From c7b954400475a65f3ba8cd040a7a5217bef4f7cb Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Tue, 17 Jun 2025 16:18:48 -0700
Subject: [PATCH] [moves] Revoke castling rights when King and Rook make moves
 of their starting squares

When the King moves, revoke all rights for the moving player. When the rook moves,
revoke castling rights for that side of the board, if it's moving off its starting
square.
---
 moves/src/make_move.rs | 55 +++++++++++++++++++++++++++++++++---------
 1 file changed, 43 insertions(+), 12 deletions(-)

diff --git a/moves/src/make_move.rs b/moves/src/make_move.rs
index 38b03cf..7b8fd33 100644
--- a/moves/src/make_move.rs
+++ b/moves/src/make_move.rs
@@ -2,10 +2,10 @@
 
 use crate::{Move, MoveRecord};
 use chessfriend_board::{
-    castle::CastleEvaluationError, movement::Movement, Board, BoardProvider, PlacePieceError,
-    PlacePieceStrategy,
+    Board, BoardProvider, CastleParameters, PlacePieceError, PlacePieceStrategy,
+    castle::CastleEvaluationError, movement::Movement,
 };
-use chessfriend_core::{Color, Piece, Rank, Square, Wing};
+use chessfriend_core::{Color, Piece, Rank, Shape, Square, Wing};
 use thiserror::Error;
 
 pub type MakeMoveResult = Result<MoveRecord, MakeMoveError>;
@@ -83,6 +83,8 @@ trait MakeMoveInternal {
 
     fn advance_board_state(
         &mut self,
+        ply: &Move,
+        piece_moved: &Piece,
         en_passant_target: Option<Square>,
         half_move_clock: HalfMoveClock,
     );
@@ -151,7 +153,7 @@ impl<T: BoardProvider> MakeMoveInternal for T {
 
         let record = MoveRecord::new(board, ply, None);
 
-        self.advance_board_state(None, HalfMoveClock::Advance);
+        self.advance_board_state(&ply, &piece, None, HalfMoveClock::Advance);
 
         Ok(record)
     }
@@ -179,7 +181,12 @@ impl<T: BoardProvider> MakeMoveInternal for T {
             _ => unreachable!(),
         };
 
-        self.advance_board_state(Some(en_passant_target), HalfMoveClock::Advance);
+        self.advance_board_state(
+            &ply,
+            &piece,
+            Some(en_passant_target),
+            HalfMoveClock::Advance,
+        );
 
         Ok(record)
     }
@@ -221,7 +228,7 @@ impl<T: BoardProvider> MakeMoveInternal for T {
 
         let record = MoveRecord::new(board, ply, Some(captured_piece));
 
-        self.advance_board_state(None, HalfMoveClock::Reset);
+        self.advance_board_state(&ply, &piece, None, HalfMoveClock::Reset);
 
         Ok(record)
     }
@@ -246,7 +253,7 @@ impl<T: BoardProvider> MakeMoveInternal for T {
 
         board.revoke_castling_right_unwrapped(active_color, wing);
 
-        self.advance_board_state(None, HalfMoveClock::Advance);
+        self.advance_board_state(&ply, &king, None, HalfMoveClock::Advance);
 
         Ok(record)
     }
@@ -280,28 +287,52 @@ impl<T: BoardProvider> MakeMoveInternal for T {
 
         let record = MoveRecord::new(board, ply, None);
 
-        self.advance_board_state(None, HalfMoveClock::Reset);
+        self.advance_board_state(&ply, &piece, None, HalfMoveClock::Reset);
 
         Ok(record)
     }
 
     fn advance_board_state(
         &mut self,
+        ply: &Move,
+        piece_moved: &Piece,
         en_passant_target: Option<Square>,
         half_move_clock: HalfMoveClock,
     ) {
         let board = self.board_mut();
 
-        match half_move_clock {
-            HalfMoveClock::Reset => board.half_move_clock = 0,
-            HalfMoveClock::Advance => board.half_move_clock += 1,
+        board.set_en_passant_target_option(en_passant_target);
+
+        match piece_moved.shape {
+            Shape::Rook => {
+                let origin = ply.origin_square();
+
+                if board.color_has_castling_right(None, Wing::KingSide) {
+                    let kingside_parameters =
+                        CastleParameters::get(board.active_color(), Wing::KingSide);
+                    if origin == kingside_parameters.origin.rook {
+                        board.revoke_castling_right(None, Wing::KingSide);
+                    }
+                }
+
+                let queenside_parameters =
+                    CastleParameters::get(board.active_color(), Wing::QueenSide);
+                if origin == queenside_parameters.origin.rook {
+                    board.revoke_castling_right(None, Wing::QueenSide);
+                }
+            }
+            Shape::King => board.revoke_all_castling_rights(),
+            _ => {}
         }
 
         let previous_active_color = board.active_color();
         let active_color = previous_active_color.next();
         board.set_active_color(active_color);
 
-        board.set_en_passant_target_option(en_passant_target);
+        match half_move_clock {
+            HalfMoveClock::Reset => board.half_move_clock = 0,
+            HalfMoveClock::Advance => board.half_move_clock += 1,
+        }
 
         if active_color == Color::White {
             board.full_move_number += 1;