promote gui

app/src/main/java/chess/io/CommandExecutor.java

@@ -1,6 +1,7 @@
 package chess.io;
 
 import chess.io.commands.MoveCommand;
+import chess.io.commands.PromoteCommand;
 import chess.model.Game;
 
 public class CommandExecutor {
@@ -18,12 +19,24 @@ public class CommandExecutor {
 		assert this.outputSystem != null : "No output system specified !";
 
 		CommandResult result = command.execute(this.game, this.outputSystem);
-		if (result == CommandResult.Moved) {
-			this.game.checkPromotion(((MoveCommand) command).getMove().getFinish());
-			this.game.checkGameStatus();
+		processResult(command, result);
+		return result;
+	}
+
+	private void processResult(Command command, CommandResult result) {
+		if (result != CommandResult.Moved)
+			return;
+
+		if (command instanceof MoveCommand move) {
+			boolean needsPromote = this.game.checkPromotion(move.getMove().getFinish());
+			if (this.game.checkGameStatus())
+				return;
+
+			if (!needsPromote)
+				this.game.switchPlayerTurn();
+		} else if (command instanceof PromoteCommand) {
 			this.game.switchPlayerTurn();
 		}
-		return result;
 	}
 
 	public void setOutputSystem(OutputSystem outputSystem) {
@@ -60,6 +73,4 @@ public class CommandExecutor {
 		this.game.OnPlayerTurn.connect(outputSystem::playerTurn);
 	}
 
-	
-
 }