
 753         var tbl = $("#refutationlines");
 754         tbl.empty();
 755
 756         // Find out where the lines start from.
 757         var base_line = [];
 758         var start_display_move_num = 0;
 759         if (hash_refutation_lines) {
 760                 base_line = current_display_line.pretty_pv.slice(0, current_display_move + 1);
 761                 start_display_move_num = base_line.length;
 762         }
 763
 764         var moves = [];
 765         for (var move in refutation_lines) {
 766                 moves.push(move);
 767         }
 768         var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
 769         moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
 770         for (var i = 0; i < moves.length; ++i) {
 771                 var line = refutation_lines[moves[i]];
 772
 773                 var tr = document.createElement("tr");
 774
 775                 var move_td = document.createElement("td");
 776                 tr.appendChild(move_td);
 777                 $(move_td).addClass("move");
 778
 779                 if (line['pv_pretty'].length == 0) {
 780                         // Not found.
 781                         $(move_td).text(line['pretty_move']);
 782                         var score_td = document.createElement("td");
 783
 784                         $(score_td).addClass("score");
 785                         $(score_td).text("—");
 786                         tr.appendChild(score_td);
 787
 788                         var depth_td = document.createElement("td");
 789                         tr.appendChild(depth_td);
 790                         $(depth_td).addClass("depth");
 791                         $(depth_td).text("—");
 792
 793                         tbl.append(tr);
 794                         continue;
 795                 }
 796
 797                 if (line['pv_pretty'].length == 0) {
 798                         $(move_td).text(line['pretty_move']);
 799                 } else {
 800                         var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
 801                         $(move_td).html(move);
 802                 }
 803
 804                 var score_td = document.createElement("td");
 805                 tr.appendChild(score_td);
 806                 $(score_td).addClass("score");
 807                 $(score_td).text(line['pretty_score']);
 808
 809                 var depth_td = document.createElement("td");
 810                 tr.appendChild(depth_td);
 811                 $(depth_td).addClass("depth");
 812                 $(depth_td).text("d" + line['depth']);
 813
 814                 var pv_td = document.createElement("td");
 815                 tr.appendChild(pv_td);
 816                 $(pv_td).addClass("pv");
 817                 $(pv_td).html(add_pv(base_fen, base_line.concat(line['pv_pretty']), move_num, toplay, start_display_move_num, 10));
 818
 819                 tbl.append(tr);
 820         }
 821
 822         // Make one of the links clickable and the other nonclickable.
 823         if (sort_refutation_lines_by_score) {
 824                 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
 825                 $("#sortbyscore1").html("<strong>Score</strong>");
 826         } else {
 827                 $("#sortbyscore0").html("<strong>Move</strong>");
 828                 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
 829         }
 830
 831         // Update the move highlight, as we've rewritten all the HTML.
 832         update_move_highlight();
 833 }
 834
 835 /**
 836  * Create a Chess.js board object, containing the given position plus the given moves,
 837  * up to the given limit.
 838  *
 839  * @param {?string} fen
 840  * @param {Array.<string>} moves
 841  * @param {number} last_move
 842  */
 843 var chess_from = function(fen, moves, last_move) {
 844         var hiddenboard = new Chess();
 845         if (fen !== null) {
 846                 hiddenboard.load(fen);
 847         }
 848         for (var i = 0; i <= last_move; ++i) {
 849                 if (moves[i] === '0-0') {
 850                         hiddenboard.move('O-O');
 851                 } else if (moves[i] === '0-0-0') {
 852                         hiddenboard.move('O-O-O');
 853                 } else {
 854                         hiddenboard.move(moves[i]);
 855                 }
 856         }
 857         return hiddenboard;
 858 }
 859
 860 var update_game_list = function(games) {
 861         $("#games").text("");
 862         if (games === null) {
 863                 return;
 864         }
 865
 866         var games_div = document.getElementById('games');
 867         for (var game_num = 0; game_num < games.length; ++game_num) {
 868                 var game = games[game_num];
 869                 var game_span = document.createElement("span");
 870                 game_span.setAttribute("class", "game");
 871
 872                 var game_name = document.createTextNode(game['name']);
 873                 if (game['url'] === backend_url) {
 874                         game_span.appendChild(game_name);
 875                 } else {
 876                         var game_a = document.createElement("a");
 877                         game_a.setAttribute("href", "#" + game['id']);
 878                         game_a.appendChild(game_name);
 879                         game_span.appendChild(game_a);
 880                 }
 881                 games_div.appendChild(game_span);
 882         }
 883 }
 884
 885 /**
 886  * Try to find a running game that matches with the current hash,
 887  * and switch to it if we're not already displaying it.
 888  */
 889 var possibly_switch_game_from_hash = function() {
 890         if (current_games === null) {
 891                 return;
 892         }
 893
 894         var hash = window.location.hash.replace(/^#/,'');
 895         for (var i = 0; i < current_games.length; ++i) {
 896                 if (current_games[i]['id'] === hash) {
 897                         if (backend_url !== current_games[i]['url']) {
 898                                 switch_backend(current_games[i]['url']);
 899                         }
 900                         return;
 901                 }
 902         }
 903 }
 904
 905 /** Update all the HTML on the page, based on current global state.
 906  */
 907 var update_board = function() {
 908         var data = displayed_analysis_data || current_analysis_data;
 909         var current_data = current_analysis_data;  // Convenience alias.
