# app/src/trading/strategies/trend.py

from __future__ import annotations

from src.integrations.exchange.service import ExchangeService
from src.trading.strategies.base import StrategyContext
from src.trading.strategies.signals import SignalResult, SignalType


class TrendStrategy:
    name = "TREND"

    _last_prices: dict[str, float] = {}
    _threshold_percent = 0.02

    # анализ простого тренда по изменению цены
    def analyze(self, context: StrategyContext) -> SignalResult:
        try:
            ticker = ExchangeService().get_price(context.symbol)
        except Exception as exc:
            return SignalResult(
                signal=SignalType.HOLD,
                reason="Не удалось получить рыночную цену. Безопасный HOLD.",
                confidence=0.0,
                payload={
                    "strategy": self.name,
                    "symbol": context.symbol,
                    "error": str(exc),
                },
            )

        symbol = ticker.symbol
        current_price = ticker.price
        previous_price = self._last_prices.get(symbol)

        self._last_prices[symbol] = current_price

        if previous_price is None or previous_price <= 0:
            return SignalResult(
                signal=SignalType.HOLD,
                reason="Недостаточно данных для определения тренда.",
                confidence=0.0,
                payload={
                    "strategy": self.name,
                    "symbol": symbol,
                    "price": current_price,
                },
            )

        change_percent = ((current_price - previous_price) / previous_price) * 100

        if change_percent >= self._threshold_percent:
            return SignalResult(
                signal=SignalType.BUY,
                reason="Цена растёт выше порога тренда.",
                confidence=min(1.0, abs(change_percent) / self._threshold_percent),
                payload={
                    "strategy": self.name,
                    "symbol": symbol,
                    "previous_price": previous_price,
                    "current_price": current_price,
                    "change_percent": round(change_percent, 5),
                },
            )

        if change_percent <= -self._threshold_percent:
            return SignalResult(
                signal=SignalType.SELL,
                reason="Цена падает ниже порога тренда.",
                confidence=min(1.0, abs(change_percent) / self._threshold_percent),
                payload={
                    "strategy": self.name,
                    "symbol": symbol,
                    "previous_price": previous_price,
                    "current_price": current_price,
                    "change_percent": round(change_percent, 5),
                },
            )

        return SignalResult(
            signal=SignalType.HOLD,
            reason="Изменение цены ниже порога тренда.",
            confidence=0.0,
            payload={
                "strategy": self.name,
                "symbol": symbol,
                "previous_price": previous_price,
                "current_price": current_price,
                "change_percent": round(change_percent, 5),
            },
        )