from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import and_, or_

from govoplan_files.backend.db.models import FileShare
from govoplan_files.backend.storage.common import utcnow


def effective_file_share_clause(*, at: datetime | None = None):
    checked_at = at or utcnow()
    return and_(
        FileShare.revoked_at.is_(None),
        or_(FileShare.expires_at.is_(None), FileShare.expires_at > checked_at),
    )


def file_share_is_active(share: FileShare, *, at: datetime | None = None) -> bool:
    if share.revoked_at is not None:
        return False
    if share.expires_at is None:
        return True
    checked_at = _aware_utc(at or utcnow())
    return _aware_utc(share.expires_at) > checked_at


def _aware_utc(value: datetime) -> datetime:
    if value.tzinfo is None:
        return value.replace(tzinfo=timezone.utc)
    return value.astimezone(timezone.utc)


__all__ = ["effective_file_share_clause", "file_share_is_active"]