hass-core/app/observer/WeatherWatcher.py
2013-09-21 17:59:31 -07:00

61 lines
2 KiB
Python

import logging
from datetime import timedelta
import ephem
from app.observer.Timer import track_time_change
STATE_CATEGORY_SUN = "weather.sun"
SUN_STATE_ABOVE_HORIZON = "above_horizon"
SUN_STATE_BELOW_HORIZON = "below_horizon"
class WeatherWatcher(object):
""" Class that keeps track of the state of the sun. """
def __init__(self, config, eventbus, statemachine):
self.logger = logging.getLogger(__name__)
self.config = config
self.eventbus = eventbus
self.statemachine = statemachine
self.observer = ephem.Observer()
self.observer.lat = self.config.get('common','latitude')
self.observer.long = self.config.get('common','longitude')
self.sun = ephem.Sun()
statemachine.add_category(STATE_CATEGORY_SUN, SUN_STATE_BELOW_HORIZON)
self._update_sun_state()
def next_sun_rising(self):
""" Returns a datetime object that points at the next sun rising. """
return ephem.localtime(self.observer.next_rising(self.sun))
def next_sun_setting(self):
""" Returns a datetime object that points at the next sun setting. """
return ephem.localtime(self.observer.next_setting(self.sun))
def _update_sun_state(self, now=None):
""" Updates the state of the sun and schedules when to check next. """
next_rising = self.next_sun_rising()
next_setting = self.next_sun_setting()
if next_rising > next_setting:
new_state = SUN_STATE_ABOVE_HORIZON
next_change = next_setting
else:
new_state = SUN_STATE_BELOW_HORIZON
next_change = next_rising
self.logger.info("Sun:{}. Next change: {}".format(new_state, next_change.strftime("%H:%M")))
self.statemachine.set_state(STATE_CATEGORY_SUN, new_state)
# +10 seconds to be sure that the change has occured
track_time_change(self.eventbus, self._update_sun_state, point_in_time=next_change + timedelta(seconds=10))