import logging
from dataclasses import dataclass
from datetime import datetime, timedelta
from typing import Iterator

from caldav import Calendar
from pydantic import BaseModel
from vobject.base import VBase

from . import caldav_principal, get_ttl_hash, run_in_executor, timed_alru_cache

_logger = logging.getLogger(__name__)


class CalEvent(BaseModel):
    summary: str
    description: str
    dtstart: datetime
    dtend: datetime


@timed_alru_cache(maxsize=20)
async def _get_calendar(
    calendar_name: str,
) -> Calendar:

    @run_in_executor
    def _get_calendar_inner() -> Calendar:
        _logger.info(f"updating {calendar_name}")
        print(f"updating {calendar_name}")

        return caldav_principal().calendar(calendar_name)

    return await _get_calendar_inner()


@dataclass(frozen=True)
class DavCalendar:
    calendar_name: str

    @property
    async def calendar(self) -> Calendar:
        return await _get_calendar(
            ttl_hash=get_ttl_hash(20),
            calendar_name=self.calendar_name,
        )

    @property
    async def events(self) -> Iterator[CalEvent]:

        async def _find_vevents() -> Iterator[VBase]:
            calendar = await self.calendar

            return (
                vevent
                for event in calendar.date_search(
                    start=datetime.now(),
                    end=datetime.now() + timedelta(days=365),
                    expand=True,
                )
                for vevent in event.vobject_instance.contents["vevent"]
            )

        return (
            CalEvent(
                summary=vevent.summary.value,
                description=vevent.description.value,
                dtstart=vevent.dtstart.value,
                dtend=vevent.dtend.value,
            )
            for vevent in await _find_vevents()
        )