"""Support for Dexcom sensors."""

from __future__ import annotations

from homeassistant.components.sensor import SensorEntity
from homeassistant.config_entries import ConfigEntry
from homeassistant.const import CONF_UNIT_OF_MEASUREMENT, CONF_USERNAME
from homeassistant.core import HomeAssistant
from homeassistant.helpers.device_registry import DeviceInfo
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.update_coordinator import (
    CoordinatorEntity,
    DataUpdateCoordinator,
)

from .const import DOMAIN, GLUCOSE_TREND_ICON, MG_DL


async def async_setup_entry(
    hass: HomeAssistant,
    config_entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up the Dexcom sensors."""
    coordinator = hass.data[DOMAIN][config_entry.entry_id]
    username = config_entry.data[CONF_USERNAME]
    unit_of_measurement = config_entry.options[CONF_UNIT_OF_MEASUREMENT]
    async_add_entities(
        [
            DexcomGlucoseTrendSensor(coordinator, username, config_entry.entry_id),
            DexcomGlucoseValueSensor(
                coordinator, username, config_entry.entry_id, unit_of_measurement
            ),
        ],
    )


class DexcomSensorEntity(CoordinatorEntity, SensorEntity):
    """Base Dexcom sensor entity."""

    _attr_has_entity_name = True

    def __init__(
        self, coordinator: DataUpdateCoordinator, username: str, entry_id: str, key: str
    ) -> None:
        """Initialize the sensor."""
        super().__init__(coordinator)
        self._attr_unique_id = f"{username}-{key}"
        self._attr_device_info = DeviceInfo(
            identifiers={(DOMAIN, entry_id)},
            name=username,
        )


class DexcomGlucoseValueSensor(DexcomSensorEntity):
    """Representation of a Dexcom glucose value sensor."""

    _attr_translation_key = "glucose_value"

    def __init__(
        self,
        coordinator: DataUpdateCoordinator,
        username: str,
        entry_id: str,
        unit_of_measurement: str,
    ) -> None:
        """Initialize the sensor."""
        super().__init__(coordinator, username, entry_id, "value")
        self._attr_native_unit_of_measurement = unit_of_measurement
        self._key = "mg_dl" if unit_of_measurement == MG_DL else "mmol_l"

    @property
    def native_value(self):
        """Return the state of the sensor."""
        if self.coordinator.data:
            return getattr(self.coordinator.data, self._key)
        return None


class DexcomGlucoseTrendSensor(DexcomSensorEntity):
    """Representation of a Dexcom glucose trend sensor."""

    _attr_translation_key = "glucose_trend"

    def __init__(
        self, coordinator: DataUpdateCoordinator, username: str, entry_id: str
    ) -> None:
        """Initialize the sensor."""
        super().__init__(coordinator, username, entry_id, "trend")

    @property
    def icon(self):
        """Return the icon for the frontend."""
        if self.coordinator.data:
            return GLUCOSE_TREND_ICON[self.coordinator.data.trend]
        return GLUCOSE_TREND_ICON[0]

    @property
    def native_value(self):
        """Return the state of the sensor."""
        if self.coordinator.data:
            return self.coordinator.data.trend_description
        return None