"""Support for ICS Calendar."""

import logging
from datetime import datetime, timedelta
from typing import Any, Optional

# import homeassistant.helpers.config_validation as cv
# import voluptuous as vol
from homeassistant.components.calendar import (
    ENTITY_ID_FORMAT,
    CalendarEntity,
    CalendarEvent,
    extract_offset,
    is_offset_reached,
)
from homeassistant.config_entries import ConfigEntry
from homeassistant.const import (
    CONF_EXCLUDE,
    CONF_INCLUDE,
    CONF_NAME,
    CONF_PASSWORD,
    CONF_PREFIX,
    CONF_URL,
    CONF_USERNAME,
)
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity import generate_entity_id
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.httpx_client import get_async_client
from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
from homeassistant.util.dt import now as hanow

from .calendardata import CalendarData
from .const import (
    CONF_ACCEPT_HEADER,
    CONF_CALENDARS,
    CONF_CONNECTION_TIMEOUT,
    CONF_DAYS,
    CONF_DOWNLOAD_INTERVAL,
    CONF_INCLUDE_ALL_DAY,
    CONF_OFFSET_HOURS,
    CONF_PARSER,
    CONF_SET_TIMEOUT,
    CONF_SUMMARY_DEFAULT,
    CONF_USER_AGENT,
    DOMAIN,
)
from .filter import Filter
from .getparser import GetParser
from .parserevent import ParserEvent

_LOGGER = logging.getLogger(__name__)


OFFSET = "!!"


MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=15)


async def async_setup_entry(
    hass: HomeAssistant,
    config_entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up the calendar in background."""
    hass.async_create_task(
        _async_setup_entry_bg_task(hass, config_entry, async_add_entities)
    )


async def _async_setup_entry_bg_task(
    hass: HomeAssistant,
    config_entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up the calendar."""
    data = hass.data[DOMAIN][config_entry.entry_id]
    device_id = f"{data[CONF_NAME]}"
    entity = ICSCalendarEntity(
        hass,
        generate_entity_id(ENTITY_ID_FORMAT, device_id, hass=hass),
        hass.data[DOMAIN][config_entry.entry_id],
        config_entry.entry_id,
    )
    async_add_entities([entity])


def setup_platform(
    hass: HomeAssistant,
    config: ConfigType,
    add_entities: AddEntitiesCallback,
    discovery_info: DiscoveryInfoType | None = None,
):
    """Set up ics_calendar platform.

    :param hass: Home Assistant object
    :type hass: HomeAssistant
    :param config: Config information for the platform
    :type config: ConfigType
    :param add_entities: Callback to add entities to HA
    :type add_entities: AddEntitiesCallback
    :param discovery_info: Config information for the platform
    :type discovery_info: DiscoveryInfoType | None, optional
    """
    _LOGGER.debug("Setting up ics calendars")
    if discovery_info is not None:
        _LOGGER.debug(
            "setup_platform: ignoring discovery_info, already imported!"
        )
        # calendars: list = discovery_info.get(CONF_CALENDARS)
        calendars = []
    else:
        _LOGGER.debug("setup_platform: discovery_info is None")
        calendars: list = config.get(CONF_CALENDARS)

    calendar_devices = []
    for calendar in calendars:
        device_data = {
            CONF_NAME: calendar.get(CONF_NAME),
            CONF_URL: calendar.get(CONF_URL),
            CONF_INCLUDE_ALL_DAY: calendar.get(CONF_INCLUDE_ALL_DAY),
            CONF_USERNAME: calendar.get(CONF_USERNAME),
            CONF_PASSWORD: calendar.get(CONF_PASSWORD),
            CONF_PARSER: calendar.get(CONF_PARSER),
            CONF_PREFIX: calendar.get(CONF_PREFIX),
            CONF_DAYS: calendar.get(CONF_DAYS),
            CONF_DOWNLOAD_INTERVAL: calendar.get(CONF_DOWNLOAD_INTERVAL),
            CONF_USER_AGENT: calendar.get(CONF_USER_AGENT),
            CONF_EXCLUDE: calendar.get(CONF_EXCLUDE),
            CONF_INCLUDE: calendar.get(CONF_INCLUDE),
            CONF_OFFSET_HOURS: calendar.get(CONF_OFFSET_HOURS),
            CONF_ACCEPT_HEADER: calendar.get(CONF_ACCEPT_HEADER),
            CONF_CONNECTION_TIMEOUT: calendar.get(CONF_CONNECTION_TIMEOUT),
        }
        device_id = f"{device_data[CONF_NAME]}"
        entity_id = generate_entity_id(ENTITY_ID_FORMAT, device_id, hass=hass)
        calendar_devices.append(
            ICSCalendarEntity(hass, entity_id, device_data)
        )

