check king attack early on

Author: van-sprundel

check-buddy/src/board.rs

@@ -430,6 +430,19 @@ impl BoardMap {
         }
         vec
     }
+    /// Find the king of the given color
+    pub fn find_king(&self, piece_color: PieceColor) -> Option<Position> {
+        for (y, row) in self.squares.iter().enumerate() {
+            for (x, p) in row.iter().enumerate() {
+                if let Some(PieceType::King) = p.get_type() {
+                    if p.get_color() == piece_color {
+                        return Some([y, x]);
+                    }
+                }
+            }
+        }
+        None
+    }
     pub fn get_piece_mut(&mut self, pos: Position) -> &mut Piece {
         self.squares[pos[0]][pos[1]].borrow_mut()
     }
@@ -570,13 +583,18 @@ impl BoardMap {
                 ..Default::default()
             };
             temp_board.make_move(position_move);
-            let next_moves = temp_board.gen_all_opponent_positions();
-            if !next_moves.iter().any(|m| {
-                let next_piece = temp_board.squares[m[0]][m[1]];
-                next_piece.is_piece()
-                    && next_piece.get_color() == temp_board.active_color
-                    && Some(PieceType::King) == next_piece.get_type()
-            }) {
+
+            let king_pos = temp_board.find_king(temp_board.active_color);
+            let opponent_color = if temp_board.active_color == PieceColor::White {
+                PieceColor::Black
+            } else {
+                PieceColor::White
+            };
+            let in_check = king_pos
+                .map(|pos| temp_board.is_square_attacked_by(pos, opponent_color))
+                .unwrap_or(false);
+
+            if !in_check {
                 legal_positions.push(to);
             }