5 * Version of this script. If the server returns a version larger than
6 * this, it is a sign we should reload to upgrade ourselves.
11 let SCRIPT_VERSION = 2021021300;
14 * The current backend URL.
19 let backend_url = "/analysis.pl";
20 let backend_hash_url = "/hash";
22 /** @type {window.ChessBoard} @private */
25 /** @type {boolean} @private */
26 let board_is_animating = false;
29 * The most recent analysis data we have from the server
30 * (about the most recent position).
34 let current_analysis_data = null;
37 * If we are displaying previous analysis or from hash, this is non-null,
38 * and will override most of current_analysis_data.
43 let displayed_analysis_data = null;
46 * Games currently in progress, if any.
58 let current_games = null;
73 /** @type {Array.<Array.<boolean>>} */
74 let occupied_by_arrows = [];
76 /** Currently displayed refutation lines (on-screen).
77 * Can either come from the current_analysis_data, displayed_analysis_data,
78 * or hash_refutation_lines.
80 let refutation_lines = [];
82 /** Refutation lines from current hash probe.
84 * If non-null, will override refutation lines from the base position.
85 * Note that these are relative to display_fen, not base_fen.
87 let hash_refutation_lines = null;
89 /** @type {!number} @private */
92 /** @type {!string} @private */
95 /** @type {number} @private */
98 /** @type {boolean} @private */
99 let truncate_display_history = true;
101 /** @type {!string|undefined} @private */
102 let highlight_from = undefined;
104 /** @type {!string|undefined} @private */
105 let highlight_to = undefined;
107 /** The HTML object of the move currently being highlighted (in red).
110 let highlighted_move = null;
112 /** Currently suggested/recommended move when dragging.
113 * @type {?{from: !string, to: !string}}
116 let recommended_move = null;
118 /** If reverse-dragging (dragging from the destination square to the
119 * source square), the destination square.
123 let reverse_dragging_from = null;
125 /** @type {?number} @private */
128 /** @type {boolean} @private */
129 let enable_sound = false;
131 /** @type {!number} @private */
135 * Our best estimate of how many milliseconds we need to add to
136 * new Date() to get the true UTC time. Calibrated against the
142 let client_clock_offset_ms = null;
144 let clock_timer = null;
146 /** The current position being analyzed, represented as a FEN string.
147 * Note that this is not necessarily the same as display_fen.
153 /** The current position on the board, represented as a FEN string.
154 * Note that board.fen() does not contain e.g. who is to play.
158 let display_fen = null;
162 * pv: Array.<string>,
165 * scores: Array<{first_move: number, score: Object}>,
166 * start_display_move_num: number
169 * "start_display_move_num" is the (half-)move number to start displaying the PV at.
170 * "score" is also evaluated at this point.
173 /** All PVs that we currently know of.
175 * Element 0 is history (or null if no history).
176 * Element 1 is current main PV, or explored line if nowhere else on the screen.
177 * All remaining elements are refutation lines (multi-PV).
179 * @type {Array.<DisplayLine>}
182 let display_lines = [];
184 /** @type {?DisplayLine} @private */
185 let current_display_line = null;
187 /** @type {boolean} @private */
188 let current_display_line_is_history = false;
190 /** @type {?number} @private */
191 let current_display_move = null;
194 * The current backend request to get main analysis (not history), if any,
195 * so that we can abort it.
197 * @type {?AbortController}
200 let current_analysis_xhr = null;
203 * The current timer to fire off a request to get main analysis (not history),
204 * if any, so that we can abort it.
209 let current_analysis_request_timer = null;
212 * The current backend request to get historic data, if any.
214 * @type {?AbortController}
217 let current_historic_xhr = null;
220 * The current backend request to get hash probes, if any, so that we can abort it.
222 * @type {?AbortController}
225 let current_hash_xhr = null;
228 * The current timer to display hash probe information (it could be waiting on the
229 * board to stop animating), if any, so that we can abort it.
234 let current_hash_display_timer = null;
236 let supports_html5_storage = function() {
238 return 'localStorage' in window && window['localStorage'] !== null;
244 // Make the unique token persistent so people refreshing the page won't count twice.
245 // Of course, you can never fully protect against people deliberately wanting to spam.
246 let get_unique = function() {
247 let use_local_storage = supports_html5_storage();
248 if (use_local_storage && window['localStorage']['unique']) {
249 return window['localStorage']['unique'];
251 let unique = Math.random();
252 if (use_local_storage) {
253 window['localStorage']['unique'] = unique;
258 let request_update = function() {
259 current_analysis_request_timer = null;
261 let handle_err = () => {
262 // Backend error or similar. Wait ten seconds, then try again.
263 current_analysis_request_timer = setTimeout(function() { request_update(); }, 10000);
266 current_analysis_xhr = new AbortController();
267 const signal = current_analysis_xhr.signal;
268 fetch(backend_url + "?ims=" + ims + "&unique=" + unique, { signal })
269 .then((response) => response.json().then(data => ({ok: response.ok, headers: response.headers, json: data}))) // ick
276 if (delay_ms === 0) {
277 process_update_response(obj.json, obj.headers);
279 setTimeout(function() { process_update_response(obj.json, obj.headers); }, delay_ms);
283 if (!backend_url.match(/history/)) {
285 current_analysis_request_timer = setTimeout(function() { request_update(); }, timeout);
289 if (err.name === 'AbortError') {
290 // Aborted because we are switching backends. Abandon and don't retry,
291 // because another one is already started for us.
299 document.body.style.opacity = null;
304 let process_update_response = function(data, headers) {
305 sync_server_clock(headers.get('Date'));
306 ims = headers.get('X-RGLM');
307 let num_viewers = headers.get('X-RGNV');
309 if (Array.isArray(data)) {
310 new_data = JSON.parse(JSON.stringify(current_analysis_data));
311 JSON_delta.patch(new_data, data);
316 let minimum_version = headers.get('X-RGMV');
317 if (minimum_version && minimum_version > SCRIPT_VERSION) {
318 // Upgrade to latest version with a force-reload.
319 location.reload(true);
322 // Verify that the PV makes sense.
324 if (new_data['pv']) {
325 let hiddenboard = new Chess(new_data['position']['fen']);
326 for (let i = 0; i < new_data['pv'].length; ++i) {
327 if (hiddenboard.move(new_data['pv'][i]) === null) {
335 possibly_play_sound(current_analysis_data, new_data);
336 current_analysis_data = new_data;
338 update_num_viewers(num_viewers);
340 console.log("Received invalid update, waiting five seconds and trying again.");
341 setTimeout(function() { location.reload(true); }, 5000);
345 let possibly_play_sound = function(old_data, new_data) {
349 if (old_data === null) {
352 let ding = document.getElementById('ding');
353 if (ding && ding.play) {
354 if (old_data['position'] && old_data['position']['fen'] &&
355 new_data['position'] && new_data['position']['fen'] &&
356 (old_data['position']['fen'] !== new_data['position']['fen'] ||
357 old_data['position']['move_num'] !== new_data['position']['move_num'])) {
364 * @type {!string} server_date_string
366 let sync_server_clock = function(server_date_string) {
367 let server_time_ms = new Date(server_date_string).getTime();
368 let client_time_ms = new Date().getTime();
369 let estimated_offset_ms = server_time_ms - client_time_ms;
371 // In order not to let the noise move us too much back and forth
372 // (the server only has one-second resolution anyway), we only
373 // change an existing skew if we are at least five seconds off.
374 if (client_clock_offset_ms === null ||
375 Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
376 client_clock_offset_ms = estimated_offset_ms;
380 let clear_arrows = function() {
381 for (let i = 0; i < arrows.length; ++i) {
383 if (arrows[i].svg.parentElement) {
384 arrows[i].svg.parentElement.removeChild(arrows[i].svg);
386 delete arrows[i].svg;
391 occupied_by_arrows = [];
392 for (let y = 0; y < 8; ++y) {
393 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
397 let redraw_arrows = function() {
398 for (let i = 0; i < arrows.length; ++i) {
399 position_arrow(arrows[i]);
403 /** @param {!number} x
406 let sign = function(x) {
416 /** See if drawing this arrow on the board would cause unduly amount of confusion.
417 * @param {!string} from The square the arrow is from (e.g. e4).
418 * @param {!string} to The square the arrow is to (e.g. e4).
421 let interfering_arrow = function(from, to) {
422 let from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
423 let from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
424 let to_col = to.charCodeAt(0) - "a1".charCodeAt(0);
425 let to_row = to.charCodeAt(1) - "a1".charCodeAt(1);
427 occupied_by_arrows[from_row][from_col] = true;
429 // Knight move: Just check that we haven't been at the destination before.
430 if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
431 (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
432 return occupied_by_arrows[to_row][to_col];
435 // Sliding piece: Check if anything except the from-square is seen before.
436 let dx = sign(to_col - from_col);
437 let dy = sign(to_row - from_row);
443 if (occupied_by_arrows[y][x]) {
446 occupied_by_arrows[y][x] = true;
447 } while (x != to_col || y != to_row);
452 /** Find a point along the coordinate system given by the given line,
453 * <t> units forward from the start of the line, <u> units to the right of it.
454 * @param {!number} x1
455 * @param {!number} x2
456 * @param {!number} y1
457 * @param {!number} y2
460 * @return {!string} The point in "x y" form, suitable for SVG paths.
462 let point_from_start = function(x1, y1, x2, y2, t, u) {
466 let norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
470 let x = x1 + dx * t + dy * u;
471 let y = y1 + dy * t - dx * u;
475 /** Find a point along the coordinate system given by the given line,
476 * <t> units forward from the end of the line, <u> units to the right of it.
