from __future__ import annotations

from abc import ABC, abstractmethod

from app.schemas import Candle


class MarketData(ABC):
    """Read-only market data source (candles + last price)."""

    @abstractmethod
    async def fetch_candles(self, symbol: str, timeframe: str, limit: int) -> list[Candle]:
        raise NotImplementedError

    @abstractmethod
    async def fetch_price(self, symbol: str) -> float:
        raise NotImplementedError

    async def close(self) -> None:
        return None