from pandas import DataFrame, Series
from daily_data import get_daily_data

def signals(data: DataFrame) -> Series:
    """
    Generate long signals based on the Decline / Advance Ratio strategy.

    Returns a Series with 'L' for long signals and 'N' for no signal.
    """
    above_200_ma = data['Close'] > data['Close'].rolling(window = 200).mean()

    start_date = data['Date'].min()
    end_date = data['Date'].max()
    advances = get_daily_data(symbol = 'IINA.Z', start_date = start_date, end_date = end_date)
    declines = get_daily_data(symbol = 'IIND.Z', start_date = start_date, end_date = end_date)

    ratio = declines['Close'] / advances['Close']
    ratio_greater_than_2 = ratio >= 2

    signals = Series('N', index = data.index)
    signals[above_200_ma & ratio_greater_than_2] = 'L'
    return signals