feat(app): 接入金币充值与会员商品下单

lib/core/data/services/store_controller.dart

@@ -0,0 +1,75 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/foundation.dart';
+
+import '../models/order.dart';
+import '../models/product.dart';
+import '../repositories/store_repository.dart';
+import '../remote/api_exception.dart';
+
+/// 商品货架状态：按类型拉取商品并创建订单。
+class StoreController extends ChangeNotifier {
+  StoreController(this._repository, {required this.type});
+
+  static const String coinPackType = AppProduct.coinPackType;
+  static const String vipType = AppProduct.vipType;
+
+  final StoreRepository _repository;
+  final String type;
+
+  List<AppProduct> products = const [];
+  bool loading = false;
+  String? error;
+  String? purchasingProductId;
+  String? purchaseError;
+  AppOrder? order;
+  bool _disposed = false;
+
+  Future<void> load() async {
+    loading = true;
+    error = null;
+    _notify();
+    try {
+      products = await _repository.fetchProducts(type: type);
+    } on ApiException catch (exception) {
+      error = exception.message;
+    } catch (_) {
+      error = 'productsLoadFailed';
+    } finally {
+      loading = false;
+      _notify();
+    }
+  }
+
+  /// 创建订单；成功后保留 [order] 供页面展示订单号。
+  Future<AppOrder?> buy(AppProduct product) async {
+    if (purchasingProductId != null) return null;
+    purchasingProductId = product.id;
+    purchaseError = null;
+    _notify();
+    try {
+      final created = await _repository.createOrder(product.id);
+      order = created;
+      return created;
+    } on ApiException catch (exception) {
+      purchaseError = exception.message;
+      return null;
+    } catch (_) {
+      purchaseError = 'orderCreateFailed';
+      return null;
+    } finally {
+      purchasingProductId = null;
+      _notify();
+    }
+  }
+
+  void _notify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+}