Support starting from a nonstandard position.
[remoteglot] / www / js / remoteglot.js
index a49fa8d..ff566ab 100644 (file)
@@ -7,7 +7,7 @@
  * @type {Number}
  * @const
  * @private */
-var SCRIPT_VERSION = 2016032202;
+var SCRIPT_VERSION = 2016113002;
 
 /**
  * The current backend URL.
@@ -47,9 +47,10 @@ var displayed_analysis_data = null;
  * @type {?Array.<{
  *      name: string,
  *      url: string,
+ *      hashurl: string,
  *      id: string,
- *      score: =Object,
- *      result: =string,
+ *      score: Object=,
+ *      result: string=,
  * }>}
  * @private
  */
@@ -93,9 +94,6 @@ var toplay = 'W';
 /** @type {number} @private */
 var ims = 0;
 
-/** @type {boolean} @private */
-var sort_refutation_lines_by_score = true;
-
 /** @type {boolean} @private */
 var truncate_display_history = true;
 
@@ -157,7 +155,7 @@ var display_fen = null;
 
 /** @typedef {{
  *    start_fen: string,
- *    pretty_pv: Array.<string>,
+ *    pv: Array.<string>,
  *    move_num: number,
  *    toplay: string,
  *    scores: Array<{first_move: number, score: Object}>,
@@ -276,13 +274,31 @@ var request_update = function() {
                        location.reload(true);
                }
 
-               possibly_play_sound(current_analysis_data, new_data);
-               current_analysis_data = new_data;
-               update_board();
-               update_num_viewers(num_viewers);
+               // Verify that the PV makes sense.
+               var valid = true;
+               if (new_data['pv']) {
+                       var hiddenboard = new Chess(new_data['position']['fen']);
+                       for (var i = 0; i < new_data['pv'].length; ++i) {
+                               if (hiddenboard.move(new_data['pv'][i]) === null) {
+                                       valid = false;
+                                       break;
+                               }
+                       }
+               }
+
+               var timeout = 100;
+               if (valid) {
+                       possibly_play_sound(current_analysis_data, new_data);
+                       current_analysis_data = new_data;
+                       update_board();
+                       update_num_viewers(num_viewers);
+               } else {
+                       console.log("Received invalid update, waiting five seconds and trying again.");
+                       location.reload(true);
+               }
 
                // Next update.
-               current_analysis_request_timer = setTimeout(function() { request_update(); }, 100);
+               current_analysis_request_timer = setTimeout(function() { request_update(); }, timeout);
        }).fail(function(jqXHR, textStatus, errorThrown) {
                if (textStatus === "abort") {
                        // Aborted because we are switching backends. Abandon and don't retry,
@@ -550,15 +566,6 @@ var create_arrow = function(from_square, to_square, fg_color, line_width, arrow_
        arrows.push(arrow);
 }
 
-// Note: invert is ignored.
-var compare_by_sort_key = function(refutation_lines, invert, a, b) {
-       var ska = refutation_lines[a]['sort_key'];
-       var skb = refutation_lines[b]['sort_key'];
-       if (ska < skb) return -1;
-       if (ska > skb) return 1;
-       return 0;
-};
-
 var compare_by_score = function(refutation_lines, invert, a, b) {
        var sa = compute_score_sort_key(refutation_lines[b]['score'], refutation_lines[b]['depth'], invert);
        var sb = compute_score_sort_key(refutation_lines[a]['score'], refutation_lines[a]['depth'], invert);
@@ -572,8 +579,8 @@ var compare_by_score = function(refutation_lines, invert, a, b) {
  * @param {!Object} data
  * @param {number} margin The maximum number of centipawns worse than the
  *     best move can be and still be included.
- * @param {boolean} margin Whether black is to play.
- * @return {Array.<string>} The UCI representation (e.g. e1g1) of all
+ * @param {boolean} invert Whether black is to play.
+ * @return {Array.<string>} The FEN representation (e.g. Ne4) of all
  *     moves, in score order.
  */
 var find_nonstupid_moves = function(data, margin, invert) {
@@ -584,8 +591,8 @@ var find_nonstupid_moves = function(data, margin, invert) {
        var pv_score = undefined;
        for (var move in data['refutation_lines']) {
                var line = data['refutation_lines'][move];
-               var score = compute_score_sort_key(line['score'], line['depth'], invert);
-               if (move == data['pv_uci'][0]) {
+               var score = compute_score_sort_key(line['score'], line['depth'], invert, false);
+               if (move == data['pv'][0]) {
                        pv_score = score;
                }
                if (best_score === undefined || score > best_score) {
@@ -606,12 +613,12 @@ var find_nonstupid_moves = function(data, margin, invert) {
        for (var move in data['refutation_lines']) {
                var line = data['refutation_lines'][move];
                var score = compute_score_sort_key(line['score'], line['depth'], invert);
-               if (move != data['pv_uci'][0] && best_score - score <= margin) {
+               if (move != data['pv'][0] && best_score - score <= margin) {
                        moves.push(move);
                }
        }
        moves = moves.sort(function(a, b) { return compare_by_score(data['refutation_lines'], data['position']['toplay'] === 'B', a, b) });
-       moves.unshift(data['pv_uci'][0]);
+       moves.unshift(data['pv'][0]);
 
