from __future__ import annotations

from datetime import datetime

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

from db.base import Base  # you already import Base in app.py
# from .user import User   # only if you normally import it here
# from .coop import Product  # if not already in this module

from .market import Product

from .user import User

class CartItem(Base):
    __tablename__ = "cart_items"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)

    # Either a logged-in user OR an anonymous session
    user_id: Mapped[int | None] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"),
        nullable=True,
    )
    session_id: Mapped[str | None] = mapped_column(
        String(128),
        nullable=True,
    )

    # IMPORTANT: link to product *id*, not slug
    product_id: Mapped[int] = mapped_column(
        ForeignKey("products.id", ondelete="CASCADE"),
        nullable=False,
    )

    quantity: Mapped[int] = mapped_column(
        Integer,
        nullable=False,
        default=1,
        server_default="1",
    )

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
    )
    deleted_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True),
        nullable=True,
    )

    # Relationships
   
    product: Mapped["Product"] = relationship(
        "Product",
        back_populates="cart_items",
    )
    user: Mapped["User | None"] = relationship("User", back_populates="cart_items")

    __table_args__ = (
        Index("ix_cart_items_user_product", "user_id", "product_id"),
        Index("ix_cart_items_session_product", "session_id", "product_id"),
    )