"""
weather helper
SPDX - License - Identifier: LGPL - 3.0 - or -later
Copyright © 2020 Project Author Pilar Monsalvete pilar_monsalvete@yahoo.es
"""
import math
import helpers.constants as cte


class Weather(object):
  """
  Weather class
  """

  @staticmethod
  def sky_temperature(ambient_temperature):
    """
    sky temperature from ambient temperature in degree Celsius
    :return: float
    """
    # Swinbank - Source sky model approximation(1963) based on cloudiness statistics(32 %) in United States
    # ambient temperatures( in °C)
    # sky temperatures( in °C)
    values = []
    for temperature in ambient_temperature:
      value = 0.037536 * math.pow((temperature + cte.celsius_to_kelvin), 1.5) \
              + 0.32 * (temperature + cte.celsius_to_kelvin) - cte.celsius_to_kelvin
      values.append(value)
    return values