test

src/backend/AutoPlayer.java

@@ -1,17 +1,258 @@
 package backend;
 
+import java.util.ArrayList;
+import java.util.Random;
+
 public class AutoPlayer {
     
+    // Piece values used for evaluation and best move to do by calculating later the profit and losses (PnL)
+    private final int PAWN_VALUE = 1;
+    private final int KNIGHT_VALUE = 3;
+    private final int BISHOP_VALUE = 3;
+    private final int ROOK_VALUE = 5;
+    private final int QUEEN_VALUE = 9;
+    private final int KING_VALUE = 100; // High value to prioritize king safety
     
-	/**
-	 * returns the best Move to try on provided board for active player
-	 * @param board
-	 * @return
-	 */
+    /// This chess AI uses a minimax algorithm with alpha-beta pruning to look 2 moves ahead so depth 4
+    // it will evaluate the material value, the center control, and the pawn advancement (ELO 1400-1800)
+  
+    private final int MAX_DEPTH = 4;
+    
+    // Time limit for search in milliseconds to avoid bug or latence during the game
+    private final long TIME_LIMIT_MS = 5000; // 5 seconds max
+    private long startTime;
+    
+    // Random generator if there are several moves equally calculated as good
+    private Random random = new Random();
+    
+    //Returns the best Move to try
     public Move computeBestMove(Board board) {
+        startTime = System.currentTimeMillis();//record start time for search
+        boolean isWhite = board.isTurnWhite();// determine player's turn
+        ArrayList<Move> possibleMoves = generateAllPossibleMoves(board, isWhite);// generate the legal moves
         
-		return null;
+        if (possibleMoves.isEmpty()) {
+            return null; // If no moves available (checkmate or stalemate)
         }
         
+        Move bestMove = null;//store best move
+        int bestScore = isWhite ? Integer.MIN_VALUE : Integer.MAX_VALUE;//best score for the move: maximize for white and minimize for black
         