 910
 911         display_lines = [];
 912
 913         // Print the history. This is pretty much the only thing that's
 914         // unconditionally taken from current_data (we're not interested in
 915         // historic history).
 916         if (current_data['position']['pretty_history']) {
 917                 add_pv('start', current_data['position']['pretty_history'], 1, 'W', 0, 8, true);
 918         } else {
 919                 display_lines.push(null);
 920         }
 921         update_history();
 922
 923         // Games currently in progress, if any.
 924         if (current_data['games']) {
 925                 current_games = current_data['games'];
 926                 possibly_switch_game_from_hash();
 927                 update_game_list(current_data['games']);
 928         } else {
 929                 current_games = null;
 930                 update_game_list(null);
 931         }
 932
 933         // The headline. Names are always fetched from current_data;
 934         // the rest can depend a bit.
 935         var headline;
 936         if (current_data &&
 937             current_data['position']['player_w'] && current_data['position']['player_b']) {
 938                 headline = current_data['position']['player_w'] + '–' +
 939                         current_data['position']['player_b'] + ', analysis';
 940         } else {
 941                 headline = 'Analysis';
 942         }
 943
 944         // Credits, where applicable. Note that we don't want the footer to change a lot
 945         // when e.g. viewing history, so if any of these changed during the game,
 946         // use the current one still.
 947         if (current_data['using_lomonosov']) {
 948                 $("#lomonosov").show();
 949         } else {
 950                 $("#lomonosov").hide();
 951         }
 952
 953         // Credits: The engine name/version.
 954         if (current_data['engine'] && current_data['engine']['name'] !== null) {
 955                 $("#engineid").text(current_data['engine']['name']);
 956         }
 957
 958         // Credits: The engine URL.
 959         if (current_data['engine'] && current_data['engine']['url']) {
 960                 $("#engineid").attr("href", current_data['engine']['url']);
 961         } else {
 962                 $("#engineid").removeAttr("href");
 963         }
 964
 965         // Credits: Engine details.
 966         if (current_data['engine'] && current_data['engine']['details']) {
 967                 $("#enginedetails").text(" (" + current_data['engine']['details'] + ")");
 968         } else {
 969                 $("#enginedetails").text("");
 970         }
 971
 972         // Credits: Move source, possibly with URL.
 973         if (current_data['move_source'] && current_data['move_source_url']) {
 974                 $("#movesource").text("Moves provided by ");
 975                 var movesource_a = document.createElement("a");
 976                 movesource_a.setAttribute("href", current_data['move_source_url']);
 977                 var movesource_text = document.createTextNode(current_data['move_source']);
 978                 movesource_a.appendChild(movesource_text);
 979                 var movesource_period = document.createTextNode(".");
 980                 document.getElementById("movesource").appendChild(movesource_a);
 981                 document.getElementById("movesource").appendChild(movesource_period);
 982         } else if (current_data['move_source']) {
 983                 $("#movesource").text("Moves provided by " + current_data['move_source'] + ".");
 984         } else {
 985                 $("#movesource").text("");
 986         }
 987
 988         var last_move;
 989         if (displayed_analysis_data) {
 990                 // Displaying some non-current position, pick out the last move
 991                 // from the history. This will work even if the fetch failed.
 992                 last_move = format_halfmove_with_number(
 993                         current_display_line.pretty_pv[current_display_move],
 994                         current_display_move + 1);
 995                 headline += ' after ' + last_move;
 996         } else if (data['position']['last_move'] !== 'none') {
 997                 last_move = format_move_with_number(
 998                         data['position']['last_move'],
 999                         data['position']['move_num'],
1000                         data['position']['toplay'] == 'W');
1001                 headline += ' after ' + last_move;
1002         } else {
1003                 last_move = null;
1004         }
1005         $("#headline").text(headline);
1006
1007         // The <title> contains a very brief headline.
1008         var title_elems = [];
1009         if (data['short_score'] !== undefined && data['short_score'] !== null) {
1010                 title_elems.push(data['short_score'].replace(/^ /, ""));
1011         }
1012         if (last_move !== null) {
1013                 title_elems.push(last_move);
1014         }
1015
1016         if (title_elems.length != 0) {
1017                 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
1018         } else {
1019                 document.title = 'analysis.sesse.net';
1020         }
1021
1022         // The last move (shown by highlighting the from and to squares).
1023         if (data['position'] && data['position']['last_move_uci']) {
1024                 highlight_from = data['position']['last_move_uci'].substr(0, 2);
1025                 highlight_to = data['position']['last_move_uci'].substr(2, 2);
1026         } else if (current_display_line_is_history && current_display_move >= 0) {
1027                 // We don't have historic analysis for this position, but we
1028                 // can reconstruct what the last move was by just replaying
1029                 // from the start.
1030                 var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1031                 var moves = hiddenboard.history({ verbose: true });
1032                 var last_move = moves.pop();
1033                 highlight_from = last_move.from;
1034                 highlight_to = last_move.to;
1035         } else {
1036                 highlight_from = highlight_to = undefined;
1037         }
1038         update_board_highlight();
1039
1040         if (data['failed']) {
1041                 $("#score").text("No analysis for this move");
1042                 $("#pvtitle").text("PV:");
1043                 $("#pv").empty();
1044                 $("#searchstats").html("&nbsp;");
1045                 $("#refutationlines").empty();
1046                 $("#whiteclock").empty();
1047                 $("#blackclock").empty();
1048                 refutation_lines = [];
1049                 update_refutation_lines();
1050                 clear_arrows();
1051                 update_displayed_line();
1052                 update_move_highlight();
1053                 return;
1054         }
1055
1056         update_clock();
1057
1058         // The score.
