"""
Definition of an asyncio compatible CalDAV calendar.

Caches events using `timed_alru_cache`.
"""

import functools
import logging
from datetime import datetime
from typing import Annotated, Self

from pydantic import BaseModel, ConfigDict, StringConstraints
from vobject.base import Component

_logger = logging.getLogger(__name__)
type StrippedStr = Annotated[str, StringConstraints(strip_whitespace=True)]


@functools.total_ordering
class CalEvent(BaseModel):
    """
    A CalDAV calendar event.

    Properties are to be named as in the EVENT component of
    RFC5545 (iCalendar).

    https://icalendar.org/iCalendar-RFC-5545/3-6-1-event-component.html
    """

    model_config = ConfigDict(frozen=True)

    summary: StrippedStr = ""
    description: StrippedStr = ""
    dtstart: datetime = datetime.now()
    dtend: datetime = datetime.now()

    def __lt__(self, other: Self) -> bool:
        """
        Order Events by start time.
        """

        return self.dtstart < other.dtstart

    def __eq__(self, other: Self) -> bool:
        """
        Compare all properties.
        """

        return self.model_dump() == other.model_dump()

    @classmethod
    def from_vevent(cls, event: Component) -> Self:
        """
        Create a CalEvent instance from a `VObject.VEvent` object.
        """

        data = {}
        keys = ("summary", "description", "dtstart", "dtend", "duration")

        for key in keys:
            try:
                data[key] = event.contents[key][0].value  # type: ignore

            except KeyError:
                pass

        if "dtend" not in data:
            data["dtend"] = data["dtstart"]

            if "duration" in data:
                try:
                    data["dtend"] += data["duration"]

                except (ValueError, TypeError, AttributeError):
                    _logger.warn(
                        "Could not add duration %s to %s",
                        repr(data["duration"]),
                        repr(data["dtstart"]),
                    )

                del data["duration"]

        return cls.model_validate(data)