X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=www%2Fjs%2Fbook.js;fp=www%2Fjs%2Fbook.js;h=bc6adfceccca4174daf9ee78d0f274028abc050e;hb=12fb90fa6c78a3753fb34f2fcb86b1856be718a5;hp=ebccd1ef2fdf99eb909134ecf3b1d5adcc6e6487;hpb=26150eda6eb2024c27bf24d3c6ea0414ae932dd2;p=remoteglot-book

diff --git a/www/js/book.js b/www/js/book.js
index ebccd1e..bc6adfc 100644
--- a/www/js/book.js
+++ b/www/js/book.js
@@ -5,6 +5,10 @@ var game = new Chess();
 var fens = [];
 var move_override = 0;
 var includetransp = true;
+var stockfish = new Worker('/js/stockfish.js');
+var engine_running = false;
+var engine_replacement_callback = null;
+var recommended_dest = null;
 
 var entity_map = {
 	"&": "&",
@@ -338,9 +342,75 @@ var onDragStart = function(source, piece, position, orientation) {
 	    (pseudogame.turn() === 'b' && piece.search(/^w/) !== -1)) {
 		return false;
 	}
+
+	recommended_dest = null;
+	get_best_dest(pseudogame, source, function(dest) {
+		$("#board").find('.square-55d63').removeClass('nonuglyhighlight');
+		if (dest !== null) {
+			var squareEl = $('#board .square-' + dest);
+			squareEl.addClass('highlight1-32417');
+		}
+		recommended_dest = dest;
+	});
+}
+
+var get_best_dest = function(game, source, cb) {
+	var moves = game.moves({ square: source, verbose: true });
+	if (moves.length == 0) {
+		cb(null);
+		return;
+	}
+	if (moves.length == 1) {
+		cb(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]);
+				}
+			}
+		};
+		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();
+	}
 }
 
 var onDrop = function(source, target) {
+	if (engine_running) {
+		// Snap end before the engine came back.
+		// Discard the result when it does.
+		engine_replacement_callback = function() {};
+	}
+	if (source == target) {
+		if (recommended_dest === null) {
+			return 'snapback';
+		} else {
+			// Accept the move. It will be changed in onSnapEnd.
+			return;
+		}
+	} else {
+		// Suggestion not asked for.
+		recommended_dest = null;
+	}
+
 	// see if the move is legal
 	var pseudogame = new Chess(current_display_fen());
 	var move = pseudogame.move({
@@ -354,6 +424,10 @@ var onDrop = function(source, target) {
 }
 
 var onSnapEnd = function(source, target) {
+	if (source == target && recommended_dest !== null) {
+		target = recommended_dest;
+	}
+	recommended_dest = null;
 	var pseudogame = new Chess(current_display_fen());
 	var move = pseudogame.move({
 		from: source,