Flutter: 项目设计 — ShopApp 架构规划

> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

// domain/entities/product.dart
// 纯 Dart 类，无外部依赖

class Product {
  final int id;
  final String name;
  final double price;
  final String imageUrl;
  final String category;
  final double rating;
  final int reviewCount;
  final int stock;
  final String currency;

  const Product({
    required this.id,
    required this.name,
    required this.price,
    required this.imageUrl,
    this.category = 'General',
    this.rating = 0.0,
    this.reviewCount = 0,
    this.stock = 0,
    this.currency = 'USD',
  });

  bool get inStock => stock > 0;
  bool get hasDiscount => false; // Extended in sale scenario
}

// domain/entities/cart_item.dart
class CartItem {
  final Product product;
  final int quantity;
  final String? selectedSize;
  final String? selectedColor;

  const CartItem({
    required this.product,
    required this.quantity,
    this.selectedSize,
    this.selectedColor,
  });

  double get lineTotal => product.price * quantity;

  CartItem copyWith({int? quantity, String? selectedSize, String? selectedColor}) =>
      CartItem(product: product, quantity: quantity ?? this.quantity,
        selectedSize: selectedSize ?? this.selectedSize,
        selectedColor: selectedColor ?? this.selectedColor);
}

// domain/entities/address.dart
class Address {
  final String name;
  final String street;
  final String city;
  final String state;
  final String zip;
  final String country;

  const Address({
    required this.name,
    required this.street,
    required this.city,
    required this.state,
    required this.zip,
    this.country = 'US',
  });

  String get fullAddress => '$street, $city, $state $zip, $country';

  Map<String, dynamic> toJson() => {
    'name': name, 'street': street, 'city': city,
    'state': state, 'zip': zip, 'country': country,
  };
}

// domain/entities/order.dart
enum OrderStatus { pending, confirmed, shipped, delivered, cancelled }

class Order {
  final String id;
  final String userId;
  final List<CartItem> items;
  final double total;
  final String currency;
  final OrderStatus status;
  final DateTime createdAt;
  final Address shippingAddress;

  const Order({
    required this.id,
    required this.userId,
    required this.items,
    required this.total,
    this.currency = 'USD',
    this.status = OrderStatus.pending,
    required this.createdAt,
    required this.shippingAddress,
  });
}

> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

firestore/
├── products/{productId}
│   ├── name: string
│   ├── price: number
│   ├── stock: number
│   ├── category: string
│   ├── rating: number
│   ├── imageUrl: string
│   └── currency: string
├── users/{userId}
│   ├── email: string
│   ├── name: string
│   ├── preferences: map
│   │   ├── theme: string
│   │   ├── currency: string
│   │   └── locale: string
│   └── addresses: array
├── orders/{orderId}
│   ├── userId: string
│   ├── items: array<{productId, quantity, price}>
│   ├── total: number
│   ├── currency: string
│   ├── status: string
│   └── createdAt: timestamp
└── reviews/{reviewId}
    ├── productId: string
    ├── userId: string
    ├── rating: number
    └── comment: string
```text


```text
> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

import 'package:flutter/material.dart';

// 设计令牌：统一颜色/间距/圆角/字体常量，供 ThemeExtension 承载

class ShopDesignTokens {
  // Colors
  static const primary = Color(0xFF0066CC);
  static const secondary = Color(0xFFFF6B35);
  static const sale = Color(0xFF4CAF50);
  static const discount = Color(0xFFEF5350);

  // Spacing
  static const xs = 4.0;
  static const sm = 8.0;
  static const md = 16.0;
  static const lg = 24.0;
  static const xl = 32.0;

  // Radius
  static const cardRadius = 12.0;
  static const buttonRadius = 8.0;
  static const inputRadius = 8.0;

  // Typography
  static const headlineSize = 24.0;
  static const titleSize = 18.0;
  static const bodySize = 14.0;
  static const captionSize = 12.0;
}

> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

shop_app/
├── lib/
│   ├── main.dart
│   ├── app.dart
│   ├── core/
│   │   ├── router/
│   │   │   └── app_router.dart
│   │   ├── network/
│   │   │   ├── dio_client.dart
│   │   │   └── api_exception.dart
│   │   ├── storage/
│   │   │   ├── secure_storage.dart
│   │   │   ├── hive_cache.dart
│   │   │   └── shared_prefs.dart
│   │   ├── theme/
│   │   │   ├── app_theme.dart
│   │   │   └── brand_tokens.dart
│   │   └── platform/
│   │       └── platform_helper.dart
│   ├── domain/
│   │   ├── entities/
│   │   │   ├── product.dart
│   │   │   ├── cart_item.dart
│   │   │   ├── order.dart
│   │   │   └── user.dart
│   │   └── repositories/
│   │       ├── product_repository.dart
│   │       ├── auth_repository.dart
│   │       └── order_repository.dart
│   ├── data/
│   │   ├── repositories/
│   │   │   ├── product_repository_impl.dart
│   │   │   ├── auth_repository_impl.dart
│   │   │   └── order_repository_impl.dart
│   │   ├── datasources/
│   │   │   ├── firestore_datasource.dart
│   │   │   └── hive_datasource.dart
│   │   └── models/
│   │       ├── product_dto.dart
│   │       └── order_dto.dart
│   ├── application/
│   │   ├── notifiers/
│   │   │   ├── auth_notifier.dart
│   │   │   ├── product_notifier.dart
│   │   │   └── cart_notifier.dart
│   │   └── providers/
│   │       └── infrastructure_providers.dart
│   ├── presentation/
│   │   ├── screens/
│   │   │   ├── home_page.dart
│   │   │   ├── detail_page.dart
│   │   │   ├── cart_page.dart
│   │   │   ├── checkout_page.dart
│   │   │   └── login_page.dart
│   │   └── widgets/
│   │       ├── product_card.dart
│   │       ├── quantity_selector.dart
│   │       ├── cart_badge.dart
│   │       └── price_tag.dart
│   └── l10n/
│       ├── app_en.arb
│       ├── app_zh.arb
│       └── app_ja.arb
├── test/
│   ├── domain/
│   ├── application/
│   └── presentation/
├── integration_test/
├── android/
├── ios/
├── web/
├── windows/
├── macos/
├── pubspec.yaml
├── l10n.yaml
└── .github/workflows/
```text


```text
> **输出：** 在本地 Flutter SDK（Flutter 3.x / Dart 3.x）运行。Piston 服务器未安装 Flutter，请在本机 `flutter run` 实操对照。实际 UI/状态会因平台略有差异。

final Map<String, List<String>> moduleDeps = {
  'core': [],
  'cart': ['core'],
  'checkout': ['core', 'cart'],
  'profile': ['core'],
  'catalog': ['core'],
};

core: 0 直接依赖
cart: 依赖 core
checkout: 依赖 core, cart
profile: 依赖 core
catalog: 依赖 core

final Map<String, String> routes = {
  '/': 'CatalogPage',
  '/cart': 'CartPage',
  '/checkout': 'CheckoutPage',
  '/profile': 'ProfilePage',
};

/         -> CatalogPage
/cart     -> CartPage
/checkout -> CheckoutPage
/profile  -> ProfilePage