        return moves;
 }
@@ -626,7 +633,7 @@ var thousands = function(x) {
 
 /**
  * @param {!string} start_fen
- * @param {Array.<string>} pretty_pv
+ * @param {Array.<string>} pv
  * @param {number} move_num
  * @param {!string} toplay
  * @param {Array<{ first_move: integer, score: Object }>} scores
@@ -634,10 +641,10 @@ var thousands = function(x) {
  * @param {number=} opt_limit
  * @param {boolean=} opt_showlast
  */
-var add_pv = function(start_fen, pretty_pv, move_num, toplay, scores, start_display_move_num, opt_limit, opt_showlast) {
+var add_pv = function(start_fen, pv, move_num, toplay, scores, start_display_move_num, opt_limit, opt_showlast) {
        display_lines.push({
                start_fen: start_fen,
-               pretty_pv: pretty_pv,
+               pv: pv,
                move_num: parseInt(move_num),
                toplay: toplay,
                scores: scores,
@@ -653,14 +660,14 @@ var add_pv = function(start_fen, pretty_pv, move_num, toplay, scores, start_disp
  */
 var print_pv = function(line_num, opt_limit, opt_showlast) {
        var display_line = display_lines[line_num];
-       var pretty_pv = display_line.pretty_pv;
+       var pv = display_line.pv;
        var move_num = display_line.move_num;
        var toplay = display_line.toplay;
 
        // Truncate PV at the start if needed.
        var start_display_move_num = display_line.start_display_move_num;
        if (start_display_move_num > 0) {
-               pretty_pv = pretty_pv.slice(start_display_move_num);
+               pv = pv.slice(start_display_move_num);
                var to_add = start_display_move_num;
                if (toplay === 'B') {
                        ++move_num;
@@ -674,45 +681,45 @@ var print_pv = function(line_num, opt_limit, opt_showlast) {
                move_num += to_add / 2;
        }
 
-       var pv = '';
+       var ret = '';
        var i = 0;
-       if (opt_limit && opt_showlast && pretty_pv.length > opt_limit) {
+       if (opt_limit && opt_showlast && 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;
+               ret = '(<a class="move" href="javascript:collapse_history(false)">…</a>) ';
+               i = 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;
+       } else if (toplay == 'B' && pv.length > 0) {
+               var move = "<a class=\"move\" id=\"automove" + line_num + "-0\" href=\"javascript:show_line(" + line_num + ", " + 0 + ");\">" + pv[0] + "</a>";
+               ret = move_num + '. … ' + move;
                toplay = 'W';
                ++i;
                ++move_num;
        }
-       for ( ; i < pretty_pv.length; ++i) {
-               var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pretty_pv[i] + "</a>";
+       for ( ; i < pv.length; ++i) {
+               var move = "<a class=\"move\" id=\"automove" + line_num + "-" + i + "\" href=\"javascript:show_line(" + line_num + ", " + i + ");\">" + pv[i] + "</a>";
 
                if (toplay == 'W') {
                        if (i > opt_limit && !opt_showlast) {
-                               return pv + ' (…)';
+                               return ret + ' (…)';
                        }
-                       if (pv != '') {
-                               pv += ' ';
+                       if (ret != '') {
+                               ret += ' ';
                        }
-                       pv += move_num + '. ' + move;
+                       ret += move_num + '. ' + move;
                        ++move_num;
                        toplay = 'B';
                } else {
-                       pv += ' ' + move;
+                       ret += ' ' + move;
                        toplay = 'W';
                }
        }
-       return pv;
+       return ret;
 }
 
