Fix a display bug on empty PV.

[remoteglot] / www / js / remoteglot.js

diff --git a/www/js/remoteglot.js b/www/js/remoteglot.js
index 4c79edfc20b43a4a8e6b32d85e26c35f4ce120de..f88e1e0dabaa6fbbdbe0bae0fee9ea6c39fddd85 100644 (file)
--- a/www/js/remoteglot.js
+++ b/www/js/remoteglot.js
@@ -1,23 +1,103 @@
 (function() {
 
 (function() {
 

+/** @type {window.ChessBoard} @private */

 var board = null;
 var board = null;

+
+/** @type {window.ChessBoard} @private */

 var hiddenboard = null;
 var hiddenboard = null;

+
+/** @type {Array.<{
+ *      from_col: number,
+ *      from_row: number,
+ *      to_col: number,
+ *      to_row: number,
+ *      line_width: number,
+ *      arrow_size: number,
+ *      fg_color: string
+ * }>}
+ * @private
+ */

 var arrows = [];
 var arrows = [];

+
+/** @type {Array.<Array.<boolean>>} */

 var occupied_by_arrows = [];
 var occupied_by_arrows = [];

+

 var refutation_lines = [];
 var refutation_lines = [];

+
+/** @type {!number} @private */

 var move_num = 1;
 var move_num = 1;

+
+/** @type {!string} @private */

 var toplay = 'W';
 var toplay = 'W';

+
+/** @type {number} @private */

 var ims = 0;
 var ims = 0;

-var sort_refutation_lines_by_score = 0;
+
+/** @type {boolean} @private */
+var sort_refutation_lines_by_score = true;
+
+/** @type {boolean} @private */
+var truncate_display_history = true;
+
+/** @type {!string|undefined} @private */

 var highlight_from = undefined;
 var highlight_from = undefined;

+
+/** @type {!string|undefined} @private */

 var highlight_to = undefined;
 var highlight_to = undefined;

-var unique = Math.random();

 
 

+/** @type {?jQuery} @private */
+var highlighted_move = null;
+
+/** @type {?number} @private */
+var unique = null;
+
+/** The current position on the board, represented as a FEN string.
+ * @type {?string}
+ * @private
+ */

 var fen = null;
 var fen = null;

+
+/** @typedef {{
+ *    start_fen: string,
+ *    uci_pv: Array.<string>,
+ *    pretty_pv: Array.<string>,
+ *    line_num: number
+ * }} DisplayLine
+ */
+
+/** @type {Array.<DisplayLine>}
+ * @private
+ */

 var display_lines = [];
 var display_lines = [];

+
+/** @type {?DisplayLine} @private */

 var current_display_line = null;
 var current_display_line = null;

+
+/** @type {?number} @private */

 var current_display_move = null;
 
 var current_display_move = null;
 

+var supports_html5_storage = function() {
+       try {
+               return 'localStorage' in window && window['localStorage'] !== null;
+       } catch (e) {
+               return false;
+       }
+}
+
+// Make the unique token persistent so people refreshing the page won't count twice.
+// Of course, you can never fully protect against people deliberately wanting to spam.
+var get_unique = function() {
+       var use_local_storage = supports_html5_storage();
+       if (use_local_storage && localStorage['unique']) {
+               return localStorage['unique'];
+       }
+       var unique = Math.random();
+       if (use_local_storage) {
+               localStorage['unique'] = unique;
+       }
+       return unique;
+}
+

 var request_update = function() {
        $.ajax({
                url: "http://analysis.sesse.net/analysis.pl?ims=" + ims + "&unique=" + unique
 var request_update = function() {
        $.ajax({
                url: "http://analysis.sesse.net/analysis.pl?ims=" + ims + "&unique=" + unique


@@ -53,6 +133,9 @@ var redraw_arrows = function() {
        }
 }
 
        }
 }
 

+/** @param {!number} x
+ * @return {!number}
+ */

 var sign = function(x) {
        if (x > 0) {
                return 1;
 var sign = function(x) {
        if (x > 0) {
                return 1;


