"""
homeassistant.components.sensor.openweathermap
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

OpenWeatherMap (OWM) service.

Configuration:

To use the OpenWeatherMap sensor you will need to add something like the
following to your config/configuration.yaml

sensor:
  platform: openweathermap
  api_key: YOUR_APP_KEY
  monitored_variables:
    - type: 'weather'
    - type: 'temperature'
    - type: 'wind_speed'
    - type: 'humidity'
    - type: 'pressure'
    - type: 'clouds'
    - type: 'rain'
    - type: 'snow'

VARIABLES:

api_key
*Required
To retrieve this value log into your account at http://openweathermap.org/

monitored_variables
*Required
An array specifying the variables to monitor.

These are the variables for the monitored_variables array:

type
*Required
The variable you wish to monitor, see the configuration example above for a
list of all available variables

Details for the API : http://bugs.openweathermap.org/projects/api/wiki

Only metric measurements are supported at the moment.

"""
import logging

from homeassistant.const import (CONF_API_KEY, TEMP_CELCIUS, TEMP_FAHRENHEIT)
from homeassistant.helpers.entity import Entity

_LOGGER = logging.getLogger(__name__)
_THROTTLED_REFRESH = None
SENSOR_TYPES = {
    'weather': ['Condition', ''],
    'temperature': ['Temperature', ''],
    'wind_speed': ['Wind speed', 'm/s'],
    'humidity': ['Humidity', '%'],
    'pressure': ['Pressure', 'hPa'],
    'clouds': ['Cloud coverage', '%'],
    'rain': ['Rain', 'mm'],
    'snow': ['Snow', 'mm']
}


def setup_platform(hass, config, add_devices, discovery_info=None):
    """ Get the OpenWeatherMap sensor. """

    if None in (hass.config.latitude, hass.config.longitude):
        _LOGGER.error("Latitude or longitude not set in Home Assistant config")
        return False

    try:
        from pyowm import OWM

    except ImportError:
        _LOGGER.exception(
            "Unable to import pyowm. "
            "Did you maybe not install the 'PyOWM' package?")

        return None

    SENSOR_TYPES['temperature'][1] = hass.config.temperature_unit
    unit = hass.config.temperature_unit
    owm = OWM(config.get(CONF_API_KEY, None))
    obs = owm.weather_at_coords(hass.config.latitude, hass.config.longitude)

    if not owm:
        _LOGGER.error(
            "Connection error "
            "Please check your settings for OpenWeatherMap.")
        return None

    dev = []
    for variable in config['monitored_variables']:
        if variable['type'] not in SENSOR_TYPES:
            _LOGGER.error('Sensor type: "%s" does not exist', variable['type'])
        else:
            dev.append(OpenWeatherMapSensor(variable['type'], obs, unit))

    add_devices(dev)


# pylint: disable=too-few-public-methods
class OpenWeatherMapSensor(Entity):
    """ Implements an OpenWeatherMap sensor. """

    def __init__(self, sensor_type, weather_data, unit):
        self.client_name = 'Weather - '
        self._name = SENSOR_TYPES[sensor_type][0]
        self.owa_client = weather_data
        self._unit = unit
        self.type = sensor_type
        self._state = None
        self._unit_of_measurement = SENSOR_TYPES[sensor_type][1]
        self.update()

    @property
    def name(self):
        return self.client_name + ' ' + self._name

    @property
    def state(self):
        """ Returns the state of the device. """
        return self._state

    @property
    def unit_of_measurement(self):
        """ Unit of measurement of this entity, if any. """
        return self._unit_of_measurement

    # pylint: disable=too-many-branches
    def update(self):
        """ Gets the latest data from OWM and updates the states. """
        data = self.owa_client.get_weather()

        if self.type == 'weather':
            self._state = data.get_detailed_status()

        if self.type == 'temperature':
            if self._unit == TEMP_CELCIUS:
                self._state = round(data.get_temperature('celsius')['temp'],
                                    1)
            elif self._unit == TEMP_FAHRENHEIT:
                self._state = round(data.get_temperature('fahrenheit')['temp'],
                                    1)
            else:
                self._state = round(data.get_temperature()['temp'], 1)

        elif self.type == 'wind_speed':
            self._state = data.get_wind()['speed']

        elif self.type == 'humidity':
            self._state = data.get_humidity()

        elif self.type == 'pressure':
            self._state = round(data.get_pressure()['press'], 0)

        elif self.type == 'clouds':
            self._state = data.get_clouds()

        elif self.type == 'rain':
            if data.get_rain():
                self._state = round(data.get_rain()['3h'], 0)
            else:
                self._state = 'not raining'
                self._unit_of_measurement = ''

        elif self.type == 'snow':
            if data.get_snow():
                self._state = round(data.get_snow(), 0)
            else:
                self._state = 'not snowing'
                self._unit_of_measurement = ''