"""Support for Lutron Caseta lights."""
from datetime import timedelta

from homeassistant.components.light import (
    ATTR_BRIGHTNESS,
    ATTR_TRANSITION,
    DOMAIN,
    ColorMode,
    LightEntity,
    LightEntityFeature,
)
from homeassistant.config_entries import ConfigEntry
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback

from . import LutronCasetaDeviceUpdatableEntity
from .const import DOMAIN as CASETA_DOMAIN
from .models import LutronCasetaData


def to_lutron_level(level):
    """Convert the given Home Assistant light level (0-255) to Lutron (0-100)."""
    return int(round((level * 100) / 255))


def to_hass_level(level):
    """Convert the given Lutron (0-100) light level to Home Assistant (0-255)."""
    return int((level * 255) // 100)


async def async_setup_entry(
    hass: HomeAssistant,
    config_entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up the Lutron Caseta light platform.

    Adds dimmers from the Caseta bridge associated with the config_entry as
    light entities.
    """
    data: LutronCasetaData = hass.data[CASETA_DOMAIN][config_entry.entry_id]
    bridge = data.bridge
    bridge_device = data.bridge_device
    light_devices = bridge.get_devices_by_domain(DOMAIN)
    async_add_entities(
        LutronCasetaLight(light_device, bridge, bridge_device)
        for light_device in light_devices
    )


class LutronCasetaLight(LutronCasetaDeviceUpdatableEntity, LightEntity):
    """Representation of a Lutron Light, including dimmable."""

    _attr_color_mode = ColorMode.BRIGHTNESS
    _attr_supported_color_modes = {ColorMode.BRIGHTNESS}
    _attr_supported_features = LightEntityFeature.TRANSITION

    @property
    def brightness(self):
        """Return the brightness of the light."""
        return to_hass_level(self._device["current_state"])

    async def _set_brightness(self, brightness, **kwargs):
        args = {}
        if ATTR_TRANSITION in kwargs:
            args["fade_time"] = timedelta(seconds=kwargs[ATTR_TRANSITION])

        await self._smartbridge.set_value(
            self.device_id, to_lutron_level(brightness), **args
        )

    async def async_turn_on(self, **kwargs):
        """Turn the light on."""
        brightness = kwargs.pop(ATTR_BRIGHTNESS, 255)

        await self._set_brightness(brightness, **kwargs)

    async def async_turn_off(self, **kwargs):
        """Turn the light off."""
        await self._set_brightness(0, **kwargs)

    @property
    def is_on(self):
        """Return true if device is on."""
        return self._device["current_state"] > 0