1059         if (data['score'] !== null) {
1060                 $("#score").text(data['score']);
1061         }
1062
1063         // The search stats.
1064         if (data['searchstats']) {
1065                 $("#searchstats").html(data['searchstats']);
1066         } else if (data['tablebase'] == 1) {
1067                 $("#searchstats").text("Tablebase result");
1068         } else if (data['nodes'] && data['nps'] && data['depth']) {
1069                 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
1070                 if (data['seldepth']) {
1071                         stats += ' (' + data['seldepth'] + ' selective)';
1072                 }
1073                 if (data['tbhits'] && data['tbhits'] > 0) {
1074                         if (data['tbhits'] == 1) {
1075                                 stats += ', one Syzygy hit';
1076                         } else {
1077                                 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
1078                         }
1079                 }
1080
1081                 $("#searchstats").text(stats);
1082         } else {
1083                 $("#searchstats").text("");
1084         }
1085
1086         // Update the board itself.
1087         base_fen = data['position']['fen'];
1088         update_displayed_line();
1089
1090         // Print the PV.
1091         $("#pvtitle").text("PV:");
1092         $("#pv").html(add_pv(data['position']['fen'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay'], 0));
1093
1094         // Update the PV arrow.
1095         clear_arrows();
1096         if (data['pv_uci'].length >= 1) {
1097                 // draw a continuation arrow as long as it's the same piece
1098                 for (var i = 0; i < data['pv_uci'].length; i += 2) {
1099                         var from = data['pv_uci'][i].substr(0, 2);
1100                         var to = data['pv_uci'][i].substr(2,4);
1101                         if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
1102                              interfering_arrow(from, to)) {
1103                                 break;
1104                         }
1105                         create_arrow(from, to, '#f66', 6, 20);
1106                 }
1107
1108                 var alt_moves = find_nonstupid_moves(data, 30);
1109                 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
1110                         create_arrow(alt_moves[i].substr(0, 2),
1111                                      alt_moves[i].substr(2, 2), '#f66', 1, 10);
1112                 }
1113         }
1114
1115         // See if all semi-reasonable moves have only one possible response.
1116         if (data['pv_uci'].length >= 2) {
1117                 var nonstupid_moves = find_nonstupid_moves(data, 300);
1118                 var response = data['pv_uci'][1];
1119                 for (var i = 0; i < nonstupid_moves.length; ++i) {
1120                         if (nonstupid_moves[i] == data['pv_uci'][0]) {
1121                                 // ignore the PV move for refutation lines.
1122                                 continue;
1123                         }
1124                         if (!data['refutation_lines'] ||
1125                             !data['refutation_lines'][nonstupid_moves[i]] ||
1126                             !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
1127                             data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
1128                                 // Incomplete PV, abort.
1129                                 response = undefined;
1130                                 break;
1131                         }
1132                         var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
1133                         if (response !== this_response) {
1134                                 // Different response depending on lines, abort.
1135                                 response = undefined;
1136                                 break;
1137                         }
1138                 }
1139
1140                 if (nonstupid_moves.length > 0 && response !== undefined) {
1141                         create_arrow(response.substr(0, 2),
1142                                      response.substr(2, 2), '#66f', 6, 20);
1143                 }
1144         }
1145
1146         // Update the refutation lines.
1147         base_fen = data['position']['fen'];
1148         move_num = parseInt(data['position']['move_num']);
1149         toplay = data['position']['toplay'];
1150         refutation_lines = hash_refutation_lines || data['refutation_lines'];
1151         update_refutation_lines();
1152
1153         // Update the sparkline last, since its size depends on how everything else reflowed.
1154         update_sparkline(data);
1155 }
1156
1157 var update_sparkline = function(data) {
1158         if (data && data['score_history']) {
1159                 var first_move_num = undefined;
1160                 for (var halfmove_num in data['score_history']) {
1161                         halfmove_num = parseInt(halfmove_num);
1162                         if (first_move_num === undefined || halfmove_num < first_move_num) {
1163                                 first_move_num = halfmove_num;
1164                         }
1165                 }
1166                 if (first_move_num !== undefined) {
1167                         var last_move_num = data['position']['move_num'] * 2 - 3;
1168                         if (data['position']['toplay'] === 'B') {
1169                                 ++last_move_num;
1170                         }
1171
1172                         // Possibly truncate some moves if we don't have enough width.
1173                         // FIXME: Sometimes width() for #scorecontainer (and by extent,
1174                         // #scoresparkcontainer) on Chrome for mobile seems to start off
1175                         // at something very small, and then suddenly snap back into place.
1176                         // Figure out why.
