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