Add user discount

lib/app.dart

@@ -16,7 +16,7 @@ class ThesisShopApp extends StatelessWidget {
 
   BlocProvider setupBlocs() {
     final userBloc = UserBloc();
-    final productBloc = ProductBloc(productService);
+    final productBloc = ProductBloc(productService, userBloc);
     final cartBloc = CartBloc(productBloc);
     return BlocProvider(
       productBloc: productBloc,

lib/bloc/cart_bloc.dart

@@ -20,10 +20,10 @@ class CartBloc implements Disposable {
 
   int get numberOfProducts => _cart.length;
   late final Stream<int> numberOfProductsStream;
-
+/*
   int numberOfProduct(Product product) => _cart[product] ?? 0;
   Stream<int> numberOfProductStream(Product product) =>
-      cartStream.map((event) => event[product] ?? 0);
+      cartStream.map((event) => event[product] ?? 0);*/
 
   double get totalPrice => cart.calculateTotalPrice();
   Stream<double> get totalPriceStream =>
@@ -53,7 +53,7 @@ class CartBloc implements Disposable {
         final productsByName = {
           for (final product in products) product.title: product
         };
-        _cart.removeWhere((key, _) => productsByName.containsKey(key.title));
+        _cart.removeWhere((key, _) => !productsByName.containsKey(key.title));
         _cart = _cart
             .map((key, value) => MapEntry(productsByName[key.title]!, value));
         _cartSink.add(_cart);
@@ -74,6 +74,7 @@ class CartBloc implements Disposable {
       final old = _cart.putIfAbsent(event.product, () => 0);
       final newQuantity = old + summand;
       _cart[event.product] = newQuantity.isNegative ? 0 : newQuantity;
+      if (_cart[event.product]! <= 0) _cart.remove(event.product);
       _cartSink.add(_cart);
     });
   }
@@ -89,5 +90,7 @@ extension CartItemConverter on Cart {
       entries.map((e) => CartItem(product: e.key, amount: e.value)).toList();
 
   double calculateTotalPrice() => entries.fold(
-      0, (previousValue, element) => previousValue + element.key.price);
+      0,
+      (previousValue, element) =>
+          previousValue + element.key.price * element.value);
 }

lib/bloc/product_bloc.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 
+import 'package:thesis_shop/bloc/user_bloc.dart';
 import 'package:thesis_shop/models/product.dart';
 import 'package:thesis_shop/service/product_service.dart';
 import 'package:thesis_shop/utils/disposable.dart';
@@ -9,7 +10,9 @@ part 'product_bloc_states.dart';
 
 class ProductBloc implements Disposable {
   final ProductService _productService;
+  final UserBloc _userBloc;
 
+  bool _hasDiscount;
   var _productsState = ProductsState.loading();
   ProductsState get productsState => _productsState;
 
@@ -23,17 +26,49 @@ class ProductBloc implements Disposable {
   Sink<LoadProductEvent> get loadProductSink =>
       _loadProductEventController.sink;
 
-  ProductBloc(this._productService) {
+  ProductBloc(this._productService, this._userBloc)
+      : _hasDiscount = _userBloc.isSignedIn {
+    _handleUserEvents();
     _handleLoadProductEvents();
   }
 
+  void _handleUserEvents() {
+    _userBloc.isSignedInStream.listen((isSignedIn) {
+      if (isSignedIn && !_hasDiscount) {
+        if (_productsState.isLoaded()) {
+          final discountedProducts = _productsState
+              .as<ProductsLoaded>()
+              .products
+              .map((product) => product.copyWithDiscount())
+              .toList();
+          _productsState = ProductsState.loaded(discountedProducts);
+          _productsStateSink.add(_productsState);
+        }
+      } else if (!isSignedIn && _hasDiscount) {
+        final undiscountedProducts = _productsState
+            .as<ProductsLoaded>()
+            .products
+            .map((product) => product.copyWithoutDiscount())
+            .toList();
+        _productsState = ProductsState.loaded(undiscountedProducts);
+        _productsStateSink.add(_productsState);
+      }
+      _hasDiscount = isSignedIn;
+    });
+  }
+
   void _handleLoadProductEvents() {
     _loadProductEventController.stream.listen((_) async {
       _productsState = ProductsState.loading();
       _productsStateSink.add(_productsState);
 
       try {
-        final products = await _productService.fetchProducts();
+        var products = await _productService.fetchProducts();
+        _hasDiscount = _userBloc.isSignedIn;
+        if (_hasDiscount) {
+          products =
+              products.map((product) => product.copyWithDiscount()).toList();
+        }
         _productsState = ProductsState.loaded(products);
         _productsStateSink.add(_productsState);
       } catch (err) {

lib/models/product.dart

@@ -8,4 +8,23 @@ class Product {
   String get priceAsString => price.toStringAsFixed(2);
 
   const Product({required this.title, required this.price});
+
+  Product copyWithDiscount() {
+    return Product(title: title, price: price * 0.8);
+  }
+
+  Product copyWithoutDiscount() {
+    return Product(title: title, price: price * 1.25);
+  }
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is Product &&
+          runtimeType == other.runtimeType &&
+          title == other.title &&
+          price == other.price;
+
+  @override
+  int get hashCode => title.hashCode ^ price.hashCode;
 }

lib/screens/cart/total_price_text.dart

@@ -15,7 +15,7 @@ class TotalPriceText extends StatelessWidget {
             child: Padding(
               padding: const EdgeInsets.all(8.0),
               child: Text(
-                'Gesamtpreis: ${snapshot.requireData}€',
+                'Gesamtpreis: ${snapshot.requireData.toStringAsFixed(2)}€',
                 style: Theme.of(context)
                     .textTheme
                     .labelLarge

lib/screens/product_list/product_item.dart

@@ -13,12 +13,12 @@ class ProductItem extends StatelessWidget {
     final cartBloc = AppState.of(context).blocProvider.cartBloc;
     return ListTile(
       title: Text('${product.title} (${product.priceAsString}€/Stück)'),
-      trailing: StreamBuilder<int>(
-          stream: cartBloc.numberOfProductStream(product),
-          initialData: cartBloc.numberOfProduct(product),
+      trailing: StreamBuilder<Cart>(
+          stream: cartBloc.cartStream,
+          initialData: cartBloc.cart,
           builder: (context, snapshot) {
             return NumberPicker(
-              value: snapshot.requireData,
+              value: snapshot.requireData[product] ?? 0,
               onUp: () => cartBloc.quantityEventSink
                   .add(IncreaseQuantityEvent(product)),
               onDown: () => cartBloc.quantityEventSink