API and database models refactoring

models/database/stock.py

@@ -0,0 +1,40 @@
+from datetime import datetime
+
+from sqlalchemy import (Boolean, Column, DateTime, Float, ForeignKey, Index,
+                        Integer, String, Text, UniqueConstraint)
+from sqlalchemy.orm import relationship
+
+# Import Base from the central database module instead of creating a new one
+from app.core.database import Base
+
+
+class Stock(Base):
+    __tablename__ = "stock"
+
+    id = Column(Integer, primary_key=True, index=True)
+    gtin = Column(
+        String, index=True, nullable=False
+    )  # Foreign key relationship would be ideal
+    location = Column(String, nullable=False, index=True)
+    quantity = Column(Integer, nullable=False, default=0)
+    reserved_quantity = Column(Integer, default=0)  # For orders being processed
+    shop_id = Column(Integer, ForeignKey("shops.id"))  # Optional: shop-specific stock
+
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(
+        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False
+    )
+
+    # Relationships
+    shop = relationship("Shop")
+
+    # Composite unique constraint to prevent duplicate GTIN-location combinations
+    __table_args__ = (
+        UniqueConstraint("gtin", "location", name="uq_stock_gtin_location"),
+        Index(
+            "idx_stock_gtin_location", "gtin", "location"
+        ),  # Composite index for efficient queries
+    )
+
+    def __repr__(self):
+        return f"<Stock(gtin='{self.gtin}', location='{self.location}', quantity={self.quantity})>"