caching for cart

mobile/lib/controllers/cart.dart

@@ -1,16 +1,38 @@
+import 'dart:convert';
+import 'dart:io';
+
 import 'package:flutter/material.dart';
+import 'package:mobile/models/cart_item.dart';
 import 'package:mobile/models/product.dart';
 import 'package:mobile/results.dart';
+import 'package:path_provider/path_provider.dart';
 
 class ProductIdException implements Exception {}
 
-class CartController extends ChangeNotifier {
+abstract class CartController extends ChangeNotifier {
+  List<CartItem> allCartItems();
+  CartItem? withProductId(int productId);
+  void incrementAmount(int productId);
+  void decrementAmount(int productId);
+  bool willRemoveOnNextDecrement(int productId);
+  void removeCartItem(int productId);
+  void addToCart(Product product);
+  int totalItemsInCart();
+  int totalPrice();
+  void clearCart();
+}
+
+class CartControllerMemory extends CartController {
   final List<CartItem> cart = [];
 
+  CartControllerMemory();
+
+  @override
   List<CartItem> allCartItems() {
     return cart;
   }
 
+  @override
   CartItem? withProductId(int productId) {
     for (var i = 0; i < cart.length; i++) {
       if (cart[i].product.id == productId) {
@@ -20,6 +42,7 @@ class CartController extends ChangeNotifier {
     return null;
   }
 
+  @override
   void incrementAmount(int productId) {
     final cartItem = withProductId(productId);
     if (cartItem == null) {
@@ -29,6 +52,7 @@ class CartController extends ChangeNotifier {
     notifyListeners();
   }
 
+  @override
   void decrementAmount(int productId) {
     final cartItem = withProductId(productId);
     if (cartItem == null) {
@@ -41,6 +65,7 @@ class CartController extends ChangeNotifier {
     notifyListeners();
   }
 
+  @override
   bool willRemoveOnNextDecrement(int productId) {
     final cartItem = withProductId(productId);
     if (cartItem == null) {
@@ -49,6 +74,7 @@ class CartController extends ChangeNotifier {
     return cartItem.amount <= 1;
   }
 
+  @override
   void removeCartItem(int productId) {
     final cartItem = withProductId(productId);
     if (cartItem == null) {
@@ -58,6 +84,7 @@ class CartController extends ChangeNotifier {
     notifyListeners();
   }
 
+  @override
   void addToCart(Product product) {
     final cartItem = withProductId(product.id);
     if (cartItem == null) {
@@ -68,17 +95,20 @@ class CartController extends ChangeNotifier {
     notifyListeners();
   }
 
+  @override
   int totalItemsInCart() {
     return cart.fold<int>(0, (prev, cartItem) => prev + cartItem.amount);
   }
 
+  @override
   int totalPrice() {
     return cart.fold<int>(
         0,
         (prev, cartItem) =>
-            prev + cartItem.amount * cartItem.product.priceInDkkCents);
+            prev + cartItem.amount * cartItem.product.priceDkkCent);
   }
 
+  @override
   void clearCart() {
     cart.clear();
     notifyListeners();
@@ -89,9 +119,63 @@ class CartController extends ChangeNotifier {
   }
 }
 
-class CartItem {
+class CartControllerCache extends CartControllerMemory {
-  final Product product;
+  static Future<File> get _cacheFile async {
-  int amount;
+    final directory = await getApplicationCacheDirectory();
+    return File("${directory.path}/cart.json").create();
+  }
 
