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 = 2016032000;
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.
54 var current_games = null;
69 /** @type {Array.<Array.<boolean>>} */
70 var occupied_by_arrows = [];
72 /** Currently displayed refutation lines (on-screen).
73 * Can either come from the current_analysis_data, displayed_analysis_data,
74 * or hash_refutation_lines.
76 var refutation_lines = [];
78 /** Refutation lines from current hash probe.
80 * If non-null, will override refutation lines from the base position.
81 * Note that these are relative to display_fen, not base_fen.
83 var hash_refutation_lines = null;
85 /** @type {!number} @private */
88 /** @type {!string} @private */
91 /** @type {number} @private */
94 /** @type {boolean} @private */
95 var sort_refutation_lines_by_score = true;
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;
131 * Our best estimate of how many milliseconds we need to add to
132 * new Date() to get the true UTC time. Calibrated against the
138 var client_clock_offset_ms = null;
140 var clock_timer = null;
142 /** The current position being analyzed, represented as a FEN string.
143 * Note that this is not necessarily the same as display_fen.
149 /** The current position on the board, represented as a FEN string.
150 * Note that board.fen() does not contain e.g. who is to play.
154 var display_fen = null;
158 * pretty_pv: Array.<string>,
161 * start_display_move_num: number
164 * "start_display_move_num" is the (half-)move number to start displaying the PV at.
167 /** All PVs that we currently know of.
169 * Element 0 is history (or null if no history).
170 * Element 1 is current main PV, or explored line if nowhere else on the screen.
171 * All remaining elements are refutation lines (multi-PV).
173 * @type {Array.<DisplayLine>}
176 var display_lines = [];
178 /** @type {?DisplayLine} @private */
179 var current_display_line = null;
181 /** @type {boolean} @private */
182 var current_display_line_is_history = false;
184 /** @type {?number} @private */
185 var current_display_move = null;
188 * The current backend request to get main analysis (not history), if any,
189 * so that we can abort it.
194 var current_analysis_xhr = null;
197 * The current timer to fire off a request to get main analysis (not history),
198 * if any, so that we can abort it.
203 var current_analysis_request_timer = null;
206 * The current backend request to get historic data, if any.
211 var current_historic_xhr = null;
214 * The current backend request to get hash probes, if any, so that we can abort it.
219 var current_hash_xhr = null;
222 * The current timer to display hash probe information (it could be waiting on the
223 * board to stop animating), if any, so that we can abort it.
228 var current_hash_display_timer = null;
230 var supports_html5_storage = function() {
232 return 'localStorage' in window && window['localStorage'] !== null;
238 // Make the unique token persistent so people refreshing the page won't count twice.
239 // Of course, you can never fully protect against people deliberately wanting to spam.
240 var get_unique = function() {
241 var use_local_storage = supports_html5_storage();
242 if (use_local_storage && localStorage['unique']) {
243 return localStorage['unique'];
245 var unique = Math.random();
246 if (use_local_storage) {
247 localStorage['unique'] = unique;
252 var request_update = function() {
253 current_analysis_request_timer = null;
255 current_analysis_xhr = $.ajax({
256 url: backend_url + "?ims=" + ims + "&unique=" + unique
257 }).done(function(data, textstatus, xhr) {
258 sync_server_clock(xhr.getResponseHeader('Date'));
259 ims = xhr.getResponseHeader('X-RGLM');
260 var num_viewers = xhr.getResponseHeader('X-RGNV');
262 if (Array.isArray(data)) {
263 new_data = JSON.parse(JSON.stringify(current_analysis_data));
264 JSON_delta.patch(new_data, data);
269 var minimum_version = xhr.getResponseHeader('X-RGMV');
270 if (minimum_version && minimum_version > SCRIPT_VERSION) {
271 // Upgrade to latest version with a force-reload.
272 location.reload(true);
275 possibly_play_sound(current_analysis_data, new_data);
276 current_analysis_data = new_data;
278 update_num_viewers(num_viewers);
281 current_analysis_request_timer = setTimeout(function() { request_update(); }, 100);
282 }).fail(function(jqXHR, textStatus, errorThrown) {
283 if (textStatus === "abort") {
284 // Aborted because we are switching backends. Abandon and don't retry,
285 // because another one is already started for us.
287 // Backend error or similar. Wait ten seconds, then try again.
288 current_analysis_request_timer = setTimeout(function() { request_update(); }, 10000);
293 var possibly_play_sound = function(old_data, new_data) {
297 if (old_data === null) {
300 var ding = document.getElementById('ding');
301 if (ding && ding.play) {
302 if (old_data['position'] && old_data['position']['fen'] &&
303 new_data['position'] && new_data['position']['fen'] &&
304 (old_data['position']['fen'] !== new_data['position']['fen'] ||
305 old_data['position']['move_num'] !== new_data['position']['move_num'])) {
312 * @type {!string} server_date_string
314 var sync_server_clock = function(server_date_string) {
315 var server_time_ms = new Date(server_date_string).getTime();
316 var client_time_ms = new Date().getTime();
317 var estimated_offset_ms = server_time_ms - client_time_ms;
319 // In order not to let the noise move us too much back and forth
320 // (the server only has one-second resolution anyway), we only
321 // change an existing skew if we are at least five seconds off.
322 if (client_clock_offset_ms === null ||
323 Math.abs(estimated_offset_ms - client_clock_offset_ms) > 5000) {
324 client_clock_offset_ms = estimated_offset_ms;
328 var clear_arrows = function() {
329 for (var i = 0; i < arrows.length; ++i) {
331 if (arrows[i].svg.parentElement) {
332 arrows[i].svg.parentElement.removeChild(arrows[i].svg);
334 delete arrows[i].svg;
339 occupied_by_arrows = [];
340 for (var y = 0; y < 8; ++y) {
341 occupied_by_arrows.push([false, false, false, false, false, false, false, false]);
345 var redraw_arrows = function() {
346 for (var i = 0; i < arrows.length; ++i) {
347 position_arrow(arrows[i]);
351 /** @param {!number} x
354 var sign = function(x) {
364 /** See if drawing this arrow on the board would cause unduly amount of confusion.
365 * @param {!string} from The square the arrow is from (e.g. e4).
366 * @param {!string} to The square the arrow is to (e.g. e4).
369 var interfering_arrow = function(from, to) {
370 var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
371 var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
372 var to_col = to.charCodeAt(0) - "a1".charCodeAt(0);
373 var to_row = to.charCodeAt(1) - "a1".charCodeAt(1);
375 occupied_by_arrows[from_row][from_col] = true;
377 // Knight move: Just check that we haven't been at the destination before.
