+
+ recommended_move = null;
+ get_best_dest(pseudogame, source, null, function(src, dest) {
+ $("#board").find('.square-55d63').removeClass('nonuglyhighlight');
+ if (dest !== null) {
+ var squareEl = $('#board .square-' + dest);
+ squareEl.addClass('highlight1-32417');
+ recommended_move = [src, dest];
+ }
+ });
+}
+
+var mousedownSquare = function(e) {
+ reverse_dragging_from = null;
+ var square = $(this).attr('data-square');
+
+ var pseudogame = new Chess(current_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;
+ get_best_dest(pseudogame, null, square, function(src, dest) {
+ if (src !== null) {
+ var squareEl = $('#board .square-' + src);
+ squareEl.addClass('highlight1-32417');
+ squareEl = $('#board .square-' + dest);
+ squareEl.addClass('highlight1-32417');
+ recommended_move = [src, dest];
+ }
+ });
+ } else {
+ recommended_src = null;
+ }
+}
+
+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_dest = function(game, source, target, cb) {
+ 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) {
+ cb(null, null);
+ return;
+ }
+ if (moves.length == 1) {
+ cb(moves[0].from, moves[0].to);
+ return;
+ }
+
+ // More than one move. Ask the engine to disambiguate.
+ var uci_moves = moves.map(function(m) { return m.from + m.to; });
+ var when_engine_is_ready = function() {
+ engine_running = true;
+ stockfish.onmessage = function(event) {
+ var res = event.data.match(/^bestmove (\S\S)(\S\S)/);
+ if (res !== null) {
+ engine_running = false;
+ if (engine_replacement_callback !== null) {
+ // We are no longer interested in this query,
+ // so just discard it and call this other callback.
+ engine_replacement_callback();
+ engine_replacement_callback = null;
+ } else {
+ cb(res[1], res[2]);
+ }
+ }
+ };
+ stockfish.postMessage("position fen " + game.fen());
+ stockfish.postMessage("go depth 6 searchmoves " + uci_moves.join(" "));
+ };
+ if (engine_running) {
+ engine_replacement_callback = when_engine_is_ready;
+ } else {
+ when_engine_is_ready();
+ }