-  CartItem({required this.product, required this.amount});
+  CartControllerCache() {
+    load();
+  }
+
+  void save() async {
+    final json =
+        jsonEncode(cart.map((cartItem) => CartItem.toJson(cartItem)).toList());
+    (await _cacheFile).writeAsString(json);
+  }
+
+  void load() async {
+    final json = await (await _cacheFile).readAsString();
+    print("Loading cache: $json");
+    if (json.isEmpty) {
+      return;
+    }
+    final res = jsonDecode(json);
+    final cartItems = (res as List<dynamic>)
+        .map(((cartItems) => CartItem.fromJson(cartItems)))
+        .toList();
+    cart.insertAll(0, cartItems);
+    notifyListeners();
+  }
+
+  @override
+  void incrementAmount(int productId) {
+    super.incrementAmount(productId);
+    save();
+  }
+
+  @override
+  void decrementAmount(int productId) {
+    super.decrementAmount(productId);
+    save();
+  }
+
+  @override
+  void removeCartItem(int productId) {
+    super.removeCartItem(productId);
+    save();
+  }
+
+  @override
+  void addToCart(Product product) {
+    super.addToCart(product);
+    save();
+  }
+
+  @override
+  void clearCart() {
+    super.clearCart();
+    save();
+  }
 }

mobile/lib/controllers/product.dart

@@ -23,7 +23,7 @@ class ProductController extends ChangeNotifier {
     }
   }
 
-  get filteredProducts {
+  List<Product> get filteredProducts {
     if (query.trim().isEmpty) {
       return products;
     }

mobile/lib/controllers/receipt.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
+import 'package:mobile/models/cart_item.dart';
 import 'package:mobile/models/product.dart';
-import 'package:mobile/controllers/cart.dart';
 
 class ReceiptController extends ChangeNotifier {
   int nextId = 0;
@@ -80,6 +80,6 @@ class ReceiptItem {
   ReceiptItem({required this.product, required this.amount});
 
   int totalPrice() {
-    return product.priceInDkkCents * amount;
+    return product.priceDkkCent * amount;
   }
 }

mobile/lib/main.dart

@@ -29,7 +29,7 @@ class MyApp extends StatelessWidget {
         ChangeNotifierProvider(create: (_) => RoutingController()),
         ChangeNotifierProvider(
             create: (_) => ProductController(server: server)),
-        ChangeNotifierProvider(create: (_) => CartController()),
+        ChangeNotifierProvider(create: (_) => CartControllerCache()),
         ChangeNotifierProvider(create: (_) => ReceiptController()),
         ChangeNotifierProvider(create: (_) => PayingStateController()),
         ChangeNotifierProvider(create: (_) => AddToCartStateController()),

mobile/lib/models/cart_item.dart

@@ -0,0 +1,19 @@
+import 'package:mobile/models/product.dart';
+
+class CartItem {
+  final Product product;
+  int amount;
+
+  CartItem({required this.product, required this.amount});
+
+  static Map<String, dynamic> toJson(CartItem cartItem) {
+    return {
+      "product": Product.toJson(cartItem.product),
+      "amount": cartItem.amount
+    };
+  }
+
+  CartItem.fromJson(Map<String, dynamic> json)
+      : product = Product.fromJson(json["product"]),
+        amount = json["amount"];
+}

mobile/lib/models/product.dart

@@ -4,24 +4,35 @@ class Product {
   final int id;
   final String name;
   final String description;
-  final int priceInDkkCents;
+  final int priceDkkCent;
   final Coordinate? location;
   final String? barcode;
 
   Product({
     required this.id,
     required this.name,
-    required this.priceInDkkCents,
+    required this.priceDkkCent,
     required this.description,
     this.location,
     this.barcode,
   });
 
+  static Map<String, dynamic> toJson(Product product) {
+    return {
+      "id": product.id,
+      "name": product.name,
+      "description": product.description,
+      "price_dkk_cent": product.priceDkkCent,
+      "location": product.location,
+      "barcode": product.barcode,
+    };
+  }
+
   Product.fromJson(Map<String, dynamic> json)
       : id = json["id"],
         name = json["name"],
         description = json["description"],
-        priceInDkkCents = json["price_dkk_cent"],
+        priceDkkCent = json["price_dkk_cent"],
         location = null,
         barcode = json["barcode"];
 }

mobile/lib/models/user.dart

@@ -6,30 +6,30 @@ class User {
   final String name;
 
   // balance is in øre
-  int balanceInDkkCents;
+  int balanceDkkCents;
 
   User({
     required this.id,
     required this.email,
     required this.name,
-    required this.balanceInDkkCents,
+    required this.balanceDkkCents,
   });
 