477 * @param {!number} x1
478 * @param {!number} x2
479 * @param {!number} y1
480 * @param {!number} y2
483 * @return {!string} The point in "x y" form, suitable for SVG paths.
485 let point_from_end = function(x1, y1, x2, y2, t, u) {
489 let norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
493 let x = x2 + dx * t + dy * u;
494 let y = y2 + dy * t - dx * u;
498 let position_arrow = function(arrow) {
500 if (arrow.svg.parentElement) {
501 arrow.svg.parentElement.removeChild(arrow.svg);
505 if (current_display_line !== null && !current_display_line_is_history) {
509 let zoom_factor = document.getElementById("board").getBoundingClientRect().width / 400.0;
510 let line_width = arrow.line_width * zoom_factor;
511 let arrow_size = arrow.arrow_size * zoom_factor;
513 let square_width = document.querySelector(".square-a8").getBoundingClientRect().width;
514 let from_y, to_y, from_x, to_x;
515 if (board.orientation() === 'black') {
516 from_y = (arrow.from_row + 0.5)*square_width;
517 to_y = (arrow.to_row + 0.5)*square_width;
518 from_x = (7 - arrow.from_col + 0.5)*square_width;
519 to_x = (7 - arrow.to_col + 0.5)*square_width;
521 from_y = (7 - arrow.from_row + 0.5)*square_width;
522 to_y = (7 - arrow.to_row + 0.5)*square_width;
523 from_x = (arrow.from_col + 0.5)*square_width;
524 to_x = (arrow.to_col + 0.5)*square_width;
527 let SVG_NS = "http://www.w3.org/2000/svg";
528 let XHTML_NS = "http://www.w3.org/1999/xhtml";
529 let svg = document.createElementNS(SVG_NS, "svg");
530 svg.setAttribute("width", /** @type{number} */ (document.getElementById("board").getBoundingClientRect().width));
531 svg.setAttribute("height", /** @type{number} */ (document.getElementById("board").getBoundingClientRect().height));
532 svg.setAttribute("style", "position: absolute");
533 svg.setAttribute("position", "absolute");
534 svg.setAttribute("version", "1.1");
535 svg.setAttribute("class", "c1");
536 svg.setAttribute("xmlns", XHTML_NS);
544 let outline = document.createElementNS(SVG_NS, "path");
545 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));
546 outline.setAttribute("xmlns", XHTML_NS);
547 outline.setAttribute("stroke", "#666");
548 outline.setAttribute("stroke-width", line_width + 2);
549 outline.setAttribute("fill", "none");
550 svg.appendChild(outline);
552 let path = document.createElementNS(SVG_NS, "path");
553 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));
554 path.setAttribute("xmlns", XHTML_NS);
555 path.setAttribute("stroke", arrow.fg_color);
556 path.setAttribute("stroke-width", line_width);
557 path.setAttribute("fill", "none");
558 svg.appendChild(path);
560 // Then the arrow head.
561 let head = document.createElementNS(SVG_NS, "path");
562 head.setAttribute("d",
563 "M " + point_from_end(x1, y1, x2, y2, 0, 0) +
564 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
565 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
566 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
567 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
568 head.setAttribute("xmlns", XHTML_NS);
569 head.setAttribute("stroke", "#000");
570 head.setAttribute("stroke-width", "1");
571 head.setAttribute("fill", arrow.fg_color);
572 svg.appendChild(head);
574 svg.style.top = '2px'; /* Border for .board-b72b1. */
575 svg.style.left = '2px';
576 svg.style.pointerEvents = 'none';
577 document.getElementById('board').appendChild(svg);
582 * @param {!string} from_square
583 * @param {!string} to_square
584 * @param {!string} fg_color
585 * @param {number} line_width
586 * @param {number} arrow_size
588 let create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
589 let from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
590 let from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
591 let to_col = to_square.charCodeAt(0) - "a1".charCodeAt(0);
592 let to_row = to_square.charCodeAt(1) - "a1".charCodeAt(1);
600 line_width: line_width,
601 arrow_size: arrow_size,
605 position_arrow(arrow);
609 let compare_by_score = function(refutation_lines, invert, a, b) {
610 let sa = compute_score_sort_key(refutation_lines[b]['score'], refutation_lines[b]['depth'], invert);
611 let sb = compute_score_sort_key(refutation_lines[a]['score'], refutation_lines[a]['depth'], invert);
616 * Fake multi-PV using the refutation lines. Find all “relevant” moves,
617 * sorted by quality, descending.
619 * @param {!Object} data
620 * @param {number} margin The maximum number of centipawns worse than the
621 * best move can be and still be included.
622 * @param {boolean} invert Whether black is to play.
623 * @return {Array.<string>} The FEN representation (e.g. Ne4) of all
624 * moves, in score order.
626 let find_nonstupid_moves = function(data, margin, invert) {
627 // First of all, if there are any moves that are more than 0.5 ahead of
628 // the primary move, the refutation lines are probably bunk, so just
630 let best_score = undefined;
631 let pv_score = undefined;
632 for (let move in data['refutation_lines']) {
633 let line = data['refutation_lines'][move];
634 let score = compute_score_sort_key(line['score'], line['depth'], invert, false);
635 if (move == data['pv'][0]) {
638 if (best_score === undefined || score > best_score) {
641 if (line['depth'] < 8) {
646 if (best_score - pv_score > 50) {
650 // Now find all moves that are within “margin” of the best score.
651 // The PV move will always be first.
653 for (let move in data['refutation_lines']) {
654 let line = data['refutation_lines'][move];
655 let score = compute_score_sort_key(line['score'], line['depth'], invert);
656 if (move != data['pv'][0] && best_score - score <= margin) {
660 moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], data['position']['toplay'] === 'B', a, b) });
661 moves.unshift(data['pv'][0]);
670 let thousands = function(x) {
671 return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
675 * @param {!string} start_fen
676 * @param {Array.<string>} pv
677 * @param {number} move_num
678 * @param {!string} toplay
679 * @param {Array<{ first_move: integer, score: Object }>} scores
680 * @param {number} start_display_move_num
681 * @param {number=} opt_limit
682 * @param {boolean=} opt_showlast
684 let add_pv = function(start_fen, pv, move_num, toplay, scores, start_display_move_num, opt_limit, opt_showlast) {
686 start_fen: start_fen,
688 move_num: parseInt(move_num),
691 start_display_move_num: start_display_move_num
693 let splicepos = null;
694 if (scores !== null && scores.length >= 1 &&
695 scores[scores.length - 1].score !== undefined &&
696 scores[scores.length - 1].score !== null &&
697 (scores[scores.length - 1].score[0] === 'T' ||
698 scores[scores.length - 1].score[0] === 't')) {
699 splicepos = scores[scores.length - 1].score[1];
701 return print_pv(display_lines.length - 1, splicepos, opt_limit, opt_showlast);
705 * @param {number} line_num
706 * @param {?number} splicepos If non-null, where the tablebase-spliced portion of the TB starts.
707 * @param {number=} opt_limit If set, show at most this number of moves.
708 * @param {boolean=} opt_showlast If limit is set, show the last moves instead of the first ones.
710 let print_pv = function(line_num, splicepos, opt_limit, opt_showlast) {
711 let display_line = display_lines[line_num];
712 let pv = display_line.pv;
713 let move_num = display_line.move_num;
714 let toplay = display_line.toplay;
716 // Truncate PV at the start if needed.
717 let start_display_move_num = display_line.start_display_move_num;
718 if (start_display_move_num > 0) {
719 pv = pv.slice(start_display_move_num);
720 let to_add = start_display_move_num;
721 if (toplay === 'B') {
726 if (to_add % 2 == 1) {
730 move_num += to_add / 2;
731 if (splicepos !== null && splicepos > 0) {
739 if (opt_limit && opt_showlast && pv.length > opt_limit) {
740 // Truncate the PV at the beginning (instead of at the end).
741 // We assume here that toplay is 'W'. We also assume that if
742 // opt_showlast is set, then it is the history, and thus,
743 // the UI should be to expand the history.
744 ret = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
745 i = pv.length - opt_limit;
750 } else if (toplay == 'B' && pv.length > 0) {
752 if (splicepos === 0) {
756 move += "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pv[0] + "</a>";
757 ret = move_num + '. … ' + move;
762 for ( ; i < pv.length; ++i) {
763 let move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pv[i] + "</a>";
764 if (splicepos === i) {
770 if (i > opt_limit && !opt_showlast) {
779 ret += move_num + '. ' + move;
793 /** Update the highlighted to/from squares on the board.
794 * Based on the global "highlight_from" and "highlight_to" letiables.
796 let update_board_highlight = function() {
797 document.getElementById("board").querySelectorAll('.square-55d63').forEach((square) => square.classList.remove('nonuglyhighlight'));
798 if ((current_display_line === null || current_display_line_is_history) &&
799 highlight_from !== undefined && highlight_to !== undefined) {
800 document.getElementById("board").querySelector('.square-' + highlight_from).classList.add('nonuglyhighlight');
801 document.getElementById("board").querySelector('.square-' + highlight_to).classList.add('nonuglyhighlight');
805 let update_history = function() {
806 if (display_lines[0] === null || display_lines[0].pv.length == 0) {
807 document.getElementById("history").innerHTML = "No history";
808 } else if (truncate_display_history) {
809 document.getElementById("history").innerHTML = print_pv(0, null, 8, true);
811 document.getElementById("history").innerHTML =
812 '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
818 * @param {!boolean} truncate_history
820 let collapse_history = function(truncate_history) {
821 truncate_display_history = truncate_history;
824 window['collapse_history'] = collapse_history;
826 /** Update the HTML display of multi-PV from the global "refutation_lines".
