remove game signals

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

@@ -2,7 +2,6 @@ package chess.model;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Stack;
 
 import chess.model.visitor.KingIdentifier;
 import chess.model.visitor.PiecePathChecker;
@@ -26,8 +25,8 @@ public class ChessBoard {
 	}
 
 	private final Cell[][] cells;
-	private final Stack<Move> moves;
-	private final Stack<Piece> ejectedPieces;
+	private Move lastMove;
+	private Piece lastEjectedPiece;
 
 	public ChessBoard() {
 		this.cells = new Cell[Coordinate.VALUE_MAX][Coordinate.VALUE_MAX];
@@ -36,43 +35,41 @@ public class ChessBoard {
 				this.cells[i][j] = new Cell();
 			}
 		}
-		this.moves = new Stack<>();
-		this.ejectedPieces = new Stack<>();
+		this.lastMove = null;
+		this.lastEjectedPiece = null;
 	}
 
 	public void applyMove(Move move) {
-		assert (move.isValid());
+		assert move.isValid() : "Invalid move !";
 		Piece deadPiece = pieceAt(move.getFinish());
 		if (deadPiece != null) {
-			deadPiece.eject(this.moves.size());
-			this.ejectedPieces.add(deadPiece);
+			this.lastEjectedPiece = deadPiece;
+		} else {
+			this.lastEjectedPiece = null;
 		}
 		Piece movingPiece = pieceAt(move.getStart());
 		pieceComes(movingPiece, move.getFinish());
 		pieceLeaves(move.getStart());
 		movingPiece.move();
-		this.moves.add(move);
+		this.lastMove = move;
 	}
 
 	public void undoLastMove() {
-		assert !this.moves.empty() : "Can't undo at the beginning!";
+		assert this.lastMove != null: "Can't undo at the beginning!";
 
-		Move move = this.moves.pop();
+		Move move = this.lastMove;
 
 		Piece movingPiece = pieceAt(move.getFinish());
 		pieceComes(movingPiece, move.getStart());
 		pieceLeaves(move.getFinish());
 		movingPiece.unMove();
 
-		if (this.ejectedPieces.empty())
+		if (this.lastEjectedPiece == null)
 			return;
 
-		Piece piece = this.ejectedPieces.lastElement();
-		if (piece.getEjectedMoveNumber() != this.moves.size())
-			return;
+		Piece piece = this.lastEjectedPiece;
 
 		pieceComes(piece, move.getFinish());
-		piece.eject(-1);
 	}
 
 	public boolean isCellEmpty(Coordinate coordinate) {

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

@@ -1,20 +1,14 @@
 package chess.model;
 
 import chess.model.pieces.Pawn;
-import common.Signal0;
-import common.Signal1;
 
 public class Game {
 	private final ChessBoard board;
 	private Color playerTurn;
 
-	public final Signal1<Coordinate> OnPromote = new Signal1<>();
-	public final Signal1<Color> OnWin = new Signal1<>();
-	public final Signal1<Color> OnPlayerTurn = new Signal1<>();
-
-	public final Signal0 OnCheck = new Signal0();
-	public final Signal0 OnMat = new Signal0();
-	public final Signal0 OnPat = new Signal0();
+	public enum GameStatus {
+		Check, CheckMate, OnGoing, Pat;
+	}
 
 	public Game(ChessBoard board) {
 		this.board = board;
@@ -30,12 +24,10 @@ public class Game {
 
 	public void resetPlayerTurn() {
 		this.playerTurn = Color.White;
-		this.OnPlayerTurn.emit(playerTurn);
 	}
 
 	public void switchPlayerTurn() {
 		playerTurn = Color.getEnemy(playerTurn);
-		this.OnPlayerTurn.emit(playerTurn);
 	}
 
 	public boolean checkPromotion(Coordinate pieceCoords) {
@@ -52,31 +44,22 @@ public class Game {
 		if (destY != enemyLine)
 			return false;
 
-		this.OnPromote.emit(pieceCoords);
 		return true;
 	}
 
-	/**
-	 * 
-	 * @return true if game should end
-	 */
-	public boolean checkGameStatus() {
+	public GameStatus checkGameStatus() {
 		final Color enemy = Color.getEnemy(getPlayerTurn());
 
-		if (this.board.isKingInCheck(enemy)) {
-			if (this.board.hasAllowedMoves(enemy)) {
-				this.OnCheck.emit();
-			} else {
-				this.OnMat.emit();
-				this.OnWin.emit(getPlayerTurn());
-				return true;
-			}
-		} else if (!board.hasAllowedMoves(enemy)) {
-			this.OnPat.emit();
-			return true;
-		}
+		if (this.board.isKingInCheck(enemy))
+			if (this.board.hasAllowedMoves(enemy))
+				return GameStatus.Check;
+			else
+				return GameStatus.CheckMate;
 
-		return false;
+		if (!board.hasAllowedMoves(enemy))
+			return GameStatus.Pat;
+
+		return GameStatus.OnGoing;
 	}
 
 	public boolean pawnShouldBePromoted() {