from __future__ import annotations

from typing import Dict, List
from .schema import SignalNode, Edge, HedgePlan


class DeterministicReplayEngine:
    """A tiny deterministic replay engine for applying deltas to a stored graph state."""

    def __init__(self) -> None:
        pass

    def apply_delta(self, state: Dict[str, object], delta: Dict[str, object]) -> Dict[str, object]:
        """Apply a delta to a state dict in a deterministic way.
        This is a minimal placeholder: keys in delta override state.
        """
        new_state = dict(state)
        for k, v in delta.items():
            new_state[k] = v
        return new_state

    def replay(self, base_state: Dict[str, object], deltas: List[Dict[str, object]]) -> Dict[str, object]:
        state = dict(base_state)
        for d in deltas:
            state = self.apply_delta(state, d)
        return state