how do sort and raiting in my flutter food app?

First of all im just trying do that plan bcse i whatch YouTube channel Mithc Koko and try add something new thats my plan:

IN PRODUCT PAGE :

1. 5 stars (collecting if each user want to rate product)
2. if user rate product 0-5 (the product position is sorted by rating in HomePage)
3. when user search, do same thing but there user can chose how to sort search.(raiting, location, price)

for now i dont realisate ratingBar for rate food im stuck there how to calculate and saveload rating and sort in Page;

This my Food class :

import 'package:combi/models/rating_manager.dart';

class Food {
  final String name;
  final String restaurantName;
  final String restaurantUid; // Add restaurantUid property
  final String description;
  final String imagePath;

  final FoodCategory category;
  final int price;
  int popularity;
  final bool favorites;

  List<Addon> availableAddons;

  Food({
    required this.name,
    required this.description,
    required this.imagePath,
    required this.price,
    required this.availableAddons,
    required this.restaurantName,
    required this.restaurantUid, // Initialize restaurantUid when creating Food objects
    this.popularity = 0,
    this.favorites = false,
    required this.category,
  });

  // Method to update popularity based on user rating
  void updatePopularity(
      int rating, int foodWeight, int restaurantWeight, int positionIndex) {
    // Calculate the new popularity score
    popularity = RatingManager.calculatePopularity(
      popularity,
      rating,
      foodWeight,
      restaurantWeight,
      positionIndex,
    );
  }

  // Method to toggle favorites
  Food toggleFavorite() {
    return Food(
      name: name,
      restaurantName: restaurantName,
      restaurantUid:
          restaurantUid, // Handle null value by providing a default value
      description: description,
      imagePath: imagePath,
      category: category,
      price: price,
      popularity: popularity,
      availableAddons: availableAddons,
      favorites: !favorites, // Toggle the value
    );
  }
}

enum FoodCategory {
  combo,
  doner,
  pizza,
  chicken,
}

class Addon {
  String name;
  int price;

  Addon({
    required this.name,
    required this.price,
  });
}

new class RatingManager:

class RatingManager {
  static int calculatePopularity(int currentPopularity, int rating,
      int foodWeight, int restaurantWeight, int positionIndex) {
    int newPopularity = (currentPopularity +
            (rating * (foodWeight + restaurantWeight) * positionIndex))
        .toInt();
    return newPopularity;
  }
}

and this how Menu load from firebase for HomePage:

class Restaurant extends ChangeNotifier {
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;

  final FirebaseAuth _auth;

  final List<Food> _menu = [];
  final String name;
  int popularity;
  final List<Food> _favoriteItems = []; // Add list of favorite foods

  Restaurant({
    required this.name,
    this.popularity = 0,
    required FirebaseAuth auth, // Pass FirebaseAuth instance as a parameter
  }) : _auth = auth {
    _loadMenu();
  }

  // Load menu from Firestore
  Future<void> _loadMenu() async {
    try {
      QuerySnapshot querySnapshot = await _firestore.collection('foods').get();
      List<Food> loadedMenu =
          querySnapshot.docs.map((doc) => _foodFromSnapshot(doc)).toList();
      _menu.addAll(loadedMenu);
      notifyListeners();

      // Check if the user is authenticated
      if (_auth.currentUser != null) {
        DocumentSnapshot userDoc = await _firestore
            .collection("Users")
            .doc(_auth.currentUser!.uid)
            .get();
        Map<String, dynamic> userData =
            userDoc.data() as Map<String, dynamic>? ?? {};
        String? userName = userData['name'];
        String? userPhoneNumber = userData['phoneNumber'];
        String? restaurantUid = userData['restaurantUid'];
        // Update SharedPreferences with user's name and phone number if available
        if (userName != null &&
            userPhoneNumber != null &&
            restaurantUid != null) {
          SharedPreferences prefs = await SharedPreferences.getInstance();
          await prefs.setString('name', userName);
          await prefs.setString('phoneNumber', userPhoneNumber);
          await prefs.setString('restaurantUid', restaurantUid);
        }
      }
    } catch (e) {
      print('Error loading menu: $e');
    }
  }

// Getter for favorite items
  List<FavoriteItem> get favoriteItems {
    // Convert favorite foods to FavoriteItem objects with selected addons
    return _favoriteItems
        .map((food) => FavoriteItem(food: food, selectedAddons: []))
        .toList();
  }

  void updatePopularity(int rating, int restaurantWeight) {
    // Calculate the new popularity score
    popularity = RatingManager.calculatePopularity(
      popularity,
      rating,
      0, // Placeholder for food weight, as it's not provided in this method
      restaurantWeight,
      0, // Placeholder for position index, as it's not provided in this method
    );
  }

