from pandas import DataFrame, Series

from ohlc import ohlc

def signals(data: DataFrame) -> Series:
    """
    Generate long signals based on the VIX 15-day high strategy.
    Returns a Series with 'L' for long signals and 'N' for no signal.
    """
    ma_200 = data['Close'].rolling(window = 200).mean()
    above_200_ma = data['Close'] > ma_200

    start_date = data['Date'].min()
    end_date = data['Date'].max()
    vix_data = ohlc(symbol='VIX.XO', start_date=start_date, end_date=end_date)

    vix_15_day_high = vix_data['High'] == vix_data['High'].rolling(window = 15).max()

    vix_close_below_open = vix_data['Close'] < vix_data['Open']

    signals = Series('N', index = data.index)
    signals[above_200_ma & vix_15_day_high & vix_close_below_open] = 'L'
    return signals