 /** Update the highlighted to/from squares on the board.
@@ -728,7 +735,7 @@ var update_board_highlight = function() {
 }
 
 var update_history = function() {
-       if (display_lines[0] === null || display_lines[0].pretty_pv.length == 0) {
+       if (display_lines[0] === null || display_lines[0].pv.length == 0) {
                $("#history").html("No history");
        } else if (truncate_display_history) {
                $("#history").html(print_pv(0, 8, true));
@@ -768,7 +775,7 @@ var update_refutation_lines = function() {
        var base_scores = display_lines[1].scores;
        var start_display_move_num = 0;
        if (hash_refutation_lines) {
-               base_line = current_display_line.pretty_pv.slice(0, current_display_move + 1);
+               base_line = current_display_line.pv.slice(0, current_display_move + 1);
                base_scores = current_display_line.scores;
                start_display_move_num = base_line.length;
        }
@@ -782,8 +789,7 @@ var update_refutation_lines = function() {
        if (current_display_line && current_display_move % 2 == 0) {
                invert = !invert;
        }
-       var compare = sort_refutation_lines_by_score ? compare_by_score : compare_by_sort_key;
-       moves = moves.sort(function(a, b) { return compare(refutation_lines, invert, a, b) });
+       moves = moves.sort(function(a, b) { return compare_by_score(refutation_lines, invert, a, b) });
        for (var i = 0; i < moves.length; ++i) {
                var line = refutation_lines[moves[i]];
 
@@ -795,9 +801,9 @@ var update_refutation_lines = function() {
 
                var scores = base_scores.concat([{ first_move: start_display_move_num, score: line['score'] }]);
 
-               if (line['pv_pretty'].length == 0) {
+               if (line['pv'].length == 0) {
                        // Not found, so just make a one-move PV.
-                       var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
+                       var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['move'] + "</a>";
                        $(move_td).html(move);
                        var score_td = document.createElement("td");
 
@@ -813,13 +819,13 @@ var update_refutation_lines = function() {
                        var pv_td = document.createElement("td");
                        tr.appendChild(pv_td);
                        $(pv_td).addClass("pv");
-                       $(pv_td).html(add_pv(base_fen, base_line.concat([ line['pretty_move'] ]), move_num, toplay, scores, start_display_move_num));
+                       $(pv_td).html(add_pv(base_fen, base_line.concat([ line['move'] ]), move_num, toplay, scores, start_display_move_num));
 
                        tbl.append(tr);
                        continue;
                }
 
-               var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['pretty_move'] + "</a>";
+               var move = "<a class=\"move\" href=\"javascript:show_line(" + display_lines.length + ", " + 0 + ");\">" + line['move'] + "</a>";
                $(move_td).html(move);
 
                var score_td = document.createElement("td");
@@ -839,20 +845,11 @@ var update_refutation_lines = function() {
                var pv_td = document.createElement("td");
                tr.appendChild(pv_td);
                $(pv_td).addClass("pv");
-               $(pv_td).html(add_pv(base_fen, base_line.concat(line['pv_pretty']), move_num, toplay, scores, start_display_move_num, 10));
+               $(pv_td).html(add_pv(base_fen, base_line.concat(line['pv']), move_num, toplay, scores, start_display_move_num, 10));
 
