Minor version bump (1.x.0) is appropriate because:

✅ New functionality added (soft delete system)
✅ Backward compatible (existing features unchanged)
✅ Significant enhancement (complete temporal tracking system)
✅ API additions (new endpoints, parameters)
✅ UI enhancements (new components, visual indicators)

backend/models.py

@@ -1,11 +1,89 @@
-from sqlalchemy import Column, Integer, String, Float, Boolean, DateTime, ForeignKey, Table
+from sqlalchemy import Column, Integer, String, Float, Boolean, DateTime, Date, ForeignKey, Table, event, DDL
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship
-from sqlalchemy.sql import func
+from sqlalchemy.sql import func, text
 from datetime import datetime
 
+# Constants for temporal tables
+FAR_FUTURE_DATE = "'9999-12-31'"
+
 Base = declarative_base()
 
+# Trigger creation SQL
+PRODUCTS_VERSIONING_TRIGGER_SQL = """
+CREATE OR REPLACE FUNCTION products_versioning_trigger()
+RETURNS TRIGGER AS $$
+BEGIN
+    -- Handle DELETE operations
+    IF TG_OP = 'DELETE' THEN
+        -- Create history record for the deleted product
+        INSERT INTO products_history (
+            id, name, category_id, brand_id, organic, weight, weight_unit,
+            created_at, updated_at, valid_from, valid_to, deleted, operation
+        ) VALUES (
+            OLD.id, OLD.name, OLD.category_id, OLD.brand_id, OLD.organic, 
+            OLD.weight, OLD.weight_unit, OLD.created_at, OLD.updated_at,
+            OLD.valid_from, CURRENT_DATE, OLD.deleted, 'D'
+        );
+        
+        RETURN OLD;
+    END IF;
+
+    -- Handle UPDATE operations
+    IF TG_OP = 'UPDATE' THEN
+        -- Check if any versioned fields have changed
+        IF (OLD.name IS DISTINCT FROM NEW.name OR
+            OLD.category_id IS DISTINCT FROM NEW.category_id OR
+            OLD.brand_id IS DISTINCT FROM NEW.brand_id OR
+            OLD.organic IS DISTINCT FROM NEW.organic OR
+            OLD.weight IS DISTINCT FROM NEW.weight OR
+            OLD.weight_unit IS DISTINCT FROM NEW.weight_unit OR
+            OLD.deleted IS DISTINCT FROM NEW.deleted) THEN
+            
+            -- Determine the valid_to date for the history record
+            DECLARE
+                history_valid_to DATE;
+            BEGIN
+                -- If valid_from was manually changed, use that as the cutoff
+                -- Otherwise, use current date for automatic versioning
+                IF OLD.valid_from IS DISTINCT FROM NEW.valid_from THEN
+                    history_valid_to = NEW.valid_from;
+                ELSE
+                    history_valid_to = CURRENT_DATE;
+                    -- For automatic versioning, update the valid_from to today
+                    NEW.valid_from = CURRENT_DATE;
+                END IF;
+                
+                -- Create history record with the old data
+                INSERT INTO products_history (
+                    id, name, category_id, brand_id, organic, weight, weight_unit,
+                    created_at, updated_at, valid_from, valid_to, deleted, operation
+                ) VALUES (
+                    OLD.id, OLD.name, OLD.category_id, OLD.brand_id, OLD.organic, 
+                    OLD.weight, OLD.weight_unit, OLD.created_at, OLD.updated_at,
+                    OLD.valid_from, history_valid_to, OLD.deleted, 'U'
+                );
+            END;
+            
+            -- Always ensure valid_to is set to far future for current version
+            NEW.valid_to = '9999-12-31';
+            NEW.updated_at = NOW();
+        END IF;
+        
+        RETURN NEW;
+    END IF;
+    
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS products_versioning_trigger ON products;
+CREATE TRIGGER products_versioning_trigger
+    BEFORE UPDATE OR DELETE ON products
+    FOR EACH ROW
+    EXECUTE FUNCTION products_versioning_trigger();
+"""
+
 # Association table for many-to-many relationship between shopping events and products
 shopping_event_products = Table(
     'shopping_event_products',
@@ -78,6 +156,11 @@ class Product(Base):
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())
     
+    # Temporal columns for versioning
+    valid_from = Column(Date, server_default=func.current_date(), nullable=False)
+    valid_to = Column(Date, server_default=text(FAR_FUTURE_DATE), nullable=False)
+    deleted = Column(Boolean, default=False, nullable=False)
+    
     # Relationships
     category = relationship("GroceryCategory", back_populates="products")
     brand = relationship("Brand", back_populates="products")
@@ -93,6 +176,41 @@ class Product(Base):
         viewonly=True
     )
 
+class ProductHistory(Base):
+    __tablename__ = "products_history"
+    
+    history_id = Column(Integer, primary_key=True, index=True)
+    id = Column(Integer, nullable=False, index=True)  # Original product ID
+    name = Column(String, nullable=False)
+    category_id = Column(Integer, nullable=False)
+    brand_id = Column(Integer, nullable=True)
+    organic = Column(Boolean, default=False)
+    weight = Column(Float, nullable=True)
+    weight_unit = Column(String, default="piece")
+    created_at = Column(DateTime(timezone=True))
+    updated_at = Column(DateTime(timezone=True))
+    
+    # Temporal columns
+    valid_from = Column(Date, nullable=False)
+    valid_to = Column(Date, nullable=False)
+    deleted = Column(Boolean, default=False, nullable=False)
+    
+    # Audit columns
+    operation = Column(String(1), nullable=False)  # 'U' for Update, 'D' for Delete
+    archived_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+
+# Create trigger after ProductHistory table is created
+@event.listens_for(ProductHistory.__table__, 'after_create')
+def create_products_versioning_trigger(target, connection, **kw):
+    """Create the products versioning trigger after the history table is created"""
+    try:
+        connection.execute(text(PRODUCTS_VERSIONING_TRIGGER_SQL))
+        print("✅ Products versioning trigger created successfully")
+    except Exception as e:
+        print(f"⚠️  Warning: Could not create products versioning trigger: {e}")
+        # Don't fail the entire application startup if trigger creation fails
+        pass
+
 class Shop(Base):
     __tablename__ = "shops"