"""Toy DER Aggregator Adapter with deterministic replay support."""

from dataclasses import dataclass, field
from typing import Any, Dict, List, Optional


@dataclass
class DERAggregatorAdapter:
    aggregator_id: str
    samples: Optional[List[Dict[str, Any]]] = None
    _cursor: int = field(init=False, default=0)

    def __post_init__(self) -> None:
        if self.samples is None:
            self.samples = []

    def aggregate(self) -> Dict[str, Any]:
        if self.samples:
            sample_list = self.samples
            if self._cursor >= len(sample_list):
                raise IndexError("No more DER aggregation samples available")
            reading = dict(sample_list[self._cursor])
            self._cursor += 1
            reading.setdefault("aggregator_id", self.aggregator_id)
            reading.setdefault("timestamp", self._cursor)
            reading.setdefault("status", "nominal")
            return reading

        return {
            "aggregator_id": self.aggregator_id,
            "timestamp": self._cursor,
            "total_power_kw": 500.0,  # fixed placeholder for deterministic behavior
            "status": "nominal",
        }