+        // Evaluate each possible move
+        for (Move move : possibleMoves) {
+            // Create a copy of the board to simulate the move without changing the real board
+            Board boardCopy = new Board(board);
+            applyMoveToBoard(boardCopy, move);//apply the move to the virtual board
+            
+            // Evaluate the resulting position using minimax
+            int score = minimax(boardCopy, MAX_DEPTH - 1, Integer.MIN_VALUE, Integer.MAX_VALUE, !isWhite);
+            
+            // Update best move based on the score
+            if ((isWhite && score > bestScore) || (!isWhite && score < bestScore) || 
+                (score == bestScore && random.nextBoolean())) { // Random choice if equal score
+                bestScore = score;//update best score
+                bestMove = move;//update best move
+            }
+            
+            // Check if time limit is exceeded and stop search if exceeded
+            if (System.currentTimeMillis() - startTime > TIME_LIMIT_MS) {
+                System.out.println("Time limit exceeded, returning best move found so far");
+                return bestMove;
+            }
+        }
+        
+        return bestMove;
+    }
+    //apply the move to the real board
+    private void applyMoveToBoard(Board board, Move move) {
+        int fromX = move.getFromX();//original X coordinate
+        int fromY = move.getFromY();//original Y coordinate
+        int toX = move.getToX();//destination X
+        int toY = move.getToY();//destination Y
+        Piece piece = move.getMovedPiece();//move the piece
+        
+        // Make the move by creating the piece a the position
+        board.setPiece(piece.isWhite(), piece.getType(), toX, toY);
+        
+        //remove the piece that moved
+        try {
+        	//access the board field for modifications
+            java.lang.reflect.Field boardField = Board.class.getDeclaredField("board");
+            boardField.setAccessible(true);//give accessibility to it
+            Piece[][] boardArray = (Piece[][]) boardField.get(board);//board array
+            boardArray[fromX][fromY] = null;//make the case empty
+        } catch (Exception e) {
+            System.err.println("Failed to update board: " + e.getMessage());
+        }
+        
+        // Increment turn
+        board.incrementTurn();
+    }
+    
+    //Minimax algorithm with alpha-beta pruning to evaluate positions
+    
+    private int minimax(Board board, int depth, int alpha, int beta, boolean isMaximizing) {
+        // Check if time limit is exceeded
+        if (System.currentTimeMillis() - startTime > TIME_LIMIT_MS) {
+            return evaluateBoard(board); // Return current evaluation if out of time
+        }
+        
+        // get the board before calculating possible moves
+        if (depth == 0) {
+            return evaluateBoard(board);//initial position
+        }
+        //all possible moves are generated
+        ArrayList<Move> possibleMoves = generateAllPossibleMoves(board, isMaximizing);
+        possibleMoves = orderMoves(possibleMoves);//order moves by their quality
+        
+        // No moves available, could be checkmate or stalemate
+        if (possibleMoves.isEmpty()) {
+            return evaluateBoard(board);// current position
+        }
+        
+        if (isMaximizing) {//white turn (maximizing player)
+            int maxEval = Integer.MIN_VALUE;//initialize with lowest value
+            for (Move move : possibleMoves) {//try each move
+                Board boardCopy = new Board(board);//create a copy of the board
+                applyMoveToBoard(boardCopy, move);//apply the move
+                int eval = minimax(boardCopy, depth - 1, alpha, beta, false);//evaluate the resulting position
+                maxEval = Math.max(maxEval, eval);//gives best evaluation
+                alpha = Math.max(alpha, eval);//gives the alpha value
+                if (beta <= alpha) {
+                    break; // Beta cutoff
+                }
+            }
+            return maxEval;//best evaluation found
+        } else {//black turn
+            int minEval = Integer.MAX_VALUE;//initialize with highest value
+            for (Move move : possibleMoves) {
+                Board boardCopy = new Board(board);
+                applyMoveToBoard(boardCopy, move);
+                int eval = minimax(boardCopy, depth - 1, alpha, beta, true);
+                minEval = Math.min(minEval, eval);
+                beta = Math.min(beta, eval);//gives beta value
+                if (beta <= alpha) {
+                    break; // Alpha cutoff
+                }
+            }
+            return minEval;//best evaluation found
+        }
+    }
+    
+    //Orders moves to improve alpha-beta pruning efficiency
+    
+    private ArrayList<Move> orderMoves(ArrayList<Move> moves) {
+        // Score each move (captures are considered first)
+        for (Move move : moves) {
+            int score = 0;//initialize score for the move
+            
+            // Prioritize captures based on a function of the Most Valuable Victim and the Least Valuable Attacker with the system of points
+            if (move.getCapturedPiece() != null) {
+                score += 10 * getPieceValue(move.getCapturedPiece().getType()) - 
+                         getPieceValue(move.getMovedPiece().getType()) / 10; // Higher score for capturing valuable pieces with less valuable ones
+            }
+            
+            // Store the score with the move
+            move.setScore(score);
+        }
+        
+        // Sort moves by score in a descending
+        moves.sort((a, b) -> Integer.compare(b.getScore(), a.getScore()));
+        
+        return moves;
+    }
+    
+    //Evaluates the current board position
+    
+    private int evaluateBoard(Board board) {
+        int score = 0;
+        
+        // Material evaluation
+        for (Piece piece : board.getPieces()) {
+            int pieceValue = getPieceValue(piece.getType());//get value of this piece
+            if (piece.isWhite()) {
+                score += pieceValue;//add value for white
+            } else {
+                score -= pieceValue;//substract value for black
+            }
+        }
+        
+        // Add position evaluation (takes in account the center control bonus)
+        for (Piece piece : board.getPieces()) {
+            int x = piece.getX();
+            int y = piece.getY();
+            
+            // Center control bonus (small bonus for controlling center squares)
+            int centerBonus = 0;
+            if ((x == 3 || x == 4) && (y == 3 || y == 4)) {//center 4 squares
+                centerBonus = 1; // Small bonus for center control
+            }
+            
+            if (piece.isWhite()) {
+                score += centerBonus;//add for white
+            } else {
+                score -= centerBonus;//subtract for black
+            }
+            
+            // Pawn advancement bonus (encourages pawn progression)
+            if (piece.getType() == PieceType.Pawn) {
+                int pawnBonus = 0;
+                if (piece.isWhite()) {
+                    pawnBonus = 7 - y; // Higher bonus as white pawns advance
+                    score += pawnBonus / 10; // Small fractional bonus
+                } else {
+                    pawnBonus = y; // Higher bonus as black pawns advance
+                    score -= pawnBonus / 10; // Small fractional bonus
+                }
+            }
+        }
+        
+        return score;//return final score
+    }
+    
+    //Gets the value of a piece
+    
+    private int getPieceValue(PieceType type) {
+        switch (type) {
+            case Pawn: return PAWN_VALUE;
+            case Knight: return KNIGHT_VALUE;
+            case Bishop: return BISHOP_VALUE;
+            case Rook: return ROOK_VALUE;
+            case Queen: return QUEEN_VALUE;
+            case King: return KING_VALUE;
+            default: return 0;// safety net to protect from bug
+        }
+    }
+    
+    //Generates all possible moves for a player
+    
+    private ArrayList<Move> generateAllPossibleMoves(Board board, boolean isWhite) {
+        ArrayList<Move> moves = new ArrayList<>();//list of all moves
+        
+        // Get all pieces of the current player
+        for (Piece piece : board.getPieces()) {
+            if (piece.isWhite() == isWhite) {//only consider pieces of the player
+                // Get valid moves for this piece
+                ArrayList<int[]> validMoves = piece.getValidMoves(board);
+                
+                for (int[] destination : validMoves) {//move object for each valid destination
+                    int toX = destination[0];//X
+                    int toY = destination[1];//Y
+                    Piece capturedPiece = board.getPiece(toX, toY);//check is a piece is capturable
+                    
+                    // Create a move object with all theses infos
+                    Move move = new Move(
+                        piece.getX(), piece.getY(),//start X Y
+                        toX, toY,				   //destination X Y
+                        piece,					   //piece moved
+                        capturedPiece			   //piece captured (if there i one)
+                    );
+                    
+                    moves.add(move);// add move to list
+                }
+            }
+        }
+        
+        return moves;//return all moves
+    }
 }