   User.fromJson(Map<String, dynamic> json)
       : email = json["email"],
         id = json["id"],
         name = json["name"],
-        balanceInDkkCents = json["balance_dkk_cent"];
+        balanceDkkCents = json["balance_dkk_cent"];
 
   void addBalanceFounds(int amount) {
-    balanceInDkkCents += amount;
+    balanceDkkCents += amount;
   }
 
   Result<int, String> pay(int amount) {
-    if (balanceInDkkCents < amount) {
+    if (balanceDkkCents < amount) {
       return Err("User can not afford paying amount $amount");
     }
-    balanceInDkkCents -= amount;
+    balanceDkkCents -= amount;
-    return Ok(balanceInDkkCents);
+    return Ok(balanceDkkCents);
   }
 }

mobile/lib/pages/all_products_page.dart

@@ -129,7 +129,7 @@ class AllProductsPage extends StatelessWidget {
                   itemBuilder: (_, idx) => ProductListItem(
                     productId: products[idx].id,
                     name: products[idx].name,
-                    price: products[idx].priceInDkkCents,
+                    price: products[idx].priceDkkCent,
                     productPage: ProductPage(product: products[idx]),
                     product: products[idx],
                   ),

mobile/lib/pages/cart_page.dart

@@ -13,7 +13,7 @@ import 'package:mobile/widgets/sized_card.dart';
 import 'package:provider/provider.dart';
 
 class CartItemView extends StatelessWidget {
-  final CartController cartRepo;
+  final CartControllerCache cartRepo;
   final int productId;
   final String name;
   final int price;
@@ -150,7 +150,7 @@ class CartPage extends StatelessWidget {
     return Column(
       children: [
         Expanded(
-          child: Consumer<CartController>(
+          child: Consumer<CartControllerCache>(
             builder: (_, cartRepo, __) {
               final cart = cartRepo.allCartItems();
               return ListView.builder(
@@ -159,7 +159,7 @@ class CartPage extends StatelessWidget {
                     cartRepo: cartRepo,
                     productId: cart[idx].product.id,
                     name: cart[idx].product.name,
-                    price: cart[idx].product.priceInDkkCents,
+                    price: cart[idx].product.priceDkkCent,
                     amount: cart[idx].amount),
                 itemCount: cart.length,
               );
@@ -202,9 +202,9 @@ class CartPage extends StatelessWidget {
                                             onPressed: () {
                                               final productRepo = context
                                                   .read<ProductController>();
-                                              final CartController cartRepo =
+                                              final CartControllerCache
-                                                  context
+                                                  cartRepo = context.read<
-                                                      .read<CartController>();
+                                                      CartControllerCache>();
                                               final productResult = productRepo
                                                   .productWithBarcode(
                                                       inputController.text);
@@ -260,8 +260,8 @@ class CartPage extends StatelessWidget {
                                 if (!context.mounted) {
                                   return;
                                 }
-                                final CartController cartRepo =
+                                final CartControllerCache cartRepo =
-                                    context.read<CartController>();
+                                    context.read<CartControllerCache>();
                                 final productRepo =
                                     context.read<ProductController>();
                                 final productResult = productRepo

mobile/lib/pages/dashboard.dart

@@ -23,7 +23,7 @@ class Dashboard extends StatelessWidget {
   Widget build(BuildContext context) {
     final pageIndexProvider = Provider.of<RoutingController>(context);
     int currentIndex = pageIndexProvider.currentIndex;
-    final CartController cartRepo = context.watch<CartController>();
+    final CartControllerCache cartRepo = context.watch<CartControllerCache>();
 
     return Scaffold(
       bottomNavigationBar: BottomNavigationBar(

mobile/lib/pages/finish_shopping_page.dart

@@ -14,7 +14,8 @@ class FinishShoppingPage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final CartController cartController = context.read<CartController>();
+    final CartControllerCache cartController =
+        context.read<CartControllerCache>();
     final ReceiptController receiptRepo = context.read<ReceiptController>();
     final PayingStateController payingStateRepo =
         context.watch<PayingStateController>();
@@ -33,7 +34,7 @@ class FinishShoppingPage extends StatelessWidget {
                   child: ListView.builder(
                       shrinkWrap: true,
                       itemBuilder: (_, idx) => ReceiptItemView(
-                          pricePerAmount: cart[idx].product.priceInDkkCents,
+                          pricePerAmount: cart[idx].product.priceDkkCent,
                           name: cart[idx].product.name,
                           amount: cart[idx].amount),
                       itemCount: cart.length),

