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.icalendar import VEvent

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:
        return caldav_principal().calendar(calendar_name)

    return await _get_calendar_inner()


@timed_alru_cache(maxsize=20)
async def _get_calendar_events(
    calendar_name: str,
) -> list[CalEvent]:

    @run_in_executor
    def _inner() -> Iterator[VEvent]:
        _logger.info(f"updating {calendar_name}")
        print(f"updating {calendar_name}")

        calendar = caldav_principal().calendar(calendar_name)
        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 _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) -> list[CalEvent]:
        return await _get_calendar_events(
            ttl_hash=get_ttl_hash(20),
            calendar_name=self.calendar_name,
        )