  Food _foodFromSnapshot(DocumentSnapshot snapshot) {
    Map<String, dynamic> data = snapshot.data() as Map<String, dynamic>;
    String categoryString = data['category'] ?? '';
    FoodCategory category =
        _getFoodCategory(categoryString); // Convert string to enum
    return Food(
      name: data['name'] ?? '',
      description: data['description'] ?? '',
      imagePath: data['imagePath'] ?? '',
      price: (data['price'] ?? 0).toInt(), // Convert double to int
      category: category,
      availableAddons: _addonsFromMapList(data['availableAddons'] ?? []),
      restaurantName: data['restaurantName'] ?? '',
      restaurantUid: data['restaurantUid'] ?? '', // Initialize restaurantUid
      popularity: (data['popularity'] ?? 0).toInt(), // Convert double to int
      favorites: data['favorites'] ?? false,
    );
  }

// Helper method to convert string to FoodCategory enum
  FoodCategory _getFoodCategory(String categoryString) {
    switch (categoryString.toLowerCase()) {
      case 'combo':
        return FoodCategory.combo;
      case 'doner':
        return FoodCategory.doner;
      case 'pizza':
        return FoodCategory.pizza;
      case 'chicken':
        return FoodCategory.chicken;
      default:
        return FoodCategory.combo; // Default to combo if category is unknown
    }
  }

  // Helper method to convert list of maps to list of Addon objects
  List<Addon> _addonsFromMapList(List<dynamic> mapList) {
    return mapList
        .map((addon) => Addon(
              name: addon['name'] ?? '',
              price: addon['price'] ?? 0,
            ))
        .toList();
  }

  // user cart - real quic))
  final List<CartItem> _cart = [];

  // delivery address (can update/change)
  String _deliveryAddress = 'город: Актобе';

  // G E T T E R S
  List<Food> get menu => _menu;
  List<CartItem> get cart => _cart;
  String get deliveryAddress => _deliveryAddress;

  // O P E R A T I O N S
  // add to cart
  void addToCart(Food food, List<Addon> selectedAddons) {
    // see if there is a cart item already with the same food and selected addons
    CartItem? cartItem = _cart.firstWhereOrNull((item) {
      // check if the food items are the same
      bool isSameFood = item.food == food;

      // check if the List of selected addons are the same
      bool isSameAddons =
          const ListEquality().equals(item.selectedAddons, selectedAddons);

      return isSameFood && isSameAddons;
    });
    // if item already exist, increase it`s quantity
    if (cartItem != null) {
      cartItem.quantity++;
    }
    // otherwise, add a new cart item to the cart
    else {
      _cart.add(
        CartItem(
          food: food,
          selectedAddons: selectedAddons,
        ),
      );
    }
    notifyListeners();
  }

// add to favorites
  void addToFavorites(Food food, List<Addon> selectedAddons) {
    // Check if the food with the same addons already exists in favorites
    FavoriteItem? existingFavorite = _favoriteItems
        .map((food) => FavoriteItem(food: food, selectedAddons: []))
        .firstWhereOrNull((favoriteItem) {
      // Check if the food items are the same
      bool isSameFood = favoriteItem.food == food;

      // Check if the list of selected addons are the same
      bool isSameAddons = const ListEquality()
          .equals(favoriteItem.selectedAddons, selectedAddons);

      return isSameFood && isSameAddons;
    });

    // If the item already exists, do nothing
    if (existingFavorite != null) {
      return;
    }

    // Otherwise, add a new favorite item to the favorites list
    _favoriteItems.add(food);

    // Toggle favorite status
    food.toggleFavorite();

    // Notify listeners
    notifyListeners();
  }

  // remove from cart
  void removeFromCart(CartItem cartItem) {
    int cartIndex = _cart.indexOf(cartItem);

    if (cartIndex != -1) {
      if (_cart[cartIndex].quantity > 1) {
        _cart[cartIndex].quantity--;
      } else {
        _cart.removeAt(cartIndex);
      }
    }
    notifyListeners();
  }

// Remove from favorites
  void removeFromFavorites(Food food) {
    int favoriteIndex = _favoriteItems.indexOf(food);

    if (favoriteIndex != -1) {
      _favoriteItems.removeAt(favoriteIndex);
    }

    // Toggle favorite status
    food.toggleFavorite();

    notifyListeners();
  }

  // get total price
  int getTotalPrice() {
    int total = 0;

    for (CartItem cartItem in _cart) {
      int itemTotal = cartItem.food.price;

      for (Addon addon in cartItem.selectedAddons) {
        itemTotal += addon.price;
      }
      total += itemTotal * cartItem.quantity;
    }
    return total;
  }

