"""Abstract base class for trading strategies."""

from abc import ABC, abstractmethod

from shared.schemas.trading import MarketSnapshot, SentimentContext, TradeSignal


class BaseStrategy(ABC):
    """Interface that every trading strategy must implement.

    Each strategy evaluates market conditions (and optionally sentiment)
    for a given ticker and returns a ``TradeSignal`` if the strategy has
    an opinion, or ``None`` if it is neutral.
    """

    name: str

    @abstractmethod
    async def evaluate(
        self,
        ticker: str,
        market: MarketSnapshot,
        sentiment: SentimentContext | None = None,
    ) -> TradeSignal | None:
        """Return a signal if this strategy has an opinion, ``None`` otherwise."""
        ...