1177                         var max_moves = Math.floor($("#scoresparkcontainer").width() / 5) - 5;
1178                         if (last_move_num - first_move_num > max_moves) {
1179                                 first_move_num = last_move_num - max_moves;
1180                         }
1181
1182                         var min_score = -100;
1183                         var max_score = 100;
1184                         var last_score = null;
1185                         var scores = [];
1186                         for (var halfmove_num = first_move_num; halfmove_num <= last_move_num; ++halfmove_num) {
1187                                 if (data['score_history'][halfmove_num]) {
1188                                         var score = data['score_history'][halfmove_num][0];
1189                                         if (score < min_score) min_score = score;
1190                                         if (score > max_score) max_score = score;
1191                                         last_score = data['score_history'][halfmove_num][0];
1192                                 }
1193                                 scores.push(last_score);
1194                         }
1195                         if (data['plot_score']) {
1196                                 scores.push(data['plot_score']);
1197                         }
1198                         // FIXME: at some widths, calling sparkline() seems to push
1199                         // #scorecontainer under the board.
1200                         $("#scorespark").sparkline(scores, {
1201                                 type: 'bar',
1202                                 zeroColor: 'gray',
1203                                 chartRangeMin: min_score,
1204                                 chartRangeMax: max_score,
1205                                 tooltipFormatter: function(sparkline, options, fields) {
1206                                         return format_tooltip(data, fields[0].offset + first_move_num);
1207                                 }
1208                         });
1209                 } else {
1210                         $("#scorespark").text("");
1211                 }
1212         } else {
1213                 $("#scorespark").text("");
1214         }
1215 }
1216
1217 /**
1218  * @param {number} num_viewers
1219  */
1220 var update_num_viewers = function(num_viewers) {
1221         if (num_viewers === null) {
1222                 $("#numviewers").text("");
1223         } else if (num_viewers == 1) {
1224                 $("#numviewers").text("You are the only current viewer");
1225         } else {
1226                 $("#numviewers").text(num_viewers + " current viewers");
1227         }
1228 }
1229
1230 var update_clock = function() {
1231         clearTimeout(clock_timer);
1232
1233         var data = displayed_analysis_data || current_analysis_data;
1234         if (data['position']) {
1235                 var result = data['position']['result'];
1236                 if (result === '1-0') {
1237                         $("#whiteclock").text("1");
1238                         $("#blackclock").text("0");
1239                         $("#whiteclock").removeClass("running-clock");
1240                         $("#blackclock").removeClass("running-clock");
1241                         return;
1242                 }
1243                 if (result === '1/2-1/2') {
1244                         $("#whiteclock").text("1/2");
1245                         $("#blackclock").text("1/2");
1246                         $("#whiteclock").removeClass("running-clock");
1247                         $("#blackclock").removeClass("running-clock");
1248                         return;
1249                 }
1250                 if (result === '0-1') {
1251                         $("#whiteclock").text("0");
1252                         $("#blackclock").text("1");
1253                         $("#whiteclock").removeClass("running-clock");
1254                         $("#blackclock").removeClass("running-clock");
1255                         return;
1256                 }
1257         }
1258
1259         var white_clock_ms = null;
1260         var black_clock_ms = null;
1261         var show_seconds = false;
1262
1263         // Static clocks.
1264         if (data['position'] &&
1265             data['position']['white_clock'] &&
1266             data['position']['black_clock']) {
1267                 white_clock_ms = data['position']['white_clock'] * 1000;
1268                 black_clock_ms = data['position']['black_clock'] * 1000;
1269         }
1270
1271         // Dynamic clock (only one, obviously).
1272         var color;
1273         if (data['position']['white_clock_target']) {
1274                 color = "white";
1275                 $("#whiteclock").addClass("running-clock");
1276                 $("#blackclock").removeClass("running-clock");
1277         } else if (data['position']['black_clock_target']) {
1278                 color = "black";
1279                 $("#whiteclock").removeClass("running-clock");
1280                 $("#blackclock").addClass("running-clock");
1281         } else {
1282                 $("#whiteclock").removeClass("running-clock");
1283                 $("#blackclock").removeClass("running-clock");
1284         }
1285         var remaining_ms;
1286         if (color) {
1287                 var now = new Date().getTime() + client_clock_offset_ms;
1288                 remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
1289                 if (color === "white") {
1290                         white_clock_ms = remaining_ms;
1291                 } else {
1292                         black_clock_ms = remaining_ms;
1293                 }
1294         }
1295
1296         if (white_clock_ms === null || black_clock_ms === null) {
1297                 $("#whiteclock").empty();
1298                 $("#blackclock").empty();
1299                 return;
1300         }
1301
1302         // If either player has ten minutes or less left, add the second counters.
1303         var show_seconds = (white_clock_ms < 60 * 10 * 1000 || black_clock_ms < 60 * 10 * 1000);
1304
1305         if (color) {
1306                 // See when the clock will change next, and update right after that.
