from core.models import Signal
from strategies.base import Strategy
from utils.indicators import ema, atr

class EmaAtr(Strategy):
    name = "ema_atr"

    def on_bar(self, symbol, df):
        p = self.p
        f, s, t = ema(df.close, p["fast"]), ema(df.close, p["slow"]), ema(df.close, p["trend"])
        a = atr(df, p["atr_period"]).iloc[-1]
        up = f.iloc[-2] <= s.iloc[-2] and f.iloc[-1] > s.iloc[-1] and df.close.iloc[-1] > t.iloc[-1]
        dn = f.iloc[-2] >= s.iloc[-2] and f.iloc[-1] < s.iloc[-1] and df.close.iloc[-1] < t.iloc[-1]
        if up or dn:
            return Signal(symbol, "buy" if up else "sell", p["sl_atr"] * a, p["tp_atr"] * a, self.name, "EMA cross")