                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(false)\">Move</a>");
-               $("#sortbyscore1").html("<strong>Score</strong>");
-       } else {
-               $("#sortbyscore0").html("<strong>Move</strong>");
-               $("#sortbyscore1").html("<a href=\"javascript:resort_refutation_lines(true)\">Score</a>");
-       }
-
        // Update the move highlight, as we've rewritten all the HTML.
        update_move_highlight();
 }
@@ -867,7 +864,7 @@ var update_refutation_lines = function() {
  */
 var chess_from = function(fen, moves, last_move) {
        var hiddenboard = new Chess();
-       if (fen !== null) {
+       if (fen !== null && fen !== undefined) {
                hiddenboard.load(fen);
        }
        for (var i = 0; i <= last_move; ++i) {
@@ -941,7 +938,7 @@ var possibly_switch_game_from_hash = function() {
        for (var i = 0; i < current_games.length; ++i) {
                if (current_games[i]['id'] === hash) {
                        if (backend_url !== current_games[i]['url']) {
-                               switch_backend(current_games[i]['url'], current_games[i]['hashurl']);
+                               switch_backend(current_games[i]);
                        }
                        return;
                }
@@ -959,8 +956,9 @@ var update_board = function() {
        // Print the history. This is pretty much the only thing that's
        // unconditionally taken from current_data (we're not interested in
        // historic history).
-       if (current_data['position']['pretty_history']) {
-               add_pv('start', current_data['position']['pretty_history'], 1, 'W', null, 0, 8, true);
+       if (current_data['position']['history']) {
+               var start = (current_data['position'] && current_data['position']['start_fen']) ? current_data['position']['start_fen'] : 'start';
+               add_pv(start, current_data['position']['history'], 1, 'W', null, 0, 8, true);
        } else {
                display_lines.push(null);
        }
@@ -1034,15 +1032,27 @@ var update_board = function() {
        if (displayed_analysis_data) {
                // Displaying some non-current position, pick out the last move
                // from the history. This will work even if the fetch failed.
-               last_move = format_halfmove_with_number(
-                       current_display_line.pretty_pv[current_display_move],
-                       current_display_move + 1);
-               headline += ' after ' + last_move;
+               if (current_display_move !== -1) {
+                       last_move = format_halfmove_with_number(
+                               current_display_line.pv[current_display_move],
+                               current_display_move);
+                       headline += ' after ' + last_move;
+               }
        } else if (data['position']['last_move'] !== 'none') {
+               // Find the previous move.
+               var previous_move_num, previous_toplay;
+               if (data['position']['toplay'] == 'B') {
+                       previous_move_num = data['position']['move_num'];
+                       previous_toplay = 'W';
+               } else {
+                       previous_move_num = data['position']['move_num'] - 1;
+                       previous_toplay = 'B';
+               }
+
                last_move = format_move_with_number(
                        data['position']['last_move'],
-                       data['position']['move_num'],
-                       data['position']['toplay'] == 'W');
+                       previous_move_num,
+                       previous_toplay == 'W');
                headline += ' after ' + last_move;
        } else {
                last_move = null;
@@ -1070,13 +1080,14 @@ var update_board = function() {
        if (data['position'] && data['position']['last_move_uci']) {
                highlight_from = data['position']['last_move_uci'].substr(0, 2);
                highlight_to = data['position']['last_move_uci'].substr(2, 2);
-       } else if (current_display_line_is_history && current_display_move >= 0) {
+       } else if (current_display_line_is_history && current_display_line && current_display_move >= 0) {
                // We don't have historic analysis for this position, but we
                // can reconstruct what the last move was by just replaying
                // from the start.
-               var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
+               var position = (data['position'] && data['position']['start_fen']) ? data['position']['start_fen'] : null;
+               var hiddenboard = chess_from(position, current_display_line.pv, current_display_move);
                var moves = hiddenboard.history({ verbose: true });
-               var last_move = moves.pop();
+               last_move = moves.pop();
                highlight_from = last_move.from;
                highlight_to = last_move.to;
        } else {
@@ -1153,48 +1164,63 @@ var update_board = function() {
        $("#pvtitle").text("PV:");
 
        var scores = [{ first_move: -1, score: data['score'] }];
-       $("#pv").html(add_pv(data['position']['fen'], data['pv_pretty'], data['position']['move_num'], data['position']['toplay'], scores, 0));
+       $("#pv").html(add_pv(data['position']['fen'], data['pv'], data['position']['move_num'], data['position']['toplay'], scores, 0));
 