src/backend/Board.java

@@ -3,21 +3,22 @@ package backend;
 import java.util.ArrayList;
 
 public class Board {
-    private int selectedX = -1;   
+
+    private int selectedX = -1;   // negative value means impossible x and y so unselected
     private int selectedY = -1;
-    private int turnNumber = 0;   
-    public int width;            
+
+    private int turnNumber = 0;   // tracks current turn
+    public int width;            // enables to define the dimensions of board (public because used in console)
     public int height;
-    private Piece[][] board;      
-    private ArrayList<int[]> highlightedPositions = new ArrayList<>(); 
-    private int[] lastPawnDoubleMove = null; // Added for en passant tracking
+    private Piece[][] board; 	  // 2D array chess board
+    private ArrayList<int[]> highlightedPositions = new ArrayList<>(); // list of valid positions to highlight
 
     public Board(int colNum, int lineNum) {
         this.width = colNum;
         this.height = lineNum;
-        this.board = new Piece[width][height];   
+        this.board = new Piece[width][height];   // first empty board *********REVIEW************
         clearConsole();
-        System.out.println(toString()); 		 
+        System.out.println(toString()); 		 // print the chess at the beginning of the game
     }
 
     public int getWidth() {
@@ -28,22 +29,28 @@ public class Board {
         return height;
     }
 
+    // new piece on the board at x,y (More specifically changes the empty cell of coordinates x,y with a new chess piece)
     public void setPiece(boolean isWhite, PieceType type, int x, int y) {
         board[x][y] = new Piece(x, y, type, isWhite);
     }
 
     public boolean isTurnWhite() {
-        return turnNumber % 2 == 0;
+        if (turnNumber % 2 == 0) { // even turns including 0 are white's ones (% calculates the reminder of the euclidean division)
+            return true;
+        } else {  				   // same reasoning, odd turns are black's ones
+            return false;
+        }
     }
 