  // get total number of items in cart
  int getTotalItemCount() {
    int totalItemCount = 0;

    for (CartItem cartItem in _cart) {
      totalItemCount += cartItem.quantity;
    }
    return totalItemCount;
  }

  // clear cart
  void clearCart() {
    _cart.clear();
    notifyListeners();
  }

  // clear favorites
  void clearFavorites() {
    _cart.clear();
    notifyListeners();
  }

  // update delivery address
  void updateDeliveryAddress(String newAddress) {
    _deliveryAddress = newAddress;
    notifyListeners();
  }

  // H E L P E R S
  // Update displayCartReceipt method
  Future<String> displayCartReceipt() async {
    try {
      final SharedPreferences prefs = await SharedPreferences.getInstance();
      final receipt = StringBuffer();
      receipt.writeln("Статус оплаты: "); //$paymentStatus
      // Format the date to include up to seconds only
      String formattedDate =
          DateFormat('yyyy-MM-dd HH:mm:ss').format(DateTime.now());

      // Append the formatted date to the receipt
      receipt.writeln("Дата: $formattedDate");
      receipt.writeln();
      receipt.writeln(
          "Restaurant Name: ${_menu.isNotEmpty ? _menu.first.restaurantName : 'Unknown'}"); // Fetch restaurantName from any item in the menu
      // receipt.writeln(
      //     "Restaurant Uid: ${_menu.isNotEmpty ? _menu.first.restaurantUid : 'Unknown'}"); // Fetch restaurantUid from any item in the menu
      receipt.writeln(
          "<<-------------------------------------------------------------------------------->>");

      // Add cart items details
      for (final cartItem in _cart) {
        receipt.writeln(
            "${cartItem.quantity} x ${cartItem.food.name} - ${_formatPrice(cartItem.food.price)}");

        if (cartItem.selectedAddons.isNotEmpty) {
          receipt.writeln(
              "      Дополнения: ${_formatAddons(cartItem.selectedAddons)}");
        }
        receipt.writeln();
      }

      // Add total items and total price
      receipt.writeln(
          "<<-------------------------------------------------------------------------------->>");
      receipt.writeln();
      receipt.writeln("Общее количество: ${getTotalItemCount()}");
      receipt.writeln("Общая сумма: ${_formatPrice(getTotalPrice())}");
      receipt.writeln(
          "<<-------------------------------------------------------------------------------->>");
      receipt.writeln("Доставка по адресу: $deliveryAddress");

      // Add saved name and phone number to the receipt
      receipt.writeln();
      receipt.writeln("Имя: ${prefs.getString('name') ?? 'Unknown'}");
      receipt.writeln(
          "Номер телефона: ${prefs.getString('phoneNumber') ?? 'Unknown'}");

      return receipt.toString();
    } catch (e) {
      print('Error displaying cart receipt: $e');
      return "Ошибка при отображении квитанции.";
    }
  }

  // format double/int value into money
  String _formatPrice(int price) {
    return '${price.toStringAsFixed(2)}₸';
  }

// format list of addons into a string summary
  String _formatAddons(List<Addon> addons) {
    return addons
        .map((addon) => "${addon.name} (${_formatPrice(addon.price)})")
        .join(", ");
  }

  Restaurant copyWith({
    String? name,
    int? popularity,
  }) {
    return Restaurant(
      name: name ?? this.name,
      popularity: popularity ?? this.popularity,
      auth: FirebaseAuth.instance,
    );
  }

  Map<String, dynamic> toMap() {
    return <String, dynamic>{
      'name': name,
      'popularity': popularity,
    };
  }

  factory Restaurant.fromMap(Map<String, dynamic> map) {
    return Restaurant(
      name: map['name'] as String,
      popularity: map['popularity'] as int,
      auth: FirebaseAuth.instance,
    );
  }

  String toJson() => json.encode(toMap());

  factory Restaurant.fromJson(String source) =>
      Restaurant.fromMap(json.decode(source) as Map<String, dynamic>);

  @override
  String toString() => 'Restaurant(name: $name, popularity: $popularity)';

  @override
  bool operator ==(covariant Restaurant other) {
    if (identical(this, other)) return true;

    return other.name == name && other.popularity == popularity;
  }

  @override
  int get hashCode => name.hashCode ^ popularity.hashCode;
}

i do something wrong, i know. Maybe someone tell me easy way or example please? Thanks!

i was try do rate and just save number with product information (it works) but after days i think i can do better and sort this rated products (and now im here) hope some body help me bcse im bored after weeks drop this project and created new one, but still wanna try that idea