Merge branch 'client-support-for-favourite' into 'main'

added client side recipe favouriting

See merge request cse1105/2025-2026/teams/csep-team-76!31

client/src/main/java/client/utils/Config.java

@@ -12,7 +12,8 @@ public class Config {
     private List<Long> favourites = new ArrayList<>();
     private List<String> shoppingList = new ArrayList<>();
 
-    public Config(){}
+    public Config() {
+    }
 
     public String getLanguage() {
         return language;
@@ -22,10 +23,6 @@ public class Config {
         return shoppingList;
     }
 
-    public List<Long> getFavourites() {
-        return favourites;
-    }
-
     public String getServerUrl() {
         return serverUrl;
     }
@@ -45,4 +42,29 @@ public class Config {
     public void setShoppingList(List<String> shoppingList) {
         this.shoppingList = shoppingList;
     }
+
+    // favourite helper
+
+    public List<Long> getFavourites() {
+        if (favourites == null) {
+            favourites = new ArrayList<>();
+        }
+        return favourites;
+    }
+// to avoid null pointers.
+
+    public boolean isFavourite(long recipeId) {
+        return getFavourites().contains(recipeId);
+    }
+
+    public void addFavourite(long recipeId) {
+        if (!getFavourites().contains(recipeId)) {
+            getFavourites().add(recipeId);
+        }
+    }
+
+    public void removeFavourite(long recipeId) {
+        getFavourites().remove(recipeId);
+    }
 }
+