created different models

lib/models/ingredient.dart

@@ -0,0 +1,16 @@
+import '../src/enums.dart' show IngredientType;
+import 'unit.dart';
+
+class Ingredient {
+  final String title;
+  final List<Unit> possibleUnits;
+  final List<String> preferredBrands;
+  final IngredientType type;
+
+  Ingredient({
+    required this.title,
+    required this.type,
+    this.possibleUnits = const [],
+    this.preferredBrands = const [],
+  });
+}

lib/models/ingredient_list_entry.dart

@@ -0,0 +1,11 @@
+import 'ingredient.dart';
+import 'unit.dart';
+
+class IngredientListEntry {
+  final Ingredient ingredient;
+  final int amount;
+  final Unit unit;
+  final bool optional;
+
+  IngredientListEntry(this.ingredient, this.amount, this.unit, this.optional);
+}

lib/models/recipe.dart

@@ -0,0 +1,31 @@
+import '../src/enums.dart' show Difficulty, Cuisine, MealCategory;
+import 'ingredient_list_entry.dart';
+
+class Recipe {
+  final int id;
+  final String title;
+  final String description;
+  final Difficulty difficulty;
+  final List<IngredientListEntry> ingredients = [];
+  final List<String> steps = [];
+  final DateTime datePublished;
+  final Duration prepTime;
+  final Duration cookTime;
+  final Duration totalTime;
+  final List<String> keywords = [];
+  final MealCategory mealCategory;
+  final Cuisine cuisine;
+
+  Recipe({
+    required this.id,
+    required this.title,
+    required this.description,
+    required this.difficulty,
+    required this.datePublished,
+    required this.prepTime,
+    required this.cookTime,
+    required this.totalTime,
+    required this.mealCategory,
+    required this.cuisine,
+  });
+}

lib/models/unit.dart

@@ -0,0 +1,9 @@
+import '../src/enums.dart' show UnitType, System;
+
+class Unit {
+  final String name;
+  final UnitType type;
+  final System system;
+
+  Unit(this.name, this.type, {this.system = System.metric});
+}