mobile/lib/pages/home_page.dart

@@ -38,7 +38,7 @@ class HomePage extends StatelessWidget {
                   sessionController: sessionController,
                   placeholder: const CircularProgressIndicator(),
                   builder: (context, user) => Text(
-                      "Saldo: ${formatDkkCents(user.balanceInDkkCents)}",
+                      "Saldo: ${formatDkkCents(user.balanceDkkCents)}",
                       style: Theme.of(context).textTheme.headlineSmall))),
         ),
         Expanded(

mobile/lib/pages/product_page.dart

@@ -38,7 +38,7 @@ class ProductPage extends StatelessWidget {
                             ),
                           ),
                           Text(
-                            formatDkkCents(product.priceInDkkCents),
+                            formatDkkCents(product.priceDkkCent),
                             style: const TextStyle(
                               fontSize: 16,
                             ),
@@ -66,7 +66,7 @@ class ProductPage extends StatelessWidget {
                       style: Theme.of(context).textTheme.bodyLarge,
                     ),
                     Text(
-                      formatDkkCents(product.priceInDkkCents),
+                      formatDkkCents(product.priceDkkCent),
                       style: Theme.of(context).textTheme.bodyLarge,
                     ),
                     Padding(
@@ -90,7 +90,7 @@ class ProductPage extends StatelessWidget {
                             duration: const Duration(seconds: 2),
                           );
                           ScaffoldMessenger.of(context).removeCurrentSnackBar();
-                          final cartRepo = context.read<CartController>();
+                          final cartRepo = context.read<CartControllerCache>();
                           cartRepo.addToCart(product);
                           ScaffoldMessenger.of(context).showSnackBar(snackBar);
                         },

mobile/lib/pages/receipt_page.dart

@@ -29,7 +29,7 @@ class ReceiptView extends StatelessWidget {
                           shrinkWrap: true,
                           itemBuilder: (_, idx) => ReceiptItemView(
                               pricePerAmount:
-                                  receiptItems[idx].product.priceInDkkCents,
+                                  receiptItems[idx].product.priceDkkCent,
                               name: receiptItems[idx].product.name,
                               amount: receiptItems[idx].amount),
                           itemCount: receiptItems.length),

mobile/lib/pages/settings_pages/saldo.dart

@@ -29,7 +29,7 @@ class SaldoSettingsPage extends StatelessWidget {
               sessionController: sessionController,
               placeholder: const CircularProgressIndicator(),
               builder: (context, user) => Text(
-                  "Nuværende saldo: ${formatDkkCents(user.balanceInDkkCents)}",
+                  "Nuværende saldo: ${formatDkkCents(user.balanceDkkCents)}",
                   style: Theme.of(context).textTheme.bodyLarge),
             ),
             ElevatedButton.icon(

