from __future__ import annotations

from typing import Dict, Any

class DERControllerAdapter:
    """Stub DER inverter controller adapter for MVP."""

    def __init__(self, site_id: str):
        self.site_id = site_id

    def build_initial_state(self) -> Dict[str, Any]:
        # Minimal initial state for a DER site
        return {"site_id": self.site_id, "state": "idle", "dispatch": {}}

    def apply_delta(self, plan_delta: Dict[str, Any]) -> Dict[str, Any]:
        # In a real adapter, apply delta to local DERs. Here we echo back.
        return {"site_id": self.site_id, "applied": plan_delta}