"""Support for SMS dongle sensor."""
import logging

import gammu  # pylint: disable=import-error

from homeassistant.const import DEVICE_CLASS_SIGNAL_STRENGTH, SIGNAL_STRENGTH_DECIBELS
from homeassistant.helpers.entity import Entity

from .const import DOMAIN, SMS_GATEWAY

_LOGGER = logging.getLogger(__name__)


async def async_setup_entry(hass, config_entry, async_add_entities):
    """Set up the GSM Signal Sensor sensor."""
    gateway = hass.data[DOMAIN][SMS_GATEWAY]
    entities = []
    imei = await gateway.get_imei_async()
    name = f"gsm_signal_imei_{imei}"
    entities.append(
        GSMSignalSensor(
            hass,
            gateway,
            name,
        )
    )
    async_add_entities(entities, True)


class GSMSignalSensor(Entity):
    """Implementation of a GSM Signal sensor."""

    def __init__(
        self,
        hass,
        gateway,
        name,
    ):
        """Initialize the GSM Signal sensor."""
        self._hass = hass
        self._gateway = gateway
        self._name = name
        self._state = None

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

    @property
    def unit_of_measurement(self):
        """Return the unit the value is expressed in."""
        return SIGNAL_STRENGTH_DECIBELS

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

    @property
    def available(self):
        """Return if the sensor data are available."""
        return self._state is not None

    @property
    def state(self):
        """Return the state of the device."""
        return self._state["SignalStrength"]

    async def async_update(self):
        """Get the latest data from the modem."""
        try:
            self._state = await self._gateway.get_signal_quality_async()
        except gammu.GSMError as exc:
            _LOGGER.error("Failed to read signal quality: %s", exc)

    @property
    def extra_state_attributes(self):
        """Return the sensor attributes."""
        return self._state

    @property
    def entity_registry_enabled_default(self) -> bool:
        """Return if the entity should be enabled when first added to the entity registry."""
        return False