from django.utils import timezone

from .models import TicketMagicLink


MAGIC_LINK_SESSION_KEY = "ticket_magic_link_id"


def grant_ticket_magic_access(request, link):
    """Grant an anonymous session access to exactly one ticket until link expiry."""
    request.session.cycle_key()
    request.session[MAGIC_LINK_SESSION_KEY] = link.pk
    remaining = max(1, int((link.expires_at - timezone.now()).total_seconds()))
    request.session.set_expiry(remaining)


def get_ticket_magic_access(request, ticket=None):
    link_id = request.session.get(MAGIC_LINK_SESSION_KEY)
    if not link_id:
        return None
    filters = {
        "pk": link_id,
        "revoked_at__isnull": True,
        "expires_at__gt": timezone.now(),
        "customer__is_active": True,
    }
    if ticket is not None:
        filters["ticket_id"] = ticket.pk
    link = TicketMagicLink.objects.select_related("customer", "ticket").filter(**filters).first()
    if link is None and ticket is None:
        request.session.pop(MAGIC_LINK_SESSION_KEY, None)
    return link