@@ -63,7 +146,11 @@ var sign = function(x) {
        }
 }
 
        }
 }
 

-// See if drawing this arrow on the board would cause unduly amount of confusion.
+/** See if drawing this arrow on the board would cause unduly amount of confusion.
+ * @param {!string} from The square the arrow is from (e.g. e4).
+ * @param {!string} to The square the arrow is to (e.g. e4).
+ * @return {boolean}
+ */

 var interfering_arrow = function(from, to) {
        var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
        var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);
 var interfering_arrow = function(from, to) {
        var from_col = from.charCodeAt(0) - "a1".charCodeAt(0);
        var from_row = from.charCodeAt(1) - "a1".charCodeAt(1);


@@ -95,6 +182,16 @@ var interfering_arrow = function(from, to) {
        return false;
 }
 
        return false;
 }
 

+/** Find a point along the coordinate system given by the given line,
+ * <t> units forward from the start of the line, <u> units to the right of it.
+ * @param {!number} x1
+ * @param {!number} x2
+ * @param {!number} y1
+ * @param {!number} y2
+ * @param {!number} t
+ * @param {!number} u
+ * @return {!string} The point in "x y" form, suitable for SVG paths.
+ */

 var point_from_start = function(x1, y1, x2, y2, t, u) {
        var dx = x2 - x1;
        var dy = y2 - y1;
 var point_from_start = function(x1, y1, x2, y2, t, u) {
        var dx = x2 - x1;
        var dy = y2 - y1;


@@ -108,6 +205,16 @@ var point_from_start = function(x1, y1, x2, y2, t, u) {
        return x + " " + y;
 }
 
        return x + " " + y;
 }
 

+/** Find a point along the coordinate system given by the given line,
+ * <t> units forward from the end of the line, <u> units to the right of it.
+ * @param {!number} x1
+ * @param {!number} x2
+ * @param {!number} y1
+ * @param {!number} y2
+ * @param {!number} t
+ * @param {!number} u
+ * @return {!string} The point in "x y" form, suitable for SVG paths.
+ */

 var point_from_end = function(x1, y1, x2, y2, t, u) {
        var dx = x2 - x1;
        var dy = y2 - y1;
 var point_from_end = function(x1, y1, x2, y2, t, u) {
        var dx = x2 - x1;
        var dy = y2 - y1;


@@ -145,8 +252,8 @@ var position_arrow = function(arrow) {
        var SVG_NS = "http://www.w3.org/2000/svg";
        var XHTML_NS = "http://www.w3.org/1999/xhtml";
        var svg = document.createElementNS(SVG_NS, "svg");
        var SVG_NS = "http://www.w3.org/2000/svg";
        var XHTML_NS = "http://www.w3.org/1999/xhtml";
        var svg = document.createElementNS(SVG_NS, "svg");

-       svg.setAttribute("width", $("#board").width());
-       svg.setAttribute("height", $("#board").height());
+       svg.setAttribute("width", /** @type{number} */ ($("#board").width()));
+       svg.setAttribute("height", /** @type{number} */ ($("#board").height()));

        svg.setAttribute("style", "position: absolute");
        svg.setAttribute("position", "absolute");
        svg.setAttribute("version", "1.1");
        svg.setAttribute("style", "position: absolute");
        svg.setAttribute("position", "absolute");
        svg.setAttribute("version", "1.1");


@@ -186,7 +293,7 @@ var position_arrow = function(arrow) {
        head.setAttribute("xmlns", XHTML_NS);
        head.setAttribute("stroke", "#000");
        head.setAttribute("stroke-width", "1");
        head.setAttribute("xmlns", XHTML_NS);
        head.setAttribute("stroke", "#000");
        head.setAttribute("stroke-width", "1");

-       head.setAttribute("fill", "#f66");
+       head.setAttribute("fill", arrow.fg_color);

        svg.appendChild(head);
 
        $(svg).css({ top: pos.top, left: pos.left });
        svg.appendChild(head);
 
        $(svg).css({ top: pos.top, left: pos.left });