        // Update the PV arrow.
        clear_arrows();
-       if (data['pv_uci'].length >= 1) {
+       if (data['pv'].length >= 1) {
+               var hiddenboard = new Chess(base_fen);
+
                // draw a continuation arrow as long as it's the same piece
-               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, 2)) ||
-                            interfering_arrow(from, to)) {
+               var last_to;
+               for (var i = 0; i < data['pv'].length; i += 2) {
+                       var move = hiddenboard.move(data['pv'][i]);
+                       if ((i >= 2 && move.from != last_to) ||
+                            interfering_arrow(move.from, move.to)) {
                                break;
                        }
-                       create_arrow(from, to, '#f66', 6, 20);
+                       create_arrow(move.from, move.to, '#f66', 6, 20);
+                       last_to = move.from;
+                       hiddenboard.move(data['pv'][i + 1]);  // To keep continuity.
                }
 
                var alt_moves = find_nonstupid_moves(data, 30, data['position']['toplay'] === 'B');
                for (var i = 1; i < alt_moves.length && i < 3; ++i) {
-                       create_arrow(alt_moves[i].substr(0, 2),
-                                    alt_moves[i].substr(2, 2), '#f66', 1, 10);
+                       hiddenboard = new Chess(base_fen);
+                       var move = hiddenboard.move(alt_moves[i]);
+                       if (move !== null) {
+                               create_arrow(move.from, move.to, '#f66', 1, 10);
+                       }
                }
        }
 
        // See if all semi-reasonable moves have only one possible response.
-       if (data['pv_uci'].length >= 2) {
+       if (data['pv'].length >= 2) {
                var nonstupid_moves = find_nonstupid_moves(data, 300, data['position']['toplay'] === 'B');
-               var response = data['pv_uci'][1];
+               var response;
+               {
+                       var hiddenboard = new Chess(base_fen);
+                       hiddenboard.move(data['pv'][0]);
+                       response = hiddenboard.move(data['pv'][1]);
+               }
                for (var i = 0; i < nonstupid_moves.length; ++i) {
-                       if (nonstupid_moves[i] == data['pv_uci'][0]) {
+                       if (nonstupid_moves[i] == data['pv'][0]) {
                                // ignore the PV move for refutation lines.
                                continue;
                        }
                        if (!data['refutation_lines'] ||
                            !data['refutation_lines'][nonstupid_moves[i]] ||
-                           !data['refutation_lines'][nonstupid_moves[i]]['pv_uci'] ||
-                           data['refutation_lines'][nonstupid_moves[i]]['pv_uci'].length < 1) {
+                           !data['refutation_lines'][nonstupid_moves[i]]['pv'] ||
+                           data['refutation_lines'][nonstupid_moves[i]]['pv'].length < 1) {
                                // Incomplete PV, abort.
                                response = undefined;
                                break;
                        }
-                       var this_response = data['refutation_lines'][nonstupid_moves[i]]['pv_uci'][1];
-                       if (response !== this_response) {
+                       var line = data['refutation_lines'][nonstupid_moves[i]];
+                       hiddenboard = new Chess(base_fen);
+                       hiddenboard.move(line['pv'][0]);
+                       var this_response = hiddenboard.move(line['pv'][1]);
+                       if (response.from !== this_response.from || response.to !== this_response.to) {
                                // Different response depending on lines, abort.
                                response = undefined;
                                break;
@@ -1202,8 +1228,7 @@ var update_board = function() {
                }
 
                if (nonstupid_moves.length > 0 && response !== undefined) {
-                       create_arrow(response.substr(0, 2),
-                                    response.substr(2, 2), '#66f', 6, 20);
+                       create_arrow(response.from, response.to, '#66f', 6, 20);
                }
        }
 
@@ -1267,7 +1292,16 @@ var update_sparkline = function(data) {
                                chartRangeMin: min_score,
                                chartRangeMax: max_score,
                                tooltipFormatter: function(sparkline, options, fields) {
-                                       return format_tooltip(data, fields[0].offset + first_move_num);
+                                       // score_history contains the Nth _position_, but format_tooltip
+                                       // wants to format the Nth _move_; thus the -1.
+                                       return format_tooltip(data, fields[0].offset + first_move_num - 1);
+                               }
+                       });
+                       $('#scorespark').bind('sparklineClick', function(event) {
+                               var sparkline = event.sparklines[0];
+                               var region = sparkline.getCurrentRegionFields();
+                               if (region[0].offset !== undefined) {
+                                       show_line(0, first_move_num + region[0].offset - 1);
                                }
                        });
                } else {
@@ -1324,7 +1358,6 @@ var update_clock = function() {
 
        var white_clock_ms = null;
        var black_clock_ms = null;
-       var show_seconds = false;
 
