fix: cleaner components seperation

src/app/core/chess/fen.utils.ts

@@ -0,0 +1,38 @@
+import { GameTurn } from '../../models/game.models';
+
+export function getPieceAtSquare(fen: string, targetSquare: string): string | null {
+  const placement = fen.split(' ')[0] ?? '';
+  const rows = placement.split('/');
+  if (rows.length !== 8 || targetSquare.length !== 2) {
+    return null;
+  }
+
+  const file = targetSquare.charCodeAt(0) - 97;
+  const rank = Number(targetSquare[1]);
+  const rowIndex = 8 - rank;
+
+  if (Number.isNaN(rank) || file < 0 || file > 7 || rowIndex < 0 || rowIndex > 7) {
+    return null;
+  }
+
+  let column = 0;
+  for (const symbol of rows[rowIndex]) {
+    if (symbol >= '1' && symbol <= '8') {
+      column += Number(symbol);
+      continue;
+    }
+
+    if (column === file) {
+      return symbol;
+    }
+
+    column += 1;
+  }
+
+  return null;
+}
+
+export function isPieceColor(pieceCode: string, turn: GameTurn): boolean {
+  const isWhitePiece = pieceCode === pieceCode.toUpperCase();
+  return (turn === 'white' && isWhitePiece) || (turn === 'black' && !isWhitePiece);
+}