check draw

app/src/main/java/chess/model/Game.java

@@ -1,5 +1,7 @@
 package chess.model;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Stack;
 
 import chess.controller.PlayerCommand;
@@ -9,6 +11,7 @@ public class Game {
 	private final ChessBoard board;
 	private Color playerTurn;
 	private final Stack<PlayerCommand> movesHistory;
+	private final Map<Color, Map<Integer, Integer>> traitsPos;
 
 	public enum GameStatus {
 		Check, CheckMate, OnGoing, Pat;
@@ -17,6 +20,9 @@ public class Game {
 	public Game(ChessBoard board) {
 		this.board = board;
 		this.movesHistory = new Stack<>();
+		this.traitsPos = new HashMap<>();
+		this.traitsPos.put(Color.Black, new HashMap<>());
+		this.traitsPos.put(Color.White, new HashMap<>());
 	}
 
 	public ChessBoard getBoard() {
@@ -31,8 +37,26 @@ public class Game {
 		this.playerTurn = Color.White;
 	}
 
-	public void switchPlayerTurn() {
+	/**
+	 * 
+	 * @param color the current player turn
+	 * @return true if a draw should be declared
+	 */
+	private boolean saveTraitPiecesPos(Color color) {
+		int piecesHash = this.board.hashPlayerPieces(color);
+		Integer count = this.traitsPos.get(color).get(piecesHash);
+		this.traitsPos.get(color).put(piecesHash, count == null ? 1 : count + 1);
+		return count == null ? false : count == (3 - 1);
+	}
+
+	/**
+	 * 
+	 * @return true if a draw should occur
+	 */
+	public boolean switchPlayerTurn() {
+		boolean draw = saveTraitPiecesPos(this.playerTurn);
 		playerTurn = Color.getEnemy(playerTurn);
+		return draw;
 	}
 
 	public GameStatus checkGameStatus() {