"""Stable ID helpers for Atlas.

These functions keep entity and claim identifiers deterministic across the app.
The same stable hash should be used for:
- atlas_id / entity IRI fragments
- claim IDs
- claim IRIs in Turtle exports

Semantics live in triples; the IDs themselves stay opaque.
"""

from __future__ import annotations

import hashlib


def stable_hash(*parts: str, length: int = 16) -> str:
    material = "|".join((part or "").strip() for part in parts)
    return hashlib.sha1(material.encode("utf-8")).hexdigest()[:length]


def claim_hash(
    subject: str,
    predicate: str,
    object_value: str,
    layer: str,
    status: str = "active",
    created_at: str | None = None,
) -> str:
    return stable_hash(subject, predicate, object_value, layer, status, created_at or "")


def entity_hash(*parts: str, length: int = 16) -> str:
    return stable_hash(*parts, length=length)