+ recommended_move = get_best_move(pseudogame, source, null, pseudogame.turn() === 'b');
+ if (recommended_move) {
+ var squareEl = $('#board .square-' + recommended_move.to);
+ squareEl.addClass('highlight1-32417');
+ }
+ return true;
+}
+
+var mousedownSquare = function(e) {
+ reverse_dragging_from = null;
+ var square = $(this).attr('data-square');
+
+ var pseudogame = new Chess(display_fen);
+ if (pseudogame.game_over() === true) {
+ return;
+ }
+
+ // If the square is empty, or has a piece of the side not to move,
+ // we handle it. If not, normal piece dragging will take it.
+ var position = board.position();
+ if (!position.hasOwnProperty(square) ||
+ (pseudogame.turn() === 'w' && position[square].search(/^b/) !== -1) ||
+ (pseudogame.turn() === 'b' && position[square].search(/^w/) !== -1)) {
+ reverse_dragging_from = square;
+ recommended_move = get_best_move(pseudogame, null, square, pseudogame.turn() === 'b');
+ if (recommended_move) {
+ var squareEl = $('#board .square-' + recommended_move.from);
+ squareEl.addClass('highlight1-32417');
+ squareEl = $('#board .square-' + recommended_move.to);
+ squareEl.addClass('highlight1-32417');
+ }
+ }
+}
+
+var mouseupSquare = function(e) {
+ if (reverse_dragging_from === null) {
+ return;
+ }
+ var source = $(this).attr('data-square');
+ var target = reverse_dragging_from;
+ reverse_dragging_from = null;
+ if (onDrop(source, target) !== 'snapback') {
+ onSnapEnd(source, target);
+ }
+ $("#board").find('.square-55d63').removeClass('highlight1-32417');
+}
+
+var get_best_move = function(game, source, target, invert) {
+ var moves = game.moves({ verbose: true });
+ if (source !== null) {
+ moves = moves.filter(function(move) { return move.from == source; });
+ }
+ if (target !== null) {
+ moves = moves.filter(function(move) { return move.to == target; });
+ }
+ if (moves.length == 0) {
+ return null;
+ }
+ if (moves.length == 1) {
+ return moves[0];
+ }
+
+ // More than one move. Use the display lines (if we have them)
+ // to disambiguate; otherwise, we have no information.
+ var move_hash = {};
+ for (var i = 0; i < moves.length; ++i) {
+ move_hash[moves[i].san] = moves[i];
+ }
+
+ // 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];
+ if (move_hash[first_move]) {
+ return move_hash[first_move];
+ }
+ }
+
+ // 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];
+ if (move_hash[first_move]) {
+ return move_hash[first_move];
+ }
+ }
+
+ var best_move = null;
+ var best_move_score = null;
+
+ for (var move in refutation_lines) {
+ var line = refutation_lines[move];
+ if (!line['score']) {
+ continue;
+ }
+ var first_move = line['pv_pretty'][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) {
+ best_move = move_hash[first_move];
+ best_move_score = score;
+ }
+ }
+ }
+ return best_move;
+}
+
+var onDrop = function(source, target) {
+ if (source === target) {
+ if (recommended_move === null) {
+ return 'snapback';
+ } else {
+ // Accept the move. It will be changed in onSnapEnd.
+ return;
+ }