From 40ee4dad535201802eadb0ef35c7eb9f10f95436 Mon Sep 17 00:00:00 2001
From: Marcel Raddatz <marcel@raddatz.cloud>
Date: Mon, 6 Apr 2026 19:44:44 +0200
Subject: [PATCH] refactor(shopping): extract mergeKey helper to eliminate
 duplicate key construction

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .../com/recipeapp/shopping/ShoppingService.java   | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/backend/src/main/java/com/recipeapp/shopping/ShoppingService.java b/backend/src/main/java/com/recipeapp/shopping/ShoppingService.java
index e0658d0..4acdd3a 100644
--- a/backend/src/main/java/com/recipeapp/shopping/ShoppingService.java
+++ b/backend/src/main/java/com/recipeapp/shopping/ShoppingService.java
@@ -90,7 +90,7 @@ public class ShoppingService {
                 if (ingredient.isStaple()) {
                     continue;
                 }
-                String key = ingredient.getId().toString() + "|" + ri.getUnit();
+                String key = mergeKey(ingredient.getId(), ri.getUnit());
                 merged.computeIfAbsent(key, k -> new MergedIngredient(ingredient, ri.getUnit()))
                         .addQuantity(ri.getQuantity())
                         .addRecipeId(recipe.getId());
@@ -103,7 +103,7 @@ public class ShoppingService {
         for (ShoppingListItem item : shoppingList.getItems()) {
             if (item.getSourceRecipes() != null && item.getSourceRecipes().length > 0) {
                 // Generated item
-                String key = (item.getIngredient() != null ? item.getIngredient().getId().toString() : "") + "|" + item.getUnit();
+                String key = mergeKey(item.getIngredient() != null ? item.getIngredient().getId() : null, item.getUnit());
                 existingByKey.put(key, item);
             } else {
                 customItems.add(item);
@@ -113,7 +113,7 @@ public class ShoppingService {
         // Merge: update existing, add new, collect keys to keep
         Set<String> mergedKeys = new HashSet<>();
         for (MergedIngredient mi : merged.values()) {
-            String key = mi.ingredient.getId().toString() + "|" + mi.unit;
+            String key = mergeKey(mi.ingredient.getId(), mi.unit);
             mergedKeys.add(key);
 
             ShoppingListItem existing = existingByKey.get(key);
@@ -133,8 +133,9 @@ public class ShoppingService {
         // Remove generated items no longer in the plan
         shoppingList.getItems().removeIf(item ->
                 item.getSourceRecipes() != null && item.getSourceRecipes().length > 0
-                        && !mergedKeys.contains(
-                        (item.getIngredient() != null ? item.getIngredient().getId().toString() : "") + "|" + item.getUnit()));
+                        && !mergedKeys.contains(mergeKey(
+                                item.getIngredient() != null ? item.getIngredient().getId() : null,
+                                item.getUnit())));
 
         shoppingList.setGeneratedAt(java.time.Instant.now());
         shoppingListRepository.save(shoppingList);
@@ -308,6 +309,10 @@ public class ShoppingService {
         );
     }
 
+    private static String mergeKey(UUID ingredientId, String unit) {
+        return (ingredientId != null ? ingredientId.toString() : "") + "|" + unit;
+    }
+
     private static class MergedIngredient {
         final Ingredient ingredient;
         final String unit;