-    public int getTurnNumber() {   
-        return turnNumber;		   
+    public int getTurnNumber() {   // this class enables to obtain the current turn number while increment adds 1 to this value for each turn
+        return turnNumber;		   // Necessarly in two functions to get rid of an infinite loop ****WHY****
     }
 
     public void incrementTurn() {
         turnNumber++;
     }
 
+    // set up the classic chess board taking it as a matrix and putting each corresponding starting piece at its place 0,0 is the top left spot of the board
     public void populateBoard() {
         // Black
         setPiece(false, PieceType.Rook, 0, 0);
@@ -79,41 +86,97 @@ public class Board {
     public void cleanBoard() {
         for (int x = 0; x < width; x++) {
             for (int y = 0; y < height; y++) {
-                board[x][y] = null;
+                board[x][y] = null; // each position becomes empty
             }
         }
     }
-
     public Piece getPiece(int x, int y) {
 		if (!isInBounds (x, y)) return null;
 		return board [x][y];
 	}
 
-    private void clearConsole() {          
+    private void clearConsole() {          // ***************CONSOLE
         for (int i = 0; i < 50; i++) {
-            System.out.println();
+            System.out.println(); // Print 50 empty lines to "clear" the console
         }
     }
 
-    public boolean isEnPassantTarget(int x, int y) {
-        if (lastPawnDoubleMove == null) return false;
-        if (lastPawnDoubleMove[2] != turnNumber - 1) return false;
-        return (lastPawnDoubleMove[0] == x && lastPawnDoubleMove[1] == y);
+    public String toString() {
+        StringBuilder str = new StringBuilder();
+        str.append("  A B C D E F G H\n"); // columns letter at the top
+
+        // representation of the rows
+        for (int y = 0; y < height; y++) {
+            str.append(8 - y).append(" "); // row number on the left
+
+            for (int x = 0; x < width; x++) {
+                if (board[x][y] == null) {
+                    str.append("- "); // empty positions
+                } else {
+                    // convert each piece of both color into a character
+                    Piece piece = board[x][y];
+                    char pieceChar;
+
+                    switch (piece.getType()) { // switch function avoids too many if-else
+                        case King:   pieceChar = 'K'; break;
+                        case Queen:  pieceChar = 'Q'; break;
+                        case Bishop: pieceChar = 'B'; break;
+                        case Knight: pieceChar = 'N'; break; // N because we already have King
+                        case Rook:   pieceChar = 'R'; break;
+                        case Pawn:   pieceChar = 'P'; break;
+                        default:     pieceChar = '?'; break; // safety net
                     }
 
+                    // Make black pieces in lowercase
+                    if (!piece.isWhite()) {
+                        pieceChar = Character.toLowerCase(pieceChar);
+                    }
+
+                    str.append(pieceChar).append(" "); // gives structure to the output
+                }
+            }
+            str.append("\n"); // change of row
+        }
+
+        // Additional infos for a proper output 
+        str.append("Turn ").append(getTurnNumber()).append(": ");
+        str.append(isTurnWhite() ? "White" : "Black");
+
+        return str.toString();
+    }
+
+    // list the placement of the pieces on the board
+    public ArrayList<Piece> getPieces() {
+        ArrayList<Piece> pieces = new ArrayList<>();
+        // collect infos for the non-empty positions
+        for (int x = 0; x < width; x++) {
+            for (int y = 0; y < height; y++) {
+                if (board[x][y] != null) {
+                    pieces.add(board[x][y]);
+                }
+            }
+        }
+        return pieces;
+    }
+
+    // user clicks on the board
     public void userTouch(int x, int y) {
-        if (selectedX == -1 && selectedY == -1) {
+        if (selectedX == -1 && selectedY == -1) {         // This condition is only possible at the very start of the game
+            // check if the position is empty and the color
             if (board[x][y] != null && board[x][y].isWhite() == isTurnWhite()) {
+                // select it as active location
                 selectedX = x;
                 selectedY = y;
-                highlightedPositions = getValidMoves(board[x][y]);
+                highlightedPositions = getValidMoves(board[x][y]); // compute moves
             }
         } else {
             if (x == selectedX && y == selectedY) {
+                // unselect it if the destination is unvalid (not highlighted)
                 selectedX = -1;
                 selectedY = -1;
                 highlightedPositions.clear();
             } else {
+                // move if valid destination
                 boolean valid = false;
                 for (int[] pos : highlightedPositions) {
                     if (pos[0] == x && pos[1] == y) {
@@ -125,14 +188,6 @@ public class Board {
                 if (valid) {
                     Piece pieceToMove = board[selectedX][selectedY];
                     