378 if ((Math.abs(to_col - from_col) == 2 && Math.abs(to_row - from_row) == 1) ||
379 (Math.abs(to_col - from_col) == 1 && Math.abs(to_row - from_row) == 2)) {
380 return occupied_by_arrows[to_row][to_col];
383 // Sliding piece: Check if anything except the from-square is seen before.
384 var dx = sign(to_col - from_col);
385 var dy = sign(to_row - from_row);
391 if (occupied_by_arrows[y][x]) {
394 occupied_by_arrows[y][x] = true;
395 } while (x != to_col || y != to_row);
400 /** Find a point along the coordinate system given by the given line,
401 * <t> units forward from the start of the line, <u> units to the right of it.
402 * @param {!number} x1
403 * @param {!number} x2
404 * @param {!number} y1
405 * @param {!number} y2
408 * @return {!string} The point in "x y" form, suitable for SVG paths.
410 var point_from_start = function(x1, y1, x2, y2, t, u) {
414 var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
418 var x = x1 + dx * t + dy * u;
419 var y = y1 + dy * t - dx * u;
423 /** Find a point along the coordinate system given by the given line,
424 * <t> units forward from the end of the line, <u> units to the right of it.
425 * @param {!number} x1
426 * @param {!number} x2
427 * @param {!number} y1
428 * @param {!number} y2
431 * @return {!string} The point in "x y" form, suitable for SVG paths.
433 var point_from_end = function(x1, y1, x2, y2, t, u) {
437 var norm = 1.0 / Math.sqrt(dx * dx + dy * dy);
441 var x = x2 + dx * t + dy * u;
442 var y = y2 + dy * t - dx * u;
446 var position_arrow = function(arrow) {
448 if (arrow.svg.parentElement) {
449 arrow.svg.parentElement.removeChild(arrow.svg);
453 if (current_display_line !== null && !current_display_line_is_history) {
457 var pos = $(".square-a8").position();
459 var zoom_factor = $("#board").width() / 400.0;
460 var line_width = arrow.line_width * zoom_factor;
461 var arrow_size = arrow.arrow_size * zoom_factor;
463 var square_width = $(".square-a8").width();
464 var from_y = (7 - arrow.from_row + 0.5)*square_width;
465 var to_y = (7 - arrow.to_row + 0.5)*square_width;
466 var from_x = (arrow.from_col + 0.5)*square_width;
467 var to_x = (arrow.to_col + 0.5)*square_width;
469 var SVG_NS = "http://www.w3.org/2000/svg";
470 var XHTML_NS = "http://www.w3.org/1999/xhtml";
471 var svg = document.createElementNS(SVG_NS, "svg");
472 svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
473 svg.setAttribute("height", /** @type{number} */ ($("#board").height()));
474 svg.setAttribute("style", "position: absolute");
475 svg.setAttribute("position", "absolute");
476 svg.setAttribute("version", "1.1");
477 svg.setAttribute("class", "c1");
478 svg.setAttribute("xmlns", XHTML_NS);
486 var outline = document.createElementNS(SVG_NS, "path");
487 outline.setAttribute("d", "M " + point_from_start(x1, y1, x2, y2, arrow_size / 2, 0) + " L " + point_from_end(x1, y1, x2, y2, -arrow_size / 2, 0));
488 outline.setAttribute("xmlns", XHTML_NS);
489 outline.setAttribute("stroke", "#666");
490 outline.setAttribute("stroke-width", line_width + 2);
491 outline.setAttribute("fill", "none");
492 svg.appendChild(outline);
494 var path = document.createElementNS(SVG_NS, "path");
495 path.setAttribute("d", "M " + point_from_start(x1, y1, x2, y2, arrow_size / 2, 0) + " L " + point_from_end(x1, y1, x2, y2, -arrow_size / 2, 0));
496 path.setAttribute("xmlns", XHTML_NS);
497 path.setAttribute("stroke", arrow.fg_color);
498 path.setAttribute("stroke-width", line_width);
499 path.setAttribute("fill", "none");
500 svg.appendChild(path);
502 // Then the arrow head.
503 var head = document.createElementNS(SVG_NS, "path");
504 head.setAttribute("d",
505 "M " + point_from_end(x1, y1, x2, y2, 0, 0) +
506 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, -arrow_size / 2) +
507 " L " + point_from_end(x1, y1, x2, y2, -arrow_size * .623, 0.0) +
508 " L " + point_from_end(x1, y1, x2, y2, -arrow_size, arrow_size / 2) +
509 " L " + point_from_end(x1, y1, x2, y2, 0, 0));
510 head.setAttribute("xmlns", XHTML_NS);
511 head.setAttribute("stroke", "#000");
512 head.setAttribute("stroke-width", "1");
513 head.setAttribute("fill", arrow.fg_color);
514 svg.appendChild(head);
516 $(svg).css({ top: pos.top, left: pos.left, 'pointer-events': 'none' });
517 document.body.appendChild(svg);
522 * @param {!string} from_square
523 * @param {!string} to_square
524 * @param {!string} fg_color
525 * @param {number} line_width
526 * @param {number} arrow_size
528 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
529 var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
530 var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
531 var to_col = to_square.charCodeAt(0) - "a1".charCodeAt(0);
532 var to_row = to_square.charCodeAt(1) - "a1".charCodeAt(1);
540 line_width: line_width,
541 arrow_size: arrow_size,
545 position_arrow(arrow);
549 var compare_by_sort_key = function(refutation_lines, a, b) {
550 var ska = refutation_lines[a]['sort_key'];
551 var skb = refutation_lines[b]['sort_key'];
552 if (ska < skb) return -1;
553 if (ska > skb) return 1;
557 var compare_by_score = function(refutation_lines, a, b) {
558 var sa = parseInt(refutation_lines[b]['score_sort_key'], 10);
559 var sb = parseInt(refutation_lines[a]['score_sort_key'], 10);
564 * Fake multi-PV using the refutation lines. Find all “relevant” moves,
565 * sorted by quality, descending.
567 * @param {!Object} data
568 * @param {number} margin The maximum number of centipawns worse than the
569 * best move can be and still be included.
570 * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
571 * moves, in score order.
