player command

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

@@ -19,6 +19,10 @@ public class CommandExecutor {
 		assert this.outputSystem != null : "No output system specified !";
 
 		CommandResult result = command.execute(this.game, this.outputSystem);
+
+		// non player commands are not supposed to return move result
+		assert result != CommandResult.Moved || command instanceof PlayerCommand;
+
 		processResult(command, result);
 		return result;
 	}
@@ -34,7 +38,7 @@ public class CommandExecutor {
 
 			if (!needsPromote)
 				this.game.switchPlayerTurn();
-		} else if (command instanceof PromoteCommand) {
+		} else if (command instanceof PlayerCommand) {
 			this.game.switchPlayerTurn();
 		}
 	}

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

@@ -0,0 +1,7 @@
+package chess.io;
+
+import chess.model.Game;
+
+public abstract class PlayerCommand extends Command{
+	public abstract void undo(Game game, OutputSystem outputSystem);
+}

app/src/main/java/chess/io/commands/CastlingCommand.java

@@ -1,15 +1,21 @@
 package chess.io.commands;
 
-import chess.io.Command;
 import chess.io.CommandResult;
 import chess.io.OutputSystem;
+import chess.io.PlayerCommand;
 import chess.model.Game;
 
-public class CastlingCommand extends Command{
+public class CastlingCommand extends PlayerCommand{
 
 	@Override
 	public CommandResult execute(Game game, OutputSystem outputSystem) {
 		return CommandResult.NotAllowed;
 	}
 
+	@Override
+	public void undo(Game game, OutputSystem outputSystem) {
+		// TODO Auto-generated method stub
+		throw new UnsupportedOperationException("Unimplemented method 'undo'");
+	}
+	
 }

app/src/main/java/chess/io/commands/GrandCastlingCommand.java

@@ -1,15 +1,21 @@
 package chess.io.commands;
 
-import chess.io.Command;
 import chess.io.CommandResult;
 import chess.io.OutputSystem;
+import chess.io.PlayerCommand;
 import chess.model.Game;
 
-public class GrandCastlingCommand extends Command{
+public class GrandCastlingCommand extends PlayerCommand {
 
 	@Override
 	public CommandResult execute(Game game, OutputSystem outputSystem) {
 		return CommandResult.NotAllowed;
 	}
 
+	@Override
+	public void undo(Game game, OutputSystem outputSystem) {
+		// TODO Auto-generated method stub
+		throw new UnsupportedOperationException("Unimplemented method 'undo'");
+	}
+
 }

app/src/main/java/chess/io/commands/MoveCommand.java

@@ -1,15 +1,15 @@
 package chess.io.commands;
 
-import chess.io.Command;
 import chess.io.CommandResult;
 import chess.io.OutputSystem;
+import chess.io.PlayerCommand;
 import chess.model.ChessBoard;
 import chess.model.Game;
 import chess.model.Move;
 import chess.model.Piece;
 import chess.model.visitor.PiecePathChecker;
 
-public class MoveCommand extends Command {
+public class MoveCommand extends PlayerCommand {
 	private final Move move;
 
 	public MoveCommand(Move move) {
@@ -49,4 +49,9 @@ public class MoveCommand extends Command {
 		return CommandResult.Moved;
 	}
 
+	@Override
+	public void undo(Game game, OutputSystem outputSystem) {
+		game.getBoard().undoLastMove();
+	}
+
 }

app/src/main/java/chess/io/commands/PromoteCommand.java

@@ -1,8 +1,8 @@
 package chess.io.commands;
 
-import chess.io.Command;
 import chess.io.CommandResult;
 import chess.io.OutputSystem;
+import chess.io.PlayerCommand;
 import chess.model.ChessBoard;
 import chess.model.Color;
 import chess.model.Coordinate;
@@ -14,7 +14,7 @@ import chess.model.pieces.Pawn;
 import chess.model.pieces.Queen;
 import chess.model.pieces.Rook;
 
-public class PromoteCommand extends Command {
+public class PromoteCommand extends PlayerCommand {
 
 	public enum PromoteType {
 		Queen,
@@ -71,4 +71,17 @@ public class PromoteCommand extends Command {
 		}
 	}
 
+	@Override
+	public void undo(Game game, OutputSystem outputSystem) {
+		final ChessBoard board = game.getBoard();
+
+		Piece promoted = board.pieceAt(this.pieceCoords);
+
+		assert promoted != null;
+
+		Color player = promoted.getColor();
+		board.pieceLeaves(this.pieceCoords);
+		board.pieceComes(new Pawn(player), this.pieceCoords);
+	}
+
 }