From 9507432bd3572d8a2c55e4c2b2974a3fb2f2dc4f Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Fri, 5 Apr 2024 23:35:46 +0100
Subject: [PATCH 1/2] Modify castling rights after rook capture

---
 src/board/chess_board/mod.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/board/chess_board/mod.rs b/src/board/chess_board/mod.rs
index 33a5580..ba010d4 100644
--- a/src/board/chess_board/mod.rs
+++ b/src/board/chess_board/mod.rs
@@ -185,6 +185,13 @@ impl ChessBoard {
             *self.piece_occupancy_mut(piece) ^= chess_move.destination();
             *self.color_occupancy_mut(opponent) ^= chess_move.destination();
             self.combined_occupancy ^= chess_move.destination();
+            // If a rook is captured, it loses its castling rights
+            let castle_rights = self.castle_rights_mut(opponent);
+            *castle_rights = match (piece, chess_move.destination().file()) {
+                (Piece::Rook, File::A) => castle_rights.without_queen_side(),
+                (Piece::Rook, File::H) => castle_rights.without_king_side(),
+                _ => *castle_rights,
+            };
         }
 
         // Revertible state modification
@@ -768,6 +775,17 @@ mod test {
         );
     }
 
+    #[test]
+    fn do_move_capture_changes_castling() {
+        let mut position = ChessBoard::from_fen("r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1").unwrap();
+        let expected = ChessBoard::from_fen("r3k2R/8/8/8/8/8/8/R3K3 b Qq - 0 1").unwrap();
+
+        let capture = Move::new(Square::H1, Square::H8, None);
+
+        position.do_move(capture);
+        assert_eq!(position, expected);
+    }
+
     #[test]
     fn do_move_and_undo() {
         // Start from default position

From f9ba6fa68090f7266163c08fcf3efd7f4f14c732 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Sat, 6 Apr 2024 00:20:09 +0100
Subject: [PATCH 2/2] Refactor castling right management in 'do_move'

I find it more readable.
---
 src/board/chess_board/mod.rs | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/board/chess_board/mod.rs b/src/board/chess_board/mod.rs
index ba010d4..c594adf 100644
--- a/src/board/chess_board/mod.rs
+++ b/src/board/chess_board/mod.rs
@@ -170,17 +170,13 @@ impl ChessBoard {
         } else {
             self.en_passant = None;
         }
-        if move_piece == Piece::King {
-            *self.castle_rights_mut(self.current_player()) = CastleRights::NoSide;
-        }
-        if move_piece == Piece::Rook {
-            let castle_rights = self.castle_rights_mut(self.current_player());
-            *castle_rights = match chess_move.start().file() {
-                File::A => castle_rights.without_queen_side(),
-                File::H => castle_rights.without_king_side(),
-                _ => *castle_rights,
-            }
-        }
+        let castle_rights = self.castle_rights_mut(self.current_player());
+        *castle_rights = match (move_piece, chess_move.start().file()) {
+            (Piece::Rook, File::A) => castle_rights.without_queen_side(),
+            (Piece::Rook, File::H) => castle_rights.without_king_side(),
+            (Piece::King, _) => CastleRights::NoSide,
+            _ => *castle_rights,
+        };
         if let Some(piece) = captured_piece {
             *self.piece_occupancy_mut(piece) ^= chess_move.destination();
             *self.color_occupancy_mut(opponent) ^= chess_move.destination();