@@ -194,6 +301,13 @@ var position_arrow = function(arrow) {
        arrow.svg = svg;
 }
 
        arrow.svg = svg;
 }
 

+/**
+ * @param {!string} from_square
+ * @param {!string} to_square
+ * @param {!string} fg_color
+ * @param {number} line_width
+ * @param {number} arrow_size
+ */

 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
        var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
        var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);
 var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_size) {
        var from_col = from_square.charCodeAt(0) - "a1".charCodeAt(0);
        var from_row = from_square.charCodeAt(1) - "a1".charCodeAt(1);


@@ -229,8 +343,16 @@ var compare_by_score = function(refutation_lines, a, b) {
        return sa - sb;
 }
 
        return sa - sb;
 }
 

-// Fake multi-PV using the refutation lines. Find all “relevant” moves,
-// sorted by quality, descending.
+/**
+ * Fake multi-PV using the refutation lines. Find all “relevant” moves,
+ * sorted by quality, descending.
+ *
+ * @param {!Object} data
+ * @param {number} margin The maximum number of centipawns worse than the
+ *     best move can be and still be included.
+ * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
+ *     moves, in score order.
+ */

 var find_nonstupid_moves = function(data, margin) {
        // First of all, if there are any moves that are more than 0.5 ahead of
        // the primary move, the refutation lines are probably bunk, so just
 var find_nonstupid_moves = function(data, margin) {
        // First of all, if there are any moves that are more than 0.5 ahead of
        // the primary move, the refutation lines are probably bunk, so just


@@ -269,31 +391,67 @@ var find_nonstupid_moves = function(data, margin) {
        return moves;
 }
 
        return moves;
 }
 

+/**
+ * @param {number} x
+ * @return {!string}
+ */

 var thousands = function(x) {
        return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 }
 
 var thousands = function(x) {
        return String(x).split('').reverse().join('').replace(/(\d{3}\B)/g, '$1,').split('').reverse().join('');
 }
 

-var print_pv = function(fen, uci_pv, pretty_pv, move_num, toplay, opt_limit) {
+/**
+ * @param {!string} fen
+ * @param {Array.<string>} uci_pv
+ * @param {Array.<string>} pretty_pv
+ * @param {number} move_num
+ * @param {!string} toplay
+ * @param {number=} opt_limit
+ * @param {boolean=} opt_showlast
+ */
+var add_pv = function(fen, uci_pv, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {

        display_lines.push({
                start_fen: fen,
                uci_pv: uci_pv,
        display_lines.push({
                start_fen: fen,
                uci_pv: uci_pv,

-               pretty_pv: pretty_pv 
+               pretty_pv: pretty_pv,
+               line_number: display_lines.length

        });
        });

+       return print_pv(display_lines.length - 1, pretty_pv, move_num, toplay, opt_limit, opt_showlast);
+}

 
 

+/**
+ * @param {number} line_num
+ * @param {Array.<string>} pretty_pv
+ * @param {number} move_num
+ * @param {!string} toplay
+ * @param {number=} opt_limit
+ * @param {boolean=} opt_showlast
+ */
+var print_pv = function(line_num, pretty_pv, move_num, toplay, opt_limit, opt_showlast) {

        var pv = '';
        var i = 0;
        var pv = '';
        var i = 0;

-       if (toplay == 'B') {
-               var move = "<a class=\"move\" href=\"javascript:show_line(" + (display_lines.length - 1) + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";
+       if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
+               // Truncate the PV at the beginning (instead of at the end).
+               // We assume here that toplay is 'W'. We also assume that if
+               // opt_showlast is set, then it is the history, and thus,
+               // the UI should be to expand the history.
+               pv = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
+               i = pretty_pv.length - opt_limit;
+               if (i % 2 == 1) {
+                       ++i;
+               }
+               move_num += i / 2;
+       } else if (toplay == 'B' && pretty_pv.length > 0) {
+               var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pretty_pv[0] + "</a>";

                pv = move_num + '. … ' + move;
                toplay = 'W';
                ++i;
                ++move_num;
        }
        for ( ; i < pretty_pv.length; ++i) {
                pv = move_num + '. … ' + move;
                toplay = 'W';
                ++i;
                ++move_num;
        }
        for ( ; i < pretty_pv.length; ++i) {

