# sid_hashers.py

from abc import ABC, abstractmethod
import hashlib


# ---------------------------------------------------------------------
# Structural hash strategy interface
# ---------------------------------------------------------------------

class StructureHashStrategy(ABC):
    """
    Abstract interface for derivation / structural hashers.
    """

    @abstractmethod
    def hash_struct(self, payload: bytes) -> str:
        """
        Hash a byte payload deterministically and return hex digest.
        """
        pass


# ---------------------------------------------------------------------
# SHA-256 default implementation
# ---------------------------------------------------------------------

class SHA256SIDHash(StructureHashStrategy):
    """
    Default SHA-256 SID hasher.
    """

    name = "sha256.sid.v1"

    def hash_struct(self, payload: bytes) -> str:
        h = hashlib.sha256()
        h.update(payload)
        return h.hexdigest()