# models/database/cart.py
"""Cart item database model."""

from sqlalchemy import (
    Column,
    Float,
    ForeignKey,
    Index,
    Integer,
    String,
    UniqueConstraint,
)
from sqlalchemy.orm import relationship

from app.core.database import Base
from models.database.base import TimestampMixin


class CartItem(Base, TimestampMixin):
    """
    Shopping cart items.

    Stores cart items per session, vendor, and product.
    Sessions are identified by a session_id string (from browser cookies).
    """

    __tablename__ = "cart_items"

    id = Column(Integer, primary_key=True, index=True)
    vendor_id = Column(Integer, ForeignKey("vendors.id"), nullable=False)
    product_id = Column(Integer, ForeignKey("products.id"), nullable=False)
    session_id = Column(String(255), nullable=False, index=True)

    # Cart details
    quantity = Column(Integer, nullable=False, default=1)
    price_at_add = Column(Float, nullable=False)  # Store price when added to cart

    # Relationships
    vendor = relationship("Vendor")
    product = relationship("Product")

    # Constraints
    __table_args__ = (
        UniqueConstraint("vendor_id", "session_id", "product_id", name="uq_cart_item"),
        Index("idx_cart_session", "vendor_id", "session_id"),
        Index("idx_cart_created", "created_at"),  # For cleanup of old carts
    )

    def __repr__(self):
        return f"<CartItem(id={self.id}, session='{self.session_id}', product_id={self.product_id}, qty={self.quantity})>"

    @property
    def line_total(self) -> float:
        """Calculate line total."""
        return self.price_at_add * self.quantity
