use sp_std::vec::Vec;

pub trait GhostHasher {
    type Hash: PartialEq + Copy + AsRef<[u8]> + AsMut<[u8]>;
    type HashBytes: AsRef<[u8]> + AsMut<[u8]> + TryFrom<Vec<u8>> + Default;

    fn from_slice(bytes: &[u8]) -> Self::Hash {
        let mut target_hash = Self::empty();

        let hash_buffer = target_hash.as_mut();
        let copy_len = bytes.len().min(hash_buffer.len());

        hash_buffer[..copy_len].copy_from_slice(&bytes[..copy_len]);

        target_hash
    }

    fn hash_to_bytes(hash: Self::Hash) -> Self::HashBytes {
        let mut bytes = Self::HashBytes::default();
        bytes.as_mut().copy_from_slice(hash.as_ref());
        bytes
    }

    fn hash(data: &[u8]) -> Self::Hash;
    fn empty() -> Self::Hash;
    fn hash_len() -> usize;
}