"""
Indicator calculation utilities for backtesting.

These functions calculate indicators directly from price data,
without requiring MT5 indicator handles.
"""

import numpy as np
import pandas as pd


def calculate_rsi(prices: pd.Series, period: int = 14) -> pd.Series:
    """Calculate RSI indicator."""
    delta = prices.diff()
    gain = (delta.where(delta > 0, 0)).rolling(window=period).mean()
    loss = (-delta.where(delta < 0, 0)).rolling(window=period).mean()
    rs = gain / loss
    rsi = 100 - (100 / (1 + rs))
    return rsi


def calculate_ema(prices: pd.Series, period: int = 50) -> pd.Series:
    """Calculate EMA indicator."""
    return prices.ewm(span=period, adjust=False).mean()


def calculate_sma(prices: pd.Series, period: int = 50) -> pd.Series:
    """Calculate SMA indicator."""
    return prices.rolling(window=period).mean()


def calculate_atr(df: pd.DataFrame, period: int = 14) -> pd.Series:
    """Calculate ATR indicator."""
    high_low = df['high'] - df['low']
    high_close = np.abs(df['high'] - df['close'].shift())
    low_close = np.abs(df['low'] - df['close'].shift())
    tr = pd.concat([high_low, high_close, low_close], axis=1).max(axis=1)
    atr = tr.rolling(window=period).mean()
    return atr


def calculate_macd(prices: pd.Series, fast: int = 12, slow: int = 26, signal: int = 9) -> pd.DataFrame:
    """Calculate MACD indicator."""
    ema_fast = prices.ewm(span=fast, adjust=False).mean()
    ema_slow = prices.ewm(span=slow, adjust=False).mean()
    macd = ema_fast - ema_slow
    signal_line = macd.ewm(span=signal, adjust=False).mean()
    histogram = macd - signal_line
    
    return pd.DataFrame({
        'macd': macd,
        'signal': signal_line,
        'histogram': histogram
    })