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use crate::piece::ChessPiece;
use game_board::{get_square_name_from_row_and_col, Board};
use std::fmt::{Display, Formatter};
/// Represents different types of simple_chess moves.
///
/// This enum captures the state and specific details of various types of legal simple_chess moves.
/// It provides functionality to apply and undo these moves on a simple_chess board.
#[derive(Debug, PartialEq, Clone, Copy)]
pub enum ChessMoveType {
/// A regular piece move which might include capturing an opponent's piece or promoting a pawn.
///
/// Fields:
/// - `original_position`: (usize, usize) - The starting position of the simple_chess piece.
/// - `new_position`: (usize, usize) - The destination position of the simple_chess piece.
/// - `piece`: ChessPiece - The simple_chess piece being moved.
/// - `taken_piece`: Option<ChessPiece> - The opponent's piece captured during this move, if any.
/// - `promotion`: Option<ChessPiece> - The piece type a pawn is promoted to, if applicable.
Move {
original_position: (usize, usize),
new_position: (usize, usize),
piece: ChessPiece,
taken_piece: Option<ChessPiece>,
promotion: Option<ChessPiece>,
},
/// A special pawn capture move where a pawn captures another pawn that has moved
/// two squares forward from its starting position on the previous turn.
///
/// Fields:
/// - `original_position`: (usize, usize) - The starting position of the pawn.
/// - `new_position`: (usize, usize) - The destination position of the pawn after capturing.
/// - `piece`: ChessPiece - The pawn performing the en passant capture.
/// - `taken_piece`: ChessPiece - The opponent's pawn being captured.
/// - `taken_piece_position`: (usize, usize) - The position of the captured pawn.
/// - `promotion`: Option<ChessPiece> - The piece type if the pawn is promoted, if applicable.
EnPassant {
original_position: (usize, usize),
new_position: (usize, usize),
piece: ChessPiece,
taken_piece: ChessPiece,
taken_piece_position: (usize, usize),
promotion: Option<ChessPiece>,
},
/// A special move involving the king and a rook where both pieces move simultaneously.
///
/// Fields:
/// - `rook_original_position`: (usize, usize) - The starting position of the rook.
/// - `rook_new_position`: (usize, usize) - The destination position of the rook.
/// - `king_original_position`: (usize, usize) - The starting position of the king.
/// - `king_new_position`: (usize, usize) - The destination position of the king.
Castle {
rook_original_position: (usize, usize),
rook_new_position: (usize, usize),
king_original_position: (usize, usize),
king_new_position: (usize, usize),
},
}
impl ChessMoveType {
/// Applies the current move to the simple_chess board.
///
/// This method performs the actual move on the board by repositioning the involved
/// pieces according to the move type.
///
/// # Arguments
///
/// * `board` - A mutable reference to the simple_chess board on which the move will be applied.
///
/// # Examples
///
/// ```
/// use simple_chess::ChessMoveType;
/// use simple_chess::Color::White;
/// use simple_chess::piece::ChessPiece;
/// use simple_chess::piece::PieceType::Pawn;
/// use game_board::Board;
/// let mut board = Board::build(8, 8).unwrap();
/// let original_position = (0, 1);
///
/// board.place_piece(ChessPiece::new(Pawn, White), original_position.0, original_position.1);
///
/// let game_move = ChessMoveType::Move {
/// original_position,
/// new_position: (0, 2),
/// piece: *board.get_piece_at_space(original_position.0, original_position.1).unwrap(),
/// taken_piece: None,
/// promotion: None,
/// };
///
/// assert!(board.get_piece_at_space(0, 2).is_none());
/// game_move.make_move(&mut board);
///
/// assert!(board.get_piece_at_space(original_position.0, original_position.1).is_none());
/// assert_eq!(Pawn, board.get_piece_at_space(0, 2).unwrap().get_piece_type());
/// assert_eq!(White, board.get_piece_at_space(0, 2).unwrap().get_color());
/// ```
pub fn make_move(&self, board: &mut Board<ChessPiece>) {
match self {
ChessMoveType::Move {
original_position,
new_position,
promotion,
..
} => {
let piece = board
.remove_piece(original_position.0, original_position.1)
.unwrap();
Self::place_piece(board, new_position, piece, *promotion);
}
ChessMoveType::EnPassant {
original_position,
new_position,
taken_piece_position,
promotion,
..
} => {
let moving_pawn = board
.remove_piece(original_position.0, original_position.1)
.unwrap();
board.remove_piece(taken_piece_position.0, taken_piece_position.1);
Self::place_piece(board, new_position, moving_pawn, *promotion);
}
ChessMoveType::Castle {
rook_original_position,
rook_new_position,
king_original_position,
king_new_position,
} => {
let rook = board
.remove_piece(rook_original_position.0, rook_original_position.1)
.unwrap();
let king = board
.remove_piece(king_original_position.0, king_original_position.1)
.unwrap();
board.place_piece(rook, rook_new_position.0, rook_new_position.1);
board.place_piece(king, king_new_position.0, king_new_position.1);
}
}
}
pub fn undo_move(&self, board: &mut Board<ChessPiece>) {
match self {
ChessMoveType::Move {
original_position,
new_position,
piece,
taken_piece,
..
} => {
Self::place_piece(board, original_position, *piece, None);
board.remove_piece(new_position.0, new_position.1);
if let Some(taken_piece) = taken_piece {
Self::place_piece(board, new_position, *taken_piece, None);
}
}
ChessMoveType::EnPassant {
original_position,
new_position,
piece,
taken_piece,
taken_piece_position,
..
} => {
Self::place_piece(board, original_position, *piece, None);
Self::place_piece(board, taken_piece_position, *taken_piece, None);
board.remove_piece(new_position.0, new_position.1);
}
ChessMoveType::Castle {
rook_original_position,
rook_new_position,
king_original_position,
king_new_position,
} => {
let rook = board
.remove_piece(rook_new_position.0, rook_new_position.1)
.unwrap();
let king = board
.remove_piece(king_new_position.0, king_new_position.1)
.unwrap();
board.place_piece(rook, rook_original_position.0, rook_original_position.1);
board.place_piece(king, king_original_position.0, king_original_position.1);
}
}
}
fn place_piece(
board: &mut Board<ChessPiece>,
new_position: &(usize, usize),
piece: ChessPiece,
promotion: Option<ChessPiece>,
) {
match promotion {
Some(promotion) => board.place_piece(promotion, new_position.0, new_position.1),
None => board.place_piece(piece, new_position.0, new_position.1),
}
}
}
impl Display for ChessMoveType {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
match self {
ChessMoveType::Move {
original_position,
new_position,
piece,
taken_piece,
promotion,
} => {
let take_string = if let Some(taken_piece) = taken_piece {
format!("takes {:?}", taken_piece.get_piece_type())
} else {
String::from("moves")
};
let promotion_string = if let Some(promotion) = promotion {
format!("promotes to {:?}", promotion.get_piece_type())
} else {
String::new()
};
write!(
f,
"{:?} at {} {} at {} {}",
piece.get_piece_type(),
get_square_name_from_row_and_col(original_position.0, original_position.1),
take_string,
get_square_name_from_row_and_col(new_position.0, new_position.1),
promotion_string
)
}
ChessMoveType::EnPassant {
original_position, ..
} => {
write!(f, "en passant from {:?}", original_position)
}
ChessMoveType::Castle { .. } => {
write!(f, "Castle")
}
}
}
}