added logic to recipe provider

lib/services/providers/recipe_provider.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:rezepte/models/difficulty.dart';
 import 'package:rezepte/models/ingredient.dart';
-import 'package:rezepte/models/steps.dart';
+import 'package:rezepte/models/cooking_step.dart';
 
 import '../../models/recipe.dart';
 
@@ -9,30 +9,75 @@ class RecipeProvider extends ChangeNotifier implements Recipe {
   String _title = '';
   String _description = '';
   Difficulty? _difficulty;
-  List<Ingredient> _ingredients = [];
+  final List<Ingredient> _ingredients = [];
-  Steps _steps = Steps();
+  final List<CookingStep> _steps = [];
 
   void clearRecipe() {
     _title = '';
     _description = '';
     _difficulty = null;
-    _ingredients = [];
+    _ingredients.clear();
-    _steps = Steps();
+    _steps.clear();
     notifyListeners();
   }
 
   @override
   String get description => _description;
 
+  set description(String description) {
+    _description = description;
+    notifyListeners();
+  }
+
   @override
   String get title => _title;
 
+  set title(String title) {
+    _title = title;
+    notifyListeners();
+  }
+
   @override
   Difficulty? get difficulty => _difficulty;
 
+  set difficulty(Difficulty? difficulty) {
+    _difficulty = difficulty;
+    notifyListeners();
+  }
+
   @override
   List<Ingredient> get ingredients => _ingredients;
 
+  void addIngredient(Ingredient ingredient) {
+    _ingredients.add(ingredient);
+    notifyListeners();
+  }
+
+  void clearIngredients({silent = false}) {
+    ingredients.clear();
+    if (!silent) notifyListeners();
+  }
+
+  void removeIngredientAt(int index, {silent = false}) {
+    ingredients.removeAt(index);
+    if (!silent) notifyListeners();
+  }
+
+  void removeIngredient(Ingredient ingredient, {silent = false}) {
+    ingredients.removeWhere((element) => element == ingredient);
+    if (!silent) notifyListeners();
+  }
+
   @override
-  Steps get steps => _steps;
+  List<CookingStep> get steps => _steps;
+
+  void addStep(CookingStep step, {silent = false}) {
+    steps.add(step);
+    if (!silent) notifyListeners();
+  }
+
+  void removeStepAt(int index, {silent = false}) {
+    steps.removeAt(index);
+    if (!silent) notifyListeners();
+  }
 }