"""
Notification helpers for preference checks.
"""
from typing import Optional

from .models import Notification, NotificationPreference


def get_notification_preference(user) -> Optional[NotificationPreference]:
    if not user:
        return None
    preference, _ = NotificationPreference.objects.get_or_create(user=user)
    return preference


def should_notify(user, notification_type: str) -> bool:
    """Check if user has enabled notification type."""
    preference = get_notification_preference(user)
    if not preference:
        return False
    if notification_type == Notification.Type.PRICE_ALERT:
        return preference.enable_price_alert
    if notification_type in (
        Notification.Type.BOUNTY_ACCEPTED,
        Notification.Type.BOUNTY_COMPLETED,
        Notification.Type.NEW_COMMENT,
    ):
        return preference.enable_bounty
    if notification_type == Notification.Type.SYSTEM:
        return preference.enable_system
    return True