-               var move = "<a class=\"move\" href=\"javascript:show_line(" + (display_lines.length - 1) + ", " + i + ");\">" + pretty_pv[i] + "</a>";
+               var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";

 
                if (toplay == 'W') {
 
                if (toplay == 'W') {

-                       if (i > opt_limit) {
+                       if (i > opt_limit && !opt_showlast) {

                                return pv + ' (…)';
                        }
                        if (pv != '') {
                                return pv + ' (…)';
                        }
                        if (pv != '') {


@@ -310,7 +468,7 @@ var print_pv = function(fen, uci_pv, pretty_pv, move_num, toplay, opt_limit) {
        return pv;
 }
 
        return pv;
 }
 

-var update_highlight = function()  {
+var update_highlight = function() {

        $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
        if (current_display_line === null && highlight_from !== undefined && highlight_to !== undefined) {
                $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');
        $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
        if (current_display_line === null && highlight_from !== undefined && highlight_to !== undefined) {
                $("#board").find('.square-' + highlight_from).addClass('nonuglyhighlight');


@@ -318,9 +476,33 @@ var update_highlight = function()  {
        }
 }
 
        }
 }
 

+var update_history = function() {
+       if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
+               $("#history").html("No history");
+       } else if (truncate_display_history) {
+               $("#history").html(print_pv(0, display_lines[0].pretty_pv, 1, 'W', 8, true));
+       } else {
+               $("#history").html(
+                       '(<a class="move" href="javascript:collapse_history(true)">collapse</a>) ' +
+                       print_pv(0, display_lines[0].pretty_pv, 1, 'W'));
+       }
+}
+
+/**
+ * @param {!boolean} truncate_history
+ */
+var collapse_history = function(truncate_history) {
+       truncate_display_history = truncate_history;
+       update_history();
+}
+window['collapse_history'] = collapse_history;
+

 var update_refutation_lines = function() {
 var update_refutation_lines = function() {

-       if (display_lines.length > 1) {
-               display_lines = [ display_lines[0] ];
+       if (fen === null) {
+               return;
+       }
+       if (display_lines.length > 2) {
+               display_lines = [ display_lines[0], display_lines[1] ];

        }
 
        var tbl = $("#refutationlines");
        }
 
        var tbl = $("#refutationlines");


@@ -360,26 +542,36 @@ var update_refutation_lines = function() {
                var pv_td = document.createElement("td");
                tr.appendChild(pv_td);
                $(pv_td).addClass("pv");
                var pv_td = document.createElement("td");
                tr.appendChild(pv_td);
                $(pv_td).addClass("pv");

-               $(pv_td).html(print_pv(fen, line['pv_uci'], line['pv_pretty'], move_num, toplay, 10));
+               $(pv_td).html(add_pv(fen, line['pv_uci'], line['pv_pretty'], move_num, toplay, 10));

 
                tbl.append(tr);
        }
 
        // Make one of the links clickable and the other nonclickable.
        if (sort_refutation_lines_by_score) {
 
                tbl.append(tr);
        }
 
        // Make one of the links clickable and the other nonclickable.
        if (sort_refutation_lines_by_score) {

-               $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(0)\">Move</a>");
+               $("#sortbyscore0").html("<a href=\"javascript:resort_refutation_lines(false)\">Move</a>");

                $("#sortbyscore1").html("<strong>Score</strong>");
        } else {
                $("#sortbyscore0").html("<strong>Move</strong>");
                $("#sortbyscore1").html("<strong>Score</strong>");
        } else {
                $("#sortbyscore0").html("<strong>Move</strong>");

-               $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(1)\">Score</a>");
+               $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");

        }
 }
 
        }
 }
 

+/**
+ * @param {Object} data
+ * @param {number} num_viewers
+ */

 var update_board = function(data, num_viewers) {
        display_lines = [];
 
        // The headline.
 var update_board = function(data, num_viewers) {
        display_lines = [];
 
        // The headline.

