"""Currency exchange rate support that comes from fixer.io."""

from datetime import timedelta
import logging
from typing import Any

from fixerio import Fixerio
from fixerio.exceptions import FixerioException
import voluptuous as vol

from homeassistant.components.sensor import (
    PLATFORM_SCHEMA as SENSOR_PLATFORM_SCHEMA,
    SensorEntity,
)
from homeassistant.const import CONF_API_KEY, CONF_NAME, CONF_TARGET
from homeassistant.core import HomeAssistant
from homeassistant.helpers import config_validation as cv
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType

_LOGGER = logging.getLogger(__name__)

ATTR_EXCHANGE_RATE = "Exchange rate"
ATTR_TARGET = "Target currency"

DEFAULT_BASE = "USD"
DEFAULT_NAME = "Exchange rate"


SCAN_INTERVAL = timedelta(days=1)

PLATFORM_SCHEMA = SENSOR_PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_API_KEY): cv.string,
        vol.Required(CONF_TARGET): cv.string,
        vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
    }
)


def setup_platform(
    hass: HomeAssistant,
    config: ConfigType,
    add_entities: AddEntitiesCallback,
    discovery_info: DiscoveryInfoType | None = None,
) -> None:
    """Set up the Fixer.io sensor."""
    api_key = config.get(CONF_API_KEY)
    name = config.get(CONF_NAME)
    target = config.get(CONF_TARGET)

    try:
        Fixerio(symbols=[target], access_key=api_key).latest()
    except FixerioException:
        _LOGGER.error("One of the given currencies is not supported")
        return

    data = ExchangeData(target, api_key)
    add_entities([ExchangeRateSensor(data, name, target)], True)


class ExchangeRateSensor(SensorEntity):
    """Representation of a Exchange sensor."""

    _attr_attribution = "Data provided by the European Central Bank (ECB)"
    _attr_icon = "mdi:currency-usd"

    def __init__(self, data, name, target):
        """Initialize the sensor."""
        self.data = data
        self._target = target
        self._name = name
        self._state = None

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

    @property
    def native_unit_of_measurement(self):
        """Return the unit of measurement of this entity, if any."""
        return self._target

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

    @property
    def extra_state_attributes(self) -> dict[str, Any] | None:
        """Return the state attributes."""
        if self.data.rate is not None:
            return {
                ATTR_EXCHANGE_RATE: self.data.rate["rates"][self._target],
                ATTR_TARGET: self._target,
            }
        return None

    def update(self) -> None:
        """Get the latest data and updates the states."""
        self.data.update()
        self._state = round(self.data.rate["rates"][self._target], 3)


class ExchangeData:
    """Get the latest data and update the states."""

    def __init__(self, target_currency, api_key):
        """Initialize the data object."""
        self.api_key = api_key
        self.rate = None
        self.target_currency = target_currency
        self.exchange = Fixerio(symbols=[self.target_currency], access_key=self.api_key)

    def update(self):
        """Get the latest data from Fixer.io."""
        self.rate = self.exchange.latest()