hass-core/homeassistant/components/sun.py
2014-02-14 11:34:09 -08:00

100 lines
3 KiB
Python

"""
homeassistant.components.sun
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Provides functionality to keep track of the sun.
"""
import logging
from datetime import timedelta
import homeassistant as ha
import homeassistant.util as util
ENTITY_ID = "sun.sun"
STATE_ABOVE_HORIZON = "above_horizon"
STATE_BELOW_HORIZON = "below_horizon"
STATE_ATTR_NEXT_RISING = "next_rising"
STATE_ATTR_NEXT_SETTING = "next_setting"
def is_on(statemachine, entity_id=None):
""" Returns if the sun is currently up based on the statemachine. """
entity_id = entity_id or ENTITY_ID
return statemachine.is_state(entity_id, STATE_ABOVE_HORIZON)
def next_setting(statemachine):
""" Returns the datetime object representing the next sun setting. """
state = statemachine.get_state(ENTITY_ID)
try:
return util.str_to_datetime(state.attributes[STATE_ATTR_NEXT_SETTING])
except (AttributeError, KeyError):
# AttributeError if state is None
# KeyError if STATE_ATTR_NEXT_SETTING does not exist
return None
def next_rising(statemachine):
""" Returns the datetime object representing the next sun rising. """
state = statemachine.get_state(ENTITY_ID)
try:
return util.str_to_datetime(state.attributes[STATE_ATTR_NEXT_RISING])
except (AttributeError, KeyError):
# AttributeError if state is None
# KeyError if STATE_ATTR_NEXT_RISING does not exist
return None
def setup(bus, statemachine, latitude, longitude):
""" Tracks the state of the sun. """
logger = logging.getLogger(__name__)
try:
import ephem
except ImportError:
logger.exception("TrackSun:Error while importing dependency ephem.")
return False
sun = ephem.Sun() # pylint: disable=no-member
def update_sun_state(now): # pylint: disable=unused-argument
""" Method to update the current state of the sun and
set time of next setting and rising. """
observer = ephem.Observer()
observer.lat = latitude
observer.long = longitude
next_rising_dt = ephem.localtime(observer.next_rising(sun))
next_setting_dt = ephem.localtime(observer.next_setting(sun))
if next_rising_dt > next_setting_dt:
new_state = STATE_ABOVE_HORIZON
next_change = next_setting_dt
else:
new_state = STATE_BELOW_HORIZON
next_change = next_rising_dt
logger.info(
"Sun:{}. Next change: {}".format(new_state,
next_change.strftime("%H:%M")))
state_attributes = {
STATE_ATTR_NEXT_RISING: util.datetime_to_str(next_rising_dt),
STATE_ATTR_NEXT_SETTING: util.datetime_to_str(next_setting_dt)
}
statemachine.set_state(ENTITY_ID, new_state, state_attributes)
# +10 seconds to be sure that the change has occured
ha.track_point_in_time(bus, update_sun_state,
next_change + timedelta(seconds=10))
update_sun_state(None)
return True