-       var headline = 'Analysis';
+       var headline;
+       if (data['position']['player_w'] && data['position']['player_b']) {
+               headline = data['position']['player_w'] + '–' +
+                       data['position']['player_b'] + ', analysis';
+       } else {
+               headline = 'Analysis';
+       }

        if (data['position']['last_move'] !== 'none') {
                headline += ' after '
                if (data['position']['toplay'] == 'W') {
        if (data['position']['last_move'] !== 'none') {
                headline += ' after '
                if (data['position']['toplay'] == 'W') {


@@ -400,26 +592,40 @@ var update_board = function(data, num_viewers) {
                $("#numviewers").text(num_viewers + " current viewers");
        }
 
                $("#numviewers").text(num_viewers + " current viewers");
        }
 

+       // The engine id.
+       if (data['id'] && data['id']['name'] !== null) {
+               $("#engineid").text(data['id']['name']);
+       }
+

        // The score.
        if (data['score'] !== null) {
                $("#score").text(data['score']);
        }
        // The score.
        if (data['score'] !== null) {
                $("#score").text(data['score']);
        }

+       if (data['short_score'] !== undefined && data['short_score'] !== null) {
+               document.title = '(' + data['short_score'] + ') analysis.sesse.net';
+       } else {
+               document.title = 'analysis.sesse.net';
+       }

 
        // The search stats.
 
        // The search stats.

-       if (data['nodes'] && data['nps'] && data['depth']) {
+       if (data['tablebase'] == 1) {
+               $("#searchstats").text("Tablebase result");
+       } else if (data['nodes'] && data['nps'] && data['depth']) {

                var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
                if (data['seldepth']) {
                        stats += ' (' + data['seldepth'] + ' selective)';
                }
                if (data['tbhits'] && data['tbhits'] > 0) {
                        if (data['tbhits'] == 1) {
                var stats = thousands(data['nodes']) + ' nodes, ' + thousands(data['nps']) + ' nodes/sec, depth ' + data['depth'] + ' ply';
                if (data['seldepth']) {
                        stats += ' (' + data['seldepth'] + ' selective)';
                }
                if (data['tbhits'] && data['tbhits'] > 0) {
                        if (data['tbhits'] == 1) {

-                               stats += ', one Nalimov hit';
+                               stats += ', one Syzygy hit';

                        } else {
                        } else {

-                               stats += ', ' + data['tbhits'] + ' Nalimov hits';
+                               stats += ', ' + thousands(data['tbhits']) + ' Syzygy hits';

                        }
                }
 
                $("#searchstats").text(stats);
                        }
                }
 
                $("#searchstats").text(stats);

+       } else {
+               $("#searchstats").text("");

        }
 
        // Update the board itself.
        }
 
        // Update the board itself.


@@ -428,14 +634,22 @@ var update_board = function(data, num_viewers) {
 
        if (data['position']['last_move_uci']) {
                highlight_from = data['position']['last_move_uci'].substr(0, 2);
 
        if (data['position']['last_move_uci']) {
                highlight_from = data['position']['last_move_uci'].substr(0, 2);

-               highlight_to = data['position']['last_move_uci'].substr(2, 4);
+               highlight_to = data['position']['last_move_uci'].substr(2, 2);

        } else {
                highlight_from = highlight_to = undefined;
        }
        update_highlight();
 
        } else {
                highlight_from = highlight_to = undefined;
        }
        update_highlight();
 

+       // Print the history.
+       if (data['position']['history']) {
+               add_pv('start', data['position']['history'], data['position']['pretty_history'], 1, 'W', 8, true);
+       } else {
+               display_lines.push(null);
+       }
+       update_history();
+

        // Print the PV.
        // Print the PV.