1307                 var next_update_ms;
1308                 if (show_seconds) {
1309                         next_update_ms = remaining_ms % 1000 + 100;
1310                 } else {
1311                         next_update_ms = remaining_ms % 60000 + 100;
1312                 }
1313                 clock_timer = setTimeout(update_clock, next_update_ms);
1314         }
1315
1316         $("#whiteclock").text(format_clock(white_clock_ms, show_seconds));
1317         $("#blackclock").text(format_clock(black_clock_ms, show_seconds));
1318 }
1319
1320 /**
1321  * @param {Number} remaining_ms
1322  * @param {boolean} show_seconds
1323  */
1324 var format_clock = function(remaining_ms, show_seconds) {
1325         if (remaining_ms <= 0) {
1326                 if (show_seconds) {
1327                         return "00:00:00";
1328                 } else {
1329                         return "00:00";
1330                 }
1331         }
1332
1333         var remaining = Math.floor(remaining_ms / 1000);
1334         var seconds = remaining % 60;
1335         remaining = (remaining - seconds) / 60;
1336         var minutes = remaining % 60;
1337         remaining = (remaining - minutes) / 60;
1338         var hours = remaining;
1339         if (show_seconds) {
1340                 return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
1341         } else {
1342                 return format_2d(hours) + ":" + format_2d(minutes);
1343         }
1344 }
1345
1346 /**
1347  * @param {Number} x
1348  */
1349 var format_2d = function(x) {
1350         if (x >= 10) {
1351                 return x;
1352         } else {
1353                 return "0" + x;
1354         }
1355 }
1356
1357 /**
1358  * @param {string} move
1359  * @param {Number} move_num
1360  * @param {boolean} white_to_play
1361  */
1362 var format_move_with_number = function(move, move_num, white_to_play) {
1363         var ret;
1364         if (white_to_play) {
1365                 ret = (move_num - 1) + '… ';
1366         } else {
1367                 ret = move_num + '. ';
1368         }
1369         ret += move;
1370         return ret;
1371 }
1372
1373 /**
1374  * @param {string} move
1375  * @param {Number} halfmove_num
1376  */
1377 var format_halfmove_with_number = function(move, halfmove_num) {
1378         return format_move_with_number(
1379                 move,
1380                 Math.floor(halfmove_num / 2) + 1,
1381                 halfmove_num % 2 == 0);
1382 }
1383
1384 /**
1385  * @param {Object} data
1386  * @param {Number} halfmove_num
1387  */
1388 var format_tooltip = function(data, halfmove_num) {
1389         if (data['score_history'][halfmove_num] ||
1390             halfmove_num === data['position']['pretty_history'].length) {
1391                 var move;
1392                 var short_score;
1393                 if (halfmove_num === data['position']['pretty_history'].length) {
1394                         move = data['position']['last_move'];
1395                         short_score = data['short_score'];
1396                 } else {
1397                         move = data['position']['pretty_history'][halfmove_num];
1398                         short_score = data['score_history'][halfmove_num][1];
1399                 }
1400                 var move_with_number = format_halfmove_with_number(move, halfmove_num);
1401
1402                 return "After " + move_with_number + ": " + short_score;
1403         } else {
1404                 for (var i = halfmove_num; i --> 0; ) {
1405                         if (data['score_history'][i]) {
1406                                 var move = data['position']['pretty_history'][i];
1407                                 return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
1408                         }
1409                 }
1410         }
1411 }
1412
1413 /**
1414  * @param {boolean} sort_by_score
1415  */
1416 var resort_refutation_lines = function(sort_by_score) {
1417         sort_refutation_lines_by_score = sort_by_score;
1418         if (supports_html5_storage()) {
1419                 localStorage['sort_refutation_lines_by_score'] = sort_by_score ? 1 : 0;
1420         }
1421         update_refutation_lines();
1422 }
1423 window['resort_refutation_lines'] = resort_refutation_lines;
1424
1425 /**
1426  * @param {boolean} truncate_history
1427  */
1428 var set_truncate_history = function(truncate_history) {
1429         truncate_display_history = truncate_history;
1430         update_refutation_lines();
1431 }
1432 window['set_truncate_history'] = set_truncate_history;
1433
1434 /**
1435  * @param {number} line_num
1436  * @param {number} move_num
1437  */
1438 var show_line = function(line_num, move_num) {
1439         if (line_num == -1) {
1440                 current_display_line = null;
1441                 current_display_move = null;
1442                 hash_refutation_lines = null;
1443                 if (displayed_analysis_data) {
1444                         // TODO: Support exiting to history position if we are in an
1445                         // analysis line of a history position.
1446                         displayed_analysis_data = null;
1447                 }
1448                 update_board();
1449                 return;
1450         } else {
1451                 current_display_line = jQuery.extend({}, display_lines[line_num]);  // Shallow clone.
1452                 current_display_move = move_num + current_display_line.start_display_move_num;
1453         }
1454         current_display_line_is_history = (line_num == 0);
1455
1456         update_historic_analysis();
1457         update_displayed_line();
1458         update_board_highlight();
1459         update_move_highlight();
1460         redraw_arrows();
1461 }
1462 window['show_line'] = show_line;
1463
1464 var prev_move = function() {
1465         if (current_display_line &&
1466             current_display_move >= current_display_line.start_display_move_num) {
1467                 --current_display_move;
1468         }
1469         update_historic_analysis();
1470         update_displayed_line();
1471         update_move_highlight();
1472 }
1473 window['prev_move'] = prev_move;
1474
1475 var next_move = function() {
1476         if (current_display_line &&
1477             current_display_move < current_display_line.pretty_pv.length - 1) {
1478                 ++current_display_move;
1479         }
1480         update_historic_analysis();
1481         update_displayed_line();
1482         update_move_highlight();
1483 }
1484 window['next_move'] = next_move;
1485
1486 var update_historic_analysis = function() {
1487         if (!current_display_line_is_history) {
1488                 return;
1489         }
1490         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1491                 displayed_analysis_data = null;
1492                 update_board();
1493         }
1494
1495         // Fetch old analysis for this line if it exists.