573 var find_nonstupid_moves = function(data, margin) {
574 // First of all, if there are any moves that are more than 0.5 ahead of
575 // the primary move, the refutation lines are probably bunk, so just
577 var best_score = undefined;
578 var pv_score = undefined;
579 for (var move in data['refutation_lines']) {
580 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
581 if (move == data['pv_uci'][0]) {
584 if (best_score === undefined || score > best_score) {
587 if (!(data['refutation_lines'][move]['depth'] >= 8)) {
592 if (best_score - pv_score > 50) {
596 // Now find all moves that are within “margin” of the best score.
597 // The PV move will always be first.
599 for (var move in data['refutation_lines']) {
600 var score = parseInt(data['refutation_lines'][move]['score_sort_key'], 10);
601 if (move != data['pv_uci'][0] && best_score - score <= margin) {
605 moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], a, b) });
606 moves.unshift(data['pv_uci'][0]);
615 var thousands = function(x) {
616 return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
620 * @param {!string} start_fen
621 * @param {Array.<string>} pretty_pv
622 * @param {number} move_num
623 * @param {!string} toplay
624 * @param {number} start_display_move_num
625 * @param {number=} opt_limit
626 * @param {boolean=} opt_showlast
628 var add_pv = function(start_fen, pretty_pv, move_num, toplay, start_display_move_num, opt_limit, opt_showlast) {
630 start_fen: start_fen,
631 pretty_pv: pretty_pv,
632 move_num: parseInt(move_num),
634 start_display_move_num: start_display_move_num,
636 return print_pv(display_lines.length - 1, opt_limit, opt_showlast);
640 * @param {number} line_num
641 * @param {number=} opt_limit
642 * @param {boolean=} opt_showlast
644 var print_pv = function(line_num, opt_limit, opt_showlast) {
645 var display_line = display_lines[line_num];
646 var pretty_pv = display_line.pretty_pv;
647 var move_num = display_line.move_num;
648 var toplay = display_line.toplay;
650 // Truncate PV at the start if needed.
651 var start_display_move_num = display_line.start_display_move_num;
652 if (start_display_move_num > 0) {
653 pretty_pv = pretty_pv.slice(start_display_move_num);
654 var to_add = start_display_move_num;
655 if (toplay === 'B') {
660 if (to_add % 2 == 1) {
664 move_num += to_add / 2;
669 if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
670 // Truncate the PV at the beginning (instead of at the end).
671 // We assume here that toplay is 'W'. We also assume that if
672 // opt_showlast is set, then it is the history, and thus,
673 // the UI should be to expand the history.
674 pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
675 i = pretty_pv.length - opt_limit;
680 } else if (toplay == 'B' && pretty_pv.length > 0) {
681 var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
682 pv = move_num + '. … ' + move;
687 for ( ; i < pretty_pv.length; ++i) {
688 var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
691 if (i > opt_limit && !opt_showlast) {
697 pv += move_num + '. ' + move;
708 /** Update the highlighted to/from squares on the board.
709 * Based on the global "highlight_from" and "highlight_to" variables.
711 var update_board_highlight = function() {
712 $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
713 if ((current_display_line === null || current_display_line_is_history) &&
714 highlight_from !== undefined && highlight_to !== undefined) {
715 $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
716 $("#board").find('.square-' + highlight_to).addClass('nonuglyhighlight');
720 var update_history = function() {
721 if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
722 $("#history").html("No history");
723 } else if (truncate_display_history) {
724 $("#history").html(print_pv(0, 8, true));
727 '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
728 print_pv(0, 1, 'W'));
733 * @param {!boolean} truncate_history
735 var collapse_history = function(truncate_history) {
736 truncate_display_history = truncate_history;
739 window['collapse_history'] = collapse_history;
741 /** Update the HTML display of multi-PV from the global "refutation_lines".
743 * Also recreates the global "display_lines".
745 var update_refutation_lines = function() {
746 if (base_fen === null) {
749 if (display_lines.length > 2) {
750 // Truncate so that only the history and PV is left.
751 display_lines = [ display_lines[0], display_lines[1] ];
753 var tbl = $("#refutationlines");
756 // Find out where the lines start from.
758 var start_display_move_num = 0;
759 if (hash_refutation_lines) {
760 base_line = current_display_line.pretty_pv.slice(0, current_display_move + 1);
761 start_display_move_num = base_line.length;
765 for (var move in refutation_lines) {
768 var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
769 moves = moves.sort(function(a, b) { return compare(refutation_lines, a, b) });
770 for (var i = 0; i < moves.length; ++i) {
771 var line = refutation_lines[moves[i]];
773 var tr = document.createElement("tr");
775 var move_td = document.createElement("td");
776 tr.appendChild(move_td);
777 $(move_td).addClass("move");
779 if (line['pv_pretty'].length == 0) {
780 // Not found, so just make a one-move PV.
781 var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
782 $(move_td).html(move);
783 var score_td = document.createElement("td");
785 $(score_td).addClass("score");
786 $(score_td).text("—");
787 tr.appendChild(score_td);
789 var depth_td = document.createElement("td");
790 tr.appendChild(depth_td);
791 $(depth_td).addClass("depth");
792 $(depth_td).text("—");
794 var pv_td = document.createElement("td");
795 tr.appendChild(pv_td);
796 $(pv_td).addClass("pv");
797 $(pv_td).html(add_pv(base_fen, base_line.concat([ line['pretty_move'] ]), move_num, toplay, start_display_move_num));
803 var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
804 $(move_td).html(move);
806 var score_td = document.createElement("td");
807 tr.appendChild(score_td);
808 $(score_td).addClass("score");
809 $(score_td).text(line['pretty_score']);
811 var depth_td = document.createElement("td");
812 tr.appendChild(depth_td);
813 $(depth_td).addClass("depth");
814 $(depth_td).text("d" + line['depth']);
816 var pv_td = document.createElement("td");
817 tr.appendChild(pv_td);
818 $(pv_td).addClass("pv");
819 $(pv_td).html(add_pv(base_fen, base_line.concat(line['pv_pretty']), move_num, toplay, start_display_move_num, 10));
824 // Make one of the links clickable and the other nonclickable.
825 if (sort_refutation_lines_by_score) {
826 $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");
827 $("#sortbyscore1").html("<strong>Score</strong>");
829 $("#sortbyscore0").html("<strong>Move</strong>");
830 $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
833 // Update the move highlight, as we've rewritten all the HTML.
834 update_move_highlight();
838 * Create a Chess.js board object, containing the given position plus the given moves,
839 * up to the given limit.
