import logging
from datetime import UTC, date, datetime, timedelta

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.models.entities import Home, HomeMembership, Notification, Product
from app.services.mail import send_mail

logger = logging.getLogger(__name__)


def create_expiry_notifications(db: Session) -> int:
    count = 0
    homes = db.scalars(select(Home)).all()
    today = date.today()
    for home in homes:
        deadline = today + timedelta(days=home.expiry_warning_days)
        products = db.scalars(
            select(Product).where(Product.home_id == home.id, Product.expires_at <= deadline)
        ).all()
        if not products:
            continue
        memberships = db.scalars(select(HomeMembership).where(HomeMembership.home_id == home.id)).all()
        for membership in memberships:
            prefs = membership.notification_preferences or {}
            if prefs.get("in_app", True):
                db.add(
                    Notification(
                        user_id=membership.user_id,
                        home_id=home.id,
                        title="NexaPantry expiry warning",
                        body=f"{len(products)} products expire soon in {home.name}.",
                        kind="expiry",
                    )
                )
                count += 1
            if prefs.get("email", False):
                try:
                    send_mail(db, membership.user.email, "NexaPantry expiry warning", f"{len(products)} products expire soon in {home.name}.")
                except Exception:
                    logger.exception("Expiry e-mail delivery failed for user %s", membership.user_id)
                    continue
    db.commit()
    return count


def mark_read(db: Session, notification: Notification) -> Notification:
    notification.read_at = datetime.now(UTC)
    return notification