Directly rename board -> position

position/src/move_generator/king.rs

@@ -0,0 +1,193 @@
+// Eryn Wells <eryn@erynwells.me>
+
+//! Declares the KingMoveGenerator type. This struct is responsible for
+//! generating the possible moves for the king in the given position.
+
+use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
+use crate::{r#move::Castle, Move, MoveBuilder, Position};
+use chessfriend_bitboard::BitBoard;
+use chessfriend_core::{Color, Piece, PlacedPiece};
+
+move_generator_declaration!(KingMoveGenerator, struct);
+move_generator_declaration!(KingMoveGenerator, new);
+move_generator_declaration!(KingMoveGenerator, getters);
+
+impl KingMoveGenerator {
+    #[allow(unused_variables)]
+    fn king_side_castle(position: &Position, color: Color) -> Option<Move> {
+        if !position.player_has_right_to_castle(color, Castle::KingSide) {
+            return None;
+        }
+
+        // TODO: Implement king side castle.
+        None
+    }
+
+    #[allow(unused_variables)]
+    fn queen_side_castle(position: &Position, color: Color) -> Option<Move> {
+        if !position.player_has_right_to_castle(color, Castle::QueenSide) {
+            return None;
+        }
+
+        // TODO: Implement queen side castle.
+        None
+    }
+}
+
+impl MoveGeneratorInternal for KingMoveGenerator {
+    fn piece(color: Color) -> Piece {
+        Piece::king(color)
+    }
+
+    fn move_set_for_piece(position: &Position, placed_piece: PlacedPiece) -> MoveSet {
+        let piece = placed_piece.piece();
+        let color = piece.color();
+        let square = placed_piece.square();
+
+        let empty_squares = position.empty_squares();
+        let opposing_pieces = position.bitboard_for_color(color.other());
+
+        let all_moves = BitBoard::king_moves(square);
+        let quiet_moves_bb = all_moves & empty_squares;
+        let capture_moves_bb = all_moves & opposing_pieces;
+
+        // TODO: Handle checks. Prevent moving a king to a square attacked by a
+        // piece of the opposite color.
+
+        let map_to_move = |sq| MoveBuilder::new(*piece, square, sq).build();
+
+        let king_side_castle = Self::king_side_castle(position, color);
+        let queen_side_castle = Self::queen_side_castle(position, color);
+        let quiet_moves = quiet_moves_bb
+            .occupied_squares()
+            .map(map_to_move)
+            .chain(king_side_castle.iter().cloned())
+            .chain(queen_side_castle.iter().cloned());
+        let capture_moves = capture_moves_bb.occupied_squares().map(map_to_move);
+
+        MoveSet::new(placed_piece)
+            .quiet_moves(quiet_moves_bb, quiet_moves)
+            .capture_moves(capture_moves_bb, capture_moves)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{position, r#move::AlgebraicMoveFormatter, PositionBuilder};
+    use chessfriend_bitboard::bitboard;
+    use chessfriend_core::{piece, Square};
+    use std::collections::HashSet;
+
+    #[test]
+    fn one_king() {
+        let pos = position![White King on E4];
+
+        let generator = KingMoveGenerator::new(&pos, Color::White);
+
+        assert_eq!(
+            generator.bitboard(),
+            bitboard![E5, F5, F4, F3, E3, D3, D4, D5]
+        );
+
+        let expected_moves = [
+            MoveBuilder::new(piece!(White King), Square::E4, Square::D5).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::E5).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::F5).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::F4).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::F3).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::E3).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::D3).build(),
+            MoveBuilder::new(piece!(White King), Square::E4, Square::D4).build(),
+        ];
+
+        let mut generated_moves: HashSet<Move> = generator.iter().cloned().collect();
+
+        for ex_move in expected_moves {
+            assert!(
+                generated_moves.remove(&ex_move),
+                "{:#?} was not generated",
+                &ex_move
+            );
+        }
+
+        assert!(
+            generated_moves.is_empty(),
+            "Moves unexpectedly present: {:#?}",
+            generated_moves
+        );
+    }
+
+    #[test]
+    fn one_king_corner() {
+        let pos = position![White King on A1];
+
+        let generator = KingMoveGenerator::new(&pos, Color::White);
+
+        let generated_bitboard = generator.bitboard();
+        let expected_bitboard = bitboard![A2, B2, B1];
+        assert_eq!(
+            generator.bitboard(),
+            bitboard![A2, B2, B1],
+            "Generated:\n{generated_bitboard}\nExpected:\n{expected_bitboard}"
+        );
+
+        let expected_moves = [
+            MoveBuilder::new(piece!(White King), Square::A1, Square::A2).build(),
+            MoveBuilder::new(piece!(White King), Square::A1, Square::B1).build(),
+            MoveBuilder::new(piece!(White King), Square::A1, Square::B2).build(),
+        ];
+
+        let mut generated_moves: HashSet<Move> = generator.iter().cloned().collect();
+
+        for ex_move in expected_moves {
+            assert!(
+                generated_moves.remove(&ex_move),
+                "{:#?} was not generated",
+                &ex_move
+            );
+        }
+
+        assert!(
+            generated_moves.is_empty(),
+            "Moves unexpectedly present: {:#?}",
+            generated_moves
+        );
+    }
+
+    #[test]
+    fn black_king_in_check_by_rook() {
+        let pos = PositionBuilder::new()
+            .place_piece(piece!(White King on E1))
+            .place_piece(piece!(White Rook on E4))
+            .place_piece(piece!(Black King on E7))
+            .to_move(Color::Black)
+            .build();
+
+        assert!(pos.is_king_in_check());
+
+        let generator = KingMoveGenerator::new(&pos, Color::Black);
+        let generated_moves: HashSet<Move> = generator.iter().cloned().collect();
+
+        let king = piece!(Black King);
+        let from_square = Square::E7;
+        let expected_moves = HashSet::from_iter([
+            MoveBuilder::new(king, from_square, Square::D6).build(),
+            MoveBuilder::new(king, from_square, Square::D7).build(),
+            MoveBuilder::new(king, from_square, Square::D8).build(),
+            MoveBuilder::new(king, from_square, Square::F6).build(),
+            MoveBuilder::new(king, from_square, Square::F7).build(),
+            MoveBuilder::new(king, from_square, Square::F8).build(),
+        ]);
+
+        assert_eq!(
+            generated_moves,
+            expected_moves,
+            "Difference: {:?}",
+            generated_moves
+                .symmetric_difference(&expected_moves)
+                .map(|mv| format!("{}", AlgebraicMoveFormatter::new(mv, &pos)))
+                .collect::<Vec<_>>()
+        );
+    }
+}