        // Static clocks.
        if (data['position'] &&
@@ -1365,8 +1398,9 @@ var update_clock = function() {
                return;
        }
 
-       // If either player has ten minutes or less left, add the second counters.
-       var show_seconds = (white_clock_ms < 60 * 10 * 1000 || black_clock_ms < 60 * 10 * 1000);
+       // If either player has twenty minutes or less left, add the second counters.
+       // This matches what DGT clocks do.
+       var show_seconds = (white_clock_ms < 60 * 20 * 1000 || black_clock_ms < 60 * 20 * 1000);
 
        if (color) {
                // See when the clock will change next, and update right after that.
@@ -1422,15 +1456,15 @@ var format_2d = function(x) {
 
 /**
  * @param {string} move
- * @param {Number} move_num
- * @param {boolean} white_to_play
+ * @param {Number} move_num Move number of this move.
+ * @param {boolean} white_to_play Whether white is to play this move.
  */
 var format_move_with_number = function(move, move_num, white_to_play) {
        var ret;
        if (white_to_play) {
-               ret = (move_num - 1) + '… ';
-       } else {
                ret = move_num + '. ';
+       } else {
+               ret = move_num + '… ';
        }
        ret += move;
        return ret;
@@ -1438,7 +1472,8 @@ var format_move_with_number = function(move, move_num, white_to_play) {
 
 /**
  * @param {string} move
- * @param {Number} halfmove_num
+ * @param {Number} halfmove_num Half-move number that is to be played,
+ *   starting from 0.
  */
 var format_halfmove_with_number = function(move, halfmove_num) {
        return format_move_with_number(
@@ -1452,42 +1487,39 @@ var format_halfmove_with_number = function(move, halfmove_num) {
  * @param {Number} halfmove_num
  */
 var format_tooltip = function(data, halfmove_num) {
-       if (data['score_history'][halfmove_num] ||
-           halfmove_num === data['position']['pretty_history'].length) {
+       if (data['score_history'][halfmove_num + 1] ||
+           (halfmove_num + 1) === data['position']['history'].length) {
+               // Position is in the history, or it is the current position
+               // (which is implicitly tacked onto the history).
                var move;
                var short_score;
-               if (halfmove_num === data['position']['pretty_history'].length) {
+               if ((halfmove_num + 1) === data['position']['history'].length) {
                        move = data['position']['last_move'];
                        short_score = format_short_score(data['score']);
                } else {
-                       move = data['position']['pretty_history'][halfmove_num];
-                       short_score = format_short_score(data['score_history'][halfmove_num]);
+                       move = data['position']['history'][halfmove_num];
+                       short_score = format_short_score(data['score_history'][halfmove_num + 1]);
+               }
+               if (halfmove_num === -1) {
+                       return "Start position: " + short_score;
+               } else {
+                       var move_with_number = format_halfmove_with_number(move, halfmove_num);
+                       return "After " + move_with_number + ": " + short_score;
                }
-               var move_with_number = format_halfmove_with_number(move, halfmove_num);
-
-               return "After " + move_with_number + ": " + short_score;
        } else {
-               for (var i = halfmove_num; i --> 0; ) {
+               for (var i = halfmove_num; i --> -1; ) {
                        if (data['score_history'][i]) {
-                               var move = data['position']['pretty_history'][i];
-                               return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
+                               var move = data['position']['history'][i];
+                               if (i === -1) {
+                                       return "[Analysis kept from start position]";
+                               } else {
+                                       return "[Analysis kept from " + format_halfmove_with_number(move, i) + "]";
+                               }
                        }
                }
        }
 }
 