-       $("#pv").html(print_pv(data['position']['fen'], data['pv_uci'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));
+       $("#pv").html(add_pv(data['position']['fen'], data['pv_uci'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay']));

 
        // Update the PV arrow.
        clear_arrows();
 
        // Update the PV arrow.
        clear_arrows();


@@ -444,7 +658,7 @@ var update_board = function(data, num_viewers) {
                for (var i = 0; i < data['pv_uci'].length; i += 2) {
                        var from = data['pv_uci'][i].substr(0, 2);
                        var to = data['pv_uci'][i].substr(2,4);
                for (var i = 0; i < data['pv_uci'].length; i += 2) {
                        var from = data['pv_uci'][i].substr(0, 2);
                        var to = data['pv_uci'][i].substr(2,4);

-                       if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 4)) ||
+                       if ((i >= 2 && from != data['pv_uci'][i - 2].substr(2, 2)) ||

                             interfering_arrow(from, to)) {
                                break;
                        }
                             interfering_arrow(from, to)) {
                                break;
                        }


@@ -454,7 +668,7 @@ var update_board = function(data, num_viewers) {
                var alt_moves = find_nonstupid_moves(data, 30);
                for (var i = 1; i < alt_moves.length && i < 3; ++i) {
                        create_arrow(alt_moves[i].substr(0, 2),
                var alt_moves = find_nonstupid_moves(data, 30);
                for (var i = 1; i < alt_moves.length && i < 3; ++i) {
                        create_arrow(alt_moves[i].substr(0, 2),

-                                    alt_moves[i].substr(2, 4), '#f66', 1, 10);
+                                    alt_moves[i].substr(2, 2), '#f66', 1, 10);

                }
        }
 
                }
        }
 


@@ -485,7 +699,7 @@ var update_board = function(data, num_viewers) {
 
                if (nonstupid_moves.length > 0 && response !== undefined) {
                        create_arrow(response.substr(0, 2),
 
                if (nonstupid_moves.length > 0 && response !== undefined) {
                        create_arrow(response.substr(0, 2),

-                                    response.substr(2, 4), '#66f', 6, 20);
+                                    response.substr(2, 2), '#66f', 6, 20);

                }
        }
 
                }
        }
 


@@ -500,12 +714,28 @@ var update_board = function(data, num_viewers) {
        setTimeout(function() { request_update(); }, 100);
 }
 
        setTimeout(function() { request_update(); }, 100);
 }
 

+/**
+ * @param {boolean} sort_by_score
+ */

 var resort_refutation_lines = function(sort_by_score) {
        sort_refutation_lines_by_score = sort_by_score;
        update_refutation_lines();
 }
 window['resort_refutation_lines'] = resort_refutation_lines;
 
 var resort_refutation_lines = function(sort_by_score) {
        sort_refutation_lines_by_score = sort_by_score;
        update_refutation_lines();
 }
 window['resort_refutation_lines'] = resort_refutation_lines;
 

+/**
+ * @param {boolean} truncate_history
+ */
+var set_truncate_history = function(truncate_history) {
+       truncate_display_history = truncate_history;
+       update_refutation_lines();
+}
+window['set_truncate_history'] = set_truncate_history;
+
+/**
+ * @param {number} line_num
+ * @param {number} move_num
+ */

 var show_line = function(line_num, move_num) {
        if (line_num == -1) {
                current_display_line = null;
 var show_line = function(line_num, move_num) {
        if (line_num == -1) {
                current_display_line = null;


@@ -521,18 +751,25 @@ var show_line = function(line_num, move_num) {
 window['show_line'] = show_line;
 
 var prev_move = function() {
 window['show_line'] = show_line;
 
 var prev_move = function() {

-       --current_display_move;
+       if (current_display_move > -1) {
+               --current_display_move;
+       }

        update_displayed_line();
 }
 window['prev_move'] = prev_move;
 
 var next_move = function() {
        update_displayed_line();
 }
 window['prev_move'] = prev_move;
 
 var next_move = function() {

-       ++current_display_move;
+       if (current_display_line && current_display_move < current_display_line.pretty_pv.length - 1) {
+               ++current_display_move;
+       }

        update_displayed_line();
 }
        update_displayed_line();
 }

-window['next_move'] = prev_move;
+window['next_move'] = next_move;

 
 var update_displayed_line = function() {
 
 var update_displayed_line = function() {

+       if (highlighted_move !== null) {
+               highlighted_move.removeClass('highlight'); 
+       }

        if (current_display_line === null) {
                $("#linenav").hide();
                $("#linemsg").show();
        if (current_display_line === null) {
                $("#linenav").hide();
                $("#linemsg").show();


