chessfriend/core/src/pieces.rs

// Eryn Wells <eryn@erynwells.me>

mod display;

pub use self::display::{PieceDisplay, PieceDisplayStyle};

use crate::{Color, Shape, Square};

#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub struct Piece {
    pub color: Color,
    pub shape: Shape,
}

macro_rules! piece_constructor {
    ($func_name:ident, $type:tt) => {
        #[must_use]
        pub fn $func_name(color: Color) -> Piece {
            Piece {
                color,
                shape: Shape::$type,
            }
        }
    };
}

macro_rules! is_shape {
    ($func_name:ident, $shape:ident) => {
        #[must_use]
        pub fn $func_name(&self) -> bool {
            self.shape == Shape::$shape
        }
    };
}

impl Piece {
    #[must_use]
    pub fn new(color: Color, shape: Shape) -> Piece {
        Piece { color, shape }
    }

    piece_constructor!(pawn, Pawn);
    piece_constructor!(knight, Knight);
    piece_constructor!(bishop, Bishop);
    piece_constructor!(rook, Rook);
    piece_constructor!(queen, Queen);
    piece_constructor!(king, King);

    is_shape!(is_pawn, Pawn);
    is_shape!(is_knight, Knight);
    is_shape!(is_bishop, Bishop);
    is_shape!(is_rook, Rook);
    is_shape!(is_queen, Queen);
    is_shape!(is_king, King);

    #[must_use]
    pub fn to_ascii(self) -> char {
        let ch = self.shape.to_ascii();
        match self.color {
            Color::White => ch,
            Color::Black => ch.to_ascii_lowercase(),
        }
    }

    #[must_use]
    fn to_unicode(self) -> char {
        match (self.color, self.shape) {
            (Color::Black, Shape::Pawn) => '♟',
            (Color::Black, Shape::Knight) => '♞',
            (Color::Black, Shape::Bishop) => '♝',
            (Color::Black, Shape::Rook) => '♜',
            (Color::Black, Shape::Queen) => '♛',
            (Color::Black, Shape::King) => '♚',
            (Color::White, Shape::Pawn) => '♙',
            (Color::White, Shape::Knight) => '♘',
            (Color::White, Shape::Bishop) => '♗',
            (Color::White, Shape::Rook) => '♖',
            (Color::White, Shape::Queen) => '♕',
            (Color::White, Shape::King) => '♔',
        }
    }
}

impl std::fmt::Display for Piece {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}",
            PieceDisplay {
                piece: *self,
                style: PieceDisplayStyle::default()
            }
        )
    }
}

impl From<PlacedPiece> for Piece {
    fn from(value: PlacedPiece) -> Self {
        value.piece
    }
}

impl From<&PlacedPiece> for Piece {
    fn from(value: &PlacedPiece) -> Self {
        value.piece
    }
}

#[deprecated]
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub struct PlacedPiece {
    pub piece: Piece,
    pub square: Square,
}

macro_rules! is_shape {
    ($func_name:ident, $shape:ident) => {
        #[must_use]
        pub fn $func_name(&self) -> bool {
            self.piece().shape == Shape::$shape
        }
    };
}

impl PlacedPiece {
    #[must_use]
    pub const fn new(piece: Piece, square: Square) -> PlacedPiece {
        PlacedPiece { piece, square }
    }

    /// The [Piece] itself
    #[inline]
    #[must_use]
    pub fn piece(&self) -> Piece {
        self.piece
    }

    is_shape!(is_pawn, Pawn);
    is_shape!(is_knight, Knight);
    is_shape!(is_bishop, Bishop);
    is_shape!(is_rook, Rook);
    is_shape!(is_queen, Queen);
    is_shape!(is_king, King);

    #[must_use]
    pub fn is_kingside_rook(&self) -> bool {
        self.is_rook()
            && match self.piece.color {
                Color::White => self.square == Square::H1,
                Color::Black => self.square == Square::H8,
            }
    }

    #[must_use]
    pub fn is_queenside_rook(&self) -> bool {
        self.is_rook()
            && match self.piece.color {
                Color::White => self.square == Square::A1,
                Color::Black => self.square == Square::A8,
            }
    }
}

impl std::fmt::Display for PlacedPiece {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}{}", self.piece, self.square)
    }
}

impl From<(&Square, &Piece)> for PlacedPiece {
    fn from(value: (&Square, &Piece)) -> Self {
        PlacedPiece::new(*value.1, *value.0)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn shape_try_from() {
        assert_eq!(Shape::try_from('p'), Ok(Shape::Pawn));
        assert_eq!(Shape::try_from("p"), Ok(Shape::Pawn));
    }

    #[test]
    fn shape_into_char() {
        assert_eq!(<Shape as Into<char>>::into(Shape::Pawn), 'P');
    }
}