#!/usr/bin/env python3
import sys
import time
import numpy as np
from typing import List

from common.realtime import Ratekeeper

def average(avg, sample):
  # Weighted avg between existing value and new sample
  return ((avg[0] * avg[1] + sample) / (avg[1] + 1), avg[1] + 1)


def sample_power(seconds=5) -> List[float]:
  rate = 123
  rk = Ratekeeper(rate, print_delay_threshold=None)

  pwrs = []
  for _ in range(rate*seconds):
    with open("/sys/bus/i2c/devices/0-0040/hwmon/hwmon1/power1_input") as f:
      pwrs.append(int(f.read()) / 1e6)
    rk.keep_time()
  return pwrs

def get_power(seconds=5):
  pwrs = sample_power(seconds)
  return np.mean(pwrs)


if __name__ == '__main__':

  sample_time = None
  if len(sys.argv) > 1:
    sample_time = int(sys.argv[1])

  start_time = time.monotonic()
  try:
    voltage_average = (0, 0)  # average, count
    current_average = (0, 0)
    power_average = (0, 0)
    while sample_time is None or time.monotonic() - start_time < sample_time:
      with open("/sys/bus/i2c/devices/0-0040/hwmon/hwmon1/in1_input") as f:
        voltage_total = int(f.read()) / 1000.

      with open("/sys/bus/i2c/devices/0-0040/hwmon/hwmon1/curr1_input") as f:
        current_total = int(f.read())

      # SOM measurements are questionable
      #with open("/sys/class/power_supply/bms/voltage_now") as f:
      #  voltage = int(f.read()) / 1e6   # volts
      #with open("/sys/class/power_supply/bms/current_now") as f:
      #  current = int(f.read()) / 1e3   # ma

      power_total = voltage_total*current_total

      # compute averages
      voltage_average = average(voltage_average, voltage_total)
      current_average = average(current_average, current_total)
      power_average = average(power_average, power_total)

      print(f"now: {power_total:.2f} mW, avg: {power_average[0]:.2f} mW")
      time.sleep(0.25)
  except KeyboardInterrupt:
    pass
  finally:
    stop_time = time.monotonic()
    print("\n----------------------Average-----------------------------------")
    voltage = voltage_average[0]
    current = current_average[0]
    power = power_average[0]
    print(f"{voltage:.2f} volts {current:12.2f} ma {power:12.2f} mW {power_total:12.2f} mW")
    print(f"  {stop_time - start_time:.2f} Seconds     {voltage_average[1]} samples")
    print("----------------------------------------------------------------")