    add_entities(calendar_devices)


class ICSCalendarEntity(CalendarEntity):
    """A CalendarEntity for an ICS Calendar."""

    def __init__(
        self,
        hass: HomeAssistant,
        entity_id: str,
        device_data,
        unique_id: str = None,
    ):
        """Construct ICSCalendarEntity.

        :param entity_id: Entity id for the calendar
        :type entity_id: str
        :param device_data: dict describing the calendar
        :type device_data: dict
        """
        _LOGGER.debug(
            "Initializing calendar: %s with URL: %s, uniqueid: %s",
            device_data[CONF_NAME],
            device_data[CONF_URL],
            unique_id,
        )
        self.data = ICSCalendarData(hass, device_data)
        self.entity_id = entity_id
        self._attr_unique_id = f"ICSCalendar.{unique_id}"
        self._event = None
        self._attr_name = device_data[CONF_NAME]
        self._last_call = None

    @property
    def event(self) -> Optional[CalendarEvent]:
        """Return the current or next upcoming event or None.

        :return: The current event as a dict
        :rtype: dict
        """
        return self._event

    @property
    def should_poll(self) -> bool:
        """Indicate if the calendar should be polled.

        If the last call to update or get_api_events was not within the minimum
        update time, then async_schedule_update_ha_state(True) is also called.
        :return: True
        :rtype: boolean
        """
        this_call = hanow()
        if (
            self._last_call is None
            or (this_call - self._last_call) > MIN_TIME_BETWEEN_UPDATES
        ):
            self._last_call = this_call
            self.async_schedule_update_ha_state(True)
        return True

    async def async_get_events(
        self, hass: HomeAssistant, start_date: datetime, end_date: datetime
    ) -> list[CalendarEvent]:
        """Get all events in a specific time frame.

        :param hass: Home Assistant object
        :type hass: HomeAssistant
        :param start_date: The first starting date to consider
        :type start_date: datetime
        :param end_date: The last starting date to consider
        :type end_date: datetime
        """
        _LOGGER.debug(
            "%s: async_get_events called; calling internal.", self.name
        )
        return await self.data.async_get_events(start_date, end_date)

    async def async_update(self):
        """Get the current or next event."""
        await self.data.async_update()
        self._event: CalendarEvent | None = self.data.event
        self._attr_extra_state_attributes = {
            "offset_reached": (
                is_offset_reached(
                    self._event.start_datetime_local, self.data.offset
                )
                if self._event
                else False
            )
        }

    async def async_create_event(self, **kwargs: Any):
        """Raise error, this is a read-only calendar."""
        raise NotImplementedError()

    async def async_delete_event(
        self,
        uid: str,
        recurrence_id: str | None = None,
        recurrence_range: str | None = None,
    ) -> None:
        """Raise error, this is a read-only calendar."""
        raise NotImplementedError()

    async def async_update_event(
        self,
        uid: str,
        event: dict[str, Any],
        recurrence_id: str | None = None,
        recurrence_range: str | None = None,
    ) -> None:
        """Raise error, this is a read-only calendar."""
        raise NotImplementedError()


class ICSCalendarData:  # pylint: disable=R0902
    """Class to use the calendar ICS client object to get next event."""

    def __init__(self, hass: HomeAssistant, device_data):
        """Set up how we are going to connect to the URL.