828 * Also recreates the global "display_lines".
830 let update_refutation_lines = function() {
831 if (base_fen === null) {
834 if (display_lines.length > 2) {
835 // Truncate so that only the history and PV is left.
836 display_lines = [ display_lines[0], display_lines[1] ];
838 let tbl = document.getElementById("refutationlines");
839 tbl.replaceChildren();
841 if (display_lines.length < 2) {
842 // Update the move highlight, as we've rewritten all the HTML.
843 update_move_highlight();
847 // Find out where the lines start from.
849 let base_scores = display_lines[1].scores;
850 let start_display_move_num = 0;
851 if (hash_refutation_lines) {
852 base_line = current_display_line.pv.slice(0, current_display_move + 1);
853 base_scores = current_display_line.scores;
854 start_display_move_num = base_line.length;
858 for (let move in refutation_lines) {
862 let invert = (toplay === 'B');
863 if (current_display_line && current_display_move % 2 == 0 && !current_display_line_is_history) {
866 moves = moves.sort(function(a, b) { return compare_by_score(refutation_lines, invert, a, b) });
867 for (let i = 0; i < moves.length; ++i) {
868 let line = refutation_lines[moves[i]];
870 let tr = document.createElement("tr");
872 let move_td = document.createElement("td");
873 tr.appendChild(move_td);
874 move_td.classList.add("move");
876 let scores = base_scores.concat([{ first_move: start_display_move_num, score: line['score'] }]);
878 if (line['pv'].length == 0) {
879 // Not found, so just make a one-move PV.
880 let move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['move'] + "</a>";
881 move_td.innerHTML = move;
882 let score_td = document.createElement("td");
884 score_td.classList.add("score");
885 score_td.textContent = "—";
886 tr.appendChild(score_td);
888 let depth_td = document.createElement("td");
889 tr.appendChild(depth_td);
890 depth_td.classList.add("depth");
891 depth_td.textContent = "—";
893 let pv_td = document.createElement("td");
894 tr.appendChild(pv_td);
895 pv_td.classList.add("pv");
896 pv_td.innerHTML = add_pv(base_fen, base_line.concat([ line['move'] ]), move_num, toplay, scores, start_display_move_num);
902 let move_link = document.createElement("a");
903 move_link.classList.add("move");
904 move_link.setAttribute("href", "javascript:show_line(" + display_lines.length + ", 0)");
905 move_link.textContent = line['move'];
906 move_td.appendChild(move_link);
908 let score_td = document.createElement("td");
909 tr.appendChild(score_td);
910 score_td.classList.add("score");
911 score_td.textContent = format_short_score(line['score']);
913 let depth_td = document.createElement("td");
914 tr.appendChild(depth_td);
915 depth_td.classList.add("depth");
916 if (line['depth'] && line['depth'] >= 0) {
917 depth_td.textContent = "d" + line['depth'];
919 depth_td.textContent = "—";
922 let pv_td = document.createElement("td");
923 tr.appendChild(pv_td);
924 pv_td.classList.add("pv");
925 pv_td.innerHTML = add_pv(base_fen, base_line.concat(line['pv']), move_num, toplay, scores, start_display_move_num, 10);
930 // Update the move highlight, as we've rewritten all the HTML.
931 update_move_highlight();
935 * Create a Chess.js board object, containing the given position plus the given moves,
936 * up to the given limit.
938 * @param {?string} fen
939 * @param {Array.<string>} moves
940 * @param {number} last_move
942 let chess_from = function(fen, moves, last_move) {
943 let hiddenboard = new Chess();
944 if (fen !== null && fen !== undefined) {
945 hiddenboard.load(fen);
947 for (let i = 0; i <= last_move; ++i) {
948 if (moves[i] === '0-0') {
949 hiddenboard.move('O-O');
950 } else if (moves[i] === '0-0-0') {
951 hiddenboard.move('O-O-O');
953 hiddenboard.move(moves[i]);
959 let update_game_list = function(games) {
960 document.getElementById("games").textContent = "";
961 if (games === null) {
965 let games_div = document.getElementById('games');
966 for (let game_num = 0; game_num < games.length; ++game_num) {
967 let game = games[game_num];
968 let game_span = document.createElement("span");
969 game_span.setAttribute("class", "game");
971 let game_name = document.createTextNode(game['name']);
972 if (game['url'] === backend_url) {
974 game_span.appendChild(game_name);
976 if (current_analysis_data && current_analysis_data['position']) {
978 if (current_analysis_data['position']['result']) {
979 score = " (" + current_analysis_data['position']['result'] + ")";
981 score = " (" + format_short_score(current_analysis_data['score']) + ")";
983 game_span.appendChild(document.createTextNode(score));
987 let game_a = document.createElement("a");
988 game_a.setAttribute("href", "#" + game['id']);
989 game_a.appendChild(game_name);
990 game_span.appendChild(game_a);
993 if (game['result']) {
994 score = " (" + game['result'] + ")";
996 score = " (" + format_short_score(game['score']) + ")";
998 game_span.appendChild(document.createTextNode(score));
1001 games_div.appendChild(game_span);
1006 * Try to find a running game that matches with the current hash,
1007 * and switch to it if we're not already displaying it.
1009 let possibly_switch_game_from_hash = function() {
1010 let history_match = window.location.hash.match(/^#history=([a-zA-Z0-9_-]+)/);
1011 if (history_match !== null) {
1012 let game_id = history_match[1];
1014 url: '/history/' + game_id + '.json',
1016 id: 'history=' + game_id
1018 switch_backend(fake_game);
1022 if (current_games === null) {
1026 let hash = window.location.hash.replace(/^#/,'');
1027 for (let i = 0; i < current_games.length; ++i) {
1028 if (current_games[i]['id'] === hash) {
1029 if (backend_url !== current_games[i]['url']) {
1030 switch_backend(current_games[i]);
1038 * If this is a Chess960 castling which doesn't move the king,
1039 * move the rook instead.
1041 let patch_move = function(move) {
1042 if (move === null) return null;
1043 if (move.from !== move.to) return move;
1045 let f = move.rook_sq & 15;
1046 let r = move.rook_sq >> 4;
1047 let from = ('abcdefgh'.substring(f,f+1) + '87654321'.substring(r,r+1));
1050 if (move.to === 'g1') {
1052 } else if (move.to === 'g8') {
1054 } else if (move.to === 'b1') {
1056 } else if (move.to === 'b8') {
1060 return { from: from, to: to };
1063 /** Update all the HTML on the page, based on current global state.
1065 let update_board = function() {
1066 document.body.style.opacity = null;
1068 let data = displayed_analysis_data || current_analysis_data;
1069 let current_data = current_analysis_data; // Convenience alias.
1073 // Print the history. This is pretty much the only thing that's
1074 // unconditionally taken from current_data (we're not interested in
1075 // historic history).
1076 if (current_data['position']['history']) {
1077 let start = (current_data['position'] && current_data['position']['start_fen']) ? current_data['position']['start_fen'] : 'start';
1078 add_pv(start, current_data['position']['history'], 1, 'W', null, 0, 8, true);
1080 display_lines.push(null);
1084 // Games currently in progress, if any.
1085 if (current_data['games']) {
1086 current_games = current_data['games'];
1087 possibly_switch_game_from_hash();
1089 current_games = null;
1091 update_game_list(current_games);
1093 // The headline. Names are always fetched from current_data;
1094 // the rest can depend a bit.
1097 current_data['position']['player_w'] && current_data['position']['player_b']) {
1098 headline = current_data['position']['player_w'] + '–' +
1099 current_data['position']['player_b'] + ', analysis';
1101 headline = 'Analysis';
1104 // Credits, where applicable. Note that we don't want the footer to change a lot
1105 // when e.g. viewing history, so if any of these changed during the game,
1106 // use the current one still.
1107 if (current_data['using_lomonosov']) {
1108 document.getElementById("lomonosov").style.display = null;
1110 document.getElementById("lomonosov").style.display = 'none';
1113 // Credits: The engine name/version.
1114 if (current_data['engine'] && current_data['engine']['name'] !== null) {
1115 document.getElementById("engineid").textContent = current_data['engine']['name'];
1118 // Credits: The engine URL.
1119 if (current_data['engine'] && current_data['engine']['url']) {
1120 document.getElementById("engineid").setAttribute("href", current_data['engine']['url']);
1122 document.getElementById("engineid").removeAttribute("href");
1125 // Credits: Engine details.
1126 if (current_data['engine'] && current_data['engine']['details']) {
1127 document.getElementById("enginedetails").textContent = " (" + current_data['engine']['details'] + ")";
1129 document.getElementById("enginedetails").textContent = "";
1132 // Credits: Move source, possibly with URL.
1133 if (current_data['move_source'] && current_data['move_source_url']) {
1134 document.getElementById("movesource").textContent = "Moves provided by ";
1135 let movesource_a = document.createElement("a");
1136 movesource_a.setAttribute("href", current_data['move_source_url']);
1137 let movesource_text = document.createTextNode(current_data['move_source']);
1138 movesource_a.appendChild(movesource_text);
1139 let movesource_period = document.createTextNode(".");
1140 document.getElementById("movesource").appendChild(movesource_a);
1141 document.getElementById("movesource").appendChild(movesource_period);
1142 } else if (current_data['move_source']) {
1143 document.getElementById("movesource").textContent = "Moves provided by " + current_data['move_source'] + ".";
1145 document.getElementById("movesource").textContent = "";
1149 if (displayed_analysis_data) {
1150 // Displaying some non-current position, pick out the last move
1151 // from the history. This will work even if the fetch failed.
