"""Support for deCONZ sensors."""
from homeassistant.const import (
    ATTR_BATTERY_LEVEL, ATTR_VOLTAGE, DEVICE_CLASS_BATTERY)
from homeassistant.core import callback
from homeassistant.helpers.dispatcher import async_dispatcher_connect
from homeassistant.util import slugify

from .const import (
    ATTR_DARK, ATTR_ON, CONF_ALLOW_CLIP_SENSOR, DOMAIN as DECONZ_DOMAIN,
    NEW_SENSOR)
from .deconz_device import DeconzDevice

DEPENDENCIES = ['deconz']

ATTR_CURRENT = 'current'
ATTR_DAYLIGHT = 'daylight'
ATTR_EVENT_ID = 'event_id'


async def async_setup_platform(
        hass, config, async_add_entities, discovery_info=None):
    """Old way of setting up deCONZ sensors."""
    pass


async def async_setup_entry(hass, config_entry, async_add_entities):
    """Set up the deCONZ sensors."""
    gateway = hass.data[DECONZ_DOMAIN]

    @callback
    def async_add_sensor(sensors):
        """Add sensors from deCONZ."""
        from pydeconz.sensor import (
            DECONZ_SENSOR, SWITCH as DECONZ_REMOTE)
        entities = []
        allow_clip_sensor = config_entry.data.get(CONF_ALLOW_CLIP_SENSOR, True)
        for sensor in sensors:
            if sensor.type in DECONZ_SENSOR and \
               not (not allow_clip_sensor and sensor.type.startswith('CLIP')):
                if sensor.type in DECONZ_REMOTE:
                    if sensor.battery:
                        entities.append(DeconzBattery(sensor, gateway))
                else:
                    entities.append(DeconzSensor(sensor, gateway))
        async_add_entities(entities, True)

    gateway.listeners.append(
        async_dispatcher_connect(hass, NEW_SENSOR, async_add_sensor))

    async_add_sensor(gateway.api.sensors.values())


class DeconzSensor(DeconzDevice):
    """Representation of a deCONZ sensor."""

    @callback
    def async_update_callback(self, reason):
        """Update the sensor's state.

        If reason is that state is updated,
        or reachable has changed or battery has changed.
        """
        if reason['state'] or \
           'reachable' in reason['attr'] or \
           'battery' in reason['attr'] or \
           'on' in reason['attr']:
            self.async_schedule_update_ha_state()

    @property
    def state(self):
        """Return the state of the sensor."""
        return self._device.state

    @property
    def device_class(self):
        """Return the class of the sensor."""
        return self._device.sensor_class

    @property
    def icon(self):
        """Return the icon to use in the frontend."""
        return self._device.sensor_icon

    @property
    def unit_of_measurement(self):
        """Return the unit of measurement of this sensor."""
        return self._device.sensor_unit

    @property
    def device_state_attributes(self):
        """Return the state attributes of the sensor."""
        from pydeconz.sensor import LIGHTLEVEL
        attr = {}
        if self._device.battery:
            attr[ATTR_BATTERY_LEVEL] = self._device.battery
        if self._device.on is not None:
            attr[ATTR_ON] = self._device.on
        if self._device.type in LIGHTLEVEL and self._device.dark is not None:
            attr[ATTR_DARK] = self._device.dark
        if self.unit_of_measurement == 'Watts':
            attr[ATTR_CURRENT] = self._device.current
            attr[ATTR_VOLTAGE] = self._device.voltage
        if self._device.sensor_class == 'daylight':
            attr[ATTR_DAYLIGHT] = self._device.daylight
        return attr


class DeconzBattery(DeconzDevice):
    """Battery class for when a device is only represented as an event."""

    def __init__(self, device, gateway):
        """Register dispatcher callback for update of battery state."""
        super().__init__(device, gateway)

        self._name = '{} {}'.format(self._device.name, 'Battery Level')
        self._unit_of_measurement = "%"

    @callback
    def async_update_callback(self, reason):
        """Update the battery's state, if needed."""
        if 'reachable' in reason['attr'] or 'battery' in reason['attr']:
            self.async_schedule_update_ha_state()

    @property
    def state(self):
        """Return the state of the battery."""
        return self._device.battery

    @property
    def name(self):
        """Return the name of the battery."""
        return self._name

    @property
    def device_class(self):
        """Return the class of the sensor."""
        return DEVICE_CLASS_BATTERY

    @property
    def unit_of_measurement(self):
        """Return the unit of measurement of this entity."""
        return self._unit_of_measurement

    @property
    def device_state_attributes(self):
        """Return the state attributes of the battery."""
        attr = {
            ATTR_EVENT_ID: slugify(self._device.name),
        }
        return attr