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use super::*;

pub trait Compress {
    type CompressedItem;

    fn compress(self) -> Self::CompressedItem;
}

pub trait Decompress<T> {
    fn decompress(self) -> T;
}

impl Compress for Option<PieceType> {
    type CompressedItem = u8;

    fn compress(self) -> Self::CompressedItem {
        match self {
            Some(piece) => piece as Self::CompressedItem + 1,
            None => 0,
        }
    }
}

impl Compress for PieceType {
    type CompressedItem = u8;

    fn compress(self) -> Self::CompressedItem {
        Some(self).compress()
    }
}

impl Compress for Square {
    type CompressedItem = u16;

    fn compress(self) -> Self::CompressedItem {
        self.to_index() as Self::CompressedItem
    }
}

impl Compress for Move {
    type CompressedItem = u16;

    fn compress(self) -> Self::CompressedItem {
        let mut compressed_move = 0;
        compressed_move ^= self.get_source().compress() << 6;
        compressed_move ^= self.get_dest().compress();
        compressed_move ^= (self.get_promotion().compress() as Self::CompressedItem) << 12;
        compressed_move
    }
}

impl Compress for Option<Move> {
    type CompressedItem = u16;

    fn compress(self) -> Self::CompressedItem {
        match self {
            Some(m) => m.compress(),
            None => Self::CompressedItem::MAX,
        }
    }
}

impl Decompress<Option<PieceType>> for u8 {
    fn decompress(self) -> Option<PieceType> {
        if self == 0 {
            return None;
        }
        Some(*get_item_unchecked!(ALL_PIECE_TYPES, (self - 1) as usize))
    }
}

impl Decompress<Option<PieceType>> for u16 {
    fn decompress(self) -> Option<PieceType> {
        (self as u8).decompress()
    }
}

impl Decompress<Square> for u16 {
    fn decompress(self) -> Square {
        *get_item_unchecked!(ALL_SQUARES, self as usize)
    }
}

impl Decompress<Option<Move>> for u16 {
    fn decompress(self) -> Option<Move> {
        if self == u16::MAX {
            return None;
        }
        let source = ((self >> 6) & 63).decompress();
        let dest = (self & 63).decompress();
        let promotion = (self >> 12).decompress();
        Some(Move::new(source, dest, promotion))
    }
}

// impl<T> Decompress<T> for CompressedObject where CompressedObject: Decompress<Option<T>> {
//     fn decompress(self) -> T {
//         self.decompress().unwrap_or_else(|| panic!("Failed to decompress"))
//     }
// }