# utils/feature_engineering.py
import pandas as pd
import numpy as np

def feature_engineering(df):
    df['hour_of_day'] = pd.to_datetime(df['timestamp']).dt.hour
    df['day_of_week'] = pd.to_datetime(df['timestamp']).dt.dayofweek
    df['amount_times_hour'] = df['amount'] * df['hour_of_day']
    df['log_amount'] = df['amount'].apply(lambda x: 0 if x == 0 else np.log(x + 1))
    df = df.drop(['timestamp', 'amount'], axis=1)
    return df