        :param device_data Information about the calendar
        """
        self.name = device_data[CONF_NAME]
        self._days = device_data[CONF_DAYS]
        self._offset_hours = device_data[CONF_OFFSET_HOURS]
        self.include_all_day = device_data[CONF_INCLUDE_ALL_DAY]
        self._summary_prefix: str = device_data[CONF_PREFIX]
        self._summary_default: str = device_data[CONF_SUMMARY_DEFAULT]
        self.parser = GetParser.get_parser(device_data[CONF_PARSER])
        self.parser.set_filter(
            Filter(device_data[CONF_EXCLUDE], device_data[CONF_INCLUDE])
        )
        self.offset = None
        self.event = None
        self._hass = hass

        self._calendar_data = CalendarData(
            get_async_client(hass),
            _LOGGER,
            {
                "name": self.name,
                "url": device_data[CONF_URL],
                "min_update_time": timedelta(
                    minutes=device_data[CONF_DOWNLOAD_INTERVAL]
                ),
            },
        )

        self._calendar_data.set_headers(
            device_data[CONF_USERNAME],
            device_data[CONF_PASSWORD],
            device_data[CONF_USER_AGENT],
            device_data[CONF_ACCEPT_HEADER],
        )

        if device_data.get(CONF_SET_TIMEOUT):
            self._calendar_data.set_timeout(
                device_data[CONF_CONNECTION_TIMEOUT]
            )

    async def async_get_events(
        self, start_date: datetime, end_date: datetime
    ) -> list[CalendarEvent]:
        """Get all events in a specific time frame.

        :param start_date: The first starting date to consider
        :type start_date: datetime
        :param end_date: The last starting date to consider
        :type end_date: datetime
        """
        event_list: list[ParserEvent] = []
        if await self._calendar_data.download_calendar():
            _LOGGER.debug("%s: Setting calendar content", self.name)
            self.parser.set_content(self._calendar_data.get())
        try:
            event_list = self.parser.get_event_list(
                start=start_date,
                end=end_date,
                include_all_day=self.include_all_day,
                offset_hours=self._offset_hours,
            )
        except:  # pylint: disable=W0702
            _LOGGER.error(
                "async_get_events: %s: Failed to parse ICS!",
                self.name,
                exc_info=True,
            )
            event_list: list[ParserEvent] = []

        for event in event_list:
            event.summary = self._summary_prefix + event.summary
            if not event.summary:
                event.summary = self._summary_default
            # Since we skipped the validation code earlier, invoke it now,
            # before passing the object outside this component
            event.validate()

        return event_list

    async def async_update(self):
        """Get the current or next event."""
        _LOGGER.debug("%s: Update was called", self.name)
        parser_event: ParserEvent | None = None
        if await self._calendar_data.download_calendar():
            _LOGGER.debug("%s: Setting calendar content", self.name)
            self.parser.set_content(self._calendar_data.get())
        try:
            parser_event: ParserEvent | None = self.parser.get_current_event(
                include_all_day=self.include_all_day,
                now=hanow(),
                days=self._days,
                offset_hours=self._offset_hours,
            )
        except:  # pylint: disable=W0702
            _LOGGER.error(
                "update: %s: Failed to parse ICS!", self.name, exc_info=True
            )
        if parser_event is not None:
            _LOGGER.debug(
                "%s: got event: %s; start: %s; end: %s; all_day: %s",
                self.name,
                parser_event.summary,
                parser_event.start,
                parser_event.end,
                parser_event.all_day,
            )
            (summary, offset) = extract_offset(parser_event.summary, OFFSET)
            parser_event.summary = self._summary_prefix + summary
            if not parser_event.summary:
                parser_event.summary = self._summary_default
            self.offset = offset
            # Invoke validation here, since it was skipped when creating the
            # ParserEvent
            parser_event.validate()
            self.event: CalendarEvent = parser_event
            return True

        _LOGGER.debug("%s: No event found!", self.name)
        return False