TCPDashboard/strategies/implementations/ema_crossover.py

"""
EMA Crossover Strategy Implementation

This module implements an Exponential Moving Average (EMA) Crossover trading strategy.
It extends the BaseStrategy and generates buy/sell signals based on the crossover
of a fast EMA and a slow EMA.
"""

import pandas as pd
from typing import List, Dict, Any

from ..base import BaseStrategy
from ..data_types import StrategyResult, StrategySignal, SignalType
from ..utils import create_indicator_key, detect_crossover_signals_vectorized


class EMAStrategy(BaseStrategy):
    """
    EMA Crossover Strategy.

    Generates buy/sell signals when a fast EMA crosses above or below a slow EMA.
    """

    def __init__(self, logger=None):
        super().__init__(logger)
        self.strategy_name = "ema_crossover"

    def get_required_indicators(self) -> List[Dict[str, Any]]:
        """
        Defines the indicators required by the EMA Crossover strategy.
        It needs two EMA indicators: a fast one and a slow one.
        """
        # Default periods for EMA crossover, can be overridden by strategy config
        return [
            {'type': 'ema', 'period': 12, 'price_column': 'close'},
            {'type': 'ema', 'period': 26, 'price_column': 'close'}
        ]

    def calculate(self, df: pd.DataFrame, indicators_data: Dict[str, pd.DataFrame], **kwargs) -> List[StrategyResult]:
        """
        Calculate EMA Crossover strategy signals.

        Args:
            df: DataFrame with OHLCV data.
            indicators_data: Dictionary of pre-calculated indicator DataFrames.
                             Expected keys: 'ema_period_12', 'ema_period_26'.
            **kwargs: Additional strategy parameters (e.g., fast_period, slow_period, price_column).

        Returns:
            List of StrategyResult objects, each containing generated signals.
        """
        # Extract EMA periods from kwargs or use defaults
        fast_period = kwargs.get('fast_period', 12)
        slow_period = kwargs.get('slow_period', 26)
        price_column = kwargs.get('price_column', 'close')

        # Generate indicator keys using shared utility function
        fast_ema_key = create_indicator_key({'type': 'ema', 'period': fast_period})
        slow_ema_key = create_indicator_key({'type': 'ema', 'period': slow_period})

        # Validate that the main DataFrame has enough data for strategy calculation (not just indicators)
        if not self.validate_dataframe(df, max(fast_period, slow_period)):
            if self.logger:
                self.logger.warning(f"{self.strategy_name}: Insufficient main DataFrame for calculation.")
            return []

        # Validate that the required indicators are present and have sufficient data
        required_indicators = [
            {'type': 'ema', 'period': fast_period},
            {'type': 'ema', 'period': slow_period}
        ]
        if not self.validate_indicators_data(indicators_data, required_indicators):
            if self.logger:
                self.logger.warning(f"{self.strategy_name}: Missing or insufficient indicator data.")
            return []

        fast_ema_df = indicators_data.get(fast_ema_key)
        slow_ema_df = indicators_data.get(slow_ema_key)

        if fast_ema_df is None or slow_ema_df is None or fast_ema_df.empty or slow_ema_df.empty:
            if self.logger:
                self.logger.warning(f"{self.strategy_name}: EMA indicator DataFrames are not found or empty.")
            return []

        # Merge all necessary data into a single DataFrame for easier processing
        # Ensure alignment by index (timestamp)
        merged_df = pd.merge(df[[price_column, 'symbol', 'timeframe']], 
                             fast_ema_df[['ema']], 
                             left_index=True, right_index=True, how='inner',
                             suffixes= ('', '_fast'))
        merged_df = pd.merge(merged_df, 
                             slow_ema_df[['ema']], 
                             left_index=True, right_index=True, how='inner',
                             suffixes= ('', '_slow'))

        # Rename columns to their logical names after merge
        merged_df.rename(columns={'ema': 'ema_fast', 'ema_slow': 'ema_slow'}, inplace=True)

        if merged_df.empty:
            if self.logger:
                self.logger.warning(f"{self.strategy_name}: Merged DataFrame is empty after indicator alignment. Check data ranges.")
            return []

        # Use vectorized signal detection for better performance
        bullish_crossover, bearish_crossover = detect_crossover_signals_vectorized(
            merged_df, 'ema_fast', 'ema_slow'
        )
        
        results: List[StrategyResult] = []
        strategy_metadata = {
            'fast_period': fast_period,
            'slow_period': slow_period
        }

        # Process bullish crossover signals
        bullish_indices = merged_df[bullish_crossover].index
        for timestamp in bullish_indices:
            row = merged_df.loc[timestamp]
            
            # Skip if any EMA values are NaN
            if pd.isna(row['ema_fast']) or pd.isna(row['ema_slow']):
                continue
                
            signal = StrategySignal(
                timestamp=timestamp,
                symbol=row['symbol'],
                timeframe=row['timeframe'],
                signal_type=SignalType.BUY,
                price=float(row[price_column]),
                confidence=0.8,
                metadata={'crossover_type': 'bullish', **strategy_metadata}
            )
            
            results.append(StrategyResult(
                timestamp=timestamp,
                symbol=row['symbol'],
                timeframe=row['timeframe'],
                strategy_name=self.strategy_name,
                signals=[signal],
                indicators_used={
                    'ema_fast': float(row['ema_fast']),
                    'ema_slow': float(row['ema_slow'])
                },
                metadata=strategy_metadata
            ))
            
            if self.logger:
                self.logger.info(f"{self.strategy_name}: BUY signal at {timestamp} for {row['symbol']}")

        # Process bearish crossover signals
        bearish_indices = merged_df[bearish_crossover].index
        for timestamp in bearish_indices:
            row = merged_df.loc[timestamp]
            
            # Skip if any EMA values are NaN
            if pd.isna(row['ema_fast']) or pd.isna(row['ema_slow']):
                continue
                
            signal = StrategySignal(
                timestamp=timestamp,
                symbol=row['symbol'],
                timeframe=row['timeframe'],
                signal_type=SignalType.SELL,
                price=float(row[price_column]),
                confidence=0.8,
                metadata={'crossover_type': 'bearish', **strategy_metadata}
            )
            
            results.append(StrategyResult(
                timestamp=timestamp,
                symbol=row['symbol'],
                timeframe=row['timeframe'],
                strategy_name=self.strategy_name,
                signals=[signal],
                indicators_used={
                    'ema_fast': float(row['ema_fast']),
                    'ema_slow': float(row['ema_slow'])
                },
                metadata=strategy_metadata
            ))
            
            if self.logger:
                self.logger.info(f"{self.strategy_name}: SELL signal at {timestamp} for {row['symbol']}")

        return results