# EnergyPrice.py
from __future__ import annotations
from dataclasses import dataclass
from datetime import datetime
import zoneinfo
from utils.time_helpers import WARSAW_TZ

@dataclass
class EnergyPriceBase:
    tz: zoneinfo.ZoneInfo = WARSAW_TZ

    def to_local_dt(self, ts: datetime) -> datetime:
        if ts.tzinfo is None:
            return ts.replace(tzinfo=self.tz)
        return ts.astimezone(self.tz)

    def has_rate(self, ts: datetime) -> bool:
        try:
            self.rate(ts)
            return True
        except KeyError:
            return False

    def rate(self, ts: datetime) -> float:
        """Return PLN/kWh (net) for given timestamp (override in subclasses)."""
        raise NotImplementedError

    def cost(self, ts: datetime, consumption_kwh: float) -> float:
        return self.rate(ts) * float(consumption_kwh)