841 * @param {?string} fen
842 * @param {Array.<string>} moves
843 * @param {number} last_move
845 var chess_from = function(fen, moves, last_move) {
846 var hiddenboard = new Chess();
848 hiddenboard.load(fen);
850 for (var i = 0; i <= last_move; ++i) {
851 if (moves[i] === '0-0') {
852 hiddenboard.move('O-O');
853 } else if (moves[i] === '0-0-0') {
854 hiddenboard.move('O-O-O');
856 hiddenboard.move(moves[i]);
862 var update_game_list = function(games) {
863 $("#games").text("");
864 if (games === null) {
868 var games_div = document.getElementById('games');
869 for (var game_num = 0; game_num < games.length; ++game_num) {
870 var game = games[game_num];
871 var game_span = document.createElement("span");
872 game_span.setAttribute("class", "game");
874 var game_name = document.createTextNode(game['name']);
875 if (game['url'] === backend_url) {
876 game_span.appendChild(game_name);
878 var game_a = document.createElement("a");
879 game_a.setAttribute("href", "#" + game['id']);
880 game_a.appendChild(game_name);
881 game_span.appendChild(game_a);
883 games_div.appendChild(game_span);
888 * Try to find a running game that matches with the current hash,
889 * and switch to it if we're not already displaying it.
891 var possibly_switch_game_from_hash = function() {
892 if (current_games === null) {
896 var hash = window.location.hash.replace(/^#/,'');
897 for (var i = 0; i < current_games.length; ++i) {
898 if (current_games[i]['id'] === hash) {
899 if (backend_url !== current_games[i]['url']) {
900 switch_backend(current_games[i]['url']);
907 /** Update all the HTML on the page, based on current global state.
909 var update_board = function() {
910 var data = displayed_analysis_data || current_analysis_data;
911 var current_data = current_analysis_data; // Convenience alias.
915 // Print the history. This is pretty much the only thing that's
916 // unconditionally taken from current_data (we're not interested in
917 // historic history).
918 if (current_data['position']['pretty_history']) {
919 add_pv('start', current_data['position']['pretty_history'], 1, 'W', 0, 8, true);
921 display_lines.push(null);
925 // Games currently in progress, if any.
926 if (current_data['games']) {
927 current_games = current_data['games'];
928 possibly_switch_game_from_hash();
929 update_game_list(current_data['games']);
931 current_games = null;
932 update_game_list(null);
935 // The headline. Names are always fetched from current_data;
936 // the rest can depend a bit.
939 current_data['position']['player_w'] && current_data['position']['player_b']) {
940 headline = current_data['position']['player_w'] + '–' +
941 current_data['position']['player_b'] + ', analysis';
943 headline = 'Analysis';
946 // Credits, where applicable. Note that we don't want the footer to change a lot
947 // when e.g. viewing history, so if any of these changed during the game,
948 // use the current one still.
949 if (current_data['using_lomonosov']) {
950 $("#lomonosov").show();
952 $("#lomonosov").hide();
955 // Credits: The engine name/version.
956 if (current_data['engine'] && current_data['engine']['name'] !== null) {
957 $("#engineid").text(current_data['engine']['name']);
960 // Credits: The engine URL.
961 if (current_data['engine'] && current_data['engine']['url']) {
962 $("#engineid").attr("href", current_data['engine']['url']);
964 $("#engineid").removeAttr("href");
967 // Credits: Engine details.
968 if (current_data['engine'] && current_data['engine']['details']) {
969 $("#enginedetails").text(" (" + current_data['engine']['details'] + ")");
971 $("#enginedetails").text("");
974 // Credits: Move source, possibly with URL.
975 if (current_data['move_source'] && current_data['move_source_url']) {
976 $("#movesource").text("Moves provided by ");
977 var movesource_a = document.createElement("a");
978 movesource_a.setAttribute("href", current_data['move_source_url']);
979 var movesource_text = document.createTextNode(current_data['move_source']);
980 movesource_a.appendChild(movesource_text);
981 var movesource_period = document.createTextNode(".");
982 document.getElementById("movesource").appendChild(movesource_a);
983 document.getElementById("movesource").appendChild(movesource_period);
984 } else if (current_data['move_source']) {
985 $("#movesource").text("Moves provided by " + current_data['move_source'] + ".");
987 $("#movesource").text("");
991 if (displayed_analysis_data) {
992 // Displaying some non-current position, pick out the last move
993 // from the history. This will work even if the fetch failed.
994 last_move = format_halfmove_with_number(
995 current_display_line.pretty_pv[current_display_move],
996 current_display_move + 1);
997 headline += ' after ' + last_move;
998 } else if (data['position']['last_move'] !== 'none') {
999 last_move = format_move_with_number(
1000 data['position']['last_move'],
1001 data['position']['move_num'],
1002 data['position']['toplay'] == 'W');
1003 headline += ' after ' + last_move;
1007 $("#headline").text(headline);
1009 // The <title> contains a very brief headline.
1010 var title_elems = [];
1011 if (data['short_score'] !== undefined && data['short_score'] !== null) {
1012 title_elems.push(data['short_score'].replace(/^ /, ""));
1014 if (last_move !== null) {
1015 title_elems.push(last_move);
1018 if (title_elems.length != 0) {
1019 document.title = '(' + title_elems.join(', ') + ') analysis.sesse.net';
1021 document.title = 'analysis.sesse.net';
1024 // The last move (shown by highlighting the from and to squares).
1025 if (data['position'] && data['position']['last_move_uci']) {
1026 highlight_from = data['position']['last_move_uci'].substr(0, 2);
1027 highlight_to = data['position']['last_move_uci'].substr(2, 2);
1028 } else if (current_display_line_is_history && current_display_move >= 0) {
1029 // We don't have historic analysis for this position, but we
1030 // can reconstruct what the last move was by just replaying
1032 var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1033 var moves = hiddenboard.history({ verbose: true });
1034 var last_move = moves.pop();
1035 highlight_from = last_move.from;
1036 highlight_to = last_move.to;
1038 highlight_from = highlight_to = undefined;
1040 update_board_highlight();
1042 if (data['failed']) {
1043 $("#score").text("No analysis for this move");
1044 $("#pvtitle").text("PV:");
1046 $("#searchstats").html(" ");
1047 $("#refutationlines").empty();
1048 $("#whiteclock").empty();
1049 $("#blackclock").empty();
1050 refutation_lines = [];
1051 update_refutation_lines();
1053 update_displayed_line();
1054 update_move_highlight();
1061 if (data['score'] !== null) {
1062 $("#score").text(data['score']);
1065 // The search stats.
