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.
10 var SCRIPT_VERSION = 2021021300;
13 * The current backend URL.
18 var backend_url = "/analysis.pl";
19 var backend_hash_url = "/hash";
21 /** @type {window.ChessBoard} @private */
24 /** @type {boolean} @private */
25 var board_is_animating = false;
28 * The most recent analysis data we have from the server
29 * (about the most recent position).
33 var current_analysis_data = null;
36 * If we are displaying previous analysis or from hash, this is non-null,
37 * and will override most of current_analysis_data.
42 var displayed_analysis_data = null;
45 * Games currently in progress, if any.
57 var current_games = null;
72 /** @type {Array.<Array.<boolean>>} */
73 var occupied_by_arrows = [];
75 /** Currently displayed refutation lines (on-screen).
76 * Can either come from the current_analysis_data, displayed_analysis_data,
77 * or hash_refutation_lines.
79 var refutation_lines = [];
81 /** Refutation lines from current hash probe.
83 * If non-null, will override refutation lines from the base position.
84 * Note that these are relative to display_fen, not base_fen.
86 var hash_refutation_lines = null;
88 /** @type {!number} @private */
91 /** @type {!string} @private */
94 /** @type {number} @private */
97 /** @type {boolean} @private */
98 var truncate_display_history = true;
100 /** @type {!string|undefined} @private */
101 var highlight_from = undefined;
103 /** @type {!string|undefined} @private */
104 var highlight_to = undefined;
106 /** The HTML object of the move currently being highlighted (in red).
109 var highlighted_move = null;
111 /** Currently suggested/recommended move when dragging.
112 * @type {?{from: !string, to: !string}}
115 var recommended_move = null;
117 /** If reverse-dragging (dragging from the destination square to the
118 * source square), the destination square.
122 var reverse_dragging_from = null;
124 /** @type {?number} @private */
127 /** @type {boolean} @private */
128 var enable_sound = false;
130 /** @type {!number} @private */
134 * Our best estimate of how many milliseconds we need to add to
135 * new Date() to get the true UTC time. Calibrated against the
141 var client_clock_offset_ms = null;
143 var clock_timer = null;
145 /** The current position being analyzed, represented as a FEN string.
146 * Note that this is not necessarily the same as display_fen.
152 /** The current position on the board, represented as a FEN string.
153 * Note that board.fen() does not contain e.g. who is to play.
157 var display_fen = null;
161 * pv: Array.<string>,
164 * scores: Array<{first_move: number, score: Object}>,
165 * start_display_move_num: number
168 * "start_display_move_num" is the (half-)move number to start displaying the PV at.
169 * "score" is also evaluated at this point.
172 /** All PVs that we currently know of.
174 * Element 0 is history (or null if no history).
175 * Element 1 is current main PV, or explored line if nowhere else on the screen.
176 * All remaining elements are refutation lines (multi-PV).
178 * @type {Array.<DisplayLine>}
181 var display_lines = [];
183 /** @type {?DisplayLine} @private */
184 var current_display_line = null;
186 /** @type {boolean} @private */
187 var current_display_line_is_history = false;
189 /** @type {?number} @private */
190 var current_display_move = null;
193 * The current backend request to get main analysis (not history), if any,
194 * so that we can abort it.
196 * @type {?AbortController}
199 var current_analysis_xhr = null;
202 * The current timer to fire off a request to get main analysis (not history),
203 * if any, so that we can abort it.
208 var current_analysis_request_timer = null;
211 * The current backend request to get historic data, if any.
213 * @type {?AbortController}
216 var current_historic_xhr = null;
219 * The current backend request to get hash probes, if any, so that we can abort it.
221 * @type {?AbortController}
224 var current_hash_xhr = null;
227 * The current timer to display hash probe information (it could be waiting on the
228 * board to stop animating), if any, so that we can abort it.
233 var current_hash_display_timer = null;
235 var supports_html5_storage = function() {
237 return 'localStorage' in window && window['localStorage'] !== null;
243 // Make the unique token persistent so people refreshing the page won't count twice.
244 // Of course, you can never fully protect against people deliberately wanting to spam.
245 var get_unique = function() {
246 var use_local_storage = supports_html5_storage();
247 if (use_local_storage && window['localStorage']['unique']) {
248 return window['localStorage']['unique'];
250 var unique = Math.random();
251 if (use_local_storage) {
252 window['localStorage']['unique'] = unique;
257 var request_update = function() {
258 current_analysis_request_timer = null;
260 let handle_err = () => {
261 // Backend error or similar. Wait ten seconds, then try again.
262 current_analysis_request_timer = setTimeout(function() { request_update(); }, 10000);
265 current_analysis_xhr = new AbortController();
266 const signal = current_analysis_xhr.signal;
267 fetch(backend_url + "?ims=" + ims + "&unique=" + unique, { signal })
268 .then((response) => response.json().then(data => ({ok: response.ok, headers: response.headers, json: data}))) // ick
275 if (delay_ms === 0) {
276 process_update_response(obj.json, obj.headers);
278 setTimeout(function() { process_update_response(obj.json, obj.headers); }, delay_ms);
282 if (!backend_url.match(/history/)) {
284 current_analysis_request_timer = setTimeout(function() { request_update(); }, timeout);
288 if (err.name === 'AbortError') {
289 // Aborted because we are switching backends. Abandon and don't retry,
290 // because another one is already started for us.
298 document.body.style.opacity = null;
303 var process_update_response = function(data, headers) {
304 sync_server_clock(headers.get('Date'));
305 ims = headers.get('X-RGLM');
306 var num_viewers = headers.get('X-RGNV');
308 if (Array.isArray(data)) {
309 new_data = JSON.parse(JSON.stringify(current_analysis_data));
310 JSON_delta.patch(new_data, data);
315 var minimum_version = headers.get('X-RGMV');
316 if (minimum_version && minimum_version > SCRIPT_VERSION) {
317 // Upgrade to latest version with a force-reload.
318 location.reload(true);
321 // Verify that the PV makes sense.
323 if (new_data['pv']) {
324 var hiddenboard = new Chess(new_data['position']['fen']);
325 for (var i = 0; i < new_data['pv'].length; ++i) {
326 if (hiddenboard.move(new_data['pv'][i]) === null) {
334 possibly_play_sound(current_analysis_data, new_data);
335 current_analysis_data = new_data;
337 update_num_viewers(num_viewers);
339 console.log("Received invalid update, waiting five seconds and trying again.");
340 setTimeout(function() { location.reload(true); }, 5000);
344 var possibly_play_sound = function(old_data, new_data) {
348 if (old_data === null) {
351 var ding = document.getElementById('ding');
352 if (ding && ding.play) {
353 if (old_data['position'] && old_data['position']['fen'] &&
354 new_data['position'] && new_data['position']['fen'] &&
355 (old_data['position']['fen'] !== new_data['position']['fen'] ||
356 old_data['position']['move_num'] !== new_data['position']['move_num'])) {
363 * @type {!string} server_date_string
365 var sync_server_clock = function(server_date_string) {
366 var server_time_ms = new Date(server_date_string).getTime();
367 var client_time_ms = new Date().getTime();
368 var estimated_offset_ms = server_time_ms - client_time_ms;
370 // In order not to let the noise move us too much back and forth
371 // (the server only has one-second resolution anyway), we only
372 // change an existing skew if we are at least five seconds off.
373 if (client_clock_offset_ms === null ||
374 Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
375 client_clock_offset_ms = estimated_offset_ms;
379 var clear_arrows = function() {
380 for (var i = 0; i < arrows.length; ++i) {
382 if (arrows[i].svg.parentElement) {
383 arrows[i].svg.parentElement.removeChild(arrows[i].svg);
385 delete arrows[i].svg;
390 occupied_by_arrows = [];
391 for (var y = 0; y < 8; ++y) {
392 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
396 var redraw_arrows = function() {
397 for (var i = 0; i < arrows.length; ++i) {
398 position_arrow(arrows[i]);
402 /** @param {!number} x
405 var sign = function(x) {
415 /** See if drawing this arrow on the board would cause unduly amount of confusion.
416 * @param {!string} from The square the arrow is from (e.g. e4).
417 * @param {!string} to The square the arrow is to (e.g. e4).
420 var interfering_arrow = function(from, to) {
421 var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
422 var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
423 var to_col = to.charCodeAt(0) - "a1".charCodeAt(0);
424 var to_row = to.charCodeAt(1) - "a1".charCodeAt(1);
426 occupied_by_arrows[from_row][from_col] = true;
428 // Knight move: Just check that we haven't been at the destination before.
429 if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
430 (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
431 return occupied_by_arrows[to_row][to_col];
434 // Sliding piece: Check if anything except the from-square is seen before.
435 var dx = sign(to_col - from_col);
436 var dy = sign(to_row - from_row);
442 if (occupied_by_arrows[y][x]) {
445 occupied_by_arrows[y][x] = true;
446 } while (x != to_col || y != to_row);
451 /** Find a point along the coordinate system given by the given line,
452 * <t> units forward from the start of the line, <u> units to the right of it.
453 * @param {!number} x1
454 * @param {!number} x2
455 * @param {!number} y1
456 * @param {!number} y2
459 * @return {!string} The point in "x y" form, suitable for SVG paths.
461 var point_from_start = function(x1, y1, x2, y2, t, u) {
465 var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
469 var x = x1 + dx * t + dy * u;
470 var y = y1 + dy * t - dx * u;
474 /** Find a point along the coordinate system given by the given line,
475 * <t> units forward from the end of the line, <u> units to the right of it.
476 * @param {!number} x1
477 * @param {!number} x2
478 * @param {!number} y1
479 * @param {!number} y2
482 * @return {!string} The point in "x y" form, suitable for SVG paths.
