import time
import os

RAPL_PATH = "/sys/class/powercap/intel-rapl:0/energy_uj"

def read_energy():
    try:
        with open(RAPL_PATH, "r") as f:
            return int(f.read().strip())
    except FileNotFoundError:
        print(f"Error: {RAPL_PATH} not found.")
        exit(1)

def calculate_power(interval=1.0):
    print(f"Monitoring CPU package power every {interval} second(s)... (Ctrl+C to stop)")
    while True:
        energy_before = read_energy()
        time.sleep(interval)
        energy_after = read_energy()

        delta_uj = energy_after - energy_before
        power_watts = (delta_uj / 1_000_000) / interval

        print(f"Power Usage: {power_watts:.2f} Watts")

if __name__ == "__main__":
    if os.geteuid() != 0:
        print("Please run this script as root.")
        exit(1)
    try:
        calculate_power(interval=1.0)
    except KeyboardInterrupt:
        print("\nStopped.")