1066 if (data['searchstats']) {
1067 $("#searchstats").html(data['searchstats']);
1068 } else if (data['tablebase'] == 1) {
1069 $("#searchstats").text("Tablebase result");
1070 } else if (data['nodes'] && data['nps'] && data['depth']) {
1071 var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
1072 if (data['seldepth']) {
1073 stats += ' (' + data['seldepth'] + ' selective)';
1075 if (data['tbhits'] && data['tbhits'] > 0) {
1076 if (data['tbhits'] == 1) {
1077 stats += ', one Syzygy hit';
1079 stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';
1083 $("#searchstats").text(stats);
1085 $("#searchstats").text("");
1088 // Update the board itself.
1089 base_fen = data['position']['fen'];
1090 update_displayed_line();
1093 $("#pvtitle").text("PV:");
1094 $("#pv").html(add_pv(data['position']['fen'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay'], 0));
1096 // Update the PV arrow.
1098 if (data['pv_uci'].length >= 1) {
1099 // draw a continuation arrow as long as it's the same piece
1100 for (var i = 0; i < data['pv_uci'].length; i += 2) {
1101 var from = data['pv_uci'][i].substr(0, 2);
1102 var to = data['pv_uci'][i].substr(2,4);
1103 if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||
1104 interfering_arrow(from, to)) {
1107 create_arrow(from, to, '#f66', 6, 20);
1110 var alt_moves = find_nonstupid_moves(data, 30);
1111 for (var i = 1; i < alt_moves.length && i < 3; ++i) {
1112 create_arrow(alt_moves[i].substr(0, 2),
1113 alt_moves[i].substr(2, 2), '#f66', 1, 10);
1117 // See if all semi-reasonable moves have only one possible response.
1118 if (data['pv_uci'].length >= 2) {
1119 var nonstupid_moves = find_nonstupid_moves(data, 300);
1120 var response = data['pv_uci'][1];
1121 for (var i = 0; i < nonstupid_moves.length; ++i) {
1122 if (nonstupid_moves[i] == data['pv_uci'][0]) {
1123 // ignore the PV move for refutation lines.
1126 if (!data['refutation_lines'] ||
1127 !data['refutation_lines'][nonstupid_moves[i]] ||
1128 !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
1129 data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
1130 // Incomplete PV, abort.
1131 response = undefined;
1134 var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
1135 if (response !== this_response) {
1136 // Different response depending on lines, abort.
1137 response = undefined;
1142 if (nonstupid_moves.length > 0 && response !== undefined) {
1143 create_arrow(response.substr(0, 2),
1144 response.substr(2, 2), '#66f', 6, 20);
1148 // Update the refutation lines.
1149 base_fen = data['position']['fen'];
1150 move_num = parseInt(data['position']['move_num']);
1151 toplay = data['position']['toplay'];
1152 refutation_lines = hash_refutation_lines || data['refutation_lines'];
1153 update_refutation_lines();
1155 // Update the sparkline last, since its size depends on how everything else reflowed.
1156 update_sparkline(data);
1159 var update_sparkline = function(data) {
1160 if (data && data['score_history']) {
1161 var first_move_num = undefined;
1162 for (var halfmove_num in data['score_history']) {
1163 halfmove_num = parseInt(halfmove_num);
1164 if (first_move_num === undefined || halfmove_num < first_move_num) {
1165 first_move_num = halfmove_num;
1168 if (first_move_num !== undefined) {
1169 var last_move_num = data['position']['move_num'] * 2 - 3;
1170 if (data['position']['toplay'] === 'B') {
1174 // Possibly truncate some moves if we don't have enough width.
1175 // FIXME: Sometimes width() for #scorecontainer (and by extent,
1176 // #scoresparkcontainer) on Chrome for mobile seems to start off
1177 // at something very small, and then suddenly snap back into place.
1179 var max_moves = Math.floor($("#scoresparkcontainer").width() / 5) - 5;
1180 if (last_move_num - first_move_num > max_moves) {
1181 first_move_num = last_move_num - max_moves;
1184 var min_score = -100;
1185 var max_score = 100;
1186 var last_score = null;
1188 for (var halfmove_num = first_move_num; halfmove_num <= last_move_num; ++halfmove_num) {
1189 if (data['score_history'][halfmove_num]) {
1190 var score = data['score_history'][halfmove_num][0];
1191 if (score < min_score) min_score = score;
1192 if (score > max_score) max_score = score;
1193 last_score = data['score_history'][halfmove_num][0];
1195 scores.push(last_score);
1197 if (data['plot_score']) {
1198 scores.push(data['plot_score']);
1200 // FIXME: at some widths, calling sparkline() seems to push
1201 // #scorecontainer under the board.
1202 $("#scorespark").sparkline(scores, {
1205 chartRangeMin: min_score,
1206 chartRangeMax: max_score,
1207 tooltipFormatter: function(sparkline, options, fields) {
1208 return format_tooltip(data, fields[0].offset + first_move_num);
1212 $("#scorespark").text("");
1215 $("#scorespark").text("");
1220 * @param {number} num_viewers
1222 var update_num_viewers = function(num_viewers) {
1223 if (num_viewers === null) {
1224 $("#numviewers").text("");
1225 } else if (num_viewers == 1) {
1226 $("#numviewers").text("You are the only current viewer");
1228 $("#numviewers").text(num_viewers + " current viewers");
1232 var update_clock = function() {
1233 clearTimeout(clock_timer);
1235 var data = displayed_analysis_data || current_analysis_data;
1236 if (data['position']) {
1237 var result = data['position']['result'];
1238 if (result === '1-0') {
1239 $("#whiteclock").text("1");
1240 $("#blackclock").text("0");
1241 $("#whiteclock").removeClass("running-clock");
1242 $("#blackclock").removeClass("running-clock");
1245 if (result === '1/2-1/2') {
1246 $("#whiteclock").text("1/2");
1247 $("#blackclock").text("1/2");
1248 $("#whiteclock").removeClass("running-clock");
1249 $("#blackclock").removeClass("running-clock");
1252 if (result === '0-1') {
1253 $("#whiteclock").text("0");
1254 $("#blackclock").text("1");
1255 $("#whiteclock").removeClass("running-clock");
1256 $("#blackclock").removeClass("running-clock");
1261 var white_clock_ms = null;
1262 var black_clock_ms = null;
1263 var show_seconds = false;
1266 if (data['position'] &&
1267 data['position']['white_clock'] &&
1268 data['position']['black_clock']) {
1269 white_clock_ms = data['position']['white_clock'] * 1000;
1270 black_clock_ms = data['position']['black_clock'] * 1000;
1273 // Dynamic clock (only one, obviously).