-                    // Check for en passant capture
-                    if (pieceToMove.getType() == PieceType.Pawn && 
-                        x != selectedX && 
-                        board[x][y] == null) {
-                        board[x][selectedY] = null; // Capture the pawn
-                    }
-                    
-                    // Handle castling
                     if(pieceToMove.getType() == PieceType.King && Math.abs(x - selectedX)==2) {
                     	y = selectedY;
                     	if (x == 6) {
@@ -142,39 +197,36 @@ public class Board {
                     		board[5][y].setX(5);
                     		board[5][y].setY(y);
                     	} else if (x == 2) {
+                            //System.out.println(board [3][y]);
+                            //System.out.println(board [0][y]);
                     		board [3][y] = board[0][y];
                     		board [0][y] = null;
+                    		//System.out.println(board [3][y]);
+                    		//System.out.println(board [0][y]);
                     		board[3][y].setMoved(true);
                     		board[3][y].setX(3); 
                     		board[3][y].setY(y);
                     	}
                     }
-                    
-                    // Track pawn double move for en passant
-                    if (pieceToMove.getType() == PieceType.Pawn && 
-                        Math.abs(y - selectedY) == 2) {
-                        lastPawnDoubleMove = new int[]{x, y, turnNumber};
-                    } else {
-                        lastPawnDoubleMove = null;
-                    }
-
-                    // Move the piece
                     board[x][y] = new Piece(x, y, pieceToMove.getType(), pieceToMove.isWhite());
-                    board[x][y].setMoved(true);
                     board[selectedX][selectedY] = null;
+                    board[x][y].setMoved(true);
                     incrementTurn();
+                    
                 }
 
+                // reset selection
                 selectedX = -1;
                 selectedY = -1;
                 highlightedPositions.clear();
+                clearConsole();
                 System.out.println(toString());
             }
         }
     }
 
     public boolean isSelected(int x, int y) {
-        return (x == selectedX && y == selectedY);
+        return (x == selectedX && y == selectedY); // true if matching position
     }
 
     public boolean isHighlighted(int x, int y) {
@@ -186,6 +238,7 @@ public class Board {
         return false;
     }
 
+    /* utility methods */
     public boolean isInBounds(int x, int y) {
         return x >= 0 && x < width && y >= 0 && y < height;
     }
@@ -194,70 +247,22 @@ public class Board {
         return piece.getValidMoves(this);
     }
 
-    public ArrayList<Piece> getPieces() {
-        ArrayList<Piece> pieces = new ArrayList<>();
-        for (int x = 0; x < width; x++) {
-            for (int y = 0; y < height; y++) {
-                if (board[x][y] != null) {
-                    pieces.add(board[x][y]);
-                }
-            }
-        }
-        return pieces;
-    }
-
-    public String toString() {
-        StringBuilder str = new StringBuilder();
-        str.append("  A B C D E F G H\n");
-
-        for (int y = 0; y < height; y++) {
-            str.append(8 - y).append(" ");
-
-            for (int x = 0; x < width; x++) {
-                if (board[x][y] == null) {
-                    str.append("- ");
-                } else {
-                    Piece piece = board[x][y];
-                    char pieceChar;
-
-                    switch (piece.getType()) {
-                        case King:   pieceChar = 'K'; break;
-                        case Queen:  pieceChar = 'Q'; break;
-                        case Bishop: pieceChar = 'B'; break;
-                        case Knight: pieceChar = 'N'; break;
-                        case Rook:   pieceChar = 'R'; break;
-                        case Pawn:   pieceChar = 'P'; break;
-                        default:     pieceChar = '?'; break;
-                    }
-
-                    if (!piece.isWhite()) {
-                        pieceChar = Character.toLowerCase(pieceChar);
-                    }
-
-                    str.append(pieceChar).append(" ");
-                }
-            }
-            str.append("\n");
-        }
-
-        str.append("Turn ").append(getTurnNumber()).append(": ");
-        str.append(isTurnWhite() ? "White" : "Black");
-
-        return str.toString();
-    }
-
     public String[] toFileRep() {
-        String[] rep = new String[height + 1];
+        String[] rep = new String[height + 1]; // height lines for the board + 1 for turn info
         
