"""Liquidity strategy — trade on volume anomalies and volume-price divergence."""

from datetime import datetime, timezone

from shared.schemas.trading import MarketSnapshot, SentimentContext, SignalDirection, TradeSignal
from shared.strategies.base import BaseStrategy


class LiquidityStrategy(BaseStrategy):
    """Generate signals based on relative volume and volume-price relationships.

    Requires at least 5 bars of historical data to compute average volume.

    **No signal** if relative_volume < 1.0 (thin liquidity).

    **Buy signal** (LONG):
        relative_volume >= 2.0 AND price is rising (close > open).

    **Sell signal** (SHORT):
        - relative_volume >= 2.0 AND price is falling (close < open), or
        - Price is rising on declining volume (relative_volume < 0.7) —
          bearish divergence.

    Signal strength = ``relative_volume / 4.0``, clamped to [0, 1].
    """

    name: str = "liquidity"

    async def evaluate(
        self,
        ticker: str,
        market: MarketSnapshot,
        sentiment: SentimentContext | None = None,
    ) -> TradeSignal | None:
        if len(market.bars) < 5:
            return None

        # Compute average volume from bars.
        volumes = [b.get("volume", 0) for b in market.bars if "volume" in b]
        if not volumes:
            return None
        avg_volume = sum(volumes) / len(volumes)
        if avg_volume <= 0:
            return None

        relative_volume = market.volume / avg_volume

        price_rising = market.close > market.open

        direction: SignalDirection | None = None

        # Bearish divergence: price rising on declining volume.
        if price_rising and relative_volume < 0.7:
            direction = SignalDirection.SHORT
        elif relative_volume < 1.0:
            # Thin liquidity — no signal.
            return None
        elif relative_volume >= 2.0:
            if price_rising:
                direction = SignalDirection.LONG
            elif market.close < market.open:
                direction = SignalDirection.SHORT
            else:
                return None
        else:
            return None

        raw_strength = relative_volume / 4.0
        strength = max(0.0, min(1.0, raw_strength))

        return TradeSignal(
            ticker=ticker,
            direction=direction,
            strength=strength,
            strategy_sources=[self.name],
            timestamp=datetime.now(tz=timezone.utc),
        )