1275 if (data['position']['white_clock_target']) {
1277 $("#whiteclock").addClass("running-clock");
1278 $("#blackclock").removeClass("running-clock");
1279 } else if (data['position']['black_clock_target']) {
1281 $("#whiteclock").removeClass("running-clock");
1282 $("#blackclock").addClass("running-clock");
1284 $("#whiteclock").removeClass("running-clock");
1285 $("#blackclock").removeClass("running-clock");
1289 var now = new Date().getTime() + client_clock_offset_ms;
1290 remaining_ms = data['position'][color + '_clock_target'] * 1000 - now;
1291 if (color === "white") {
1292 white_clock_ms = remaining_ms;
1294 black_clock_ms = remaining_ms;
1298 if (white_clock_ms === null || black_clock_ms === null) {
1299 $("#whiteclock").empty();
1300 $("#blackclock").empty();
1304 // If either player has ten minutes or less left, add the second counters.
1305 var show_seconds = (white_clock_ms < 60 * 10 * 1000 || black_clock_ms < 60 * 10 * 1000);
1308 // See when the clock will change next, and update right after that.
1311 next_update_ms = remaining_ms % 1000 + 100;
1313 next_update_ms = remaining_ms % 60000 + 100;
1315 clock_timer = setTimeout(update_clock, next_update_ms);
1318 $("#whiteclock").text(format_clock(white_clock_ms, show_seconds));
1319 $("#blackclock").text(format_clock(black_clock_ms, show_seconds));
1323 * @param {Number} remaining_ms
1324 * @param {boolean} show_seconds
1326 var format_clock = function(remaining_ms, show_seconds) {
1327 if (remaining_ms <= 0) {
1335 var remaining = Math.floor(remaining_ms / 1000);
1336 var seconds = remaining % 60;
1337 remaining = (remaining - seconds) / 60;
1338 var minutes = remaining % 60;
1339 remaining = (remaining - minutes) / 60;
1340 var hours = remaining;
1342 return format_2d(hours) + ":" + format_2d(minutes) + ":" + format_2d(seconds);
1344 return format_2d(hours) + ":" + format_2d(minutes);
1351 var format_2d = function(x) {
1360 * @param {string} move
1361 * @param {Number} move_num
1362 * @param {boolean} white_to_play
1364 var format_move_with_number = function(move, move_num, white_to_play) {
1366 if (white_to_play) {
1367 ret = (move_num - 1) + '… ';
1369 ret = move_num + '. ';
1376 * @param {string} move
1377 * @param {Number} halfmove_num
1379 var format_halfmove_with_number = function(move, halfmove_num) {
1380 return format_move_with_number(
1382 Math.floor(halfmove_num / 2) + 1,
1383 halfmove_num % 2 == 0);
1387 * @param {Object} data
1388 * @param {Number} halfmove_num
1390 var format_tooltip = function(data, halfmove_num) {
1391 if (data['score_history'][halfmove_num] ||
1392 halfmove_num === data['position']['pretty_history'].length) {
1395 if (halfmove_num === data['position']['pretty_history'].length) {
1396 move = data['position']['last_move'];
1397 short_score = data['short_score'];
1399 move = data['position']['pretty_history'][halfmove_num];
1400 short_score = data['score_history'][halfmove_num][1];
1402 var move_with_number = format_halfmove_with_number(move, halfmove_num);
1404 return "After " + move_with_number + ": " + short_score;
1406 for (var i = halfmove_num; i --> 0; ) {
1407 if (data['score_history'][i]) {
1408 var move = data['position']['pretty_history'][i];
1409 return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
1416 * @param {boolean} sort_by_score
1418 var resort_refutation_lines = function(sort_by_score) {
1419 sort_refutation_lines_by_score = sort_by_score;
1420 if (supports_html5_storage()) {
1421 localStorage['sort_refutation_lines_by_score'] = sort_by_score ? 1 : 0;
1423 update_refutation_lines();
1425 window['resort_refutation_lines'] = resort_refutation_lines;
1428 * @param {boolean} truncate_history
1430 var set_truncate_history = function(truncate_history) {
1431 truncate_display_history = truncate_history;
1432 update_refutation_lines();
1434 window['set_truncate_history'] = set_truncate_history;
1437 * @param {number} line_num
1438 * @param {number} move_num
1440 var show_line = function(line_num, move_num) {
1441 if (line_num == -1) {
1442 current_display_line = null;
1443 current_display_move = null;
1444 hash_refutation_lines = null;
1445 if (displayed_analysis_data) {
1446 // TODO: Support exiting to history position if we are in an
1447 // analysis line of a history position.
1448 displayed_analysis_data = null;
1453 current_display_line = jQuery.extend({}, display_lines[line_num]); // Shallow clone.
1454 current_display_move = move_num + current_display_line.start_display_move_num;
1456 current_display_line_is_history = (line_num == 0);
1458 update_historic_analysis();
1459 update_displayed_line();
1460 update_board_highlight();
1461 update_move_highlight();
1464 window['show_line'] = show_line;
1466 var prev_move = function() {
1467 if (current_display_line &&
1468 current_display_move >= current_display_line.start_display_move_num) {
1469 --current_display_move;
1471 update_historic_analysis();
1472 update_displayed_line();
1473 update_move_highlight();
1475 window['prev_move'] = prev_move;
1477 var next_move = function() {
1478 if (current_display_line &&
1479 current_display_move < current_display_line.pretty_pv.length - 1) {
1480 ++current_display_move;
1482 update_historic_analysis();
1483 update_displayed_line();
1484 update_move_highlight();
1486 window['next_move'] = next_move;
1488 var update_historic_analysis = function() {
1489 if (!current_display_line_is_history) {
1492 if (current_display_move == current_display_line.pretty_pv.length - 1) {
1493 displayed_analysis_data = null;
1497 // Fetch old analysis for this line if it exists.
1498 var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
1499 var filename = "/history/move" + (current_display_move + 1) + "-" +
1500 hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
1502 current_historic_xhr = $.ajax({
1504 }).done(function(data, textstatus, xhr) {
1505 displayed_analysis_data = data;
1507 }).fail(function(jqXHR, textStatus, errorThrown) {
1508 if (textStatus === "abort") {
1509 // Aborted because we are switching backends. Don't do anything;
1510 // we will already have been cleared.