1152 if (current_display_move !== -1) {
1153 last_move = format_halfmove_with_number(
1154 current_display_line.pv[current_display_move],
1155 current_display_move);
1156 headline += ' after ' + last_move;
1158 } else if (data['position']['last_move'] !== 'none') {
1159 // Find the previous move.
1160 let previous_move_num, previous_toplay;
1161 if (data['position']['toplay'] == 'B') {
1162 previous_move_num = data['position']['move_num'];
1163 previous_toplay = 'W';
1165 previous_move_num = data['position']['move_num'] - 1;
1166 previous_toplay = 'B';
1169 last_move = format_move_with_number(
1170 data['position']['last_move'],
1172 previous_toplay == 'W');
1173 headline += ' after ' + last_move;
1177 document.getElementById("headline").textContent = headline;
1179 // The <title> contains a very brief headline.
1180 let title_elems = [];
1181 if (data['position'] && data['position']['result']) {
1182 title_elems.push(data['position']['result']);
1183 } else if (data['score']) {
1184 title_elems.push(format_short_score(data['score']));
1186 if (last_move !== null) {
1187 title_elems.push(last_move);
1190 if (title_elems.length != 0) {
1191 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
1193 document.title = 'analysis.sesse.net';
1196 // The last move (shown by highlighting the from and to squares).
1197 if (data['position'] && data['position']['last_move_uci']) {
1198 highlight_from = data['position']['last_move_uci'].substr(0, 2);
1199 highlight_to = data['position']['last_move_uci'].substr(2, 2);
1200 } else if (current_display_line_is_history && current_display_line && current_display_move >= 0) {
1201 // We don't have historic analysis for this position, but we
1202 // can reconstruct what the last move was by just replaying
1204 let position = (data['position'] && data['position']['start_fen']) ? data['position']['start_fen'] : null;
1205 let hiddenboard = chess_from(position, current_display_line.pv, current_display_move);
1206 let moves = hiddenboard.history({ verbose: true });
1207 last_move = moves.pop();
1208 highlight_from = last_move.from;
1209 highlight_to = last_move.to;
1211 highlight_from = highlight_to = undefined;
1213 update_board_highlight();
1215 if (data['failed']) {
1216 document.getElementById("score").textContent = "No analysis for this move";
1217 document.getElementById("pvtitle").textContent = "PV:";
1218 document.getElementById("pv").replaceChildren();
1219 document.getElementById("searchstats").innerHTML = " ";
1220 document.getElementById("refutationlines").replaceChildren();
1221 document.getElementById("whiteclock").replaceChildren();
1222 document.getElementById("blackclock").replaceChildren();
1223 refutation_lines = [];
1224 update_refutation_lines();
1226 update_displayed_line();
1227 update_move_highlight();
1231 if (clock_timer !== null) {
1232 clearTimeout(clock_timer);
1237 if (current_display_line && !current_display_line_is_history) {
1239 if (current_display_line.scores && current_display_line.scores.length > 0) {
1240 for (let i = 0; i < current_display_line.scores.length; ++i) {
1241 if (current_display_move < current_display_line.scores[i].first_move) {
1244 score = current_display_line.scores[i].score;
1248 document.getElementById("score").textContent = format_long_score(score);
1250 document.getElementById("score").textContent = "No score for this line";
1252 } else if (data['score']) {
1253 document.getElementById("score").textContent = format_long_score(data['score']);
1256 // The search stats.
1257 if (data['searchstats']) {
1258 document.getElementById("searchstats").innerHTML = data['searchstats'];
1259 } else if (data['tablebase'] == 1) {
1260 document.getElementById("searchstats").textContent = "Tablebase result";
1261 } else if (data['nodes'] && data['nps'] && data['depth']) {
1262 let stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
1263 if (data['seldepth']) {
1264 stats += ' (' + data['seldepth'] + ' selective)';
1266 if (data['tbhits'] && data['tbhits'] > 0) {
1267 if (data['tbhits'] == 1) {
1268 stats += ', one Syzygy hit';
1270 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
1274 document.getElementById("searchstats").textContent = stats;
1276 document.getElementById("searchstats").textContent = "";
1279 // Update the board itself.
1280 base_fen = data['position']['fen'];
1281 update_displayed_line();
1284 document.getElementById("pvtitle").textContent = "PV:";
1286 let scores = [{ first_move: -1, score: data['score'] }];
1287 document.getElementById("pv").innerHTML = add_pv(data['position']['fen'], data['pv'], data['position']['move_num'], data['position']['toplay'], scores, 0);
1289 // Update the PV arrow.
1291 if (data['pv'].length >= 1) {
1292 let hiddenboard = new Chess(base_fen);
1294 // draw a continuation arrow as long as it's the same piece
1296 for (let i = 0; i < data['pv'].length; i += 2) {
1297 let move = patch_move(hiddenboard.move(data['pv'][i]));
1299 if ((i >= 2 && move.from != last_to) ||
1300 interfering_arrow(move.from, move.to)) {
1303 create_arrow(move.from, move.to, '#f66', 6, 20);
1305 hiddenboard.move(data['pv'][i + 1]); // To keep continuity.
1308 let alt_moves = find_nonstupid_moves(data, 30, data['position']['toplay'] === 'B');
1309 for (let i = 1; i < alt_moves.length && i < 3; ++i) {
1310 hiddenboard = new Chess(base_fen);
1311 let move = patch_move(hiddenboard.move(alt_moves[i]));
1312 if (move !== null) {
1313 create_arrow(move.from, move.to, '#f66', 1, 10);
1318 // See if all semi-reasonable moves have only one possible response.
1319 if (data['pv'].length >= 2) {
1320 let nonstupid_moves = find_nonstupid_moves(data, 300, data['position']['toplay'] === 'B');
1321 let hiddenboard = new Chess(base_fen);
1322 hiddenboard.move(data['pv'][0]);
1323 let response = hiddenboard.move(data['pv'][1]);
1324 for (let i = 0; i < nonstupid_moves.length; ++i) {
1325 if (nonstupid_moves[i] == data['pv'][0]) {
1326 // ignore the PV move for refutation lines.
1329 if (!data['refutation_lines'] ||
1330 !data['refutation_lines'][nonstupid_moves[i]] ||
1331 !data['refutation_lines'][nonstupid_moves[i]]['pv'] ||
1332 data['refutation_lines'][nonstupid_moves[i]]['pv'].length < 2) {
1333 // Incomplete PV, abort.
1334 response = undefined;
1337 let line = data['refutation_lines'][nonstupid_moves[i]];
1338 hiddenboard = new Chess(base_fen);
1339 hiddenboard.move(line['pv'][0]);
1340 let this_response = hiddenboard.move(line['pv'][1]);
1341 if (this_response === null) {
1342 console.log("BUG: ", i);
1344 console.log(line['pv']);
1346 if (response.from !== this_response.from || response.to !== this_response.to) {
1347 // Different response depending on lines, abort.
1348 response = undefined;
1353 if (nonstupid_moves.length > 0 && response !== undefined) {
1354 create_arrow(response.from, response.to, '#66f', 6, 20);
1358 // Update the refutation lines.
1359 base_fen = data['position']['fen'];
1360 move_num = parseInt(data['position']['move_num']);
1361 toplay = data['position']['toplay'];
1362 refutation_lines = hash_refutation_lines || data['refutation_lines'];
1363 update_refutation_lines();
1365 // Update the sparkline last, since its size depends on how everything else reflowed.
1366 update_sparkline(data);
1369 let update_sparkline = function(data) {
1370 let scorespark = document.getElementById('scoresparkcontainer');
1371 scorespark.textContent = '';
1372 if (data && data['score_history']) {
1373 let first_move_num = undefined;
1374 for (let halfmove_num in data['score_history']) {
1375 halfmove_num = parseInt(halfmove_num);
1376 if (first_move_num === undefined || halfmove_num < first_move_num) {
1377 first_move_num = halfmove_num;
1380 if (first_move_num !== undefined) {
1381 let last_move_num = data['position']['move_num'] * 2 - 3;
1382 if (data['position']['toplay'] === 'B') {
1386 // Possibly truncate some moves if we don't have enough width.
1387 let max_moves = Math.floor(scorespark.getBoundingClientRect().width / 5) - 3;
1388 if (last_move_num - first_move_num > max_moves) {
1389 first_move_num = last_move_num - max_moves;
1394 let last_score = null;
1396 for (let halfmove_num = first_move_num; halfmove_num <= last_move_num; ++halfmove_num) {
1397 if (data['score_history'][halfmove_num]) {
1398 let score = compute_plot_score(data['score_history'][halfmove_num]);
1400 if (score < min_score) min_score = score;
1401 if (score > max_score) max_score = score;
1403 scores.push(last_score);
1405 if (data['score']) {
1406 let score = compute_plot_score(data['score']);
1408 if (score < min_score) min_score = score;
1409 if (score > max_score) max_score = score;
1412 const h = scorespark.getBoundingClientRect().height;
1414 let base_y = h - h * min_score / (min_score - max_score);
1415 for (let i = 0; i < scores.length; ++i) {
1416 let rect = document.createElementNS('http://www.w3.org/2000/svg', 'rect');
1417 //rect.setAttributeNS(null, 'stroke', "#000000");
1418 rect.setAttributeNS(null, 'x', i * 5)
1419 rect.setAttributeNS(null, 'width', 4);
1420 let extent = scores[i] * h / (max_score - min_score);
1421 if (extent > 0 && extent < 1) {
1423 } else if (extent < 0 && extent > -1) {
1428 if (scores[i] === 0) {
1429 color = [0.5, 0.5, 0.5];
1430 rect.setAttributeNS(null, 'y', base_y - 1);
1431 rect.setAttributeNS(null, 'height', 1);
1432 } else if (scores[i] > 0) {
1433 color = [0.2, 0.4, 0.8];
1434 rect.setAttributeNS(null, 'y', base_y - extent);
1435 rect.setAttributeNS(null, 'height', extent);
1437 color = [1.0, 0.267, 0.267];
1438 rect.setAttributeNS(null, 'y', base_y);
1439 rect.setAttributeNS(null, 'height', -extent);
1441 let hlcolor = [color[0], color[1], color[2]];
1442 if (scores[i] !== 0) {
1443 hlcolor[0] = Math.min(hlcolor[0] * 1.4, 1.0);
1444 hlcolor[1] = Math.min(hlcolor[1] * 1.4, 1.0);
1445 hlcolor[2] = Math.min(hlcolor[2] * 1.4, 1.0);
1447 rect.style.fill = 'rgb(' + color[0]*100.0 + '%, ' + color[1]*100.0 + '%, ' + color[2]*100.0 + '%)';
1449 // score_history contains the Nth _position_, but format_tooltip
1450 // wants to format the Nth _move_; thus the -1.