mobile/lib/server/mock_server.dart

@@ -11,90 +11,80 @@ class MockServer implements Server {
       Product(
           id: nextId++,
           name: "Minimælk",
-          priceInDkkCents: 1200,
+          priceDkkCent: 1200,
           description: "Konventionel minimælk med fedtprocent på 0,4%"),
       Product(
           id: nextId++,
           name: "Letmælk",
-          priceInDkkCents: 1300,
+          priceDkkCent: 1300,
           description: "Konventionel letmælk med fedtprocent på 1,5%",
           location: Coordinate(x: 1800, y: 100)),
       Product(
           id: nextId++,
           name: "Frilands Øko Supermælk",
-          priceInDkkCents: 2000,
+          priceDkkCent: 2000,
           description:
               "Økologisk mælk af frilandskøer med fedtprocent på 3,5%. Ikke homogeniseret eller pasteuriseret. Skaber store muskler og styrker knoglerne 💪"),
       Product(
           id: nextId++,
           name: "Øko Gulerødder 1 kg",
-          priceInDkkCents: 1000,
+          priceDkkCent: 1000,
           description: ""),
       Product(
-          id: nextId++,
+          id: nextId++, name: "Øko Agurk", priceDkkCent: 1000, description: ""),
-          name: "Øko Agurk",
-          priceInDkkCents: 1000,
-          description: ""),
       Product(
           id: nextId++,
           name: "Æbler 1 kg",
-          priceInDkkCents: 1000,
+          priceDkkCent: 1000,
           description: ""),
       Product(
           id: nextId++,
           name: "Basmati Ris",
-          priceInDkkCents: 2000,
+          priceDkkCent: 2000,
           description: ""),
       Product(
           id: nextId++,
           name: "Haribo Mix",
-          priceInDkkCents: 3000,
+          priceDkkCent: 3000,
           description: ""),
-      Product(
+      Product(id: nextId++, name: "Smør", priceDkkCent: 3000, description: ""),
-          id: nextId++, name: "Smør", priceInDkkCents: 3000, description: ""),
       Product(
           id: nextId++,
           name: "Harboe Cola",
-          priceInDkkCents: 500,
+          priceDkkCent: 500,
           description: ""),
       Product(
           id: nextId++,
           barcode: "5060337502900",
           name: "Monster Energi Drik",
-          priceInDkkCents: 1500,
+          priceDkkCent: 1500,
           description: ""),
       Product(
           id: nextId++,
           barcode: "5712870659220",
           name: "Amper Energi Drik",
-          priceInDkkCents: 750,
+          priceDkkCent: 750,
           description: ""),
       Product(
           id: nextId++,
           barcode: "5710326001937",
           name: "Danskvand Med Brus",
-          priceInDkkCents: 500,
+          priceDkkCent: 500,
           description: "Med smag a blåbær"),
       Product(
-          id: nextId++,
+          id: nextId++, name: "Spaghetti", priceDkkCent: 1000, description: ""),
-          name: "Spaghetti",
-          priceInDkkCents: 1000,
-          description: ""),
       Product(
-          id: nextId++,
+          id: nextId++, name: "Rød Cecil", priceDkkCent: 6000, description: ""),
-          name: "Rød Cecil",
-          priceInDkkCents: 6000,
-          description: ""),
       Product(
           id: nextId++,
           name: "Jägermeister 750 ml",
-          priceInDkkCents: 12000,
+          priceDkkCent: 12000,
           description: ""),
       Product(
           id: nextId++,
           barcode: "5711953068881",
           name: "Protein Chokoladedrik",
-          priceInDkkCents: 1500,
+          priceDkkCent: 1500,
           description: "Arla's protein chokolade drik der giver store muskler"),
     ]);
   }
@@ -128,7 +118,7 @@ class MockServer implements Server {
             id: 0,
             email: "test@test.com",
             name: "testuser",
-            balanceInDkkCents: 10000));
+            balanceDkkCents: 10000));
   }
 
   @override

mobile/lib/utils/price.dart

@@ -1,6 +1,6 @@
 import 'package:intl/intl.dart';
 
-String formatDkkCents(int priceInDkkCents) {
+String formatDkkCents(int priceDkkCents) {
   final formatter = NumberFormat("###,##0.00", "da_DK");
-  return "${formatter.format(priceInDkkCents / 100.0)} kr";
+  return "${formatter.format(priceDkkCents / 100.0)} kr";
 }

mobile/pubspec.lock

@@ -268,7 +268,7 @@ packages:
     source: hosted
     version: "1.9.1"
   path_provider:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: path_provider
       sha256: "50c5dd5b6e1aaf6fb3a78b33f6aa3afca52bf903a8a5298f53101fdaee55bbcd"

mobile/pubspec.yaml

@@ -39,6 +39,7 @@ dependencies:
   google_fonts: ^6.2.1
   intl: ^0.20.2
   http: ^1.3.0
+  path_provider: ^2.1.5
 
 dev_dependencies:
   flutter_test: