"""
smoothing.py
Simple exponential smoothing and plotting for time series data.
"""

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
from statsmodels.tsa.holtwinters import SimpleExpSmoothing

def simple_exponential_smoothing(series, smoothing_level=None, optimized=True):
    """Apply Simple Exponential Smoothing to a pandas Series."""
    model = SimpleExpSmoothing(series.dropna())
    fit = model.fit(smoothing_level=smoothing_level, optimized=optimized)
    return fit.fittedvalues, fit

def plot_ses(series, smoothing_level=None, optimized=True, title='Simple Exponential Smoothing'):
    """Plot original series and SES smoothed series."""
    fitted_values, _ = simple_exponential_smoothing(series, smoothing_level, optimized)
    plt.figure(figsize=(10,6))
    plt.plot(series, label='Original', color='blue')
    plt.plot(fitted_values, label='SES Smoothed', color='green')
    plt.title(title)
    plt.legend(loc='best')
    plt.show()