"""DataUpdateCoordinator for the Airly integration."""
from asyncio import timeout
from datetime import timedelta
import logging
from math import ceil

from aiohttp import ClientSession
from aiohttp.client_exceptions import ClientConnectorError
from airly import Airly
from airly.exceptions import AirlyError

from homeassistant.core import HomeAssistant
from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
from homeassistant.util import dt as dt_util

from .const import (
    ATTR_API_ADVICE,
    ATTR_API_CAQI,
    ATTR_API_CAQI_DESCRIPTION,
    ATTR_API_CAQI_LEVEL,
    DOMAIN,
    MAX_UPDATE_INTERVAL,
    MIN_UPDATE_INTERVAL,
    NO_AIRLY_SENSORS,
)

_LOGGER = logging.getLogger(__name__)


def set_update_interval(instances_count: int, requests_remaining: int) -> timedelta:
    """Return data update interval.

    The number of requests is reset at midnight UTC so we calculate the update
    interval based on number of minutes until midnight, the number of Airly instances
    and the number of remaining requests.
    """
    now = dt_util.utcnow()
    midnight = dt_util.find_next_time_expression_time(
        now, seconds=[0], minutes=[0], hours=[0]
    )
    minutes_to_midnight = (midnight - now).total_seconds() / 60
    interval = timedelta(
        minutes=min(
            max(
                ceil(minutes_to_midnight / requests_remaining * instances_count),
                MIN_UPDATE_INTERVAL,
            ),
            MAX_UPDATE_INTERVAL,
        )
    )

    _LOGGER.debug("Data will be update every %s", interval)

    return interval


class AirlyDataUpdateCoordinator(DataUpdateCoordinator):
    """Define an object to hold Airly data."""

    def __init__(
        self,
        hass: HomeAssistant,
        session: ClientSession,
        api_key: str,
        latitude: float,
        longitude: float,
        update_interval: timedelta,
        use_nearest: bool,
    ) -> None:
        """Initialize."""
        self.latitude = latitude
        self.longitude = longitude
        # Currently, Airly only supports Polish and English
        language = "pl" if hass.config.language == "pl" else "en"
        self.airly = Airly(api_key, session, language=language)
        self.use_nearest = use_nearest

        super().__init__(hass, _LOGGER, name=DOMAIN, update_interval=update_interval)

    async def _async_update_data(self) -> dict[str, str | float | int]:
        """Update data via library."""
        data: dict[str, str | float | int] = {}
        if self.use_nearest:
            measurements = self.airly.create_measurements_session_nearest(
                self.latitude, self.longitude, max_distance_km=5
            )
        else:
            measurements = self.airly.create_measurements_session_point(
                self.latitude, self.longitude
            )
        async with timeout(20):
            try:
                await measurements.update()
            except (AirlyError, ClientConnectorError) as error:
                raise UpdateFailed(error) from error

        _LOGGER.debug(
            "Requests remaining: %s/%s",
            self.airly.requests_remaining,
            self.airly.requests_per_day,
        )

        # Airly API sometimes returns None for requests remaining so we update
        # update_interval only if we have valid value.
        if self.airly.requests_remaining:
            self.update_interval = set_update_interval(
                len(self.hass.config_entries.async_entries(DOMAIN)),
                self.airly.requests_remaining,
            )

        values = measurements.current["values"]
        index = measurements.current["indexes"][0]
        standards = measurements.current["standards"]

        if index["description"] == NO_AIRLY_SENSORS:
            raise UpdateFailed("Can't retrieve data: no Airly sensors in this area")
        for value in values:
            data[value["name"]] = value["value"]
        for standard in standards:
            data[f"{standard['pollutant']}_LIMIT"] = standard["limit"]
            data[f"{standard['pollutant']}_PERCENT"] = standard["percent"]
        data[ATTR_API_CAQI] = index["value"]
        data[ATTR_API_CAQI_LEVEL] = index["level"].lower().replace("_", " ")
        data[ATTR_API_CAQI_DESCRIPTION] = index["description"]
        data[ATTR_API_ADVICE] = index["advice"]
        return data
