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use square::Square;
use bitboard::Bitboard;
use attacks;
use types::{CastlingSide, Color, Pockets, RemainingChecks, Role};
use board::Board;
use option_filter::OptionFilterExt;
pub trait Setup {
fn board(&self) -> &Board;
fn pockets(&self) -> Option<&Pockets>;
fn turn(&self) -> Color;
fn castling_rights(&self) -> Bitboard;
fn ep_square(&self) -> Option<Square>;
fn remaining_checks(&self) -> Option<&RemainingChecks>;
fn halfmove_clock(&self) -> u32;
fn fullmoves(&self) -> u32;
fn us(&self) -> Bitboard {
self.board().by_color(self.turn())
}
fn our(&self, role: Role) -> Bitboard {
self.us() & self.board().by_role(role)
}
fn them(&self) -> Bitboard {
self.board().by_color(!self.turn())
}
fn their(&self, role: Role) -> Bitboard {
self.them() & self.board().by_role(role)
}
}
pub struct SwapTurn<S: Setup>(pub S);
impl<S: Setup> Setup for SwapTurn<S> {
fn turn(&self) -> Color {
!self.0.turn()
}
fn board(&self) -> &Board { self.0.board() }
fn pockets(&self) -> Option<&Pockets> { self.0.pockets() }
fn castling_rights(&self) -> Bitboard { self.0.castling_rights() }
fn ep_square(&self) -> Option<Square> { self.0.ep_square() }
fn remaining_checks(&self) -> Option<&RemainingChecks> { self.0.remaining_checks() }
fn halfmove_clock(&self) -> u32 { self.0.halfmove_clock() }
fn fullmoves(&self) -> u32 { self.0.fullmoves() }
}
#[derive(Clone, Debug)]
pub struct Castling {
chess960: bool,
rook: [[Option<Square>; 2]; 2],
path: [[Bitboard; 2]; 2],
}
impl Castling {
pub fn empty() -> Castling {
Castling {
chess960: false,
rook: [[None; 2]; 2],
path: [[Bitboard(0); 2]; 2],
}
}
pub fn default() -> Castling {
Castling {
chess960: false,
rook: [
[Some(Square::H8), Some(Square::A8)],
[Some(Square::H1), Some(Square::A1)],
],
path: [
[Bitboard(0x6000_0000_0000_0000), Bitboard(0x0e00_0000_0000_0000)],
[Bitboard(0x0000_0000_0000_0060), Bitboard(0x0000_0000_0000_000e)],
]
}
}
pub fn from_setup(setup: &Setup) -> Result<Castling, Castling> {
let mut castling = Castling::empty();
let castling_rights = setup.castling_rights();
let rooks = castling_rights & setup.board().rooks();
for color in &[Color::Black, Color::White] {
if let Some(king) = setup.board().king_of(*color) {
if king.file() == 0 || king.file() == 7 || king.rank() != color.fold(0, 7) {
continue;
}
let side = rooks & setup.board().by_color(*color) &
Bitboard::relative_rank(*color, 0);
if let Some(a_side) = OptionFilterExt::filter(side.first(), |rook| rook.file() < king.file()) {
let rto = CastlingSide::QueenSide.rook_to(*color);
let kto = CastlingSide::QueenSide.king_to(*color);
castling.chess960 |= king.file() != 4 || a_side.file() != 0;
castling.rook[*color as usize][CastlingSide::QueenSide as usize] = Some(a_side);
castling.path[*color as usize][CastlingSide::QueenSide as usize] =
attacks::between(king, a_side).with(rto).with(kto).without(king).without(a_side);
}
if let Some(h_side) = OptionFilterExt::filter(side.last(), |rook| king.file() < rook.file()) {
let rto = CastlingSide::KingSide.rook_to(*color);
let kto = CastlingSide::KingSide.king_to(*color);
castling.chess960 |= king.file() != 4 || h_side.file() != 7;
castling.rook[*color as usize][CastlingSide::KingSide as usize] = Some(h_side);
castling.path[*color as usize][CastlingSide::KingSide as usize] =
attacks::between(king, h_side).with(rto).with(kto).without(king).without(h_side);
}
}
}
if castling.castling_rights() == castling_rights {
Ok(castling)
} else {
Err(castling)
}
}
pub fn discard_rook(&mut self, square: Square) {
self.rook[0][0] = OptionFilterExt::filter(self.rook[0][0], |sq| *sq != square);
self.rook[0][1] = OptionFilterExt::filter(self.rook[0][1], |sq| *sq != square);
self.rook[1][0] = OptionFilterExt::filter(self.rook[1][0], |sq| *sq != square);
self.rook[1][1] = OptionFilterExt::filter(self.rook[1][1], |sq| *sq != square);
}
pub fn discard_side(&mut self, color: Color) {
self.rook[color as usize] = [None, None];
}
#[inline]
pub fn rook(&self, color: Color, side: CastlingSide) -> Option<Square> {
self.rook[color as usize][side as usize]
}
#[inline]
pub fn path(&self, color: Color, side: CastlingSide) -> Bitboard {
self.path[color as usize][side as usize]
}
pub fn castling_rights(&self) -> Bitboard {
let mut mask = Bitboard(0);
mask.extend(self.rook[0][0]);
mask.extend(self.rook[0][1]);
mask.extend(self.rook[1][0]);
mask.extend(self.rook[1][1]);
mask
}
pub fn is_chess960(&self) -> bool {
self.chess960
}
}
#[cfg(test)]
mod tests {
use super::*;
struct _AssertObjectSafe(Box<Setup>);
}