484 var point_from_end = function(x1, y1, x2, y2, t, u) {
488 var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
492 var x = x2 + dx * t + dy * u;
493 var y = y2 + dy * t - dx * u;
497 var position_arrow = function(arrow) {
499 if (arrow.svg.parentElement) {
500 arrow.svg.parentElement.removeChild(arrow.svg);
504 if (current_display_line !== null && !current_display_line_is_history) {
508 var zoom_factor = document.getElementById("board").getBoundingClientRect().width / 400.0;
509 var line_width = arrow.line_width * zoom_factor;
510 var arrow_size = arrow.arrow_size * zoom_factor;
512 var square_width = document.querySelector(".square-a8").getBoundingClientRect().width;
513 var from_y, to_y, from_x, to_x;
514 if (board.orientation() === 'black') {
515 from_y = (arrow.from_row + 0.5)*square_width;
516 to_y = (arrow.to_row + 0.5)*square_width;
517 from_x = (7 - arrow.from_col + 0.5)*square_width;
518 to_x = (7 - arrow.to_col + 0.5)*square_width;
520 from_y = (7 - arrow.from_row + 0.5)*square_width;
521 to_y = (7 - arrow.to_row + 0.5)*square_width;
522 from_x = (arrow.from_col + 0.5)*square_width;
523 to_x = (arrow.to_col + 0.5)*square_width;
526 var SVG_NS = "http://www.w3.org/2000/svg";
527 var XHTML_NS = "http://www.w3.org/1999/xhtml";
528 var svg = document.createElementNS(SVG_NS, "svg");
529 svg.setAttribute("width", /** @type{number} */ (document.getElementById("board").getBoundingClientRect().width));
530 svg.setAttribute("height", /** @type{number} */ (document.getElementById("board").getBoundingClientRect().height));
531 svg.setAttribute("style", "position: absolute");
532 svg.setAttribute("position", "absolute");
533 svg.setAttribute("version", "1.1");
534 svg.setAttribute("class", "c1");
535 svg.setAttribute("xmlns", XHTML_NS);
543 var outline = document.createElementNS(SVG_NS, "path");
544 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));
545 outline.setAttribute("xmlns", XHTML_NS);
546 outline.setAttribute("stroke", "#666");
547 outline.setAttribute("stroke-width", line_width + 2);
548 outline.setAttribute("fill", "none");
549 svg.appendChild(outline);
551 var path = document.createElementNS(SVG_NS, "path");
552 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));
553 path.setAttribute("xmlns", XHTML_NS);
554 path.setAttribute("stroke", arrow.fg_color);
555 path.setAttribute("stroke-width", line_width);
556 path.setAttribute("fill", "none");
557 svg.appendChild(path);
559 // Then the arrow head.
560 var head = document.createElementNS(SVG_NS, "path");
561 head.setAttribute("d",
562 "M " + point_from_end(x1, y1, x2, y2, 0, 0) +
563 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
564 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
565 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
566 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
567 head.setAttribute("xmlns", XHTML_NS);
568 head.setAttribute("stroke", "#000");
569 head.setAttribute("stroke-width", "1");
570 head.setAttribute("fill", arrow.fg_color);
571 svg.appendChild(head);
573 svg.style.top = '2px'; /* Border for .board-b72b1. */
574 svg.style.left = '2px';
575 svg.style.pointerEvents = 'none';
576 document.getElementById('board').appendChild(svg);
581 * @param {!string} from_square
582 * @param {!string} to_square
583 * @param {!string} fg_color
584 * @param {number} line_width
585 * @param {number} arrow_size
587 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
588 var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
589 var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
590 var to_col = to_square.charCodeAt(0) - "a1".charCodeAt(0);
591 var to_row = to_square.charCodeAt(1) - "a1".charCodeAt(1);
599 line_width: line_width,
600 arrow_size: arrow_size,
604 position_arrow(arrow);
608 var compare_by_score = function(refutation_lines, invert, a, b) {
609 var sa = compute_score_sort_key(refutation_lines[b]['score'], refutation_lines[b]['depth'], invert);
610 var sb = compute_score_sort_key(refutation_lines[a]['score'], refutation_lines[a]['depth'], invert);
615 * Fake multi-PV using the refutation lines. Find all “relevant” moves,
616 * sorted by quality, descending.
618 * @param {!Object} data
619 * @param {number} margin The maximum number of centipawns worse than the
620 * best move can be and still be included.
621 * @param {boolean} invert Whether black is to play.
622 * @return {Array.<string>} The FEN representation (e.g. Ne4) of all
623 * moves, in score order.
625 var find_nonstupid_moves = function(data, margin, invert) {
626 // First of all, if there are any moves that are more than 0.5 ahead of
627 // the primary move, the refutation lines are probably bunk, so just
629 var best_score = undefined;
630 var pv_score = undefined;
631 for (var move in data['refutation_lines']) {
632 var line = data['refutation_lines'][move];
633 var score = compute_score_sort_key(line['score'], line['depth'], invert, false);
634 if (move == data['pv'][0]) {
637 if (best_score === undefined || score > best_score) {
640 if (line['depth'] < 8) {
645 if (best_score - pv_score > 50) {
649 // Now find all moves that are within “margin” of the best score.
650 // The PV move will always be first.
652 for (var move in data['refutation_lines']) {
653 var line = data['refutation_lines'][move];
654 var score = compute_score_sort_key(line['score'], line['depth'], invert);
655 if (move != data['pv'][0] && best_score - score <= margin) {
659 moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], data['position']['toplay'] === 'B', a, b) });
660 moves.unshift(data['pv'][0]);
669 var thousands = function(x) {
670 return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
674 * @param {!string} start_fen
675 * @param {Array.<string>} pv
676 * @param {number} move_num
677 * @param {!string} toplay
678 * @param {Array<{ first_move: integer, score: Object }>} scores
679 * @param {number} start_display_move_num
680 * @param {number=} opt_limit
681 * @param {boolean=} opt_showlast
683 var add_pv = function(start_fen, pv, move_num, toplay, scores, start_display_move_num, opt_limit, opt_showlast) {
685 start_fen: start_fen,
687 move_num: parseInt(move_num),
690 start_display_move_num: start_display_move_num
692 var splicepos = null;
693 if (scores !== null && scores.length >= 1 &&
694 scores[scores.length - 1].score !== undefined &&
695 scores[scores.length - 1].score !== null &&
696 (scores[scores.length - 1].score[0] === 'T' ||
697 scores[scores.length - 1].score[0] === 't')) {
698 splicepos = scores[scores.length - 1].score[1];
700 return print_pv(display_lines.length - 1, splicepos, opt_limit, opt_showlast);
704 * @param {number} line_num
705 * @param {?number} splicepos If non-null, where the tablebase-spliced portion of the TB starts.
706 * @param {number=} opt_limit If set, show at most this number of moves.
707 * @param {boolean=} opt_showlast If limit is set, show the last moves instead of the first ones.
709 var print_pv = function(line_num, splicepos, opt_limit, opt_showlast) {
710 var display_line = display_lines[line_num];
711 var pv = display_line.pv;
712 var move_num = display_line.move_num;
713 var toplay = display_line.toplay;
715 // Truncate PV at the start if needed.
716 var start_display_move_num = display_line.start_display_move_num;
717 if (start_display_move_num > 0) {
718 pv = pv.slice(start_display_move_num);
719 var to_add = start_display_move_num;
720 if (toplay === 'B') {
725 if (to_add % 2 == 1) {
729 move_num += to_add / 2;
730 if (splicepos !== null && splicepos > 0) {
738 if (opt_limit && opt_showlast && pv.length > opt_limit) {
739 // Truncate the PV at the beginning (instead of at the end).
740 // We assume here that toplay is 'W'. We also assume that if
741 // opt_showlast is set, then it is the history, and thus,
742 // the UI should be to expand the history.
743 ret = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
744 i = pv.length - opt_limit;
749 } else if (toplay == 'B' && pv.length > 0) {
751 if (splicepos === 0) {
755 move += "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pv[0] + "</a>";
756 ret = move_num + '. … ' + move;
761 for ( ; i < pv.length; ++i) {
762 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pv[i] + "</a>";
763 if (splicepos === i) {
769 if (i > opt_limit && !opt_showlast) {
778 ret += move_num + '. ' + move;
792 /** Update the highlighted to/from squares on the board.
793 * Based on the global "highlight_from" and "highlight_to" variables.
795 var update_board_highlight = function() {
796 document.getElementById("board").querySelector('.square-55d63').classList.remove('nonuglyhighlight');
797 if ((current_display_line === null || current_display_line_is_history) &&
798 highlight_from !== undefined && highlight_to !== undefined) {
799 document.getElementById("board").querySelector('.square-' + highlight_from).classList.add('nonuglyhighlight');
800 document.getElementById("board").querySelector('.square-' + highlight_to).classList.add('nonuglyhighlight');
804 var update_history = function() {
805 if (display_lines[0] === null || display_lines[0].pv.length == 0) {
806 document.getElementById("history").innerHTML = "No history";
807 } else if (truncate_display_history) {
808 document.getElementById("history").innerHTML = print_pv(0, null, 8, true);
810 document.getElementById("history").innerHTML =
811 '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
817 * @param {!boolean} truncate_history
819 var collapse_history = function(truncate_history) {
820 truncate_display_history = truncate_history;
823 window['collapse_history'] = collapse_history;
825 /** Update the HTML display of multi-PV from the global "refutation_lines".
827 * Also recreates the global "display_lines".
829 var update_refutation_lines = function() {
830 if (base_fen === null) {
833 if (display_lines.length > 2) {
834 // Truncate so that only the history and PV is left.
835 display_lines = [ display_lines[0], display_lines[1] ];
837 var tbl = document.getElementById("refutationlines");
838 tbl.replaceChildren();
840 if (display_lines.length < 2) {
844 // Find out where the lines start from.
846 var base_scores = display_lines[1].scores;
847 var start_display_move_num = 0;
848 if (hash_refutation_lines) {
849 base_line = current_display_line.pv.slice(0, current_display_move + 1);
850 base_scores = current_display_line.scores;
851 start_display_move_num = base_line.length;
855 for (var move in refutation_lines) {
859 var invert = (toplay === 'B');
860 if (current_display_line && current_display_move % 2 == 0 && !current_display_line_is_history) {
863 moves = moves.sort(function(a, b) { return compare_by_score(refutation_lines, invert, a, b) });
864 for (var i = 0; i < moves.length; ++i) {
865 var line = refutation_lines[moves[i]];
867 var tr = document.createElement("tr");
869 var move_td = document.createElement("td");
870 tr.appendChild(move_td);
871 move_td.classList.add("move");
873 var scores = base_scores.concat([{ first_move: start_display_move_num, score: line['score'] }]);
875 if (line['pv'].length == 0) {
876 // Not found, so just make a one-move PV.
877 var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['move'] + "</a>";
878 move_td.innerHTML = move;
879 var score_td = document.createElement("td");
881 score_td.classList.add("score");
882 score_td.textContent = "—";
883 tr.appendChild(score_td);
885 var depth_td = document.createElement("td");
886 tr.appendChild(depth_td);
887 depth_td.classList.add("depth");
888 depth_td.textContent = "—";
890 var pv_td = document.createElement("td");
891 tr.appendChild(pv_td);
892 pv_td.classList.add("pv");
893 pv_td.innerHTML = add_pv(base_fen, base_line.concat([ line['move'] ]), move_num, toplay, scores, start_display_move_num);
899 var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['move'] + "</a>";
900 move_td.innerHTML = move;
902 var score_td = document.createElement("td");
903 tr.appendChild(score_td);
904 score_td.classList.add("score");
905 score_td.textContent = format_short_score(line['score']);
907 var depth_td = document.createElement("td");
908 tr.appendChild(depth_td);
909 depth_td.classList.add("depth");
910 if (line['depth'] && line['depth'] >= 0) {
911 depth_td.textContent = "d" + line['depth'];
913 depth_td.textContent = "—";
916 var pv_td = document.createElement("td");
917 tr.appendChild(pv_td);
918 pv_td.classList.add("pv");
919 pv_td.innerHTML = add_pv(base_fen, base_line.concat(line['pv']), move_num, toplay, scores, start_display_move_num, 10);
924 // Update the move highlight, as we've rewritten all the HTML.
925 update_move_highlight();
929 * Create a Chess.js board object, containing the given position plus the given moves,
930 * up to the given limit.
932 * @param {?string} fen
933 * @param {Array.<string>} moves
934 * @param {number} last_move
936 var chess_from = function(fen, moves, last_move) {
937 var hiddenboard = new Chess();
938 if (fen !== null && fen !== undefined) {
939 hiddenboard.load(fen);
941 for (var i = 0; i <= last_move; ++i) {
942 if (moves[i] === '0-0') {
943 hiddenboard.move('O-O');
944 } else if (moves[i] === '0-0-0') {
945 hiddenboard.move('O-O-O');
947 hiddenboard.move(moves[i]);
953 var update_game_list = function(games) {
954 document.getElementById("games").textContent = "";
955 if (games === null) {
959 var games_div = document.getElementById('games');
960 for (var game_num = 0; game_num < games.length; ++game_num) {
961 var game = games[game_num];
962 var game_span = document.createElement("span");
963 game_span.setAttribute("class", "game");
965 var game_name = document.createTextNode(game['name']);
966 if (game['url'] === backend_url) {
968 game_span.appendChild(game_name);
970 if (current_analysis_data && current_analysis_data['position']) {
972 if (current_analysis_data['position']['result']) {
973 score = " (" + current_analysis_data['position']['result'] + ")";
975 score = " (" + format_short_score(current_analysis_data['score']) + ")";
977 game_span.appendChild(document.createTextNode(score));
981 var game_a = document.createElement("a");
982 game_a.setAttribute("href", "#" + game['id']);
983 game_a.appendChild(game_name);
984 game_span.appendChild(game_a);
987 if (game['result']) {
988 score = " (" + game['result'] + ")";
990 score = " (" + format_short_score(game['score']) + ")";
992 game_span.appendChild(document.createTextNode(score));
995 games_div.appendChild(game_span);
1000 * Try to find a running game that matches with the current hash,
1001 * and switch to it if we're not already displaying it.
1003 var possibly_switch_game_from_hash = function() {
1004 var history_match = window.location.hash.match(/^#history=([a-zA-Z0-9_-]+)/);
1005 if (history_match !== null) {
1006 var game_id = history_match[1];
1008 url: '/history/' + game_id + '.json',
1010 id: 'history=' + game_id
1012 switch_backend(fake_game);
1016 if (current_games === null) {
1020 var hash = window.location.hash.replace(/^#/,'');
1021 for (var i = 0; i < current_games.length; ++i) {
1022 if (current_games[i]['id'] === hash) {
1023 if (backend_url !== current_games[i]['url']) {
1024 switch_backend(current_games[i]);
1032 * If this is a Chess960 castling which doesn't move the king,
1033 * move the rook instead.
1035 var patch_move = function(move) {
1036 if (move === null) return null;
1037 if (move.from !== move.to) return move;
1039 var f = move.rook_sq & 15;
1040 var r = move.rook_sq >> 4;
1041 var from = ('abcdefgh'.substring(f,f+1) + '87654321'.substring(r,r+1));
1044 if (move.to === 'g1') {
1046 } else if (move.to === 'g8') {
1048 } else if (move.to === 'b1') {
1050 } else if (move.to === 'b8') {
1054 return { from: from, to: to };
1057 /** Update all the HTML on the page, based on current global state.
1059 var update_board = function() {
1060 document.body.style.opacity = null;
1062 var data = displayed_analysis_data || current_analysis_data;
1063 var current_data = current_analysis_data; // Convenience alias.
1067 // Print the history. This is pretty much the only thing that's
1068 // unconditionally taken from current_data (we're not interested in
1069 // historic history).
1070 if (current_data['position']['history']) {
1071 var start = (current_data['position'] && current_data['position']['start_fen']) ? current_data['position']['start_fen'] : 'start';
1072 add_pv(start, current_data['position']['history'], 1, 'W', null, 0, 8, true);
1074 display_lines.push(null);
1078 // Games currently in progress, if any.
1079 if (current_data['games']) {
1080 current_games = current_data['games'];
1081 possibly_switch_game_from_hash();
1083 current_games = null;
1085 update_game_list(current_games);
1087 // The headline. Names are always fetched from current_data;
1088 // the rest can depend a bit.
1091 current_data['position']['player_w'] && current_data['position']['player_b']) {
1092 headline = current_data['position']['player_w'] + '–' +
1093 current_data['position']['player_b'] + ', analysis';
1095 headline = 'Analysis';
1098 // Credits, where applicable. Note that we don't want the footer to change a lot
1099 // when e.g. viewing history, so if any of these changed during the game,
1100 // use the current one still.
1101 if (current_data['using_lomonosov']) {
1102 document.getElementById("lomonosov").style.display = null;
1104 document.getElementById("lomonosov").style.display = 'none';
1107 // Credits: The engine name/version.
1108 if (current_data['engine'] && current_data['engine']['name'] !== null) {
1109 document.getElementById("engineid").textContent = current_data['engine']['name'];
1112 // Credits: The engine URL.
1113 if (current_data['engine'] && current_data['engine']['url']) {
1114 document.getElementById("engineid").setAttribute("href", current_data['engine']['url']);
1116 document.getElementById("engineid").removeAttribute("href");
1119 // Credits: Engine details.
1120 if (current_data['engine'] && current_data['engine']['details']) {
1121 document.getElementById("enginedetails").textContent = " (" + current_data['engine']['details'] + ")";
1123 document.getElementById("enginedetails").textContent = "";
1126 // Credits: Move source, possibly with URL.
1127 if (current_data['move_source'] && current_data['move_source_url']) {
1128 document.getElementById("movesource").textContent = "Moves provided by ";
1129 var movesource_a = document.createElement("a");
1130 movesource_a.setAttribute("href", current_data['move_source_url']);
1131 var movesource_text = document.createTextNode(current_data['move_source']);
1132 movesource_a.appendChild(movesource_text);
1133 var movesource_period = document.createTextNode(".");
1134 document.getElementById("movesource").appendChild(movesource_a);
1135 document.getElementById("movesource").appendChild(movesource_period);
1136 } else if (current_data['move_source']) {
1137 document.getElementById("movesource").textContent = "Moves provided by " + current_data['move_source'] + ".";
1139 document.getElementById("movesource").textContent = "";
1143 if (displayed_analysis_data) {
1144 // Displaying some non-current position, pick out the last move
1145 // from the history. This will work even if the fetch failed.
1146 if (current_display_move !== -1) {
1147 last_move = format_halfmove_with_number(
1148 current_display_line.pv[current_display_move],
1149 current_display_move);
1150 headline += ' after ' + last_move;
1152 } else if (data['position']['last_move'] !== 'none') {
1153 // Find the previous move.
1154 var previous_move_num, previous_toplay;
1155 if (data['position']['toplay'] == 'B') {
1156 previous_move_num = data['position']['move_num'];
1157 previous_toplay = 'W';
1159 previous_move_num = data['position']['move_num'] - 1;
1160 previous_toplay = 'B';
1163 last_move = format_move_with_number(
1164 data['position']['last_move'],
1166 previous_toplay == 'W');
1167 headline += ' after ' + last_move;
1171 document.getElementById("headline").textContent = headline;
1173 // The <title> contains a very brief headline.
1174 var title_elems = [];
1175 if (data['position'] && data['position']['result']) {
1176 title_elems.push(data['position']['result']);
1177 } else if (data['score']) {
1178 title_elems.push(format_short_score(data['score']));
1180 if (last_move !== null) {
1181 title_elems.push(last_move);
1184 if (title_elems.length != 0) {
1185 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
1187 document.title = 'analysis.sesse.net';
1190 // The last move (shown by highlighting the from and to squares).
1191 if (data['position'] && data['position']['last_move_uci']) {
1192 highlight_from = data['position']['last_move_uci'].substr(0, 2);
1193 highlight_to = data['position']['last_move_uci'].substr(2, 2);
1194 } else if (current_display_line_is_history && current_display_line && current_display_move >= 0) {
1195 // We don't have historic analysis for this position, but we
1196 // can reconstruct what the last move was by just replaying
1198 var position = (data['position'] && data['position']['start_fen']) ? data['position']['start_fen'] : null;
1199 var hiddenboard = chess_from(position, current_display_line.pv, current_display_move);
1200 var moves = hiddenboard.history({ verbose: true });
1201 last_move = moves.pop();
1202 highlight_from = last_move.from;
1203 highlight_to = last_move.to;
1205 highlight_from = highlight_to = undefined;
1207 update_board_highlight();
1209 if (data['failed']) {
1210 document.getElementById("score").textContent = "No analysis for this move";
1211 document.getElementById("pvtitle").textContent = "PV:";
1212 document.getElementById("pv").replaceChildren();
1213 document.getElementById("searchstats").innerHTML = " ";
1214 document.getElementById("refutationlines").replaceChildren();
1215 document.getElementById("whiteclock").replaceChildren();
1216 document.getElementById("blackclock").replaceChildren();
1217 refutation_lines = [];
1218 update_refutation_lines();
1220 update_displayed_line();
1221 update_move_highlight();
1228 if (current_display_line && !current_display_line_is_history) {
1230 if (current_display_line.scores && current_display_line.scores.length > 0) {
1231 for (var i = 0; i < current_display_line.scores.length; ++i) {
1232 if (current_display_move < current_display_line.scores[i].first_move) {
1235 score = current_display_line.scores[i].score;
1239 document.getElementById("score").textContent = format_long_score(score);
1241 document.getElementById("score").textContent = "No score for this line";
1243 } else if (data['score']) {
1244 document.getElementById("score").textContent = format_long_score(data['score']);
1247 // The search stats.
1248 if (data['searchstats']) {
1249 document.getElementById("searchstats").innerHTML = data['searchstats'];
1250 } else if (data['tablebase'] == 1) {
1251 document.getElementById("searchstats").textContent = "Tablebase result";
1252 } else if (data['nodes'] && data['nps'] && data['depth']) {
1253 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
1254 if (data['seldepth']) {
1255 stats += ' (' + data['seldepth'] + ' selective)';
1257 if (data['tbhits'] && data['tbhits'] > 0) {
1258 if (data['tbhits'] == 1) {
1259 stats += ', one Syzygy hit';
1261 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
1265 document.getElementById("searchstats").textContent = stats;
1267 document.getElementById("searchstats").textContent = "";
1270 // Update the board itself.
1271 base_fen = data['position']['fen'];
1272 update_displayed_line();
1275 document.getElementById("pvtitle").textContent = "PV:";
1277 var scores = [{ first_move: -1, score: data['score'] }];
1278 document.getElementById("pv").innerHTML = add_pv(data['position']['fen'], data['pv'], data['position']['move_num'], data['position']['toplay'], scores, 0);
1280 // Update the PV arrow.
1282 if (data['pv'].length >= 1) {
1283 var hiddenboard = new Chess(base_fen);
1285 // draw a continuation arrow as long as it's the same piece
1287 for (var i = 0; i < data['pv'].length; i += 2) {
1288 var move = patch_move(hiddenboard.move(data['pv'][i]));
1290 if ((i >= 2 && move.from != last_to) ||
1291 interfering_arrow(move.from, move.to)) {
1294 create_arrow(move.from, move.to, '#f66', 6, 20);
1296 hiddenboard.move(data['pv'][i + 1]); // To keep continuity.
1299 var alt_moves = find_nonstupid_moves(data, 30, data['position']['toplay'] === 'B');
1300 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
1301 hiddenboard = new Chess(base_fen);
1302 var move = patch_move(hiddenboard.move(alt_moves[i]));
1303 if (move !== null) {
1304 create_arrow(move.from, move.to, '#f66', 1, 10);
1309 // See if all semi-reasonable moves have only one possible response.
1310 if (data['pv'].length >= 2) {
1311 var nonstupid_moves = find_nonstupid_moves(data, 300, data['position']['toplay'] === 'B');
1314 var hiddenboard = new Chess(base_fen);
1315 hiddenboard.move(data['pv'][0]);
1316 response = hiddenboard.move(data['pv'][1]);
1318 for (var i = 0; i < nonstupid_moves.length; ++i) {
1319 if (nonstupid_moves[i] == data['pv'][0]) {
1320 // ignore the PV move for refutation lines.
1323 if (!data['refutation_lines'] ||
1324 !data['refutation_lines'][nonstupid_moves[i]] ||
1325 !data['refutation_lines'][nonstupid_moves[i]]['pv'] ||
1326 data['refutation_lines'][nonstupid_moves[i]]['pv'].length < 2) {
1327 // Incomplete PV, abort.
1328 response = undefined;
1331 var line = data['refutation_lines'][nonstupid_moves[i]];
1332 hiddenboard = new Chess(base_fen);
1333 hiddenboard.move(line['pv'][0]);
1334 var this_response = hiddenboard.move(line['pv'][1]);
1335 if (this_response === null) {
1336 console.log("BUG: ", i);
1338 console.log(line['pv']);
1340 if (response.from !== this_response.from || response.to !== this_response.to) {
1341 // Different response depending on lines, abort.
1342 response = undefined;
1347 if (nonstupid_moves.length > 0 && response !== undefined) {
1348 create_arrow(response.from, response.to, '#66f', 6, 20);
1352 // Update the refutation lines.
1353 base_fen = data['position']['fen'];
1354 move_num = parseInt(data['position']['move_num']);
1355 toplay = data['position']['toplay'];
1356 refutation_lines = hash_refutation_lines || data['refutation_lines'];
1357 update_refutation_lines();
1359 // Update the sparkline last, since its size depends on how everything else reflowed.
1360 update_sparkline(data);
1363 var update_sparkline = function(data) {
1364 let scorespark = document.getElementById('scoresparkcontainer');
1365 scorespark.textContent = '';
1366 if (data && data['score_history']) {
1367 var first_move_num = undefined;
1368 for (var halfmove_num in data['score_history']) {
1369 halfmove_num = parseInt(halfmove_num);
1370 if (first_move_num === undefined || halfmove_num < first_move_num) {
1371 first_move_num = halfmove_num;
1374 if (first_move_num !== undefined) {
1375 var last_move_num = data['position']['move_num'] * 2 - 3;
1376 if (data['position']['toplay'] === 'B') {
1380 // Possibly truncate some moves if we don't have enough width.
1381 var max_moves = Math.floor(scorespark.getBoundingClientRect().width / 5) - 3;
1382 if (last_move_num - first_move_num > max_moves) {
1383 first_move_num = last_move_num - max_moves;
1388 var last_score = null;
1390 for (var halfmove_num = first_move_num; halfmove_num <= last_move_num; ++halfmove_num) {
1391 if (data['score_history'][halfmove_num]) {
1392 var score = compute_plot_score(data['score_history'][halfmove_num]);
1394 if (score < min_score) min_score = score;
1395 if (score > max_score) max_score = score;
1397 scores.push(last_score);
1399 if (data['score']) {
1400 scores.push(compute_plot_score(data['score']));
1403 const h = scorespark.getBoundingClientRect().height;
1405 let base_y = h - h * min_score / (min_score - max_score);
1406 for (let i = 0; i < scores.length; ++i) {
1407 let rect = document.createElementNS('http://www.w3.org/2000/svg', 'rect');
1408 //rect.setAttributeNS(null, 'stroke', "#000000");
1409 rect.setAttributeNS(null, 'x', i * 5)
1410 rect.setAttributeNS(null, 'width', 4);
1411 let extent = scores[i] * h / (max_score - min_score);
1412 if (extent > 0 && extent < 1) {
1414 } else if (extent < 0 && extent > -1) {
1419 if (scores[i] === 0) {
1420 color = [0.5, 0.5, 0.5];
1421 rect.setAttributeNS(null, 'y', base_y - 1);
1422 rect.setAttributeNS(null, 'height', 1);
1423 } else if (scores[i] > 0) {
1424 color = [0.2, 0.4, 0.8];
1425 rect.setAttributeNS(null, 'y', base_y - extent);
1426 rect.setAttributeNS(null, 'height', extent);
1428 color = [1.0, 0.267, 0.267];
1429 rect.setAttributeNS(null, 'y', base_y);
1430 rect.setAttributeNS(null, 'height', -extent);
1432 let hlcolor = [color[0], color[1], color[2]];
1433 if (scores[i] !== 0) {
1434 hlcolor[0] = Math.min(hlcolor[0] * 1.4, 1.0);
1435 hlcolor[1] = Math.min(hlcolor[1] * 1.4, 1.0);
1436 hlcolor[2] = Math.min(hlcolor[2] * 1.4, 1.0);
1438 rect.style.fill = 'rgb(' + color[0]*100.0 + '%, ' + color[1]*100.0 + '%, ' + color[2]*100.0 + '%)';
1440 // score_history contains the Nth _position_, but format_tooltip
1441 // wants to format the Nth _move_; thus the -1.
1442 const tooltip = format_tooltip(data, i + first_move_num - 1);
1443 rect.addEventListener('mouseenter', (e) => draw_hover(e, hlcolor, tooltip));
1444 rect.addEventListener('mousemove', (e) => draw_hover(e, hlcolor, tooltip));
1445 rect.addEventListener('mouseleave', (e) => hide_hover(e, color));
1446 rect.addEventListener('click', (e) => show_line(0, i + first_move_num - 1));
1447 scorespark.appendChild(rect);
1453 var draw_hover = function(e, color, tooltip) {
1454 e.target.style.fill = 'rgb(' + color[0]*100.0 + '%, ' + color[1]*100.0 + '%, ' + color[2]*100.0 + '%)';
1456 let hover = document.getElementById('sparklinehover');
1457 hover.textContent = tooltip;
1458 hover.style.display = 'initial';
1460 let left = Math.max(e.pageX + 10, window.pageXOffset);
1461 let top = Math.max(e.pageY - hover.getBoundingClientRect().height, window.pageYOffset);
1462 left = Math.min(left, window.pageXOffset + document.documentElement.clientWidth - hover.getBoundingClientRect().width);
1464 hover.style.left = left + 'px';
1465 hover.style.top = top + 'px';
1468 var hide_hover = function(e, color) {
1469 e.target.style.fill = 'rgb(' + color[0]*100.0 + '%, ' + color[1]*100.0 + '%, ' + color[2]*100.0 + '%)';
1470 document.getElementById('sparklinehover').style.display = 'none';
1474 * @param {number} num_viewers
1476 var update_num_viewers = function(num_viewers) {
1478 if (num_viewers === null) {
1480 } else if (num_viewers == 1) {
1481 text = "You are the only current viewer";
1483 text = num_viewers + " current viewers";
1485 if (display_fen !== null) {
1486 var counter = Math.floor(display_fen.split(" ")[4] / 2);
1487 if (counter >= 20) {
1488 text = text.replace("current ", "");
1489 text += " | 50-move rule: " + counter;
1492 document.getElementById("numviewers").textContent = text;
1495 var update_clock = function() {
1496 clearTimeout(clock_timer);
1498 var data = displayed_analysis_data || current_analysis_data;
1501 if (data['position']) {
1502 var result = data['position']['result'];
1503 if (result === '1-0') {
1504 document.getElementById("whiteclock").textContent = "1";
1505 document.getElementById("blackclock").textContent = "0";
1506 document.getElementById("whiteclock").classList.remove("running-clock");
1507 document.getElementById("blackclock").classList.remove("running-clock");
1510 if (result === '1/2-1/2') {
1511 document.getElementById("whiteclock").textContent = "1/2";
1512 document.getElementById("blackclock").textContent = "1/2";
1513 document.getElementById("whiteclock").classList.remove("running-clock");
1514 document.getElementById("blackclock").classList.remove("running-clock");
1517 if (result === '0-1') {
1518 document.getElementById("whiteclock").textContent = "0";
1519 document.getElementById("blackclock").textContent = "1";
1520 document.getElementById("whiteclock").classList.remove("running-clock");
1521 document.getElementById("blackclock").classList.remove("running-clock");
1526 var white_clock_ms = null;
1527 var black_clock_ms = null;
1530 if (data['position'] &&
1531 data['position']['white_clock'] &&
1532 data['position']['black_clock']) {
1533 white_clock_ms = data['position']['white_clock'] * 1000;
1534 black_clock_ms = data['position']['black_clock'] * 1000;
1537 // Dynamic clock (only one, obviously).
1539 if (data['position']['white_clock_target']) {
1541 document.getElementById("whiteclock").classList.add("running-clock");
1542 document.getElementById("blackclock").classList.remove("running-clock");
1543 } else if (data['position']['black_clock_target']) {
1545 document.getElementById("whiteclock").classList.remove("running-clock");
1546 document.getElementById("blackclock").classList.add("running-clock");
1548 document.getElementById("whiteclock").classList.remove("running-clock");
1549 document.getElementById("blackclock").classList.remove("running-clock");
1553 var now = new Date().getTime() + client_clock_offset_ms;
1554 remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
1555 if (color === "white") {
1556 white_clock_ms = remaining_ms;
1558 black_clock_ms = remaining_ms;
1562 if (white_clock_ms === null || black_clock_ms === null) {
1563 document.getElementById("whiteclock").replaceChildren();
1564 document.getElementById("blackclock").replaceChildren();
1568 // If either player has twenty minutes or less left, add the second counters.
1569 // This matches what DGT clocks do.
1570 var show_seconds = (white_clock_ms < 60 * 20 * 1000 || black_clock_ms < 60 * 20 * 1000);
1573 // See when the clock will change next, and update right after that.
1576 next_update_ms = remaining_ms % 1000 + 100;
1578 next_update_ms = remaining_ms % 60000 + 100;
1580 clock_timer = setTimeout(update_clock, next_update_ms);
1583 document.getElementById("whiteclock").textContent = format_clock(white_clock_ms, show_seconds);
1584 document.getElementById("blackclock").textContent = format_clock(black_clock_ms, show_seconds);
1588 * @param {Number} remaining_ms
1589 * @param {boolean} show_seconds
1591 var format_clock = function(remaining_ms, show_seconds) {
1592 if (remaining_ms <= 0) {
1600 var remaining = Math.floor(remaining_ms / 1000);
1601 var seconds = remaining % 60;
1602 remaining = (remaining - seconds) / 60;
1603 var minutes = remaining % 60;
1604 remaining = (remaining - minutes) / 60;
1605 var hours = remaining;
1607 return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
1609 return format_2d(hours) + ":" + format_2d(minutes);
1616 var format_2d = function(x) {
1625 * @param {string} move
1626 * @param {Number} move_num Move number of this move.
1627 * @param {boolean} white_to_play Whether white is to play this move.
1629 var format_move_with_number = function(move, move_num, white_to_play) {
1631 if (white_to_play) {
1632 ret = move_num + '. ';
1634 ret = move_num + '… ';
1641 * @param {string} move
1642 * @param {Number} halfmove_num Half-move number that is to be played,
1645 var format_halfmove_with_number = function(move, halfmove_num) {
1646 return format_move_with_number(
1648 Math.floor(halfmove_num / 2) + 1,
1649 halfmove_num % 2 == 0);
1653 * @param {Object} data
1654 * @param {Number} halfmove_num
1656 var format_tooltip = function(data, halfmove_num) {
1657 if (data['score_history'][halfmove_num + 1] ||
1658 (halfmove_num + 1) === data['position']['history'].length) {
1659 // Position is in the history, or it is the current position
1660 // (which is implicitly tacked onto the history).
1663 if ((halfmove_num + 1) === data['position']['history'].length) {
1664 move = data['position']['last_move'];
1665 short_score = format_short_score(data['score']);
1667 move = data['position']['history'][halfmove_num];
1668 short_score = format_short_score(data['score_history'][halfmove_num + 1]);
1670 if (halfmove_num === -1) {
1671 return "Start position: " + short_score;
1673 var move_with_number = format_halfmove_with_number(move, halfmove_num);
1674 return "After " + move_with_number + ": " + short_score;
1677 for (var i = halfmove_num; i --> -1; ) {
1678 if (data['score_history'][i]) {
1679 var move = data['position']['history'][i];
1681 return "[Analysis kept from start position]";
1683 return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
1691 * @param {boolean} truncate_history
1693 var set_truncate_history = function(truncate_history) {
1694 truncate_display_history = truncate_history;
1695 update_refutation_lines();
1697 window['set_truncate_history'] = set_truncate_history;
1700 * @param {number} line_num
1701 * @param {number} move_num
1703 var show_line = function(line_num, move_num) {
1704 if (line_num == -1) {
1705 current_display_line = null;
1706 current_display_move = null;
1707 hash_refutation_lines = null;
1708 if (displayed_analysis_data) {
1709 // TODO: Support exiting to history position if we are in an
1710 // analysis line of a history position.
1711 displayed_analysis_data = null;
1716 current_display_line = {...display_lines[line_num]}; // Shallow clone.
1717 current_display_move = move_num + current_display_line.start_display_move_num;
1719 current_display_line_is_history = (line_num == 0);
1721 update_historic_analysis();
1722 update_displayed_line();
1723 update_board_highlight();
1724 update_move_highlight();
1727 window['show_line'] = show_line;
1729 var prev_move = function() {
1730 if (current_display_line &&
1731 current_display_move >= current_display_line.start_display_move_num) {
1732 --current_display_move;
1734 update_historic_analysis();
1735 update_displayed_line();
1736 update_move_highlight();
1738 window['prev_move'] = prev_move;
1740 var next_move = function() {
1741 if (current_display_line &&
1742 current_display_move < current_display_line.pv.length - 1) {
1743 ++current_display_move;
1745 update_historic_analysis();
1746 update_displayed_line();
1747 update_move_highlight();
1749 window['next_move'] = next_move;
1751 var next_game = function() {
1752 if (current_games === null) {
1756 // Try to find the game we are currently looking at.
1757 for (var game_num = 0; game_num < current_games.length; ++game_num) {
1758 var game = current_games[game_num];
1759 if (game['url'] === backend_url) {
1760 var next_game_num = (game_num + 1) % current_games.length;
1761 switch_backend(current_games[next_game_num]);
1766 // Couldn't find it; give up.
1769 var update_historic_analysis = function() {
1770 if (!current_display_line_is_history) {
1773 if (current_display_move == current_display_line.pv.length - 1) {
1774 displayed_analysis_data = null;
1778 // Fetch old analysis for this line if it exists.
1779 var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pv, current_display_move);
1780 var filename = "/history/move" + (current_display_move + 1) + "-" +
1781 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1783 let handle_err = () => {
1784 displayed_analysis_data = {'failed': true};
1788 current_historic_xhr = new AbortController();
1789 const signal = current_analysis_xhr.signal;
1790 fetch(filename, { signal })
1791 .then((response) => response.json().then(data => ({ok: response.ok, json: data}))) // ick
1797 displayed_analysis_data = obj.json;
1801 if (err.name === 'AbortError') {
1802 // Aborted because we are switching backends. Abandon and don't retry,
1803 // because another one is already started for us.
1812 * @param {string} fen
1814 var update_imbalance = function(fen) {
1815 var hiddenboard = new Chess(fen);
1816 var imbalance = {'k': 0, 'q': 0, 'r': 0, 'b': 0, 'n': 0, 'p': 0};
1817 for (var row = 0; row < 8; ++row) {
1818 for (var col = 0; col < 8; ++col) {
1819 var col_text = String.fromCharCode('a1'.charCodeAt(0) + col);
1820 var row_text = String.fromCharCode('a1'.charCodeAt(1) + row);
1821 var square = col_text + row_text;
1822 var contents = hiddenboard.get(square);
1823 if (contents !== null) {
1824 if (contents.color === 'w') {
1825 ++imbalance[contents.type];
1827 --imbalance[contents.type];
1832 var white_imbalance = '';
1833 var black_imbalance = '';
1834 for (var piece in imbalance) {
1835 for (var i = 0; i < imbalance[piece]; ++i) {
1836 white_imbalance += '<img src="' + svg_pieces['w' + piece.toUpperCase()] + '" alt="" style="width: 15px;height: 15px;" class="imbalance-piece">';
1837 white_imbalance += '<img src="' + svg_pieces['b' + piece.toUpperCase()] + '" alt="" style="width: 15px;height: 15px;" class="imbalance-inverted-piece">';
1839 for (var i = 0; i < -imbalance[piece]; ++i) {
1840 black_imbalance += '<img src="' + svg_pieces['b' + piece.toUpperCase()] + '" alt="" style="width: 15px;height: 15px;" class="imbalance-piece">';
1841 black_imbalance += '<img src="' + svg_pieces['w' + piece.toUpperCase()] + '" alt="" style="width: 15px;height: 15px;" class="imbalance-inverted-piece">';
1844 document.getElementById('whiteimbalance').innerHTML = white_imbalance;
1845 document.getElementById('blackimbalance').innerHTML = black_imbalance;
1848 /** Mark the currently selected move in red.
1849 * Also replaces the PV with the current displayed line if it's not shown
1850 * anywhere else on the screen.
1852 var update_move_highlight = function() {
1853 if (highlighted_move !== null) {
1854 highlighted_move.classList.remove('highlight');
1856 if (current_display_line) {
1857 var display_line_num = find_display_line_matching_num();
1858 if (display_line_num === null) {
1859 // Replace the PV with the (complete) line.
1860 document.getElementById("pvtitle").textContent = "Exploring:";
1861 current_display_line.start_display_move_num = 0;
1862 display_lines.push(current_display_line);
1863 document.getElementById("pv").innerHTML = print_pv(display_lines.length - 1, null); // FIXME
1864 display_line_num = display_lines.length - 1;
1866 // Clear out the PV, so it's not selected by anything later.
1867 display_lines[1].pv = [];
1870 highlighted_move = document.getElementById("automove" + display_line_num + "-" + (current_display_move - current_display_line.start_display_move_num));
1871 if (highlighted_move !== null) {
1872 highlighted_move.classList.add('highlight');
1878 * See if the current displayed line is identical to any of the ones
1879 * we have on screen. (It might not be if e.g. the analysis reloaded
1880 * since we started looking.)
1884 var find_display_line_matching_num = function() {
1885 for (var i = 0; i < display_lines.length; ++i) {
1886 var line = display_lines[i];
1887 if (line.start_display_move_num > 0) continue;
1888 if (current_display_line.start_fen !== line.start_fen) continue;
1889 if (current_display_line.pv.length !== line.pv.length) continue;
1891 for (var j = 0; j < line.pv.length; ++j) {
1892 if (current_display_line.pv[j] !== line.pv[j]) {
1904 /** Update the board based on the currently displayed line.
1906 * TODO: This should really be called only whenever something changes,
1907 * instead of all the time.
1909 var update_displayed_line = function() {
1910 if (current_display_line === null) {
1911 document.getElementById("linenav").style.display = 'none';
1912 document.getElementById("linemsg").style.display = 'revert';
1913 display_fen = base_fen;
1914 set_board_position(base_fen);
1915 update_imbalance(base_fen);
1919 document.getElementById("linenav").style.display = 'revert';
1920 document.getElementById("linemsg").style.display = 'none';
1922 if (current_display_move <= 0) {
1923 document.getElementById("prevmove").innerHTML = "Previous";
1925 document.getElementById("prevmove").innerHTML = "<a href=\"javascript:prev_move();\">Previous</a></span>";
1927 if (current_display_move == current_display_line.pv.length - 1) {
1928 document.getElementById("nextmove").innerHTML = "Next";
1930 document.getElementById("nextmove").innerHTML = "<a href=\"javascript:next_move();\">Next</a></span>";
1933 var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pv, current_display_move);
1934 set_board_position(hiddenboard.fen());
1935 if (display_fen !== hiddenboard.fen() && !current_display_line_is_history) {
1936 // Fire off a hash request, since we're now off the main position
1937 // and it just changed.
1938 explore_hash(hiddenboard.fen());
1940 display_fen = hiddenboard.fen();
1941 update_imbalance(hiddenboard.fen());
1944 var set_board_position = function(new_fen) {
1945 board_is_animating = true;
1946 var old_fen = board.fen();
1947 board.position(new_fen);
1948 if (board.fen() === old_fen) {
1949 board_is_animating = false;
1954 * @param {boolean} param_enable_sound
1956 var set_sound = function(param_enable_sound) {
1957 enable_sound = param_enable_sound;
1959 document.getElementById("soundon").innerHTML = "<strong>On</strong>";
1960 document.getElementById("soundoff").innerHTML = "<a href=\"javascript:set_sound(false)\">Off</a>";
1962 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1963 // and also preload the file since the user has selected audio.
1964 var ding = document.getElementById('ding');
1965 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1966 ding.src = 'ding.opus';
1970 document.getElementById("soundon").innerHTML = "<a href=\"javascript:set_sound(true)\">On</a>";
1971 document.getElementById("soundoff").innerHTML = "<strong>Off</strong>";
1973 if (supports_html5_storage()) {
1974 window['localStorage']['enable_sound'] = enable_sound ? 1 : 0;
1977 window['set_sound'] = set_sound;
1979 /** Send off a hash probe request to the backend.
1980 * @param {string} fen
1982 var explore_hash = function(fen) {
1983 // If we already have a backend response going, abort it.
1984 if (current_hash_xhr) {
1985 current_hash_xhr.abort();
1987 if (current_hash_display_timer) {
1988 clearTimeout(current_hash_display_timer);
1989 current_hash_display_timer = null;
1991 document.getElementById("refutationlines").replaceChildren();
1993 current_hash_xhr = new AbortController();
1994 const signal = current_analysis_xhr.signal;
1995 fetch(backend_hash_url + "?fen=" + fen, { signal })
1996 .then((response) => response.json())
1997 .then((data) => { show_explore_hash_results(data, fen); })
1998 .catch((err) => {});
2001 /** Process the JSON response from a hash probe request.
2002 * @param {!Object} data
2003 * @param {string} fen
2005 var show_explore_hash_results = function(data, fen) {
2006 if (board_is_animating) {
2007 // Updating while the animation is still going causes
2008 // the animation to jerk. This is pretty crude, but it will do.
2009 current_hash_display_timer = setTimeout(function() { show_explore_hash_results(data, fen); }, 100);
2012 current_hash_display_timer = null;
2013 hash_refutation_lines = data['lines'];
2017 // almost all of this stuff comes from the chessboard.js example page
2018 var onDragStart = function(source, piece, position, orientation) {
2019 var pseudogame = new Chess(display_fen);
2020 if (pseudogame.game_over() === true ||
2021 (pseudogame.turn() === 'w' && piece.search(/^b/) !== -1) ||
2022 (pseudogame.turn() === 'b' && piece.search(/^w/) !== -1)) {
2026 recommended_move = get_best_move(pseudogame, source, null, pseudogame.turn() === 'b');
2027 if (recommended_move) {
2028 var squareEl = document.querySelector('#board .square-' + recommended_move.to);
2029 squareEl.classList.add('highlight1-32417');
2034 var mousedownSquare = function(e) {
2035 if (!e.target || !e.target.matches('.square-55d63')) {
2039 reverse_dragging_from = null;
2040 var square = e.target.getAttribute('data-square');
2042 var pseudogame = new Chess(display_fen);
2043 if (pseudogame.game_over() === true) {
2047 // If the square is empty, or has a piece of the side not to move,
2048 // we handle it. If not, normal piece dragging will take it.
2049 var position = board.position();
2050 if (!position.hasOwnProperty(square) ||
2051 (pseudogame.turn() === 'w' && position[square].search(/^b/) !== -1) ||
2052 (pseudogame.turn() === 'b' && position[square].search(/^w/) !== -1)) {
2053 reverse_dragging_from = square;
2054 recommended_move = get_best_move(pseudogame, null, square, pseudogame.turn() === 'b');
2055 if (recommended_move) {
2056 var squareEl = document.querySelector('#board .square-' + recommended_move.from);
2057 squareEl.classList.add('highlight1-32417');
2058 squareEl = document.querySelector('#board .square-' + recommended_move.to);
2059 squareEl.classList.add('highlight1-32417');
2064 var mouseupSquare = function(e) {
2065 if (!e.target || !e.target.matches('.square-55d63')) {
2068 if (reverse_dragging_from === null) {
2071 var source = e.target.getAttribute('data-square');
2072 var target = reverse_dragging_from;
2073 reverse_dragging_from = null;
2074 if (onDrop(source, target) !== 'snapback') {
2075 onSnapEnd(source, target);
2077 document.getElementById("board").querySelectorAll('.square-55d63.highlight1-32417').forEach((square) => {
2078 square.classList.remove('highlight1-32417');
2082 var get_best_move = function(game, source, target, invert) {
2083 var moves = game.moves({ verbose: true });
2084 if (source !== null) {
2085 moves = moves.filter(function(move) { return move.from == source; });
2087 if (target !== null) {
2088 moves = moves.filter(function(move) { return move.to == target; });
2090 if (moves.length == 0) {
2093 if (moves.length == 1) {
2097 // More than one move. Use the display lines (if we have them)
2098 // to disambiguate; otherwise, we have no information.
2100 for (var i = 0; i < moves.length; ++i) {
2101 move_hash[moves[i].san] = moves[i];
2104 // See if we're already exploring some line.
2105 if (current_display_line &&
2106 current_display_move < current_display_line.pv.length - 1) {
2107 var first_move = current_display_line.pv[current_display_move + 1];
2108 if (move_hash[first_move]) {
2109 return move_hash[first_move];
2113 // History and PV take priority over the display lines.
2114 for (var i = 0; i < 2; ++i) {
2115 var line = display_lines[i];
2116 var first_move = line.pv[line.start_display_move_num];
2117 if (move_hash[first_move]) {
2118 return move_hash[first_move];
2122 var best_move = null;
2123 var best_move_score = null;
2125 for (var move in refutation_lines) {
2126 var line = refutation_lines[move];
2127 if (!line['score']) {
2130 var first_move = line['pv'][0];
2131 if (move_hash[first_move]) {
2132 var score = compute_score_sort_key(line['score'], line['depth'], invert);
2133 if (best_move_score === null || score > best_move_score) {
2134 best_move = move_hash[first_move];
2135 best_move_score = score;
2142 var onDrop = function(source, target) {
2143 if (source === target) {
2144 if (recommended_move === null) {
2147 // Accept the move. It will be changed in onSnapEnd.
2151 // Suggestion not asked for.
2152 recommended_move = null;
2155 // see if the move is legal
2156 var pseudogame = new Chess(display_fen);
2157 var move = pseudogame.move({
2160 promotion: 'q' // NOTE: always promote to a queen for example simplicity
2164 if (move === null) return 'snapback';
2167 var onSnapEnd = function(source, target) {
2168 if (source === target && recommended_move !== null) {
2169 source = recommended_move.from;
2170 target = recommended_move.to;
2172 recommended_move = null;
2173 var pseudogame = new Chess(display_fen);
2174 var move = pseudogame.move({
2177 promotion: 'q' // NOTE: always promote to a queen for example simplicity
2180 if (current_display_line &&
2181 current_display_move < current_display_line.pv.length - 1 &&
2182 current_display_line.pv[current_display_move + 1] === move.san) {
2187 // Walk down the displayed lines until we find one that starts with
2188 // this move, then select that. Note that this gives us a good priority
2189 // order (history first, then PV, then multi-PV lines).
2190 for (var i = 0; i < display_lines.length; ++i) {
2191 if (i == 1 && current_display_line) {
2192 // Do not choose PV if not on it.
2195 var line = display_lines[i];
2196 if (line.pv[line.start_display_move_num] === move.san) {
2202 // Shouldn't really be here if we have hash probes, but there's really
2203 // nothing we can do.
2205 // End of dragging-related code.
2207 var fmt_cp = function(v) {
2211 return "+" + (v / 100).toFixed(2);
2214 return "-" + (v / 100).toFixed(2);
2218 var format_short_score = function(score) {
2222 if (score[0] === 'T' || score[0] === 't') {
2223 var ret = "TB\u00a0";
2224 if (score[2]) { // Is a bound.
2225 ret = score[2] + "\u00a0TB\u00a0";
2227 if (score[0] === 'T') {
2228 return ret + Math.ceil(score[1] / 2);
2230 return ret + "-" + Math.ceil(score[1] / 2);
2232 } else if (score[0] === 'M' || score[0] === 'm') {
2233 var sign = (score[0] === 'm') ? '-' : '';
2234 if (score[2]) { // Is a bound.
2235 return score[2] + "\u00a0M " + sign + score[1];
2237 return "M " + sign + score[1];
2239 } else if (score[0] === 'd') {
2241 } else if (score[0] === 'cp') {
2242 if (score[2]) { // Is a bound.
2243 return score[2] + "\u00a0" + fmt_cp(score[1]);
2245 return fmt_cp(score[1]);
2251 var format_long_score = function(score) {
2255 if (score[0] === 'T') {
2256 if (score[1] == 0) {
2257 return "Won for white (tablebase)";
2259 return "White wins in " + Math.ceil(score[1] / 2);
2261 } else if (score[0] === 't') {
2262 if (score[1] == -1) {
2263 return "Won for black (tablebase)";
2265 return "Black wins in " + Math.ceil(score[1] / 2);
2267 } else if (score[0] === 'M') {
2268 if (score[1] == 0) {
2269 return "White wins by checkmate";
2271 return "White mates in " + score[1];
2273 } else if (score[0] === 'm') {
2274 if (score[1] == 0) {
2275 return "Black wins by checkmate";
2277 return "Black mates in " + score[1];
2279 } else if (score[0] === 'd') {
2280 return "Theoretical draw";
2281 } else if (score[0] === 'cp') {
2282 return "Score: " + format_short_score(score);
2287 var compute_plot_score = function(score) {
2288 if (score[0] === 'M' || score[0] === 'T') {
2290 } else if (score[0] === 'm' || score[0] === 't') {
2292 } else if (score[0] === 'd') {
2294 } else if (score[0] === 'cp') {
2295 if (score[1] > 500) {
2297 } else if (score[1] < -500) {
2307 * @param score The score digest tuple.
2308 * @param {?number} depth Depth the move has been computed to, or null.
2309 * @param {boolean} invert Whether black is to play.
2310 * @param {boolean=} depth_secondary_key
2313 var compute_score_sort_key = function(score, depth, invert, depth_secondary_key) {
2318 if (score[0] === 'T') {
2319 // White reaches TB win.
2320 s = 89999 - score[1];
2321 } else if (score[0] === 't') {
2322 // Black reaches TB win.
2323 s = -(89999 - score[1]);
2324 } else if (score[0] === 'M') {
2326 s = 99999 - score[1];
2327 } else if (score[0] === 'm') {
2329 s = -(99999 - score[1]);
2330 } else if (score[0] === 'd') {
2332 } else if (score[0] === 'cp') {
2337 if (depth_secondary_key) {
2338 return s * 200 + (depth || 0);
2348 * @param {Object} game
2350 var switch_backend = function(game) {
2351 // Stop looking at historic data.
2352 current_display_line = null;
2353 current_display_move = null;
2354 displayed_analysis_data = null;
2355 if (current_historic_xhr) {
2356 current_historic_xhr.abort();
2359 // If we already have a backend response going, abort it.
2360 if (current_analysis_xhr) {
2361 current_analysis_xhr.abort();
2363 if (current_hash_xhr) {
2364 current_hash_xhr.abort();
2367 // Otherwise, we should have a timer going to start a new one.
2369 if (current_analysis_request_timer) {
2370 clearTimeout(current_analysis_request_timer);
2371 current_analysis_request_timer = null;
2373 if (current_hash_display_timer) {
2374 clearTimeout(current_hash_display_timer);
2375 current_hash_display_timer = null;
2378 // Request an immediate fetch with the new backend.
2379 backend_url = game['url'];
2380 backend_hash_url = game['hashurl'];
2381 window.location.hash = '#' + game['id'];
2382 current_analysis_data = null;
2386 window['switch_backend'] = switch_backend;
2388 window['flip'] = function() { board.flip(); redraw_arrows(); };
2389 window['set_delay_ms'] = function(ms) { delay_ms = ms; console.log('Delay is now ' + ms + ' ms.'); };
2391 // Mostly from Wikipedia's chess set as of October 2022, but some pieces are from
2392 // the 2013 version, as I like those better (and it matches the 2014 PNGs; nobody
2393 // really likes change, do they?). That is wK, bK, bQ. wQ is also slightly different,
2394 // but not enough to notice.
