X-Git-Url: https://git.auder.net/?a=blobdiff_plain;f=public%2Fjavascripts%2Fbase_rules.js;h=63b535dab609c5a8ff879b0b2e4066eaee7088af;hb=15c1295af871a5f416b0e5b43127512c8095497a;hp=5020094ce6582c326473acbc74f1e1b9b1901348;hpb=a3c86ec9b60326a8ae3d8f237493fb09627aed95;p=vchess.git

diff --git a/public/javascripts/base_rules.js b/public/javascripts/base_rules.js
index 5020094c..63b535da 100644
--- a/public/javascripts/base_rules.js
+++ b/public/javascripts/base_rules.js
@@ -727,6 +727,12 @@ class ChessRules
 			this.kingPos[c] = [move.start.x, move.start.y];
 	}
 
+	// Hash of position+flags+turn after a move is played (to detect repetitions)
+	getHashState()
+	{
+		return hex_md5(this.getFen() + " " + this.turn);
+	}
+
 	play(move, ingame)
 	{
 		// DEBUG:
@@ -741,6 +747,9 @@ class ChessRules
 		this.moves.push(move);
 		this.epSquares.push( this.getEpSquare(move) );
 		VariantRules.PlayOnBoard(this.board, move);
+
+		if (!!ingame)
+			move.hash = this.getHashState();
 	}
 
 	undo(move)
@@ -760,22 +769,24 @@ class ChessRules
 	//////////////
 	// END OF GAME
 
-	// Basic check for 3 repetitions (in the last moves only)
-	// TODO: extend to usual 3-repetition recognition (storing FEN with move?)
+	// Check for 3 repetitions (position + flags + turn)
 	checkRepetition()
 	{
-		if (this.moves.length >= 8)
+		if (!this.hashStates)
+			this.hashStates = {};
+		const startIndex =
+			Object.values(this.hashStates).reduce((a,b) => { return a+b; }, 0)
+		// Update this.hashStates with last move (or all moves if continuation)
+		// NOTE: redundant storage, but faster and moderate size
+		for (let i=startIndex; i<this.moves.length; i++)
 		{
-			const L = this.moves.length;
-			if (_.isEqual(this.moves[L-1], this.moves[L-5]) &&
-				_.isEqual(this.moves[L-2], this.moves[L-6]) &&
-				_.isEqual(this.moves[L-3], this.moves[L-7]) &&
-				_.isEqual(this.moves[L-4], this.moves[L-8]))
-			{
-				return true;
-			}
+			const move = this.moves[i];
+			if (!this.hashStates[move.hash])
+				this.hashStates[move.hash] = 1;
+			else
+				this.hashStates[move.hash]++;
 		}
-		return false;
+		return Object.values(this.hashStates).some(elt => { return (elt >= 3); });
 	}
 
 	// Is game over ? And if yes, what is the score ?