import pandas as pd
from strategies.base_strategy import BaseStrategy
import logging

class SingleSmaStrategy(BaseStrategy):
    """
    A strategy based on the price crossing a single Simple Moving Average (SMA).
    """
    def calculate_signals(self, df: pd.DataFrame) -> pd.DataFrame:
        sma_period = self.params.get('sma_period', 0)
        
        if not sma_period or len(df) < sma_period:
            logging.warning(f"Not enough data for SMA period {sma_period}. Need {sma_period}, have {len(df)}.")
            df['signal'] = 0
            return df
            
        df['sma'] = df['close'].rolling(window=sma_period).mean()
        
        # Signal is 1 when price is above SMA, -1 when below
        df['signal'] = 0
        df.loc[df['close'] > df['sma'], 'signal'] = 1
        df.loc[df['close'] < df['sma'], 'signal'] = -1
        
        return df