modified highlights and move to not eat pieces of the same color

src/backend/Board.java

@@ -153,11 +153,15 @@ public class Board {
 			}
 			else { // we know we already have a piece so we move it to another position 
 				if( this.positionOccupied(x, y) == true) { 
+					if (pieces.get(whatPiece(x,y)).isWhite() != pieces.get(whatPiece(this.x,this.y)).isWhite()) {//check if we do not move to a position occupied by a piece of the same color 
 						this.pieces.remove(whatPiece(x,y)); //if there is a piece at the position we want to move we remove it from the array list
 					}
+				}
+				if(this.positionOccupied(x, y) == false || pieces.get(whatPiece(x,y)).isWhite() != pieces.get(whatPiece(this.x,this.y)).isWhite()) {//moves the piece only if the position selected is not occupied by a piece of the same color
 					int indexPiece = this.whatPiece(this.x, this.y);
 					pieces.get(indexPiece).setX(x);
 					pieces.get(indexPiece).setY(y);
+				}
 				// we now reset our parameters 
 				this.x=-1;
 				this.y=-1;
@@ -350,11 +354,11 @@ public class Board {
 						if((x == this.x) && (positionOccupied(x,y)==false)) {//advance one case
 							highlight = true;
 						}
-						if((Math.abs(x-this.x) == 1) && (positionOccupied(x,y))) {//eat the piece in diagonal, if existing
+						if((Math.abs(x-this.x) == 1) && (positionOccupied(x,y)) && pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()) {//highlight the piece in diagonal, if existing
 							highlight = true;
 						}
 					}
-					if((y == this.y-2) && (this.y == 6) && (x == this.x)) {//move by two if not moved
+					if((y == this.y-2) && (this.y == 6) && (x == this.x) && (positionOccupied(this.x,this.y-1))==false) {//move by two if not moved and if no piece in front
 						highlight = true;
 					}
 				}
@@ -364,36 +368,63 @@ public class Board {
 						if((x == this.x) && (positionOccupied(x,y)==false)) {
 							highlight = true;
 						}
-						if((Math.abs(x-this.x) == 1) && (positionOccupied(x,y))) {
+						if((Math.abs(x-this.x) == 1) && (positionOccupied(x,y))  && pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()) {
 							highlight = true;
 						}
 					}
-					if((y == this.y+2) && (this.y == 1) && (x == this.x)) {
+					if((y == this.y+2) && (this.y == 1) && (x == this.x) && (positionOccupied(this.x,this.y+1) == false)) {
 						highlight = true;
 					}
 				}
 			}
 			
-			if (pieces.get(indexPieceSelect).getType() == PieceType.King) { //highlight for Kings
+			if (pieces.get(indexPieceSelect).getType() == PieceType.King) { //highlight for Kings THIS IS NOT OPTIMISED BC OF WHATPIECE (SAME FOR ALL FOLLOWING PIECES)
+				if(positionOccupied(x,y) == false) {
 					if((Math.abs(x-this.x) <= 1) && (Math.abs(y-this.y) <= 1)) { //consider all cases at distance one from the king
 						if ((Math.abs(x-this.x) != 0) || (Math.abs(y-this.y) != 0)) { //check if we are not considering the place where the king is 
 							highlight = true;
 						}
 					}
 				}
+				else {
+					if(pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()){
+						if((Math.abs(x-this.x) <= 1) && (Math.abs(y-this.y) <= 1)) { //consider all cases at distance one from the king
+							if ((Math.abs(x-this.x) != 0) || (Math.abs(y-this.y) != 0)) { //check if we are not considering the place where the king is 
+								highlight = true;
+							}
+						}
+					}
+				}
+			}
 			
 			if (pieces.get(indexPieceSelect).getType() == PieceType.Knight) { //highlight for knights
+				if(positionOccupied(x,y) == false) {
 					if (((Math.abs(x-this.x) == 1) && (Math.abs(y-this.y) == 2)) || ((Math.abs(x-this.x) == 2) && (Math.abs(y-this.y) == 1))) {//consider all positions at 2 by 1 from the knight
 						highlight = true;
 					}
 				}
+				else {
+					if(pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()){
+						if (((Math.abs(x-this.x) == 1) && (Math.abs(y-this.y) == 2)) || ((Math.abs(x-this.x) == 2) && (Math.abs(y-this.y) == 1))) {//consider all positions at 2 by 1 from the knight
+							highlight = true;
+						}
+					}
+				}
+			}
 			
 			if (pieces.get(indexPieceSelect).getType() == PieceType.Bishop) { //highlight for bishops
 				int numHighlight = highlightBishop().get(0).size();
 				for(int i = 0; i < numHighlight; i++) {
 					if ((x == highlightBishop().get(0).get(i)) && (y == highlightBishop().get(1).get(i))) {//check if the considered x and y are in the list of positions that should be highlighted
+						if(positionOccupied(x,y) == false) {
 							highlight = true;
 						}
+						else {
+							if(pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()) {
+								highlight = true;
+							}
+						}
+					}
 				}
 			}
 			
@@ -401,8 +432,15 @@ public class Board {
 				int numHighlight = highlightQueen().get(0).size();
 				for(int i = 0; i < numHighlight; i++) {
 					if ((x == highlightQueen().get(0).get(i)) && (y == highlightQueen().get(1).get(i))) {//check if the considered x and y are in the list of positions that should be highlighted
+						if(positionOccupied(x,y) == false) {
 							highlight = true;
 						}
+						else {
+							if(pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()) {
+								highlight = true;
+							}
+						}
+					}
 				}
 			}
 			
@@ -410,8 +448,15 @@ public class Board {
 				int numHighlight = highlightRook().get(0).size();
 				for(int i = 0; i < numHighlight; i++) {
 					if ((x == highlightRook().get(0).get(i)) && (y == highlightRook().get(1).get(i))) {//check if the considered x and y are in the list of positions that should be highlighted
+						if(positionOccupied(x,y) == false) {
 							highlight = true;
 						}
+						else {
+							if(pieces.get(whatPiece(x,y)).isWhite() != pieces.get(indexPieceSelect).isWhite()) {
+								highlight = true;
+							}
+						}
+					}
 				}
 			}
 		}