+        // taking each row
         for (int y = 0; y < height; y++) {
             StringBuilder line = new StringBuilder();
+            //now each column
             for (int x = 0; x < width; x++) {
                 if (board[x][y] == null) {
-                    line.append("-");
+                    line.append("-"); //empty square
                 } else {
+                    // Convert each piece to a character using the same logic as toString()
                     Piece piece = board[x][y];
-                    String pieceChar = piece.getType().getSummary();
+                    String pieceChar = piece.getType().getSummary(); //get the character representation
                     
+                    // Make black pieces lowercase, just like in toString()
                     if (!piece.isWhite()) {
                         pieceChar = pieceChar.toLowerCase();
                     }
@@ -265,65 +270,112 @@ public class Board {
                     line.append(pieceChar);
                 }
                 
+                // Add a comma after each square except the last one
                 if (x < width - 1) {
                     line.append(",");
                 }
             }
             
-            rep[y] = line.toString();
+            rep[y] = line.toString();//store line
         }
         
+        // Add turn information as the last line
         rep[height] = isTurnWhite() ? "W" : "B";
         
         return rep;
     }
 
     public Board(String[] fileRepresentation) {
-        this.height = fileRepresentation.length - 1;
-        this.width = fileRepresentation[0].split(",").length;
+        // Determine board dimensions from the file
+        this.height = fileRepresentation.length - 1; // Last line is turn info
+        this.width = fileRepresentation[0].split(",").length;//width counting with commas
         this.board = new Piece[width][height];
-        this.selectedX = -1;
+        this.selectedX = -1;//no position selected at beginning
         this.selectedY = -1;
-        this.highlightedPositions = new ArrayList<>();
+        this.highlightedPositions = new ArrayList<>();//no highlighted position at beginning
         
+        // Process each row
         for (int y = 0; y < height; y++) {
-            String[] squares = fileRepresentation[y].split(",");
+            String[] squares = fileRepresentation[y].split(",");//split rows with commas
             
-            for (int x = 0; x < width; x++) {
+            for (int x = 0; x < width; x++) {//take the square infos
                 String squareData = squares[x];
                 
+                // Skip empty squares
                 if (squareData.equals("-")) {
                     continue;
                 }
                 
-                char pieceChar = squareData.charAt(0);
+                char pieceChar = squareData.charAt(0);//take the character of the piece
+                
+                // Determine color by case: uppercase = white, lowercase = black
                 boolean isWhite = Character.isUpperCase(pieceChar);
                 
+                // Convert to uppercase for the fromSummary method if it's lowercase
                 if (!isWhite) {
                     pieceChar = Character.toUpperCase(pieceChar);
                 }
                 
+                // Get piece type
                 PieceType type = PieceType.fromSummary(pieceChar);
+                
+                // Create the piece
                 setPiece(isWhite, type, x, y);
             }
         }
         
+        // Set turn information
         String turnInfo = fileRepresentation[height];
-        this.turnNumber = turnInfo.equals("W") ? 0 : 1;
+        this.turnNumber = turnInfo.equals("W") ? 0 : 1;//white=even, black=odd
         
         clearConsole();
         System.out.println(toString());
     }
 
+
+    /* additional functionality to implement later */
     public void undoLastMove() {
         // TODO
     }
 
     public void playMove(Move move) {
-        // TODO
+    	int fromX = move.getFromX();
+        int fromY = move.getFromY();
+        int toX = move.getToX();
+        int toY = move.getToY();
+        Piece piece = board[fromX][fromY];
+        
+        // Make the move
+        board[toX][toY] = new Piece(toX, toY, piece.getType(), piece.isWhite());
+        board[toX][toY].setMoved(true);
+        board[fromX][fromY] = null;
+        
+        incrementTurn();
     }
 