1451 const tooltip = format_tooltip(data, i + first_move_num - 1);
1452 rect.addEventListener('mouseenter', (e) => draw_hover(e, hlcolor, tooltip));
1453 rect.addEventListener('mousemove', (e) => draw_hover(e, hlcolor, tooltip));
1454 rect.addEventListener('mouseleave', (e) => hide_hover(e, color));
1455 rect.addEventListener('click', (e) => { hide_hover(e, color); show_line(0, i + first_move_num - 1) });
1456 scorespark.appendChild(rect);
1462 let draw_hover = function(e, color, tooltip) {
1463 e.target.style.fill = 'rgb(' + color[0]*100.0 + '%, ' + color[1]*100.0 + '%, ' + color[2]*100.0 + '%)';
1465 let hover = document.getElementById('sparklinehover');
1466 hover.textContent = tooltip;
1467 hover.style.display = 'initial';
1469 let left = Math.max(e.pageX + 10, window.pageXOffset);
1470 let top = Math.max(e.pageY - hover.getBoundingClientRect().height, window.pageYOffset);
1471 left = Math.min(left, window.pageXOffset + document.documentElement.clientWidth - hover.getBoundingClientRect().width);
1473 hover.style.left = left + 'px';
1474 hover.style.top = top + 'px';
1477 let hide_hover = function(e, color) {
1478 e.target.style.fill = 'rgb(' + color[0]*100.0 + '%, ' + color[1]*100.0 + '%, ' + color[2]*100.0 + '%)';
1479 document.getElementById('sparklinehover').style.display = 'none';
1483 * @param {number} num_viewers
1485 let update_num_viewers = function(num_viewers) {
1487 if (num_viewers === null) {
1489 } else if (num_viewers == 1) {
1490 text = "You are the only current viewer";
1492 text = num_viewers + " current viewers";
1494 if (display_fen !== null) {
1495 let counter = Math.floor(display_fen.split(" ")[4] / 2);
1496 if (counter >= 20) {
1497 text = text.replace("current ", "");
1498 text += " | 50-move rule: " + counter;
1501 document.getElementById("numviewers").textContent = text;
1504 let update_clock = function() {
1507 let data = displayed_analysis_data || current_analysis_data;
1510 if (data['position']) {
1511 let result = data['position']['result'];
1512 if (result === '1-0') {
1513 document.getElementById("whiteclock").textContent = "1";
1514 document.getElementById("blackclock").textContent = "0";
1515 document.getElementById("whiteclock").classList.remove("running-clock");
1516 document.getElementById("blackclock").classList.remove("running-clock");
1519 if (result === '1/2-1/2') {
1520 document.getElementById("whiteclock").textContent = "1/2";
1521 document.getElementById("blackclock").textContent = "1/2";
1522 document.getElementById("whiteclock").classList.remove("running-clock");
1523 document.getElementById("blackclock").classList.remove("running-clock");
1526 if (result === '0-1') {
1527 document.getElementById("whiteclock").textContent = "0";
1528 document.getElementById("blackclock").textContent = "1";
1529 document.getElementById("whiteclock").classList.remove("running-clock");
1530 document.getElementById("blackclock").classList.remove("running-clock");
1535 let white_clock_ms = null;
1536 let black_clock_ms = null;
1539 if (data['position'] &&
1540 data['position']['white_clock'] &&
1541 data['position']['black_clock']) {
1542 white_clock_ms = data['position']['white_clock'] * 1000;
1543 black_clock_ms = data['position']['black_clock'] * 1000;
1546 // Dynamic clock (only one, obviously).
1548 if (data['position']['white_clock_target']) {
1550 document.getElementById("whiteclock").classList.add("running-clock");
1551 document.getElementById("blackclock").classList.remove("running-clock");
1552 } else if (data['position']['black_clock_target']) {
1554 document.getElementById("whiteclock").classList.remove("running-clock");
1555 document.getElementById("blackclock").classList.add("running-clock");
1557 document.getElementById("whiteclock").classList.remove("running-clock");
1558 document.getElementById("blackclock").classList.remove("running-clock");
1562 let now = new Date().getTime() + client_clock_offset_ms;
1563 remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
1564 if (color === "white") {
1565 white_clock_ms = remaining_ms;
1567 black_clock_ms = remaining_ms;
1571 if (white_clock_ms === null || black_clock_ms === null) {
1572 document.getElementById("whiteclock").replaceChildren();
1573 document.getElementById("blackclock").replaceChildren();
1577 // If either player has twenty minutes or less left, add the second counters.
1578 // This matches what DGT clocks do.
1579 let show_seconds = (white_clock_ms < 60 * 20 * 1000 || black_clock_ms < 60 * 20 * 1000);
1582 // See when the clock will change next, and update right after that.
1585 next_update_ms = remaining_ms % 1000 + 100;
1587 next_update_ms = remaining_ms % 60000 + 100;
1589 clock_timer = setTimeout(update_clock, next_update_ms);
1592 document.getElementById("whiteclock").textContent = format_clock(white_clock_ms, show_seconds);
1593 document.getElementById("blackclock").textContent = format_clock(black_clock_ms, show_seconds);
1597 * @param {Number} remaining_ms
1598 * @param {boolean} show_seconds
1600 let format_clock = function(remaining_ms, show_seconds) {
1601 if (remaining_ms <= 0) {
1609 let remaining = Math.floor(remaining_ms / 1000);
1610 let seconds = remaining % 60;
1611 remaining = (remaining - seconds) / 60;
1612 let minutes = remaining % 60;
1613 remaining = (remaining - minutes) / 60;
1614 let hours = remaining;
1616 return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
1618 return format_2d(hours) + ":" + format_2d(minutes);
1625 let format_2d = function(x) {
1634 * @param {string} move
1635 * @param {Number} move_num Move number of this move.
1636 * @param {boolean} white_to_play Whether white is to play this move.
1638 let format_move_with_number = function(move, move_num, white_to_play) {
1640 if (white_to_play) {
1641 ret = move_num + '. ';
1643 ret = move_num + '… ';
1650 * @param {string} move
1651 * @param {Number} halfmove_num Half-move number that is to be played,
1654 let format_halfmove_with_number = function(move, halfmove_num) {
1655 return format_move_with_number(
1657 Math.floor(halfmove_num / 2) + 1,
1658 halfmove_num % 2 == 0);
1662 * @param {Object} data
1663 * @param {Number} halfmove_num
1665 let format_tooltip = function(data, halfmove_num) {
1666 if (data['score_history'][halfmove_num + 1] ||
1667 (halfmove_num + 1) === data['position']['history'].length) {
1668 // Position is in the history, or it is the current position
1669 // (which is implicitly tacked onto the history).
1672 if ((halfmove_num + 1) === data['position']['history'].length) {
1673 move = data['position']['last_move'];
1674 short_score = format_short_score(data['score']);
1676 move = data['position']['history'][halfmove_num];
1677 short_score = format_short_score(data['score_history'][halfmove_num + 1]);
1679 if (halfmove_num === -1) {
1680 return "Start position: " + short_score;
1682 let move_with_number = format_halfmove_with_number(move, halfmove_num);
1683 return "After " + move_with_number + ": " + short_score;
1686 for (let i = halfmove_num; i --> -1; ) {
1687 if (data['score_history'][i]) {
1688 let move = data['position']['history'][i];
1690 return "[Analysis kept from start position]";
1692 return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
1700 * @param {boolean} truncate_history
1702 let set_truncate_history = function(truncate_history) {
1703 truncate_display_history = truncate_history;
1704 update_refutation_lines();
1706 window['set_truncate_history'] = set_truncate_history;
1709 * @param {number} line_num
1710 * @param {number} move_num
1712 let show_line = function(line_num, move_num) {
1713 if (line_num == -1) {
1714 current_display_line = null;
1715 current_display_move = null;
1716 hash_refutation_lines = null;
1717 if (displayed_analysis_data) {
1718 // TODO: Support exiting to history position if we are in an
1719 // analysis line of a history position.
1720 displayed_analysis_data = null;
1725 current_display_line = {...display_lines[line_num]}; // Shallow clone.
1726 current_display_move = move_num + current_display_line.start_display_move_num;
1728 current_display_line_is_history = (line_num == 0);
1730 update_historic_analysis();
1731 update_displayed_line();
1732 update_board_highlight();
1733 update_move_highlight();
1736 window['show_line'] = show_line;
1738 let prev_move = function() {
1739 if (current_display_line &&
1740 current_display_move >= current_display_line.start_display_move_num) {
1741 --current_display_move;
1743 update_historic_analysis();
1744 update_displayed_line();
1745 update_move_highlight();
1747 window['prev_move'] = prev_move;
1749 let next_move = function() {
1750 if (current_display_line &&
1751 current_display_move < current_display_line.pv.length - 1) {
1752 ++current_display_move;
1754 update_historic_analysis();
1755 update_displayed_line();
1756 update_move_highlight();
1758 window['next_move'] = next_move;
1760 let next_game = function() {
1761 if (current_games === null) {
1765 // Try to find the game we are currently looking at.
