feat(ingredients): make units nullable

internal/processor/ingredient_processor.go

@@ -27,8 +27,11 @@ func NewIngredientProcessor(ingredientRepo IngredientRepository, unitRepo UnitRe
 }
 
 func (p *IngredientProcessorImpl) CreateIngredient(ctx context.Context, req *models.CreateIngredientRequest) (*models.IngredientResponse, error) {
-	if _, err := p.unitRepo.GetByID(ctx, req.UnitID, req.OrganizationID); err != nil {
-		return nil, err
+	// The unit is optional, so it is only validated when one is supplied.
+	if req.UnitID != nil {
+		if _, err := p.unitRepo.GetByID(ctx, *req.UnitID, req.OrganizationID); err != nil {
+			return nil, err
+		}
 	}
 
 	ingredient := &entities.Ingredient{
@@ -107,8 +110,8 @@ func (p *IngredientProcessorImpl) UpdateIngredient(ctx context.Context, id uuid.
 		return nil, err
 	}
 
-	if req.UnitID != existing.UnitID {
-		if _, err := p.unitRepo.GetByID(ctx, req.UnitID, organizationID); err != nil {
+	if req.UnitID != nil && (existing.UnitID == nil || *req.UnitID != *existing.UnitID) {
+		if _, err := p.unitRepo.GetByID(ctx, *req.UnitID, organizationID); err != nil {
 			return nil, err
 		}
 	}

internal/processor/ingredient_unit_converter_processor.go

@@ -266,15 +266,27 @@ func (p *IngredientUnitConverterProcessorImpl) GetUnitsByIngredientID(ctx contex
 		return nil, fmt.Errorf("failed to get ingredient: %w", err)
 	}
 
-	// Get the base unit details
-	baseUnit, err := p.unitRepo.GetByID(ctx, ingredient.UnitID, organizationID)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get base unit: %w", err)
+	response := &models.IngredientUnitsResponse{
+		IngredientID:   ingredientID,
+		IngredientName: ingredient.Name,
 	}
 
-	// Start with the base unit
-	units := []*models.UnitResponse{
-		mappers.MapUnitEntityToResponse(baseUnit),
+	units := make([]*models.UnitResponse, 0)
+	unitMap := make(map[uuid.UUID]bool)
+
+	// An ingredient does not necessarily have a unit assigned yet. When it has
+	// none there is no base unit to start from, so the only units on offer are
+	// the ones its converters mention.
+	if ingredient.UnitID != nil {
+		baseUnit, err := p.unitRepo.GetByID(ctx, *ingredient.UnitID, organizationID)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get base unit: %w", err)
+		}
+
+		units = append(units, mappers.MapUnitEntityToResponse(baseUnit))
+		unitMap[baseUnit.ID] = true
+		response.BaseUnitID = &baseUnit.ID
+		response.BaseUnitName = baseUnit.Name
 	}
 
 	// Get all converters for this ingredient
@@ -283,10 +295,6 @@ func (p *IngredientUnitConverterProcessorImpl) GetUnitsByIngredientID(ctx contex
 		return nil, fmt.Errorf("failed to get converters: %w", err)
 	}
 
-	// Add unique units from converters
-	unitMap := make(map[uuid.UUID]bool)
-	unitMap[baseUnit.ID] = true
-
 	for _, converter := range converters {
 		if converter.IsActive {
 			// Add FromUnit if not already added
@@ -309,13 +317,7 @@ func (p *IngredientUnitConverterProcessorImpl) GetUnitsByIngredientID(ctx contex
 		}
 	}
 
-	response := &models.IngredientUnitsResponse{
-		IngredientID:   ingredientID,
-		IngredientName: ingredient.Name,
-		BaseUnitID:     baseUnit.ID,
-		BaseUnitName:   baseUnit.Name,
-		Units:          units,
-	}
+	response.Units = units
 
 	return response, nil
 }

internal/processor/order_ingredient_transaction_processor.go

@@ -371,8 +371,8 @@ func (p *OrderIngredientTransactionProcessorImpl) CalculateWasteQuantities(ctx c
 
 		// Get unit name
 		unitName := "unit" // default
-		if ingredient.UnitID != uuid.Nil {
-			unit, err := p.unitRepo.GetByID(ctx, ingredient.UnitID, organizationID)
+		if ingredient.UnitID != nil {
+			unit, err := p.unitRepo.GetByID(ctx, *ingredient.UnitID, organizationID)
 			if err == nil {
 				unitName = unit.Name
 			}

internal/processor/purchase_order_processor.go

@@ -462,13 +462,15 @@ func (p *PurchaseOrderProcessorImpl) UpdatePurchaseOrderStatus(ctx context.Conte
 				return nil, fmt.Errorf("failed to get ingredient %s: %w", *item.IngredientID, err)
 			}
 
-			// Convert quantity to ingredient's base unit if needed
+			// Convert quantity to ingredient's base unit if needed. An ingredient
+			// without a unit has no base unit to convert into, so the purchased
+			// quantity is taken as-is.
 			quantityToAdd := *item.Quantity
-			if *item.UnitID != ingredient.UnitID {
+			if ingredient.UnitID != nil && *item.UnitID != *ingredient.UnitID {
 				// Convert from purchase unit to ingredient's base unit
-				convertedQuantity, err := p.unitConverterRepo.ConvertQuantity(ctx, *item.IngredientID, *item.UnitID, ingredient.UnitID, organizationID, *item.Quantity)
+				convertedQuantity, err := p.unitConverterRepo.ConvertQuantity(ctx, *item.IngredientID, *item.UnitID, *ingredient.UnitID, organizationID, *item.Quantity)
 				if err != nil {
-					return nil, fmt.Errorf("failed to convert quantity for ingredient %s from unit %s to %s: %w", *item.IngredientID, *item.UnitID, ingredient.UnitID, err)
+					return nil, fmt.Errorf("failed to convert quantity for ingredient %s from unit %s to %s: %w", *item.IngredientID, *item.UnitID, *ingredient.UnitID, err)
 				}
 				quantityToAdd = convertedQuantity
 			}