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use crate::Color;
/// What castle rights does a particular player have?
///
/// > rule: <https://en.wikipedia.org/wiki/Castling>
#[derive(Debug, Clone, Copy, PartialOrd, PartialEq, Eq)]
pub enum CastleRights {
/// No right to Castle.
NoRights,
/// Right to Castle only on King side (little Castle).
KingSide,
/// Right to Castle only on Queen side (big Castle).
QueenSide,
/// Right to Castle in both side (little and big Castle).
Both,
}
impl CastleRights {
/// Convert [`usize`] to [`CastleRights`].
///
/// # Panics
///
/// Panic if index is not in range 0..=3.
pub fn from_index(index: usize) -> CastleRights {
match index {
0 => CastleRights::NoRights,
1 => CastleRights::KingSide,
2 => CastleRights::QueenSide,
3 => CastleRights::Both,
e => panic!("IndexError for CastleRights: {}", e),
}
}
/// Convert [`CastleRights`] to [`usize`].
pub fn to_index(&self) -> usize {
*self as usize
}
/// Check the castling on the king side.
pub fn has_kingside(&self) -> bool {
self.to_index() & 1 == 1
}
/// Check the castling on the queen side.
pub fn has_queenside(&self) -> bool {
self.to_index() & 2 == 2
}
/// Convert the castle rights to an FEN compatible [`String`].
///
/// ```
/// use chess::{CastleRights, Color};
///
/// assert_eq!(CastleRights::NoRights.to_string(Color::Black), "");
/// assert_eq!(CastleRights::KingSide.to_string(Color::White), "K");
/// assert_eq!(CastleRights::QueenSide.to_string(Color::Black), "q");
/// assert_eq!(CastleRights::Both.to_string(Color::White), "KQ");
/// ```
pub fn to_string(&self, color: Color) -> String {
let result = match *self {
CastleRights::NoRights => "",
CastleRights::KingSide => "k",
CastleRights::QueenSide => "q",
CastleRights::Both => "kq",
};
match color {
Color::White => result.to_uppercase(),
Color::Black => result.to_string(),
}
}
}