1766 for (let game_num = 0; game_num < current_games.length; ++game_num) {
1767 let game = current_games[game_num];
1768 if (game['url'] === backend_url) {
1769 let next_game_num = (game_num + 1) % current_games.length;
1770 switch_backend(current_games[next_game_num]);
1775 // Couldn't find it; give up.
1778 let update_historic_analysis = function() {
1779 if (!current_display_line_is_history) {
1782 if (current_display_move == current_display_line.pv.length - 1) {
1783 displayed_analysis_data = null;
1787 // Fetch old analysis for this line if it exists.
1788 let hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pv, current_display_move);
1789 let filename = "/history/move" + (current_display_move + 1) + "-" +
1790 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1792 let handle_err = () => {
1793 displayed_analysis_data = {'failed': true};
1797 current_historic_xhr = new AbortController();
1798 const signal = current_analysis_xhr.signal;
1799 fetch(filename, { signal })
1800 .then((response) => response.json().then(data => ({ok: response.ok, json: data}))) // ick
1806 displayed_analysis_data = obj.json;
1810 if (err.name === 'AbortError') {
1811 // Aborted because we are switching backends. Abandon and don't retry,
1812 // because another one is already started for us.
1821 * @param {string} fen
1823 let update_imbalance = function(fen) {
1824 let hiddenboard = new Chess(fen);
1825 let imbalance = {'k': 0, 'q': 0, 'r': 0, 'b': 0, 'n': 0, 'p': 0};
1826 for (let row = 0; row < 8; ++row) {
1827 for (let col = 0; col < 8; ++col) {
1828 let col_text = String.fromCharCode('a1'.charCodeAt(0) + col);
1829 let row_text = String.fromCharCode('a1'.charCodeAt(1) + row);
1830 let square = col_text + row_text;
1831 let contents = hiddenboard.get(square);
1832 if (contents !== null) {
1833 if (contents.color === 'w') {
1834 ++imbalance[contents.type];
1836 --imbalance[contents.type];
1841 let white_imbalance = document.getElementById('whiteimbalance');
1842 let black_imbalance = document.getElementById('blackimbalance');
1843 white_imbalance.textContent = '';
1844 black_imbalance.textContent = '';
1845 for (let piece in imbalance) {
1846 for (let i = 0; i < imbalance[piece]; ++i) {
1847 let i1 = document.createElement('img');
1848 i1.src = svg_pieces['w' + piece.toUpperCase()];
1849 i1.setAttribute('alt', piece.toUpperCase());
1850 i1.classList.add('imbalance-piece');
1851 white_imbalance.appendChild(i1);
1853 let i2 = document.createElement('img');
1854 i2.src = svg_pieces['b' + piece.toUpperCase()];
1855 i2.setAttribute('alt', piece.toUpperCase());
1856 i2.classList.add('imbalance-inverted-piece');
1857 white_imbalance.appendChild(i2);
1859 for (let i = 0; i < -imbalance[piece]; ++i) {
1860 let i1 = document.createElement('img');
1861 i1.src = svg_pieces['b' + piece.toUpperCase()];
1862 i1.setAttribute('alt', piece.toUpperCase());
1863 i1.classList.add('imbalance-piece');
1864 black_imbalance.appendChild(i1);
1866 let i2 = document.createElement('img');
1867 i2.src = svg_pieces['w' + piece.toUpperCase()];
1868 i2.setAttribute('alt', piece.toUpperCase());
1869 i2.classList.add('imbalance-inverted-piece');
1870 black_imbalance.appendChild(i2);
1875 /** Mark the currently selected move in red.
1876 * Also replaces the PV with the current displayed line if it's not shown
1877 * anywhere else on the screen.
1879 let update_move_highlight = function() {
1880 if (highlighted_move !== null) {
1881 highlighted_move.classList.remove('highlight');
1883 if (current_display_line) {
1884 let display_line_num = find_display_line_matching_num();
1885 if (display_line_num === null) {
1886 // Replace the PV with the (complete) line.
1887 document.getElementById("pvtitle").textContent = "Exploring:";
1888 current_display_line.start_display_move_num = 0;
1889 display_lines.push(current_display_line);
1890 document.getElementById("pv").innerHTML = print_pv(display_lines.length - 1, null); // FIXME
1891 display_line_num = display_lines.length - 1;
1893 // Clear out the PV, so it's not selected by anything later.
1894 display_lines[1].pv = [];
1897 highlighted_move = document.getElementById("automove" + display_line_num + "-" + (current_display_move - current_display_line.start_display_move_num));
1898 if (highlighted_move !== null) {
1899 highlighted_move.classList.add('highlight');
1905 * See if the current displayed line is identical to any of the ones
1906 * we have on screen. (It might not be if e.g. the analysis reloaded
1907 * since we started looking.)
1911 let find_display_line_matching_num = function() {
1912 for (let i = 0; i < display_lines.length; ++i) {
1913 let line = display_lines[i];
1914 if (line.start_display_move_num > 0) continue;
1915 if (current_display_line.start_fen !== line.start_fen) continue;
1916 if (current_display_line.pv.length !== line.pv.length) continue;
1918 for (let j = 0; j < line.pv.length; ++j) {
1919 if (current_display_line.pv[j] !== line.pv[j]) {
1931 /** Update the board based on the currently displayed line.
1933 * TODO: This should really be called only whenever something changes,
1934 * instead of all the time.
1936 let update_displayed_line = function() {
1937 if (current_display_line === null) {
1938 document.getElementById("linenav").style.display = 'none';
1939 document.getElementById("linemsg").style.display = 'revert';
1940 display_fen = base_fen;
1941 set_board_position(base_fen);
1942 update_imbalance(base_fen);
1946 document.getElementById("linenav").style.display = 'revert';
1947 document.getElementById("linemsg").style.display = 'none';
1949 if (current_display_move <= 0) {
1950 document.getElementById("prevmove").innerHTML = "Previous";
1952 document.getElementById("prevmove").innerHTML = "<a href=\"javascript:prev_move();\">Previous</a></span>";
1954 if (current_display_move == current_display_line.pv.length - 1) {
1955 document.getElementById("nextmove").innerHTML = "Next";
1957 document.getElementById("nextmove").innerHTML = "<a href=\"javascript:next_move();\">Next</a></span>";
1960 let hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pv, current_display_move);
1961 set_board_position(hiddenboard.fen());
1962 if (display_fen !== hiddenboard.fen() && !current_display_line_is_history) {
1963 // Fire off a hash request, since we're now off the main position
1964 // and it just changed.
1965 explore_hash(hiddenboard.fen());
1967 display_fen = hiddenboard.fen();
1968 update_imbalance(hiddenboard.fen());
1971 let set_board_position = function(new_fen) {
1972 board_is_animating = true;
1973 let old_fen = board.fen();
1974 board.position(new_fen);
1975 if (board.fen() === old_fen) {
1976 board_is_animating = false;
1981 * @param {boolean} param_enable_sound
1983 let set_sound = function(param_enable_sound) {
1984 enable_sound = param_enable_sound;
1986 document.getElementById("soundon").innerHTML = "<strong>On</strong>";
1987 document.getElementById("soundoff").innerHTML = "<a href=\"javascript:set_sound(false)\">Off</a>";
1989 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1990 // and also preload the file since the user has selected audio.
1991 let ding = document.getElementById('ding');
1992 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1993 ding.src = 'ding.opus';
1997 document.getElementById("soundon").innerHTML = "<a href=\"javascript:set_sound(true)\">On</a>";
1998 document.getElementById("soundoff").innerHTML = "<strong>Off</strong>";
2000 if (supports_html5_storage()) {
2001 window['localStorage']['enable_sound'] = enable_sound ? 1 : 0;
2004 window['set_sound'] = set_sound;
2006 /** Send off a hash probe request to the backend.
2007 * @param {string} fen
2009 let explore_hash = function(fen) {
2010 // If we already have a backend response going, abort it.
2011 if (current_hash_xhr) {
2012 current_hash_xhr.abort();
2014 if (current_hash_display_timer) {
2015 clearTimeout(current_hash_display_timer);
2016 current_hash_display_timer = null;
2018 document.getElementById("refutationlines").replaceChildren();
2020 current_hash_xhr = new AbortController();
2021 const signal = current_analysis_xhr.signal;
2022 fetch(backend_hash_url + "?fen=" + fen, { signal })
2023 .then((response) => response.json())
2024 .then((data) => { show_explore_hash_results(data, fen); })
2026 // Truncate the lines, since we already cleared the display.
2027 display_lines = [ display_lines[0], display_lines[1] ];
2028 update_move_highlight();
2032 /** Process the JSON response from a hash probe request.
2033 * @param {!Object} data
2034 * @param {string} fen
2036 let show_explore_hash_results = function(data, fen) {
2037 if (board_is_animating) {
2038 // Updating while the animation is still going causes
2039 // the animation to jerk. This is pretty crude, but it will do.
2040 current_hash_display_timer = setTimeout(function() { show_explore_hash_results(data, fen); }, 100);
2043 current_hash_display_timer = null;
2044 hash_refutation_lines = data['lines'];
2048 // almost all of this stuff comes from the chessboard.js example page
2049 let onDragStart = function(source, piece, position, orientation) {
2050 let pseudogame = new Chess(display_fen);
2051 if (pseudogame.game_over() === true ||
2052 (pseudogame.turn() === 'w' && piece.search(/^b/) !== -1) ||
2053 (pseudogame.turn() === 'b' && piece.search(/^w/) !== -1)) {
2057 recommended_move = get_best_move(pseudogame, source, null, pseudogame.turn() === 'b');
2058 if (recommended_move) {
2059 let squareEl = document.querySelector('#board .square-' + recommended_move.to);
2060 squareEl.classList.add('highlight1-32417');
2065 let mousedownSquare = function(e) {
2066 if (!e.target || !e.target.closest('.square-55d63')) {
2070 reverse_dragging_from = null;
2071 let square = e.target.closest('.square-55d63').getAttribute('data-square');
2073 let pseudogame = new Chess(display_fen);
2074 if (pseudogame.game_over() === true) {
2078 // If the square is empty, or has a piece of the side not to move,
2079 // we handle it. If not, normal piece dragging will take it.
2080 let position = board.position();
2081 if (!position.hasOwnProperty(square) ||
2082 (pseudogame.turn() === 'w' && position[square].search(/^b/) !== -1) ||
2083 (pseudogame.turn() === 'b' && position[square].search(/^w/) !== -1)) {
2084 reverse_dragging_from = square;
2085 recommended_move = get_best_move(pseudogame, null, square, pseudogame.turn() === 'b');
2086 if (recommended_move) {
2087 let squareEl = document.querySelector('#board .square-' + recommended_move.from);
2088 squareEl.classList.add('highlight1-32417');
2089 squareEl = document.querySelector('#board .square-' + recommended_move.to);
2090 squareEl.classList.add('highlight1-32417');
2095 let mouseupSquare = function(e) {
2096 if (!e.target || !e.target.closest('.square-55d63')) {
2099 if (reverse_dragging_from === null) {
2102 let source = e.target.closest('.square-55d63').getAttribute('data-square');
2103 let target = reverse_dragging_from;
2104 reverse_dragging_from = null;
2105 if (onDrop(source, target) !== 'snapback') {
2106 onSnapEnd(source, target);
2108 document.getElementById("board").querySelectorAll('.square-55d63.highlight1-32417').forEach((square) => {
2109 square.classList.remove('highlight1-32417');
2113 let get_best_move = function(game, source, target, invert) {
2114 let moves = game.moves({ verbose: true });
2115 if (source !== null) {
2116 moves = moves.filter(function(move) { return move.from == source; });
2118 if (target !== null) {
2119 moves = moves.filter(function(move) { return move.to == target; });
2121 if (moves.length == 0) {
2124 if (moves.length == 1) {
2128 // More than one move. Use the display lines (if we have them)
2129 // to disambiguate; otherwise, we have no information.
2131 for (let i = 0; i < moves.length; ++i) {
2132 move_hash[moves[i].san] = moves[i];
2135 // See if we're already exploring some line.
2136 if (current_display_line &&
2137 current_display_move < current_display_line.pv.length - 1) {
2138 let first_move = current_display_line.pv[current_display_move + 1];
2139 if (move_hash[first_move]) {
2140 return move_hash[first_move];
2144 // History and PV take priority over the display lines.
2145 for (let i = 0; i < 2; ++i) {
2146 let line = display_lines[i];
2147 let first_move = line.pv[line.start_display_move_num];
2148 if (move_hash[first_move]) {
2149 return move_hash[first_move];
2153 let best_move = null;
2154 let best_move_score = null;
2156 for (let move in refutation_lines) {
2157 let line = refutation_lines[move];
2158 if (!line['score']) {
2161 let first_move = line['pv'][0];
2162 if (move_hash[first_move]) {
2163 let score = compute_score_sort_key(line['score'], line['depth'], invert);
2164 if (best_move_score === null || score > best_move_score) {
2165 best_move = move_hash[first_move];
2166 best_move_score = score;
2173 let onDrop = function(source, target) {
2174 if (source === target) {
2175 if (recommended_move === null) {
2178 // Accept the move. It will be changed in onSnapEnd.
2182 // Suggestion not asked for.
2183 recommended_move = null;
2186 // see if the move is legal
2187 let pseudogame = new Chess(display_fen);
2188 let move = pseudogame.move({
2191 promotion: 'q' // NOTE: always promote to a queen for example simplicity
2195 if (move === null) return 'snapback';
2198 let onSnapEnd = function(source, target) {
2199 if (source === target && recommended_move !== null) {
2200 source = recommended_move.from;
2201 target = recommended_move.to;
2203 recommended_move = null;
2204 let pseudogame = new Chess(display_fen);
2205 let move = pseudogame.move({
2208 promotion: 'q' // NOTE: always promote to a queen for example simplicity
2211 // Move ahead on the line we're on -- this includes history if we've
2213 if (current_display_line &&
2214 current_display_move < current_display_line.pv.length - 1 &&
2215 current_display_line.pv[current_display_move + 1] === move.san) {
2220 // Walk down the displayed lines until we find one that starts with
2221 // this move, then select that. Note that this gives us a good priority
2222 // order (PV, then multi-PV lines; history was already dealt with above,
2223 // as it's the only line that originates backwards).
2224 for (let i = 1; i < display_lines.length; ++i) {
2225 if (i == 1 && current_display_line) {
2226 // Do not choose PV if not on it.
2229 let line = display_lines[i];
2230 if (line.pv[line.start_display_move_num] === move.san) {
2236 // Shouldn't really be here if we have hash probes, but there's really
2237 // nothing we can do.
2239 // End of dragging-related code.
2241 let fmt_cp = function(v) {
2245 return "+" + (v / 100).toFixed(2);
2248 return "-" + (v / 100).toFixed(2);
2252 let format_short_score = function(score) {
2256 if (score[0] === 'T' || score[0] === 't') {
2257 let ret = "TB\u00a0";
2258 if (score[2]) { // Is a bound.
2259 ret = score[2] + "\u00a0TB\u00a0";
2261 if (score[0] === 'T') {
2262 return ret + Math.ceil(score[1] / 2);
2264 return ret + "-" + Math.ceil(score[1] / 2);
2266 } else if (score[0] === 'M' || score[0] === 'm') {
2267 let sign = (score[0] === 'm') ? '-' : '';
2268 if (score[2]) { // Is a bound.
2269 return score[2] + "\u00a0M " + sign + score[1];
2271 return "M " + sign + score[1];
2273 } else if (score[0] === 'd') {
2275 } else if (score[0] === 'cp') {
2276 if (score[2]) { // Is a bound.
2277 return score[2] + "\u00a0" + fmt_cp(score[1]);
2279 return fmt_cp(score[1]);
2285 let format_long_score = function(score) {
2289 if (score[0] === 'T') {
2290 if (score[1] == 0) {
2291 return "Won for white (tablebase)";
2293 return "White wins in " + Math.ceil(score[1] / 2);
2295 } else if (score[0] === 't') {
2296 if (score[1] == -1) {
2297 return "Won for black (tablebase)";
2299 return "Black wins in " + Math.ceil(score[1] / 2);
2301 } else if (score[0] === 'M') {
2302 if (score[1] == 0) {
2303 return "White wins by checkmate";
2305 return "White mates in " + score[1];
2307 } else if (score[0] === 'm') {
2308 if (score[1] == 0) {
2309 return "Black wins by checkmate";
2311 return "Black mates in " + score[1];
2313 } else if (score[0] === 'd') {
2314 return "Theoretical draw";
2315 } else if (score[0] === 'cp') {
2316 return "Score: " + format_short_score(score);
2321 let compute_plot_score = function(score) {
2322 if (score[0] === 'M' || score[0] === 'T') {
2324 } else if (score[0] === 'm' || score[0] === 't') {
2326 } else if (score[0] === 'd') {
2328 } else if (score[0] === 'cp') {
2329 if (score[1] > 500) {
2331 } else if (score[1] < -500) {
2341 * @param score The score digest tuple.
2342 * @param {?number} depth Depth the move has been computed to, or null.
2343 * @param {boolean} invert Whether black is to play.
2344 * @param {boolean=} depth_secondary_key
2347 let compute_score_sort_key = function(score, depth, invert, depth_secondary_key) {
2352 if (score[0] === 'T') {
2353 // White reaches TB win.
2354 s = 89999 - score[1];
2355 } else if (score[0] === 't') {
2356 // Black reaches TB win.
2357 s = -(89999 - score[1]);
2358 } else if (score[0] === 'M') {
2360 s = 99999 - score[1];
2361 } else if (score[0] === 'm') {
2363 s = -(99999 - score[1]);
2364 } else if (score[0] === 'd') {
2366 } else if (score[0] === 'cp') {
2371 if (depth_secondary_key) {
2372 return s * 200 + (depth || 0);
2382 * @param {Object} game
2384 let switch_backend = function(game) {
2385 // Stop looking at historic data.
2386 current_display_line = null;
2387 current_display_move = null;
2388 displayed_analysis_data = null;
2389 if (current_historic_xhr) {
2390 current_historic_xhr.abort();
2393 // If we already have a backend response going, abort it.
2394 if (current_analysis_xhr) {
2395 current_analysis_xhr.abort();
2397 if (current_hash_xhr) {
2398 current_hash_xhr.abort();
2401 // Otherwise, we should have a timer going to start a new one.
2403 if (current_analysis_request_timer) {
2404 clearTimeout(current_analysis_request_timer);
2405 current_analysis_request_timer = null;
2407 if (current_hash_display_timer) {
2408 clearTimeout(current_hash_display_timer);
2409 current_hash_display_timer = null;
2412 // Request an immediate fetch with the new backend.