1512 displayed_analysis_data = {'failed': true};
1519 * @param {string} fen
1521 var update_imbalance = function(fen) {
1522 var hiddenboard = new Chess(fen);
1523 var imbalance = {'k': 0, 'q': 0, 'r': 0, 'b': 0, 'n': 0, 'p': 0};
1524 for (var row = 0; row < 8; ++row) {
1525 for (var col = 0; col < 8; ++col) {
1526 var col_text = String.fromCharCode('a1'.charCodeAt(0) + col);
1527 var row_text = String.fromCharCode('a1'.charCodeAt(1) + row);
1528 var square = col_text + row_text;
1529 var contents = hiddenboard.get(square);
1530 if (contents !== null) {
1531 if (contents.color === 'w') {
1532 ++imbalance[contents.type];
1534 --imbalance[contents.type];
1539 var white_imbalance = '';
1540 var black_imbalance = '';
1541 for (var piece in imbalance) {
1542 for (var i = 0; i < imbalance[piece]; ++i) {
1543 white_imbalance += '<img src="img/chesspieces/wikipedia/w' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1545 for (var i = 0; i < -imbalance[piece]; ++i) {
1546 black_imbalance += '<img src="img/chesspieces/wikipedia/b' + piece.toUpperCase() + '.png" alt="" style="width: 15px;height: 15px;">';
1549 $('#whiteimbalance').html(white_imbalance);
1550 $('#blackimbalance').html(black_imbalance);
1553 /** Mark the currently selected move in red.
1554 * Also replaces the PV with the current displayed line if it's not shown
1555 * anywhere else on the screen.
1557 var update_move_highlight = function() {
1558 if (highlighted_move !== null) {
1559 highlighted_move.removeClass('highlight');
1561 if (current_display_line) {
1562 // See if the current displayed line is identical to any of the ones
1563 // we have on screen. (It might not be if e.g. the analysis reloaded
1564 // since we started looking.)
1565 var display_line_num = null;
1566 for (var i = 0; i < display_lines.length; ++i) {
1567 var line = display_lines[i];
1568 if (line.start_display_move_num > 0) continue;
1569 if (current_display_line.start_fen !== line.start_fen) continue;
1570 if (current_display_line.pretty_pv.length !== line.pretty_pv.length) continue;
1572 for (var j = 0; j < line.pretty_pv.length; ++j) {
1573 if (current_display_line.pretty_pv[j] !== line.pretty_pv[j]) {
1579 display_line_num = i;
1584 if (display_line_num === null) {
1585 // Replace the PV with the (complete) line.
1586 $("#pvtitle").text("Exploring:");
1587 current_display_line.start_display_move_num = 0;
1588 display_lines.push(current_display_line);
1589 $("#pv").html(print_pv(display_lines.length - 1));
1590 display_line_num = display_lines.length - 1;
1593 highlighted_move = $("#automove" + display_line_num + "-" + (current_display_move - current_display_line.start_display_move_num));
1594 highlighted_move.addClass('highlight');
1598 var update_displayed_line = function() {
1599 if (current_display_line === null) {
1600 $("#linenav").hide();
1601 $("#linemsg").show();
1602 display_fen = base_fen;
1603 board.position(base_fen);
1604 update_imbalance(base_fen);
1608 $("#linenav").show();
1609 $("#linemsg").hide();
1611 if (current_display_move <= 0) {
1612 $("#prevmove").html("Previous");
1614 $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
1616 if (current_display_move == current_display_line.pretty_pv.length - 1) {
1617 $("#nextmove").html("Next");
1619 $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
1622 var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pretty_pv, current_display_move);
1623 display_fen = hiddenboard.fen();
1624 board_is_animating = true;
1625 var old_fen = board.fen();
1626 board.position(hiddenboard.fen());
1627 if (board.fen() === old_fen) {
1628 board_is_animating = false;
1629 } else if (!current_display_line_is_history) {
1630 // Fire off a hash request, since we're now off the main position
1631 // and it just changed.
1632 explore_hash(display_fen);
1634 update_imbalance(hiddenboard.fen());
1638 * @param {boolean} param_enable_sound
1640 var set_sound = function(param_enable_sound) {
1641 enable_sound = param_enable_sound;
1643 $("#soundon").html("<strong>On</strong>");
1644 $("#soundoff").html("<a href=\"javascript:set_sound(false)\">Off</a>");
1646 // Seemingly at least Firefox prefers MP3 over Opus; tell it otherwise,
1647 // and also preload the file since the user has selected audio.
1648 var ding = document.getElementById('ding');
1649 if (ding && ding.canPlayType && ding.canPlayType('audio/ogg; codecs="opus"') === 'probably') {
1650 ding.src = 'ding.opus';
1654 $("#soundon").html("<a href=\"javascript:set_sound(true)\">On</a>");
1655 $("#soundoff").html("<strong>Off</strong>");
1657 if (supports_html5_storage()) {
1658 localStorage['enable_sound'] = enable_sound ? 1 : 0;
1661 window['set_sound'] = set_sound;
1663 /** Send off a hash probe request to the backend.
1664 * @param {string} fen
1666 var explore_hash = function(fen) {
1667 // If we already have a backend response going, abort it.
1668 if (current_hash_xhr) {
1669 current_hash_xhr.abort();
1671 if (current_hash_display_timer) {
1672 clearTimeout(current_hash_display_timer);
1673 current_hash_display_timer = null;
1675 $("#refutationlines").empty();
1676 current_hash_xhr = $.ajax({
1677 url: backend_hash_url + "?fen=" + fen
1678 }).done(function(data, textstatus, xhr) {
1679 show_explore_hash_results(data, fen);
1683 /** Process the JSON response from a hash probe request.
1684 * @param {!Object} data
1685 * @param {string} fen
1687 var show_explore_hash_results = function(data, fen) {
1688 if (board_is_animating) {
1689 // Updating while the animation is still going causes
1690 // the animation to jerk. This is pretty crude, but it will do.
1691 current_hash_display_timer = setTimeout(function() { show_explore_hash_results(data, fen); }, 100);
1694 current_hash_display_timer = null;
1695 hash_refutation_lines = data['lines'];
1699 // almost all of this stuff comes from the chessboard.js example page
1700 var onDragStart = function(source, piece, position, orientation) {
1701 var pseudogame = new Chess(display_fen);
1702 if (pseudogame.game_over() === true ||
1703 (pseudogame.turn() === 'w' && piece.search(/^b/) !== -1) ||
1704 (pseudogame.turn() === 'b' && piece.search(/^w/) !== -1)) {
1708 recommended_move = get_best_move(pseudogame, source, null);
1709 if (recommended_move) {
1710 var squareEl = $('#board .square-' + recommended_move.to);
1711 squareEl.addClass('highlight1-32417');
1716 var mousedownSquare = function(e) {
1717 reverse_dragging_from = null;
1718 var square = $(this).attr('data-square');
1720 var pseudogame = new Chess(display_fen);
1721 if (pseudogame.game_over() === true) {
1725 // If the square is empty, or has a piece of the side not to move,
1726 // we handle it. If not, normal piece dragging will take it.
