from datetime import datetime

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

from core.db import Base


class Cart(Base):
    __tablename__ = "carts"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), unique=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())

    items: Mapped[list["CartItem"]] = relationship(
        "CartItem", back_populates="cart", cascade="all, delete-orphan", lazy="joined"
    )


class CartItem(Base):
    __tablename__ = "cart_items"
    __table_args__ = (UniqueConstraint("cart_id", "product_id", name="uq_cart_product"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    cart_id: Mapped[int] = mapped_column(ForeignKey("carts.id", ondelete="CASCADE"))
    product_id: Mapped[int] = mapped_column(ForeignKey("products.id", ondelete="CASCADE"))
    qty: Mapped[int] = mapped_column(Integer, default=1)

    cart: Mapped["Cart"] = relationship("Cart", back_populates="items")