"""Calendar platform for Withings."""
from __future__ import annotations

from collections.abc import Callable
from datetime import datetime

from aiowithings import WithingsClient, WorkoutCategory

from homeassistant.components.calendar import CalendarEntity, CalendarEvent
from homeassistant.config_entries import ConfigEntry
from homeassistant.const import Platform
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback
import homeassistant.helpers.entity_registry as er

from . import DOMAIN, WithingsData
from .coordinator import WithingsWorkoutDataUpdateCoordinator
from .entity import WithingsEntity


async def async_setup_entry(
    hass: HomeAssistant,
    entry: ConfigEntry,
    async_add_entities: AddEntitiesCallback,
) -> None:
    """Set up the calendar platform for entity."""
    ent_reg = er.async_get(hass)
    withings_data: WithingsData = hass.data[DOMAIN][entry.entry_id]

    workout_coordinator = withings_data.workout_coordinator

    calendar_setup_before = ent_reg.async_get_entity_id(
        Platform.CALENDAR,
        DOMAIN,
        f"withings_{entry.unique_id}_workout",
    )

    if workout_coordinator.data is not None or calendar_setup_before:
        async_add_entities(
            [WithingsWorkoutCalendarEntity(withings_data.client, workout_coordinator)],
        )
    else:
        remove_calendar_listener: Callable[[], None]

        def _async_add_calendar_entity() -> None:
            """Add calendar entity."""
            if workout_coordinator.data is not None:
                async_add_entities(
                    [
                        WithingsWorkoutCalendarEntity(
                            withings_data.client, workout_coordinator
                        )
                    ],
                )
                remove_calendar_listener()

        remove_calendar_listener = workout_coordinator.async_add_listener(
            _async_add_calendar_entity
        )


def get_event_name(category: WorkoutCategory) -> str:
    """Return human-readable category."""
    name = category.name.lower().capitalize()
    return name.replace("_", " ")


class WithingsWorkoutCalendarEntity(
    CalendarEntity, WithingsEntity[WithingsWorkoutDataUpdateCoordinator]
):
    """A calendar entity."""

    _attr_translation_key = "workout"

    def __init__(
        self, client: WithingsClient, coordinator: WithingsWorkoutDataUpdateCoordinator
    ) -> None:
        """Create the Calendar entity."""
        super().__init__(coordinator, "workout")
        self.client = client

    @property
    def event(self) -> CalendarEvent | None:
        """Return the next upcoming event."""
        return None

    async def async_get_events(
        self, hass: HomeAssistant, start_date: datetime, end_date: datetime
    ) -> list[CalendarEvent]:
        """Get all events in a specific time frame."""
        workouts = await self.client.get_workouts_in_period(
            start_date.date(), end_date.date()
        )
        event_list = []
        for workout in workouts:
            event = CalendarEvent(
                start=workout.start_date,
                end=workout.end_date,
                summary=get_event_name(workout.category),
            )

            event_list.append(event)

        return event_list