from __future__ import annotations

from typing import List, Tuple

from .core import DeltaStore, Morphism, Object, PlanDelta


class DeltaSyncEngine:
    """Lightweight offline-first delta-sync engine."""

    def __init__(self, store: DeltaStore | None = None) -> None:
        self.store = store or DeltaStore()
        self.remote_version = 0
        self.local_version = 0

    def apply_delta(self, delta: PlanDelta) -> None:
        if any(existing.delta_id == delta.delta_id for existing in self.store.deltas):
            return
        self.store.add_delta(delta)
        self.local_version += 1

    def snapshot(self) -> List[PlanDelta]:
        return list(self.store.deltas)

    def delta_with_cipher(self, delta: PlanDelta) -> Tuple[PlanDelta, str]:
        delta.tags["hash"] = f"hash-{delta.delta_id}-{self.local_version}"
        return delta, delta.tags["hash"]


__all__ = ["DeltaSyncEngine", "DeltaStore", "Object", "Morphism", "PlanDelta"]