use crate::position::Level;

/// A trait describing the operations that make a type suitable for use as
/// a leaf or node value in a merkle tree.
pub trait Hashable: Sized {
    fn empty_leaf() -> Self;

    fn combine(level: Level, a: &Self, b: &Self) -> Self;

    fn empty_root(level: Level) -> Self {
        Level::from(0)
            .iter_to(level)
            .fold(Self::empty_leaf(), |v, lvl| Self::combine(lvl, &v, &v))
    }
}