[board, moves] Reorganize castling_right API on Board

Board::color_has_castling_right takes an Option<Color> which it unwraps. With that
unwrapped Color, it can call…

Board::color_has_castling_right_unwrapped, which performs the evaluation with a
non-Option Color.

Clean up some imports.

board/src/board.rs

@@ -1,11 +1,10 @@
 // Eryn Wells <eryn@erynwells.me>
 
 use crate::{
-    castle,
+    PieceSet, castle,
     display::DiagramFormatter,
     piece_sets::{PlacePieceError, PlacePieceStrategy},
     zobrist::{ZobristHash, ZobristState},
-    PieceSet,
 };
 use chessfriend_bitboard::BitBoard;
 use chessfriend_core::{Color, Piece, Shape, Square, Wing};
@@ -109,11 +108,16 @@ impl Board {
 
     #[must_use]
     pub fn active_color_has_castling_right(&self, wing: Wing) -> bool {
-        self.color_has_castling_right(self.active_color, wing)
+        self.color_has_castling_right_unwrapped(self.active_color, wing)
     }
 
     #[must_use]
-    pub fn color_has_castling_right(&self, color: Color, wing: Wing) -> bool {
+    pub fn color_has_castling_right(&self, color: Option<Color>, wing: Wing) -> bool {
+        self.color_has_castling_right_unwrapped(self.unwrap_color(color), wing)
+    }
+
+    #[must_use]
+    pub fn color_has_castling_right_unwrapped(&self, color: Color, wing: Wing) -> bool {
         self.castling_rights.color_has_right(color, wing)
     }
 
@@ -129,7 +133,12 @@ impl Board {
         self.update_zobrist_hash_castling_rights(old_rights);
     }
 
-    pub fn revoke_castling_right(&mut self, color: Color, wing: Wing) {
+    pub fn revoke_castling_right(&mut self, color: Option<Color>, wing: Wing) {
+        let color = self.unwrap_color(color);
+        self.revoke_castling_right_unwrapped(color, wing);
+    }
+
+    pub fn revoke_castling_right_unwrapped(&mut self, color: Color, wing: Wing) {
         let old_rights = self.castling_rights;
         self.castling_rights.revoke(color, wing);
         self.update_zobrist_hash_castling_rights(old_rights);

board/src/castle.rs

@@ -46,7 +46,7 @@ impl Board {
 
         let color = self.unwrap_color(color);
 
-        if !self.color_has_castling_right(color, wing) {
+        if !self.color_has_castling_right_unwrapped(color, wing) {
             return Err(CastleEvaluationError::NoRights { color, wing });
         }
 
@@ -94,7 +94,7 @@ impl Board {
 mod tests {
     use super::*;
     use crate::test_board;
-    use chessfriend_core::{piece, Color, Wing};
+    use chessfriend_core::{Color, Wing, piece};
 
     #[test]
     fn king_on_starting_square_can_castle() {
@@ -104,8 +104,8 @@ mod tests {
             White Rook on H1
         );
 
-        assert!(board.color_has_castling_right(Color::White, Wing::KingSide));
-        assert!(board.color_has_castling_right(Color::White, Wing::QueenSide));
+        assert!(board.color_has_castling_right_unwrapped(Color::White, Wing::KingSide));
+        assert!(board.color_has_castling_right_unwrapped(Color::White, Wing::QueenSide));
     }
 
     #[test]

board/src/fen.rs

@@ -1,8 +1,8 @@
 // Eryn Wells <eryn@erynwells.me>
 
-use crate::{piece_sets::PlacePieceStrategy, Board};
+use crate::{Board, piece_sets::PlacePieceStrategy};
 use chessfriend_core::{
-    coordinates::ParseSquareError, piece, Color, File, Piece, Rank, Square, Wing,
+    Color, File, Piece, Rank, Square, Wing, coordinates::ParseSquareError, piece,
 };
 use std::fmt::Write;
 use thiserror::Error;
@@ -123,7 +123,7 @@ impl ToFenStr for Board {
             (Color::Black, Wing::QueenSide),
         ]
         .map(|(color, castle)| {
-            if !self.color_has_castling_right(color, castle) {
+            if !self.color_has_castling_right_unwrapped(color, castle) {
                 return "";
             }