From b985aa283f9ddd4e9d5e0308bed871d981725bf8 Mon Sep 17 00:00:00 2001
From: Rithvik Sriram <r.sriram-1@student.tudelft.nl>
Date: Thu, 15 Jan 2026 15:24:21 +0100
Subject: [PATCH] added a special warning message when user tries to add
 duplicate ingredients

---
 .../client/scenes/FoodpalApplicationCtrl.java | 19 ++++++++++++-------
 .../scenes/recipe/IngredientsPopupCtrl.java   |  9 ++++++++-
 .../java/client/utils/server/ServerUtils.java |  5 +++++
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/client/src/main/java/client/scenes/FoodpalApplicationCtrl.java b/client/src/main/java/client/scenes/FoodpalApplicationCtrl.java
index 3242d21..d553712 100644
--- a/client/src/main/java/client/scenes/FoodpalApplicationCtrl.java
+++ b/client/src/main/java/client/scenes/FoodpalApplicationCtrl.java
@@ -534,13 +534,18 @@ public class FoodpalApplicationCtrl implements LocaleAware {
         // Wait for the user to enter a value
         Optional<String> result = dialog.showAndWait();
 
-        result.ifPresent(name -> {
-            // Create a new Ingredient object
-            Ingredient newIngredient = new Ingredient();
-            newIngredient.setName(name);
-
-            // Add the new ingredient to the ListView
-            ingredientListView.getItems().add(newIngredient);
+        result.ifPresent(recipeName ->{
+            String trim = recipeName.trim();
+            if(trim.isEmpty()){
+                showError("Invalid Input", "Cannot have empty ingredient name");
+                return;
+            }
+            if(ingredientListView.getItems().stream()
+                    .map(Ingredient::getName)
+                    .anyMatch(ingName -> ingName.equalsIgnoreCase(trim))){
+                showError("Duplicate Ingredient", "Cannot have duplicate ingredients," +
+                        " Please provide unique Ingredient names");
+            }
         });
     }
 
diff --git a/client/src/main/java/client/scenes/recipe/IngredientsPopupCtrl.java b/client/src/main/java/client/scenes/recipe/IngredientsPopupCtrl.java
index de27245..7d6a4f3 100644
--- a/client/src/main/java/client/scenes/recipe/IngredientsPopupCtrl.java
+++ b/client/src/main/java/client/scenes/recipe/IngredientsPopupCtrl.java
@@ -66,7 +66,14 @@ public class IngredientsPopupCtrl {
         try {
             server.createIngredient(name);  // calls POST /api/ingredients
             refresh();                      // reload list from server
-        } catch (IOException | InterruptedException e) {
+        } catch (IOException e) {
+            if (e.getMessage() != null && e.getMessage().startsWith("DUPLICATE:")) {
+                showError("An ingredient with the name" + name + " already exists." +
+                        " Please provide a different name.");
+            } else {
+                showError("Failed to create ingredient: " + e.getMessage());
+            }
+        }  catch (InterruptedException e){
             showError("Failed to create ingredient: " + e.getMessage());
         }
     }
diff --git a/client/src/main/java/client/utils/server/ServerUtils.java b/client/src/main/java/client/utils/server/ServerUtils.java
index 5330fdd..2d4bcc0 100644
--- a/client/src/main/java/client/utils/server/ServerUtils.java
+++ b/client/src/main/java/client/utils/server/ServerUtils.java
@@ -278,6 +278,11 @@ public class ServerUtils {
                 .build();
 
         HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
+
+        if (response.statusCode() == 409) {
+            throw new IOException("An ingredient with the name '" + name + "' already exists.");
+        }
+
         if (response.statusCode() != statusOK) {
             throw new IOException("Failed to create ingredient. Server responds with: " + response.body());
         }