1496         var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1497         var filename = "/history/move" + (current_display_move + 1) + "-" +
1498                 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1499
1500         current_historic_xhr = $.ajax({
1501                 url: filename
1502         }).done(function(data, textstatus, xhr) {
1503                 displayed_analysis_data = data;
1504                 update_board();
1505         }).fail(function(jqXHR, textStatus, errorThrown) {
1506                 if (textStatus === "abort") {
1507                         // Aborted because we are switching backends. Don't do anything;
1508                         // we will already have been cleared.
1509                 } else {
1510                         displayed_analysis_data = {'failed': true};
1511                         update_board();
1512                 }
1513         });
1514 }
1515
1516 /**
1517  * @param {string} fen
1518  */
1519 var update_imbalance = function(fen) {
1520         var hiddenboard = new Chess(fen);
1521         var imbalance = {'k': 0, 'q': 0, 'r': 0, 'b': 0, 'n': 0, 'p': 0};
1522         for (var row = 0; row < 8; ++row) {
1523                 for (var col = 0; col < 8; ++col) {
1524                         var col_text = String.fromCharCode('a1'.charCodeAt(0) + col);
1525                         var row_text = String.fromCharCode('a1'.charCodeAt(1) + row);
1526                         var square = col_text + row_text;
1527                         var contents = hiddenboard.get(square);
1528                         if (contents !== null) {
1529                                 if (contents.color === 'w') {
1530                                         ++imbalance[contents.type];
1531                                 } else {
1532                                         --imbalance[contents.type];
1533                                 }
1534                         }
1535                 }
1536         }
1537         var white_imbalance = '';
1538         var black_imbalance = '';
1539         for (var piece in imbalance) {
1540                 for (var i = 0; i < imbalance[piece]; ++i) {
1541                         white_imbalance += '<img src="img/chesspieces/wikipedia/w' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1542                 }
1543                 for (var i = 0; i < -imbalance[piece]; ++i) {
1544                         black_imbalance += '<img src="img/chesspieces/wikipedia/b' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1545                 }
1546         }
1547         $('#whiteimbalance').html(white_imbalance);
1548         $('#blackimbalance').html(black_imbalance);
1549 }
1550
1551 /** Mark the currently selected move in red.
1552  * Also replaces the PV with the current displayed line if it's not shown
1553  * anywhere else on the screen.
1554  */
1555 var update_move_highlight = function() {
1556         if (highlighted_move !== null) {
1557                 highlighted_move.removeClass('highlight');
1558         }
1559         if (current_display_line) {
1560                 // See if the current displayed line is identical to any of the ones
1561                 // we have on screen. (It might not be if e.g. the analysis reloaded
1562                 // since we started looking.)
1563                 var display_line_num = null;
1564                 for (var i = 0; i < display_lines.length; ++i) {
1565                         var line = display_lines[i];
1566                         if (line.start_display_move_num > 0) continue;
1567                         if (current_display_line.start_fen !== line.start_fen) continue;
1568                         if (current_display_line.pretty_pv.length !== line.pretty_pv.length) continue;
1569                         var ok = true;
1570                         for (var j = 0; j < line.pretty_pv.length; ++j) {
1571                                 if (current_display_line.pretty_pv[j] !== line.pretty_pv[j]) {
1572                                         ok = false;
1573                                         break;
1574                                 }
1575                         }
1576                         if (ok) {
1577                                 display_line_num = i;
1578                                 break;
1579                         }
1580                 }
1581
1582                 if (display_line_num === null) {
1583                         // Replace the PV with the (complete) line.
1584                         $("#pvtitle").text("Exploring:");
1585                         current_display_line.start_display_move_num = 0;
1586                         display_lines.push(current_display_line);
1587                         $("#pv").html(print_pv(display_lines.length - 1));
1588                         display_line_num = display_lines.length - 1;
1589                 }
1590
1591                 highlighted_move = $("#automove" + display_line_num + "-" + (current_display_move - current_display_line.start_display_move_num));
1592                 highlighted_move.addClass('highlight');
1593         }
1594 }
1595
1596 var update_displayed_line = function() {
1597         if (current_display_line === null) {
1598                 $("#linenav").hide();
1599                 $("#linemsg").show();
1600                 display_fen = base_fen;
1601                 board.position(base_fen);
1602                 update_imbalance(base_fen);
1603                 return;
1604         }
1605
1606         $("#linenav").show();
1607         $("#linemsg").hide();
1608
1609         if (current_display_move <= 0) {
1610                 $("#prevmove").html("Previous");
1611         } else {
1612                 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
1613         }
1614         if (current_display_move == current_display_line.pretty_pv.length - 1) {
1615                 $("#nextmove").html("Next");
1616         } else {
1617                 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
1618         }
1619
1620         var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pretty_pv, current_display_move);
1621         display_fen = hiddenboard.fen();
1622         board_is_animating = true;
1623         var old_fen = board.fen();
1624         board.position(hiddenboard.fen());
1625         if (board.fen() === old_fen) {
1626                 board_is_animating = false;
1627         } else if (!current_display_line_is_history) {
1628                 // Fire off a hash request, since we're now off the main position
1629                 // and it just changed.
1630                 explore_hash(display_fen);
1631         }
1632         update_imbalance(hiddenboard.fen());
1633 }
1634
1635 /**
1636  * @param {boolean} param_enable_sound
1637  */
1638 var set_sound = function(param_enable_sound) {
1639         enable_sound = param_enable_sound;
1640         if (enable_sound) {
1641                 $("#soundon").html("<strong>On</strong>");
1642                 $("#soundoff").html("<a href=\"javascript:set_sound(false)\">Off</a>");
1643
1644                 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1645                 // and also preload the file since the user has selected audio.