2395 const svg_pieces = {
2396 '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>',
2397 'wQ': '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:%23ffffff;stroke:%23000000;stroke-width:1.5;stroke-linejoin:round%22><path d=%22M 9,26 C 17.5,24.5 30,24.5 36,26 L 38.5,13.5 L 31,25 L 30.7,10.9 L 25.5,24.5 L 22.5,10 L 19.5,24.5 L 14.3,10.9 L 14,25 L 6.5,13.5 L 9,26 z%22/><path d=%22M 9,26 C 9,28 10.5,28 11.5,30 C 12.5,31.5 12.5,31 12,33.5 C 10.5,34.5 11,36 11,36 C 9.5,37.5 11,38.5 11,38.5 C 17.5,39.5 27.5,39.5 34,38.5 C 34,38.5 35.5,37.5 34,36 C 34,36 34.5,34.5 33,33.5 C 32.5,31 32.5,31.5 33.5,30 C 34.5,28 36,28 36,26 C 27.5,24.5 17.5,24.5 9,26 z%22/><path d=%22M 11.5,30 C 15,29 30,29 33.5,30%22 style=%22fill:none%22/><path d=%22M 12,33.5 C 18,32.5 27,32.5 33,33.5%22 style=%22fill:none%22/><circle cx=%226%22 cy=%2212%22 r=%222%22/><circle cx=%2214%22 cy=%229%22 r=%222%22/><circle cx=%2222.5%22 cy=%228%22 r=%222%22/><circle cx=%2231%22 cy=%229%22 r=%222%22/><circle cx=%2239%22 cy=%2212%22 r=%222%22/></g></svg>',
2398 'wR': '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:%23ffffff;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 9,39 L 36,39 L 36,36 L 9,36 L 9,39 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 12,36 L 12,32 L 33,32 L 33,36 L 12,36 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 11,14 L 11,9 L 15,9 L 15,11 L 20,11 L 20,9 L 25,9 L 25,11 L 30,11 L 30,9 L 34,9 L 34,14%22 style=%22stroke-linecap:butt%22/><path d=%22M 34,14 L 31,17 L 14,17 L 11,14%22/><path d=%22M 31,17 L 31,29.5 L 14,29.5 L 14,17%22 style=%22stroke-linecap:butt;stroke-linejoin:miter%22/><path d=%22M 31,29.5 L 32.5,32 L 12.5,32 L 14,29.5%22/><path d=%22M 11,14 L 34,14%22 style=%22fill:none;stroke:%23000000;stroke-linejoin:miter%22/></g></svg>',
2399 'wB': '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:%23ffffff;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:%23000000;stroke-linejoin:miter%22/></g></svg>',
2400 'wN': '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:%23ffffff;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:%23ffffff;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:%23000000;stroke:%23000000%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:%23000000;stroke:%23000000%22/></g></svg>',
2401 'wP': '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:%23ffffff;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>',
2402 'bK': '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 id=%22path6570%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:%23000000;fill-opacity:1;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:%23000000;stroke:%23000000%22/><path d=%22M 20,8 L 25,8%22 style=%22fill:none;stroke:%23000000;stroke-linejoin:miter%22/><path d=%22M 32,29.5 C 32,29.5 40.5,25.5 38.03,19.85 C 34.15,14 25,18 22.5,24.5 L 22.51,26.6 L 22.5,24.5 C 20,18 9.906,14 6.997,19.85 C 4.5,25.5 11.85,28.85 11.85,28.85%22 style=%22fill:none;stroke:%23ffffff%22/><path d=%22M 11.5,30 C 17,27 27,27 32.5,30 M 11.5,33.5 C 17,30.5 27,30.5 32.5,33.5 M 11.5,37 C 17,34 27,34 32.5,37%22 style=%22fill:none;stroke:%23ffffff%22/></g></svg>',
2403 'bQ': '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:svg=%22http://www.w3.org/2000/svg%22 xmlns=%22http://www.w3.org/2000/svg%22 version=%221.1%22 width=%2245%22 height=%2245%22 id=%22svg3128%22><defs/><g id=%22layer1%22><path d=%22M 8 12 A 2 2 0 1 1 4,12 A 2 2 0 1 1 8 12 z%22 style=%22opacity:1;fill:%23000000;fill-opacity:1;stroke:%23000000;stroke-width:1;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 id=%22path5571%22/><path d=%22M 9 13 A 2 2 0 1 1 5,13 A 2 2 0 1 1 9 13 z%22 transform=%22translate(15.5,-5.5)%22 style=%22opacity:1;fill:%23000000;fill-opacity:1;stroke:%23000000;stroke-width:1;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 id=%22path5573%22/><path d=%22M 9 13 A 2 2 0 1 1 5,13 A 2 2 0 1 1 9 13 z%22 transform=%22translate(32,-1)%22 style=%22opacity:1;fill:%23000000;fill-opacity:1;stroke:%23000000;stroke-width:1;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 id=%22path5575%22/><path d=%22M 9 13 A 2 2 0 1 1 5,13 A 2 2 0 1 1 9 13 z%22 transform=%22translate(7,-4.5)%22 style=%22opacity:1;fill:%23000000;fill-opacity:1;stroke:%23000000;stroke-width:1;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 id=%22path5577%22/><path d=%22M 9 13 A 2 2 0 1 1 5,13 A 2 2 0 1 1 9 13 z%22 transform=%22translate(24,-4)%22 style=%22opacity:1;fill:%23000000;fill-opacity:1;stroke:%23000000;stroke-width:1;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1%22 id=%22path5579%22/><path d=%22M 9,26 C 17.5,24.5 30,24.5 36,26 L 38,14 L 31,25 L 31,11 L 25.5,24.5 L 22.5,9.5 L 19.5,24.5 L 14,10.5 L 14,25 L 7,14 L 9,26 z %22 style=%22fill:%23000000;fill-opacity:1;fill-rule:evenodd;stroke:%23000000;stroke-width:1px;stroke-linecap:butt;stroke-linejoin:round;stroke-opacity:1%22 id=%22path5581%22/><path d=%22M 9,26 C 9,28 10.5,28 11.5,30 C 12.5,31.5 12.5,31 12,33.5 C 10.5,34.5 10.5,36 10.5,36 C 9,37.5 11,38.5 11,38.5 C 17.5,39.5 27.5,39.5 34,38.5 C 34,38.5 35.5,37.5 34,36 C 34,36 34.5,34.5 33,33.5 C 32.5,31 32.5,31.5 33.5,30 C 34.5,28 36,28 36,26 C 27.5,24.5 17.5,24.5 9,26 z %22 style=%22fill:%23000000;fill-opacity:1;fill-rule:evenodd;stroke:%23000000;stroke-width:1px;stroke-linecap:butt;stroke-linejoin:round;stroke-opacity:1%22 id=%22path5583%22/><path d=%22M 11.5,30 C 15,29 30,29 33.5,30%22 style=%22fill:none;fill-opacity:0.75;fill-rule:evenodd;stroke:%23ffffff;stroke-width:1px;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1%22 id=%22path5585%22/><path d=%22M 12,33.5 C 18,32.5 27,32.5 33,33.5%22 style=%22fill:none;fill-opacity:0.75;fill-rule:evenodd;stroke:%23ffffff;stroke-width:1px;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1%22 id=%22path5587%22/><path d=%22M 10.5,36 C 15.5,35 29,35 34,36%22 style=%22fill:none;fill-opacity:0.75;fill-rule:evenodd;stroke:%23ffffff;stroke-width:1px;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1%22 id=%22path5589%22/></g></svg>',
2404 'bR': '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:%23000000;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 9,39 L 36,39 L 36,36 L 9,36 L 9,39 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 12.5,32 L 14,29.5 L 31,29.5 L 32.5,32 L 12.5,32 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 12,36 L 12,32 L 33,32 L 33,36 L 12,36 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 14,29.5 L 14,16.5 L 31,16.5 L 31,29.5 L 14,29.5 z %22 style=%22stroke-linecap:butt;stroke-linejoin:miter%22/><path d=%22M 14,16.5 L 11,14 L 34,14 L 31,16.5 L 14,16.5 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 11,14 L 11,9 L 15,9 L 15,11 L 20,11 L 20,9 L 25,9 L 25,11 L 30,11 L 30,9 L 34,9 L 34,14 L 11,14 z %22 style=%22stroke-linecap:butt%22/><path d=%22M 12,35.5 L 33,35.5 L 33,35.5%22 style=%22fill:none;stroke:%23ffffff;stroke-width:1;stroke-linejoin:miter%22/><path d=%22M 13,31.5 L 32,31.5%22 style=%22fill:none;stroke:%23ffffff;stroke-width:1;stroke-linejoin:miter%22/><path d=%22M 14,29.5 L 31,29.5%22 style=%22fill:none;stroke:%23ffffff;stroke-width:1;stroke-linejoin:miter%22/><path d=%22M 14,16.5 L 31,16.5%22 style=%22fill:none;stroke:%23ffffff;stroke-width:1;stroke-linejoin:miter%22/><path d=%22M 11,14 L 34,14%22 style=%22fill:none;stroke:%23ffffff;stroke-width:1;stroke-linejoin:miter%22/></g></svg>',
2405 '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>',
2406 '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>',
2407 '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>',
2410 var svg_piece_theme = function(piece) {
2411 return svg_pieces[piece];
2414 var init = function() {
2415 unique = get_unique();
2417 // Load settings from HTML5 local storage if available.
2418 if (supports_html5_storage() && window['localStorage']['enable_sound']) {
2419 set_sound(parseInt(window['localStorage']['enable_sound']));
2425 board = new window.ChessBoard('board', {
2426 onMoveEnd: function() { board_is_animating = false; },
2429 pieceTheme: svg_piece_theme,
2430 onDragStart: onDragStart,
2432 onSnapEnd: onSnapEnd
2434 document.getElementById("board").addEventListener('mousedown', mousedownSquare);
2435 document.getElementById("board").addEventListener('mouseup', mouseupSquare);
2438 window.addEventListener('resize', function() {
2440 update_sparkline(displayed_analysis_data || current_analysis_data);
2441 update_board_highlight();
2444 window.addEventListener('keyup', function(event) {
2445 if (event.which == 39) { // Left arrow.
2447 } else if (event.which == 37) { // Right arrow.
2449 } else if (event.which >= 49 && event.which <= 57) { // 1-9.
2450 var num = event.which - 49;
2451 if (current_games && current_games.length >= num) {
2452 switch_backend(current_games[num]);
2454 } else if (event.which == 78) { // N.
2458 window.addEventListener('hashchange', possibly_switch_game_from_hash, false);
2459 possibly_switch_game_from_hash();
2461 document.addEventListener('DOMContentLoaded', init);