from sqlalchemy import ForeignKey, Index, Integer, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from fooder.domain.base import Base, CommonMixin
from fooder.domain.product import Product
from fooder.domain.user import User


class UserProductUsage(Base, CommonMixin):
    """Counts how many processed entries a user has for a product.
    Used to sort products by usage frequency."""

    __table_args__ = (
        UniqueConstraint("user_id", "product_id"),
        # Covers outerjoin on (product_id, user_id) in list_for_user
        Index("ix_userproductusage_product_user", "product_id", "user_id"),
    )

    product_id: Mapped[int] = mapped_column(Integer, ForeignKey("product.id"))
    product: Mapped[Product] = relationship(lazy="selectin")
    user_id: Mapped[int] = mapped_column(Integer, ForeignKey("user.id"), index=True)
    user: Mapped[User] = relationship(lazy="selectin")
    count: Mapped[int]