@@ -543,7 +780,7 @@ var update_displayed_line = function() {
        $("#linenav").show();
        $("#linemsg").hide();
 
        $("#linenav").show();
        $("#linemsg").hide();
 

-       if (current_display_move == 0) {
+       if (current_display_move <= 0) {

                $("#prevmove").html("Previous");
        } else {
                $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
                $("#prevmove").html("Previous");
        } else {
                $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");


@@ -556,14 +793,55 @@ var update_displayed_line = function() {
 
        hiddenboard.position(current_display_line.start_fen, false);
        for (var i = 0; i <= current_display_move; ++i) {
 
        hiddenboard.position(current_display_line.start_fen, false);
        for (var i = 0; i <= current_display_move; ++i) {

+               var pos = hiddenboard.position();

                var move = current_display_line.uci_pv[i];
                var move = current_display_line.uci_pv[i];

-               move = move.substr(0, 2) + "-" + move.substr(2, 4);
+               var source = move.substr(0, 2);
+               var target = move.substr(2, 2);
+               var promo = move.substr(4, 1);
+
+               // Check if we need to do en passant.
+               var piece = pos[source];
+               if (piece == "wP" || piece == "bP") {
+                       if (source.substr(0, 1) != target.substr(0, 1) &&
+                           pos[target] === undefined) {
+                               var ep_square = target.substr(0, 1) + source.substr(1, 1);
+                               delete pos[ep_square];
+                               hiddenboard.position(pos, false);
+                       }
+               }
+
+               move = source + "-" + target;

                hiddenboard.move(move, false);
                hiddenboard.move(move, false);

+               pos = hiddenboard.position();
+
+               // Do promotion if needed.
+               if (promo != "") {
+                       pos[target] = pos[target].substr(0, 1) + promo.toUpperCase();
+                       hiddenboard.position(pos, false);
+               }
+
+               // chessboard.js does not automatically move the rook on castling
+               // (issue #51; marked as won't fix), so update it ourselves.
+               if (move == "e1-g1" && hiddenboard.position().g1 == "wK") {  // white O-O
+                       hiddenboard.move("h1-f1", false);
+               } else if (move == "e1-c1" && hiddenboard.position().c1 == "wK") {  // white O-O-O
+                       hiddenboard.move("a1-d1", false);
+               } else if (move == "e8-g8" && hiddenboard.position().g8 == "bK") {  // black O-O
+                       hiddenboard.move("h8-f8", false);
+               } else if (move == "e8-c8" && hiddenboard.position().c8 == "bK") {  // black O-O-O
+                       hiddenboard.move("a8-d8", false);
+               }

        }
        }

+
+       highlighted_move = $("#automove" + current_display_line.line_number + "-" + current_display_move);
+       highlighted_move.addClass('highlight'); 
+

        board.position(hiddenboard.position());
 }
 
 var init = function() {
        board.position(hiddenboard.position());
 }
 
 var init = function() {

+       unique = get_unique();
+

        // Create board.
        board = new window.ChessBoard('board', 'start');
        hiddenboard = new window.ChessBoard('hiddenboard', 'start');
        // Create board.
        board = new window.ChessBoard('board', 'start');
        hiddenboard = new window.ChessBoard('hiddenboard', 'start');


@@ -574,6 +852,13 @@ var init = function() {
                update_highlight();
                redraw_arrows();
        });
                update_highlight();
                redraw_arrows();
        });

+       $(window).keyup(function(event) {
+               if (event.which == 39) {
+                       next_move();
+               } else if (event.which == 37) {
+                       prev_move();
+               }
+       });

 };
 $(document).ready(init);
 
 };
 $(document).ready(init);