feat: pallets and boxes for deals

models/shipping.py

@@ -0,0 +1,58 @@
+from typing import TYPE_CHECKING, Optional
+
+from sqlalchemy import ForeignKey
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from models import BaseModel
+
+if TYPE_CHECKING:
+    from models import Deal, Product
+
+
+class Pallet(BaseModel):
+    __tablename__ = 'pallets'
+    id: Mapped[int] = mapped_column(primary_key=True)
+
+    deal_id: Mapped[int] = mapped_column(ForeignKey('deals.id'))
+    deal: Mapped['Deal'] = relationship(back_populates='pallets')
+
+    boxes: Mapped[list['Box']] = relationship(
+        back_populates='pallet',
+        uselist=True,
+        lazy='joined',
+        cascade='all, delete-orphan',
+    )
+
+    shipping_products: Mapped[list['ShippingProduct']] = relationship(
+        back_populates='pallet',
+        uselist=True,
+        lazy='joined',
+        cascade='all, delete-orphan',
+    )
+
+
+class ShippingProduct(BaseModel):
+    __tablename__ = 'shipping_products'
+    id: Mapped[int] = mapped_column(primary_key=True)
+    quantity: Mapped[int] = mapped_column()
+
+    product_id: Mapped[int] = mapped_column(ForeignKey('products.id'))
+    product: Mapped['Product'] = relationship(lazy='joined')
+
+    pallet_id: Mapped[int] = mapped_column(ForeignKey('pallets.id'))
+    pallet: Mapped['Pallet'] = relationship(lazy='joined')
+
+
+class Box(BaseModel):
+    __tablename__ = 'boxes'
+    id: Mapped[int] = mapped_column(primary_key=True)
+
+    quantity: Mapped[int] = mapped_column()
+
+    product_id: Mapped[int] = mapped_column(ForeignKey('products.id'))
+    product: Mapped['Product'] = relationship(lazy='joined')
+
+    pallet_id: Mapped[Optional[int]] = mapped_column(ForeignKey('pallets.id'))
+    pallet: Mapped[Pallet] = relationship(back_populates='boxes')
+
+    deal_id: Mapped[Optional[int]] = mapped_column(ForeignKey('deals.id'))
+    deal: Mapped['Deal'] = relationship(back_populates='boxes')