-/**
- * @param {boolean} sort_by_score
- */
-var resort_refutation_lines = function(sort_by_score) {
-       sort_refutation_lines_by_score = sort_by_score;
-       if (supports_html5_storage()) {
-               localStorage['sort_refutation_lines_by_score'] = sort_by_score ? 1 : 0;
-       }
-       update_refutation_lines();
-}
-window['resort_refutation_lines'] = resort_refutation_lines;
-
 /**
  * @param {boolean} truncate_history
  */
@@ -1540,7 +1572,7 @@ window['prev_move'] = prev_move;
 
 var next_move = function() {
        if (current_display_line &&
-           current_display_move < current_display_line.pretty_pv.length - 1) {
+           current_display_move < current_display_line.pv.length - 1) {
                ++current_display_move;
        }
        update_historic_analysis();
@@ -1559,7 +1591,7 @@ var next_game = function() {
                var game = current_games[game_num];
                if (game['url'] === backend_url) {
                        var next_game_num = (game_num + 1) % current_games.length;
-                       switch_backend(current_games[next_game_num]['url'], current_games[next_game_num]['hashurl']);
+                       switch_backend(current_games[next_game_num]);
                        return;
                }
        }
@@ -1571,13 +1603,13 @@ var update_historic_analysis = function() {
        if (!current_display_line_is_history) {
                return;
        }
-       if (current_display_move == current_display_line.pretty_pv.length - 1) {
+       if (current_display_move == current_display_line.pv.length - 1) {
                displayed_analysis_data = null;
                update_board();
        }
 
        // Fetch old analysis for this line if it exists.
-       var hiddenboard = chess_from(null, current_display_line.pretty_pv, current_display_move);
+       var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pv, current_display_move);
        var filename = "/history/move" + (current_display_move + 1) + "-" +
                hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
 
@@ -1651,7 +1683,7 @@ var update_move_highlight = function() {
                        display_line_num = display_lines.length - 1;
 
                        // Clear out the PV, so it's not selected by anything later.
-                       display_lines[1].pretty_pv = [];
+                       display_lines[1].pv = [];
                }
 
                highlighted_move = $("#automove" + display_line_num + "-" + (current_display_move - current_display_line.start_display_move_num));
@@ -1671,10 +1703,10 @@ var find_display_line_matching_num = function() {
                var line = display_lines[i];
                if (line.start_display_move_num > 0) continue;
                if (current_display_line.start_fen !== line.start_fen) continue;
-               if (current_display_line.pretty_pv.length !== line.pretty_pv.length) continue;
+               if (current_display_line.pv.length !== line.pv.length) continue;
                var ok = true;
-               for (var j = 0; j < line.pretty_pv.length; ++j) {
-                       if (current_display_line.pretty_pv[j] !== line.pretty_pv[j]) {
+               for (var j = 0; j < line.pv.length; ++j) {
+                       if (current_display_line.pv[j] !== line.pv[j]) {
                                ok = false;
                                break;
                        }
@@ -1709,13 +1741,13 @@ var update_displayed_line = function() {
        } else {
                $("#prevmove").html("<a href=\"javascript:prev_move();\">Previous</a></span>");
        }
-       if (current_display_move == current_display_line.pretty_pv.length - 1) {
+       if (current_display_move == current_display_line.pv.length - 1) {
                $("#nextmove").html("Next");
        } else {
                $("#nextmove").html("<a href=\"javascript:next_move();\">Next</a></span>");
        }
 
-       var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pretty_pv, current_display_move);
+       var hiddenboard = chess_from(current_display_line.start_fen, current_display_line.pv, current_display_move);
        set_board_position(hiddenboard.fen());
        if (display_fen !== hiddenboard.fen() && !current_display_line_is_history) {
                // Fire off a hash request, since we're now off the main position
@@ -1877,8 +1909,8 @@ var get_best_move = function(game, source, target, invert) {
 
