"""Request/async tenant context (``TENANCY.md`` §3.2, §7).

``current_tenant`` is a ``ContextVar`` so the scoped managers can resolve the
tenant without threading it through every call. It is bound by
``TenantMiddleware`` for requests and must be bound explicitly by Celery tasks
and management commands.
"""

from __future__ import annotations

from collections.abc import Iterator
from contextlib import contextmanager
from contextvars import ContextVar, Token
from typing import TYPE_CHECKING, Any

if TYPE_CHECKING:
    from .models import Tenant

__all__ = [
    "current_tenant",
    "get_current_tenant",
    "set_current_tenant",
    "reset_current_tenant",
    "tenant_context",
]

current_tenant: ContextVar[Tenant | None] = ContextVar("current_tenant", default=None)


def get_current_tenant() -> Tenant | None:
    return current_tenant.get()


def set_current_tenant(tenant: Tenant | None) -> Token:
    return current_tenant.set(tenant)


def reset_current_tenant(token: Token) -> None:
    current_tenant.reset(token)


@contextmanager
def tenant_context(tenant: Tenant | None) -> Iterator[None]:
    """Binds ``tenant`` for the duration of the block and always restores it."""
    token = set_current_tenant(tenant)
    try:
        yield
    finally:
        reset_current_tenant(token)


def tenant_id_or_none() -> Any:
    tenant = get_current_tenant()
    return tenant.pk if tenant is not None else None