1646                 var ding = document.getElementById('ding');
1647                 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1648                         ding.src = 'ding.opus';
1649                         ding.load();
1650                 }
1651         } else {
1652                 $("#soundon").html("<a href=\"javascript:set_sound(true)\">On</a>");
1653                 $("#soundoff").html("<strong>Off</strong>");
1654         }
1655         if (supports_html5_storage()) {
1656                 localStorage['enable_sound'] = enable_sound ? 1 : 0;
1657         }
1658 }
1659 window['set_sound'] = set_sound;
1660
1661 /** Send off a hash probe request to the backend.
1662  * @param {string} fen
1663  */
1664 var explore_hash = function(fen) {
1665         // If we already have a backend response going, abort it.
1666         if (current_hash_xhr) {
1667                 current_hash_xhr.abort();
1668         }
1669         if (current_hash_display_timer) {
1670                 clearTimeout(current_hash_display_timer);
1671                 current_hash_display_timer = null;
1672         }
1673         current_hash_xhr = $.ajax({
1674                 url: backend_hash_url + "?fen=" + fen
1675         }).done(function(data, textstatus, xhr) {
1676                 show_explore_hash_results(data, fen);
1677         });
1678 }
1679
1680 /** Process the JSON response from a hash probe request.
1681  * @param {!Object} data
1682  * @param {string} fen
1683  */
1684 var show_explore_hash_results = function(data, fen) {
1685         if (board_is_animating) {
1686                 // Updating while the animation is still going causes
1687                 // the animation to jerk. This is pretty crude, but it will do.
1688                 current_hash_display_timer = setTimeout(function() { show_explore_hash_results(data, fen); }, 100);
1689                 return;
1690         }
1691         current_hash_display_timer = null;
1692         hash_refutation_lines = data['lines'];
1693         update_board();
1694 }
1695
1696 // almost all of this stuff comes from the chessboard.js example page
1697 var onDragStart = function(source, piece, position, orientation) {
1698         var pseudogame = new Chess(display_fen);
1699         if (pseudogame.game_over() === true ||
1700             (pseudogame.turn() === 'w' && piece.search(/^b/) !== -1) ||
1701             (pseudogame.turn() === 'b' && piece.search(/^w/) !== -1)) {
1702                 return false;
1703         }
1704
1705         recommended_move = get_best_move(pseudogame, source, null);
1706         if (recommended_move) {
1707                 var squareEl = $('#board .square-' + recommended_move.to);
1708                 squareEl.addClass('highlight1-32417');
1709         }
1710         return true;
1711 }
1712
1713 var mousedownSquare = function(e) {
1714         reverse_dragging_from = null;
1715         var square = $(this).attr('data-square');
1716
1717         var pseudogame = new Chess(display_fen);
1718         if (pseudogame.game_over() === true) {
1719                 return;
1720         }
1721
1722         // If the square is empty, or has a piece of the side not to move,
1723         // we handle it. If not, normal piece dragging will take it.
1724         var position = board.position();
1725         if (!position.hasOwnProperty(square) ||
1726             (pseudogame.turn() === 'w' && position[square].search(/^b/) !== -1) ||
1727             (pseudogame.turn() === 'b' && position[square].search(/^w/) !== -1)) {
1728                 reverse_dragging_from = square;
1729                 recommended_move = get_best_move(pseudogame, null, square);
1730                 if (recommended_move) {
1731                         var squareEl = $('#board .square-' + recommended_move.from);
1732                         squareEl.addClass('highlight1-32417');
1733                         squareEl = $('#board .square-' + recommended_move.to);
1734                         squareEl.addClass('highlight1-32417');
1735                 }
1736         }
1737 }
1738
1739 var mouseupSquare = function(e) {
1740         if (reverse_dragging_from === null) {
1741                 return;
1742         }
1743         var source = $(this).attr('data-square');
1744         var target = reverse_dragging_from;
1745         reverse_dragging_from = null;
1746         if (onDrop(source, target) !== 'snapback') {
1747                 onSnapEnd(source, target);
1748         }
1749         $("#board").find('.square-55d63').removeClass('highlight1-32417');
1750 }
1751
1752 var get_best_move = function(game, source, target) {
1753         var moves = game.moves({ verbose: true });
1754         if (source !== null) {
1755                 moves = moves.filter(function(move) { return move.from == source; });
1756         }
1757         if (target !== null) {
1758                 moves = moves.filter(function(move) { return move.to == target; });
1759         }
1760         if (moves.length == 0) {
1761                 return null;
1762         }
1763         if (moves.length == 1) {
1764                 return moves[0];
1765         }
1766
1767         // More than one move. Use the display lines (if we have them)
1768         // to disambiguate; otherwise, we have no information.
1769         var move_hash = {};
1770         for (var i = 0; i < moves.length; ++i) {
1771                 move_hash[moves[i].san] = moves[i];
1772         }
1773
1774         var best_move = null;
1775         var best_move_score = null;
1776
1777         for (var move in refutation_lines) {
1778                 var line = refutation_lines[move];
1779                 var score = parseInt(line['score_sort_key'], 10);
1780                 if (score < -1000000) {  // Two zeros less than in the server (just some margin).