        // See if we're already exploring some line.
        if (current_display_line &&
-           current_display_move < current_display_line.pretty_pv.length - 1) {
-               var first_move = current_display_line.pretty_pv[current_display_move + 1];
+           current_display_move < current_display_line.pv.length - 1) {
+               var first_move = current_display_line.pv[current_display_move + 1];
                if (move_hash[first_move]) {
                        return move_hash[first_move];
                }
@@ -1887,7 +1919,7 @@ var get_best_move = function(game, source, target, invert) {
        // History and PV take priority over the display lines.
        for (var i = 0; i < 2; ++i) {
                var line = display_lines[i];
-               var first_move = line.pretty_pv[line.start_display_move_num];
+               var first_move = line.pv[line.start_display_move_num];
                if (move_hash[first_move]) {
                        return move_hash[first_move];
                }
@@ -1901,7 +1933,7 @@ var get_best_move = function(game, source, target, invert) {
                if (!line['score']) {
                        continue;
                }
-               var first_move = line['pv_pretty'][0];
+               var first_move = line['pv'][0];
                if (move_hash[first_move]) {
                        var score = compute_score_sort_key(line['score'], line['depth'], invert);
                        if (best_move_score === null || score > best_move_score) {
@@ -1952,8 +1984,8 @@ var onSnapEnd = function(source, target) {
        });
 
        if (current_display_line &&
-           current_display_move < current_display_line.pretty_pv.length - 1 &&
-           current_display_line.pretty_pv[current_display_move + 1] === move.san) {
+           current_display_move < current_display_line.pv.length - 1 &&
+           current_display_line.pv[current_display_move + 1] === move.san) {
                next_move();
                return;
        }
@@ -1962,8 +1994,12 @@ var onSnapEnd = function(source, target) {
        // this move, then select that. Note that this gives us a good priority
        // order (history first, then PV, then multi-PV lines).
        for (var i = 0; i < display_lines.length; ++i) {
+               if (i == 1 && current_display_line) {
+                       // Do not choose PV if not on it.
+                       continue;
+               }
                var line = display_lines[i];
-               if (line.pretty_pv[line.start_display_move_num] === move.san) {
+               if (line.pv[line.start_display_move_num] === move.san) {
                        show_line(i, 0);
                        return;
                }
@@ -2050,9 +2086,10 @@ var compute_plot_score = function(score) {
  * @param score The score digest tuple.
  * @param {?number} depth Depth the move has been computed to, or null.
  * @param {boolean} invert Whether black is to play.
+ * @param {boolean=} depth_secondary_key
  * @return {number}
  */
-var compute_score_sort_key = function(score, depth, invert) {
+var compute_score_sort_key = function(score, depth, invert, depth_secondary_key) {
        var s;
        if (!score) {
                return -10000000;
@@ -2072,16 +2109,20 @@ var compute_score_sort_key = function(score, depth, invert) {
        }
        if (s) {
                if (invert) s = -s;
-               return s * 200 + (depth || 0);
+               if (depth_secondary_key) {
+                       return s * 200 + (depth || 0);
+               } else {
+                       return s;
+               }
        } else {
                return null;
        }
 }
 
 /**
- * @param {string} new_backend_url
+ * @param {Object} game
  */
-var switch_backend = function(new_backend_url, new_backend_hash_url) {
+var switch_backend = function(game) {
        // Stop looking at historic data.
        current_display_line = null;
        current_display_move = null;
@@ -2110,8 +2151,9 @@ var switch_backend = function(new_backend_url, new_backend_hash_url) {
        }
 
        // Request an immediate fetch with the new backend.
-       backend_url = new_backend_url;
-       backend_hash_url = new_backend_hash_url;
+       backend_url = game['url'];
+       backend_hash_url = game['hashurl'];
+       window.location.hash = '#' + game['id'];
        current_analysis_data = null;
        ims = 0;
        request_update();
@@ -2127,11 +2169,6 @@ var init = function() {
        } else {
                set_sound(false);
        }
-       if (supports_html5_storage() && localStorage['sort_refutation_lines_by_score']) {
-               sort_refutation_lines_by_score = parseInt(localStorage['sort_refutation_lines_by_score']);
-       } else {
-               sort_refutation_lines_by_score = true;
-       }
 
        // Create board.
        board = new window.ChessBoard('board', {
@@ -2160,7 +2197,7 @@ var init = function() {
                } else if (event.which >= 49 && event.which <= 57) {  // 1-9.
                        var num = event.which - 49;
                        if (current_games && current_games.length >= num) {
-                               switch_backend(current_games[num]['url'], current_games[num]['hashurl']);
+                               switch_backend(current_games[num]);
                        }
                } else if (event.which == 78) {  // N.
                        next_game();