"""Read-time and durable expiry semantics for API-key assignments."""
from __future__ import annotations

from datetime import date, datetime
from typing import Any
from zoneinfo import ZoneInfo

from sqlalchemy import and_, or_

from app.domains.apikey.models import ApiKeyAssignment

SHANGHAI = ZoneInfo("Asia/Shanghai")


def expiry_today() -> date:
    """The calendar day used by the user-facing validity contract."""
    return datetime.now(SHANGHAI).date()


def effective_assignment_status(
    status: str,
    valid_until: date | None,
    *,
    today: date | None = None,
) -> str:
    """Project a stale active row as expired without mutating it."""
    current_day = today or expiry_today()
    if status == "active" and valid_until is not None and valid_until < current_day:
        return "expired"
    return status


def effective_status_condition(status: str, *, today: date | None = None) -> Any:
    """SQL predicate matching the projected status used in responses."""
    current_day = today or expiry_today()
    overdue = and_(
        ApiKeyAssignment.status == "active",
        ApiKeyAssignment.valid_until.is_not(None),
        ApiKeyAssignment.valid_until < current_day,
    )
    if status == "expired":
        return or_(ApiKeyAssignment.status == "expired", overdue)
    if status == "active":
        return and_(
            ApiKeyAssignment.status == "active",
            or_(
                ApiKeyAssignment.valid_until.is_(None),
                ApiKeyAssignment.valid_until >= current_day,
            ),
        )
    return ApiKeyAssignment.status == status


__all__ = [
    "effective_assignment_status",
    "effective_status_condition",
    "expiry_today",
]