-    public Board(Board board) {
-        // TODO
+
+    // Copy constructor that creates a copy of another board
+    
+    public Board(Board otherBoard) {
+    	this.width = otherBoard.width;
+        this.height = otherBoard.height;
+        this.turnNumber = otherBoard.turnNumber;
+        this.selectedX = -1; // Don't copy selection because negative in a matrix
+        this.selectedY = -1;
+        this.board = new Piece[width][height];
+        this.highlightedPositions = new ArrayList<>();
+        
+        // Deep copy the board pieces
+        for (int x = 0; x < width; x++) {
+            for (int y = 0; y < height; y++) {
+                if (otherBoard.board[x][y] != null) {
+                    Piece original = otherBoard.board[x][y];
+                    this.board[x][y] = new Piece(x, y, original.getType(), original.isWhite());
+                    // Remove the hasMoved check since it doesn't exist
                 }
             }
+        }
+    }
+}
+   
+

src/backend/Move.java

@@ -1,12 +1,48 @@
 package backend;
 
-import java.util.Optional;
+// Represents a chess move from one position to another
 
-/**
- * Represents a chess move, including the starting and ending positions,
- * the moving piece, and an optional captured piece.
- */
 public class Move {
+    private int fromX;			// Starting X coordinate
+    private int fromY;			// Starting Y coordinate
+    private int toX;			// Destination X coordinate
+    private int toY;			// Destination Y coordinate
+    private Piece movedPiece;	// The piece being moved
+    private Piece capturedPiece;// The piece being captured (null if none)
+    private int score = 0; // Used for move ordering in alpha-beta pruning
     
+    //Constructor for a move
     
+    public Move(int fromX, int fromY, int toX, int toY, Piece movedPiece, Piece capturedPiece) {
+        this.fromX = fromX;
+        this.fromY = fromY;
+        this.toX = toX;
+        this.toY = toY;
+        this.movedPiece = movedPiece;
+        this.capturedPiece = capturedPiece;
+    }
+    
+    // Getters to access move properties
+    public int getFromX() { return fromX; }
+    public int getFromY() { return fromY; }
+    public int getToX() { return toX; }
+    public int getToY() { return toY; }
+    public Piece getMovedPiece() { return movedPiece; }
+    public Piece getCapturedPiece() { return capturedPiece; }
+    
+    // Method for move ordering
+    public void setScore(int score) {
+        this.score = score;
+    }
+    
+    public int getScore() {
+        return score;//return the evaluation score of the move
+    }
+    
+    @Override
+    public String toString() {//coordinates into chess notation
+        String from = (char)('a' + fromX) + "" + (8 - fromY);
+        String to = (char)('a' + toX) + "" + (8 - toY);
+        return from + " -> " + to;
+    }
 }

src/backend/Piece.java

@@ -70,7 +70,7 @@ public class Piece {
                     }
                 }
 
-            // diagonal captures (including en passant)
+                // diagonal captures
                 for (int dx = -1; dx <= 1; dx += 2) {
                     int nx = x + dx;
                     if (board.isInBounds(nx, nextY)) {
@@ -78,14 +78,6 @@ public class Piece {
                     	if (target != null && target.isWhite() != this.isWhite()) {
                     		moves.add(new int[]{nx, nextY});
                     	}
-                    // Check for en passant
-                    else if (target == null && 
-                            board.getPiece(nx, y) != null && 
-                            board.getPiece(nx, y).getType() == PieceType.Pawn &&
-                            board.getPiece(nx, y).isWhite() != this.isWhite() &&
-                            board.isEnPassantTarget(nx, y)) {
-                        moves.add(new int[]{nx, nextY});
-                    }
                     }
                 }
                 break;
@@ -203,5 +195,4 @@ public class Piece {
             ny += dy;
         }
     }
-	
 }