"""Favorites: toggle save/unsave, check status, list."""
from sqlalchemy.exc import IntegrityError
from app.extensions import db
from app.models.favorite import Favorite


def is_favorited(user_id: int, listing_id: int) -> bool:
    return Favorite.query.filter_by(
        user_id=user_id, listing_id=listing_id).first() is not None


def toggle_favorite(user_id: int, listing_id: int) -> bool:
    """Add if not present; remove if present. Returns True if now favorited."""
    existing = Favorite.query.filter_by(
        user_id=user_id, listing_id=listing_id).first()
    if existing:
        db.session.delete(existing)
        db.session.commit()
        return False
    fav = Favorite(user_id=user_id, listing_id=listing_id)
    db.session.add(fav)
    try:
        db.session.commit()
    except IntegrityError:
        db.session.rollback()
    return True


def user_favorites(user_id: int, page=1, per_page=20):
    return (Favorite.query
            .filter_by(user_id=user_id)
            .order_by(Favorite.created_at.desc())
            .paginate(page=page, per_page=per_page, error_out=False))