1781                         continue;
1782                 }
1783                 var first_move = line['pv_pretty'][0];
1784                 if (move_hash[first_move]) {
1785                         if (best_move_score === null || line['score_sort_key'] > best_move_score) {
1786                                 best_move = move_hash[first_move];
1787                                 best_move_score = line['score_sort_key'];
1788                         }
1789                 }
1790         }
1791         return best_move;
1792 }
1793
1794 var onDrop = function(source, target) {
1795         if (source === target) {
1796                 if (recommended_move === null) {
1797                         return 'snapback';
1798                 } else {
1799                         // Accept the move. It will be changed in onSnapEnd.
1800                         return;
1801                 }
1802         } else {
1803                 // Suggestion not asked for.
1804                 recommended_move = null;
1805         }
1806
1807         // see if the move is legal
1808         var pseudogame = new Chess(display_fen);
1809         var move = pseudogame.move({
1810                 from: source,
1811                 to: target,
1812                 promotion: 'q' // NOTE: always promote to a queen for example simplicity
1813         });
1814
1815         // illegal move
1816         if (move === null) return 'snapback';
1817 }
1818
1819 var onSnapEnd = function(source, target) {
1820         if (source === target && recommended_move !== null) {
1821                 source = recommended_move.from;
1822                 target = recommended_move.to;
1823         }
1824         recommended_move = null;
1825         var pseudogame = new Chess(display_fen);
1826         var move = pseudogame.move({
1827                 from: source,
1828                 to: target,
1829                 promotion: 'q' // NOTE: always promote to a queen for example simplicity
1830         });
1831
1832         if (current_display_line &&
1833             current_display_move < current_display_line.pretty_pv.length - 1 &&
1834             current_display_line.pretty_pv[current_display_move] === move.san) {
1835                 next_move();
1836                 return;
1837         }
1838
1839         // Walk down the displayed lines until we find one that starts with
1840         // this move, then select that. Note that this gives us a good priority
1841         // order (history first, then PV, then multi-PV lines).
1842         for (var i = 0; i < display_lines.length; ++i) {
1843                 var line = display_lines[i];
1844                 if (line.pretty_pv[line.start_display_move_num] === move.san) {
1845                         show_line(i, 0);
1846                         return;
1847                 }
1848         }
1849
1850         // Shouldn't really be here if we have hash probes, but there's really
1851         // nothing we can do.
1852 }
1853 // End of dragging-related code.
1854
1855 /**
1856  * @param {string} new_backend_url
1857  */
1858 var switch_backend = function(new_backend_url) {
1859         // Stop looking at historic data.
1860         current_display_line = null;
1861         current_display_move = null;
1862         displayed_analysis_data = null;
1863         if (current_historic_xhr) {
1864                 current_historic_xhr.abort();
1865         }
1866
1867         // If we already have a backend response going, abort it.
1868         if (current_analysis_xhr) {
1869                 current_analysis_xhr.abort();
1870         }
1871         if (current_hash_xhr) {
1872                 current_hash_xhr.abort();
1873         }
1874
1875         // Otherwise, we should have a timer going to start a new one.
1876         // Kill that, too.
1877         if (current_analysis_request_timer) {
1878                 clearTimeout(current_analysis_request_timer);
1879                 current_analysis_request_timer = null;
1880         }
1881         if (current_hash_display_timer) {
1882                 clearTimeout(current_hash_display_timer);
1883                 current_hash_display_timer = null;
1884         }
1885
1886         // Request an immediate fetch with the new backend.
1887         backend_url = new_backend_url;
1888         current_analysis_data = null;
1889         ims = 0;
1890         request_update();
1891 }
1892 window['switch_backend'] = switch_backend;
1893
1894 var init = function() {
1895         unique = get_unique();
1896
1897         // Load settings from HTML5 local storage if available.
1898         if (supports_html5_storage() && localStorage['enable_sound']) {
1899                 set_sound(parseInt(localStorage['enable_sound']));
1900         } else {
1901                 set_sound(false);
1902         }
1903         if (supports_html5_storage() && localStorage['sort_refutation_lines_by_score']) {
1904                 sort_refutation_lines_by_score = parseInt(localStorage['sort_refutation_lines_by_score']);
1905         } else {
1906                 sort_refutation_lines_by_score = true;
1907         }
1908
1909         // Create board.
1910         board = new window.ChessBoard('board', {
1911                 onMoveEnd: function() { board_is_animating = false; },
1912
1913                 draggable: true,
1914                 onDragStart: onDragStart,
1915                 onDrop: onDrop,
1916                 onSnapEnd: onSnapEnd
1917         });
1918         $("#board").on('mousedown', '.square-55d63', mousedownSquare);
1919         $("#board").on('mouseup', '.square-55d63', mouseupSquare);
1920
1921         request_update();
1922         $(window).resize(function() {
1923                 board.resize();
1924                 update_sparkline(displayed_analysis_data || current_analysis_data);
1925                 update_board_highlight();
1926                 redraw_arrows();
1927         });
1928         $(window).keyup(function(event) {
1929                 if (event.which == 39) {
1930                         next_move();
1931                 } else if (event.which == 37) {
1932                         prev_move();
1933                 }
1934         });
1935         window.addEventListener('hashchange', possibly_switch_game_from_hash, false);
1936 };
1937 $(document).ready(init);
1938
1939 })();