1727 var position = board.position();
1728 if (!position.hasOwnProperty(square) ||
1729 (pseudogame.turn() === 'w' && position[square].search(/^b/) !== -1) ||
1730 (pseudogame.turn() === 'b' && position[square].search(/^w/) !== -1)) {
1731 reverse_dragging_from = square;
1732 recommended_move = get_best_move(pseudogame, null, square);
1733 if (recommended_move) {
1734 var squareEl = $('#board .square-' + recommended_move.from);
1735 squareEl.addClass('highlight1-32417');
1736 squareEl = $('#board .square-' + recommended_move.to);
1737 squareEl.addClass('highlight1-32417');
1742 var mouseupSquare = function(e) {
1743 if (reverse_dragging_from === null) {
1746 var source = $(this).attr('data-square');
1747 var target = reverse_dragging_from;
1748 reverse_dragging_from = null;
1749 if (onDrop(source, target) !== 'snapback') {
1750 onSnapEnd(source, target);
1752 $("#board").find('.square-55d63').removeClass('highlight1-32417');
1755 var get_best_move = function(game, source, target) {
1756 var moves = game.moves({ verbose: true });
1757 if (source !== null) {
1758 moves = moves.filter(function(move) { return move.from == source; });
1760 if (target !== null) {
1761 moves = moves.filter(function(move) { return move.to == target; });
1763 if (moves.length == 0) {
1766 if (moves.length == 1) {
1770 // More than one move. Use the display lines (if we have them)
1771 // to disambiguate; otherwise, we have no information.
1773 for (var i = 0; i < moves.length; ++i) {
1774 move_hash[moves[i].san] = moves[i];
1777 // History and PV take priority over the display lines.
1778 for (var i = 0; i < 2; ++i) {
1779 var line = display_lines[i];
1780 var first_move = line.pretty_pv[line.start_display_move_num];
1781 if (move_hash[first_move]) {
1782 return move_hash[first_move];
1786 var best_move = null;
1787 var best_move_score = null;
1789 for (var move in refutation_lines) {
1790 var line = refutation_lines[move];
1791 var score = parseInt(line['score_sort_key'], 10);
1792 if (score < -1000000) { // Two zeros less than in the server (just some margin).
1795 var first_move = line['pv_pretty'][0];
1796 if (move_hash[first_move]) {
1797 var score = parseInt(line['score_sort_key'], 10);
1798 if (best_move_score === null || score > best_move_score) {
1799 best_move = move_hash[first_move];
1800 best_move_score = score;
1807 var onDrop = function(source, target) {
1808 if (source === target) {
1809 if (recommended_move === null) {
1812 // Accept the move. It will be changed in onSnapEnd.
1816 // Suggestion not asked for.
1817 recommended_move = null;
1820 // see if the move is legal
1821 var pseudogame = new Chess(display_fen);
1822 var move = pseudogame.move({
1825 promotion: 'q' // NOTE: always promote to a queen for example simplicity
1829 if (move === null) return 'snapback';
1832 var onSnapEnd = function(source, target) {
1833 if (source === target && recommended_move !== null) {
1834 source = recommended_move.from;
1835 target = recommended_move.to;
1837 recommended_move = null;
1838 var pseudogame = new Chess(display_fen);
1839 var move = pseudogame.move({
1842 promotion: 'q' // NOTE: always promote to a queen for example simplicity
1845 if (current_display_line &&
1846 current_display_move < current_display_line.pretty_pv.length - 1 &&
1847 current_display_line.pretty_pv[current_display_move] === move.san) {
1852 // Walk down the displayed lines until we find one that starts with
1853 // this move, then select that. Note that this gives us a good priority
1854 // order (history first, then PV, then multi-PV lines).
1855 for (var i = 0; i < display_lines.length; ++i) {
1856 var line = display_lines[i];
1857 if (line.pretty_pv[line.start_display_move_num] === move.san) {
1863 // Shouldn't really be here if we have hash probes, but there's really
1864 // nothing we can do.
1866 // End of dragging-related code.
1869 * @param {string} new_backend_url
1871 var switch_backend = function(new_backend_url) {
1872 // Stop looking at historic data.
1873 current_display_line = null;
1874 current_display_move = null;
1875 displayed_analysis_data = null;
1876 if (current_historic_xhr) {
1877 current_historic_xhr.abort();
1880 // If we already have a backend response going, abort it.
1881 if (current_analysis_xhr) {
1882 current_analysis_xhr.abort();
1884 if (current_hash_xhr) {
1885 current_hash_xhr.abort();
1888 // Otherwise, we should have a timer going to start a new one.
1890 if (current_analysis_request_timer) {
1891 clearTimeout(current_analysis_request_timer);
1892 current_analysis_request_timer = null;
1894 if (current_hash_display_timer) {
1895 clearTimeout(current_hash_display_timer);
1896 current_hash_display_timer = null;
1899 // Request an immediate fetch with the new backend.
1900 backend_url = new_backend_url;
1901 current_analysis_data = null;
1905 window['switch_backend'] = switch_backend;
1907 var init = function() {
1908 unique = get_unique();
1910 // Load settings from HTML5 local storage if available.
1911 if (supports_html5_storage() && localStorage['enable_sound']) {
1912 set_sound(parseInt(localStorage['enable_sound']));
1916 if (supports_html5_storage() && localStorage['sort_refutation_lines_by_score']) {
1917 sort_refutation_lines_by_score = parseInt(localStorage['sort_refutation_lines_by_score']);
1919 sort_refutation_lines_by_score = true;
1923 board = new window.ChessBoard('board', {
1924 onMoveEnd: function() { board_is_animating = false; },
1927 onDragStart: onDragStart,
1929 onSnapEnd: onSnapEnd
1931 $("#board").on('mousedown', '.square-55d63', mousedownSquare);
1932 $("#board").on('mouseup', '.square-55d63', mouseupSquare);
1935 $(window).resize(function() {
1937 update_sparkline(displayed_analysis_data || current_analysis_data);
1938 update_board_highlight();
1941 $(window).keyup(function(event) {
1942 if (event.which == 39) {
1944 } else if (event.which == 37) {
1948 window.addEventListener('hashchange', possibly_switch_game_from_hash, false);
1950 $(document).ready(init);