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lib/common/utils/order/terminal_order_recovery.dart

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+import 'package:dio/dio.dart';
+
+import 'package:pj_supermarket_cloud/common/models/api/hard_api_models.dart';
+
+/// 处理下单响应丢失后的只读对账；调用方继续使用原本地订单号，不自动重放扣款请求。
+abstract class TerminalOrderRecovery {
+  /// 网络超时、断连及网关服务错误可能丢失已成功响应，明确业务拒绝无需轮询。
+  static bool shouldQuery(DioException error) {
+    return error.type == DioExceptionType.connectionTimeout ||
+        error.type == DioExceptionType.sendTimeout ||
+        error.type == DioExceptionType.receiveTimeout ||
+        error.type == DioExceptionType.connectionError ||
+        (error.type == DioExceptionType.badResponse &&
+            (error.response?.statusCode ?? 0) >= 500);
+  }
+
+  /// 有限次读取原订单，只有状态、支付方式、金额及必要的人员均吻合才恢复成功。
+  ///
+  /// 现金/第三方核销的实付值沿用后端旧约定，金额比对使用商品额与餐费，避免误判。
+  /// 查询异常（包括后端尚未部署新接口的 404）只会消耗本次尝试，不会触发再次扣款。
+  static Future<String?> recover({
+    required Future<ServiceOrderByAndroidCode?> Function() lookup,
+    required String payType,
+    required String? userId,
+    required int totalPrice,
+    required int extraPrice,
+    int attempts = 5,
+    Duration interval = const Duration(seconds: 2),
+  }) async {
+    for (var attempt = 0; attempt < attempts; attempt++) {
+      if (attempt > 0) await Future<void>.delayed(interval);
+      ServiceOrderByAndroidCode? order;
+      try {
+        order = await lookup();
+      } catch (_) {
+        continue;
+      }
+      if (order == null) continue;
+      if (order.orderId.isEmpty ||
+          order.orderStatus != '5' ||
+          order.payType != payType ||
+          order.totalPrice != totalPrice ||
+          order.extraPrice != extraPrice ||
+          (userId != null && order.userId != userId)) {
+        return null;
+      }
+      return order.orderId;
+    }
+    return null;
+  }
+}