Day 46

Day 43 (design chess application)/Chess.java

@@ -1,30 +0,0 @@
-
-//Main class and GUI
-
-public class Chess {
-	private GameBoard board;
-	//Remembers the initial click square for the user's move
-	//Stack of GameBoard states for the move undo.
-	//Stack of tuples (moves) so they can be displayed.
-
-	public void start() {
-		//Set up the initial board
-	}
-
-	//Reset to the intial game position.
-	public void reset() {
-	}
-
-	//AI makes a move
-	public void moveAI() {
-	}
-
-	//For the human moving
-	public void mouseClick() {
-	}
-
-	//Undo button for the most recent move
-	public void undo() {
-	}
-
-}

Day 43 (design chess application)/GameState.java

@@ -1,26 +0,0 @@
-
-public class GameState {
-	//Tracks the game board as a 1D array of Square objects (effectively 12 x 12) with 2 layers of sentinel squares all around.
-	//Knows whose turn it is
-
-	public GameState() {
-
-		reset();
-	}
-
-	public void reset() {
-	}
-
-	public void attemptMove(int sourceX, int sourceY, int destX, int destY) {
-		//See if it is legal.
-		//Change the board state accordingly.
-	}
-
-	public Moves[] getAllPossibleMoves() {
-	}
-
-	// returns something like "checkmate", "stalemate", etc.
-	public String getFeedback() {
-	}
-
-}

Day 43, 45, 46 (chess application design)/Chess.java

@@ -0,0 +1,56 @@
+
+//Main class and GUI
+
+public class Chess {
+	private GameBoard board;
+
+	//User's first click for a move.
+	private Integer clickRow;  //null means no first click made currently.
+	private Integer clickColumn;
+
+	private ArrayList<GameState> gameStateHistory; //Stack of GameBoard states for the move undo.
+	private ArrayList<Move> moveHistory;  //Stack of tuples (moves) so they can be displayed.
+	private ArrayList<String> moveNotationHistory;  //Stack of move notations.
+
+	public void start() {
+		//Set up graphics on the screen, buttons
+		//Set up the initial board
+		//Set up empty move history, game history,  notation history.
+		//clickRow and clickCol are null
+		//Set up mouse/click events
+	}
+
+	//Reset to the intial game position.
+	public void reset() {
+		//Set up the initial board
+		//Clear out clickRo and clickCol
+		//Clera out all the histories.
+	}
+
+	//AI makes a move
+	public void moveAI() {
+		//Ask the gameState for a list of all legal moves.
+		//Get one of those in the list uniformly at random.
+		makeMove(...);
+	}
+
+	private void makeMove(...) {
+		//Clone the gameState object for the current state of the game, tell it to make the move, add it to the move history
+		//add the notation for it
+		//add the move to the history as well
+	}
+
+	//For the human moving
+	public void mouseClick() {
+		//If it is the first click (null check) then record it, updtae the GUI to show highlighting
+		//else attempt the move:
+
+		makeMove(...);
+	}
+
+	//Undo button for the most recent move
+	public void undo() {
+		//Pop those 3 history object things and update the GUI.
+	}
+
+}

Day 43, 45, 46 (chess application design)/GameState.java

@@ -0,0 +1,26 @@
+
+// We are making this an *immutable* class.  The state that an object has when constructed is its state permanently.
+// Instead of making changes to objects we create new ones (with attemptMove() and the constructor).
+
+public class GameState {
+	Square[] boardSquares; //Tracks the game board as a 1D array of Square objects (effectively 12 x 12) with 2 layers of sentinel squares all around.
+	boolean isWhitesTurn;  //Knows whose turn it is
+
+	public GameState() {
+		//Set turn to white
+		//Initialize squares with legal starting position.
+	}
+
+	public GameState attemptMove(Move m) {
+		//See if it is legal.
+		//Change the board state accordingly.
+	}
+
+	public Moves[] getAllPossibleMoves() {
+	}
+
+	// returns something like "checkmate", "stalemate", etc.
+	public String getFeedback() {
+	}
+
+}

Day 43, 45, 46 (chess application design)/Move.java

@@ -1,9 +1,9 @@
 
 public class Move {
 	//source and dest coordinates
-	//boolean check or not
+
-	//boolean capture or not
+	public Move(...source...dest...) {
-	//boolean checkmate or not
+	}
 
 
 	//returns something like e2-e4 or Qc8++

Day 43, 45, 46 (chess application design)/refactoring Move.txt

@@ -0,0 +1,13 @@
+Design change to the Move class:
+	Two things that felt wrong:
+		1) Some Move objects will be half-constructed temporarily (move history) or permanently (enumeration of legal moves)
+		2) A Move object can't determine by itself which piece moved, whether it was a capture, check, checkmate, or stalemate.
+	What if we recompute the notation whenever needed, on the fly?
+		* Depending on the GUI implementation, making n moves may result in O(n^2) notation calculations
+	Observations:
+		* Whoever determines move notation needs to know the relevant board states and the move itself (the Chess class).
+		* Move notation can be stored as such; it isn't necessary to have 3 or 4 boolean variables for check, capture, etc.
+		* Move notation should be cached to avoid recalculations and potential O(n^2)-time behavior
+	Conclusion:
+		Put it in the Chess class, because we have access to the relevant board states and the move itself.
+		[Maybe the parallel arrays in the Chess class can be made into a single array of Turn objects...]