2413 backend_url = game['url'];
2414 backend_hash_url = game['hashurl'];
2415 window.location.hash = '#' + game['id'];
2416 current_analysis_data = null;
2420 window['switch_backend'] = switch_backend;
2422 window['flip'] = function() { board.flip(); redraw_arrows(); };
2423 window['set_delay_ms'] = function(ms) { delay_ms = ms; console.log('Delay is now ' + ms + ' ms.'); };
2425 // Mostly from Wikipedia's chess set as of October 2022, but some pieces are from
2426 // the 2013 version, as I like those better (and it matches the 2014 PNGs; nobody
2427 // really likes change, do they?). That is wK, bK, bQ. wQ is also slightly different,
2428 // but not enough to notice.
2429 const svg_pieces = {
2430 'wK': 'data:image/svg+xml,<?xml version=%221.0%22 encoding=%22UTF-8%22 standalone=%22no%22?>%0A<!DOCTYPE svg PUBLIC %22-//W3C//DTD SVG 1.1//EN%22 %22http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22>%0A<svg xmlns=%22http://www.w3.org/2000/svg%22 version=%221.1%22 width=%2245%22 height=%2245%22><g style=%22fill:none;fill-opacity:1;fill-rule:evenodd;stroke:%23000000;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22><path d=%22M 22.5,11.63 L 22.5,6%22 style=%22fill:none;stroke:%23000000;stroke-linejoin:miter%22/><path d=%22M 20,8 L 25,8%22 style=%22fill:none;stroke:%23000000;stroke-linejoin:miter%22/><path d=%22M 22.5,25 C 22.5,25 27,17.5 25.5,14.5 C 25.5,14.5 24.5,12 22.5,12 C 20.5,12 19.5,14.5 19.5,14.5 C 18,17.5 22.5,25 22.5,25%22 style=%22fill:%23ffffff;stroke:%23000000;stroke-linecap:butt;stroke-linejoin:miter%22/><path d=%22M 11.5,37 C 17,40.5 27,40.5 32.5,37 L 32.5,30 C 32.5,30 41.5,25.5 38.5,19.5 C 34.5,13 25,16 22.5,23.5 L 22.5,27 L 22.5,23.5 C 19,16 9.5,13 6.5,19.5 C 3.5,25.5 11.5,29.5 11.5,29.5 L 11.5,37 z %22 style=%22fill:%23ffffff;stroke:%23000000%22/><path d=%22M 11.5,30 C 17,27 27,27 32.5,30%22 style=%22fill:none;stroke:%23000000%22/><path d=%22M 11.5,33.5 C 17,30.5 27,30.5 32.5,33.5%22 style=%22fill:none;stroke:%23000000%22/><path d=%22M 11.5,37 C 17,34 27,34 32.5,37%22 style=%22fill:none;stroke:%23000000%22/></g></svg>',
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2439 'bB': 'data:image/svg+xml,<?xml version=%221.0%22 encoding=%22UTF-8%22 standalone=%22no%22?>%0A<!DOCTYPE svg PUBLIC %22-//W3C//DTD SVG 1.1//EN%22 %22http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22>%0A<svg xmlns=%22http://www.w3.org/2000/svg%22 version=%221.1%22 width=%2245%22 height=%2245%22><g style=%22opacity:1;fill:none;fill-rule:evenodd;fill-opacity:1;stroke:%23000000;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 transform=%22translate(0,0.6)%22><g style=%22fill:%23000000;stroke:%23000000;stroke-linecap:butt%22><path d=%22M 9,36 C 12.39,35.03 19.11,36.43 22.5,34 C 25.89,36.43 32.61,35.03 36,36 C 36,36 37.65,36.54 39,38 C 38.32,38.97 37.35,38.99 36,38.5 C 32.61,37.53 25.89,38.96 22.5,37.5 C 19.11,38.96 12.39,37.53 9,38.5 C 7.65,38.99 6.68,38.97 6,38 C 7.35,36.54 9,36 9,36 z%22/><path d=%22M 15,32 C 17.5,34.5 27.5,34.5 30,32 C 30.5,30.5 30,30 30,30 C 30,27.5 27.5,26 27.5,26 C 33,24.5 33.5,14.5 22.5,10.5 C 11.5,14.5 12,24.5 17.5,26 C 17.5,26 15,27.5 15,30 C 15,30 14.5,30.5 15,32 z%22/><path d=%22M 25 8 A 2.5 2.5 0 1 1 20,8 A 2.5 2.5 0 1 1 25 8 z%22/></g><path d=%22M 17.5,26 L 27.5,26 M 15,30 L 30,30 M 22.5,15.5 L 22.5,20.5 M 20,18 L 25,18%22 style=%22fill:none;stroke:%23ffffff;stroke-linejoin:miter%22/></g></svg>',
2440 'bN': 'data:image/svg+xml,<?xml version=%221.0%22 encoding=%22UTF-8%22 standalone=%22no%22?>%0A<!DOCTYPE svg PUBLIC %22-//W3C//DTD SVG 1.1//EN%22 %22http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22>%0A<svg xmlns=%22http://www.w3.org/2000/svg%22 version=%221.1%22 width=%2245%22 height=%2245%22><g style=%22opacity:1;fill:none;fill-opacity:1;fill-rule:evenodd;stroke:%23000000;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 transform=%22translate(0,0.3)%22><path d=%22M 22,10 C 32.5,11 38.5,18 38,39 L 15,39 C 15,30 25,32.5 23,18%22 style=%22fill:%23000000;stroke:%23000000%22/><path d=%22M 24,18 C 24.38,20.91 18.45,25.37 16,27 C 13,29 13.18,31.34 11,31 C 9.958,30.06 12.41,27.96 11,28 C 10,28 11.19,29.23 10,30 C 9,30 5.997,31 6,26 C 6,24 12,14 12,14 C 12,14 13.89,12.1 14,10.5 C 13.27,9.506 13.5,8.5 13.5,7.5 C 14.5,6.5 16.5,10 16.5,10 L 18.5,10 C 18.5,10 19.28,8.008 21,7 C 22,7 22,10 22,10%22 style=%22fill:%23000000;stroke:%23000000%22/><path d=%22M 9.5 25.5 A 0.5 0.5 0 1 1 8.5,25.5 A 0.5 0.5 0 1 1 9.5 25.5 z%22 style=%22fill:%23ffffff;stroke:%23ffffff%22/><path d=%22M 15 15.5 A 0.5 1.5 0 1 1 14,15.5 A 0.5 1.5 0 1 1 15 15.5 z%22 transform=%22matrix(0.866,0.5,-0.5,0.866,9.693,-5.173)%22 style=%22fill:%23ffffff;stroke:%23ffffff%22/><path d=%22M 24.55,10.4 L 24.1,11.85 L 24.6,12 C 27.75,13 30.25,14.49 32.5,18.75 C 34.75,23.01 35.75,29.06 35.25,39 L 35.2,39.5 L 37.45,39.5 L 37.5,39 C 38,28.94 36.62,22.15 34.25,17.66 C 31.88,13.17 28.46,11.02 25.06,10.5 L 24.55,10.4 z %22 style=%22fill:%23ffffff;stroke:none%22/></g></svg>',
2441 'bP': 'data:image/svg+xml,<?xml version=%221.0%22 encoding=%22UTF-8%22 standalone=%22no%22?>%0A<!DOCTYPE svg PUBLIC %22-//W3C//DTD SVG 1.1//EN%22 %22http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22>%0A<svg xmlns=%22http://www.w3.org/2000/svg%22 version=%221.1%22 width=%2245%22 height=%2245%22><path d=%22m 22.5,9 c -2.21,0 -4,1.79 -4,4 0,0.89 0.29,1.71 0.78,2.38 C 17.33,16.5 16,18.59 16,21 c 0,2.03 0.94,3.84 2.41,5.03 C 15.41,27.09 11,31.58 11,39.5 H 34 C 34,31.58 29.59,27.09 26.59,26.03 28.06,24.84 29,23.03 29,21 29,18.59 27.67,16.5 25.72,15.38 26.21,14.71 26.5,13.89 26.5,13 c 0,-2.21 -1.79,-4 -4,-4 z%22 style=%22opacity:1;fill:%23000000;fill-opacity:1;fill-rule:nonzero;stroke:%23000000;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22/></svg>',
2444 let svg_piece_theme = function(piece) {
2445 return svg_pieces[piece];
2448 let init = function() {
2449 unique = get_unique();
2451 // Load settings from HTML5 local storage if available.
2452 if (supports_html5_storage() && window['localStorage']['enable_sound']) {
2453 set_sound(parseInt(window['localStorage']['enable_sound']));
2459 board = new window.ChessBoard('board', {
2460 onMoveEnd: function() { board_is_animating = false; },
2463 pieceTheme: svg_piece_theme,
2464 onDragStart: onDragStart,
2466 onSnapEnd: onSnapEnd
2468 document.getElementById("board").addEventListener('mousedown', mousedownSquare);
2469 document.getElementById("board").addEventListener('mouseup', mouseupSquare);
2472 window.addEventListener('resize', function() {
2474 update_sparkline(displayed_analysis_data || current_analysis_data);
2475 update_board_highlight();
2478 window.addEventListener('keyup', function(event) {
2479 if (event.which == 39) { // Left arrow.
2481 } else if (event.which == 37) { // Right arrow.
2483 } else if (event.which >= 49 && event.which <= 57) { // 1-9.
2484 let num = event.which - 49;
2485 if (current_games && current_games.length >= num) {
2486 switch_backend(current_games[num]);
2488 } else if (event.which == 78) { // N.
2492 window.addEventListener('hashchange', possibly_switch_game_from_hash, false);
2493 possibly_switch_game_from_hash();
2495 document.addEventListener('DOMContentLoaded', init);