fix(import): 修复导入 504 超时 + 添加上传进度显示

nginx:
- 新增 /api/v1/import/ 专属 location，proxy_read_timeout 延长至 300s

后端:
- ImportInventory 预加载商品/仓库/库存（3 次 bulk query 替代 N+1）
- 批量写 inventory_log（CreateInBatches 替代逐行 Create）

前端:
- settings 导入行：显示"上传 XX%"进度条和"导入数据（Ns）"计时
- Dio 超时设置为 send=120s / receive=300s

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/screens/inventory/inventory_list_screen.dart

@@ -99,42 +99,94 @@ class _InventoryListScreenState extends ConsumerState<InventoryListScreen> {
     final file = result.files.first;
     final bytes = file.bytes;
     if (bytes == null) return;
+    if (!context.mounted) return;
 
     final token = ref.read(authStateProvider).user?.accessToken ?? '';
-    final dio = Dio(BaseOptions(baseUrl: AppConfig.apiBaseUrl));
+    final dio = Dio(BaseOptions(
+      baseUrl: AppConfig.apiBaseUrl,
+      sendTimeout: const Duration(seconds: 120),
+      receiveTimeout: const Duration(seconds: 300),
+    ));
     dio.options.headers['Authorization'] = 'Bearer $token';
 
-    if (!context.mounted) return;
-    ScaffoldMessenger.of(context).showSnackBar(
-      const SnackBar(content: Text('导入中，请稍候...'), duration: Duration(seconds: 60)),
+    final stateNotifier = ValueNotifier<_ImportState>(
+      const _ImportState(stage: _ImportStage.uploading, uploadPercent: 0),
     );
 
+    BuildContext? dialogCtx;
+    showDialog(
+      context: context,
+      barrierDismissible: false,
+      builder: (ctx) {
+        dialogCtx = ctx;
+        return PopScope(
+          canPop: false,
+          child: _ImportProgressDialog(stateNotifier: stateNotifier),
+        );
+      },
+    );
+
+    Timer? processingTimer;
+    bool uploadDone = false;
+    int elapsed = 0;
+
+    void closeDialog() {
+      processingTimer?.cancel();
+      if (dialogCtx != null && dialogCtx!.mounted) {
+        Navigator.of(dialogCtx!).pop();
+      }
+    }
+
     try {
       final formData = FormData.fromMap({
         'file': MultipartFile.fromBytes(bytes, filename: file.name),
       });
-      final resp = await dio.post('/import/inventory', data: formData);
-      final data = resp.data as Map<String, dynamic>;
-      final imported = data['imported'] ?? 0;
-      final skipped = data['skipped'] ?? 0;
-      final errors = (data['errors'] as List?)?.cast<String>() ?? [];
 
-      if (!context.mounted) return;
-      ScaffoldMessenger.of(context).hideCurrentSnackBar();
-      ScaffoldMessenger.of(context).showSnackBar(SnackBar(
-        content: Text('导入完成：$imported 条成功，$skipped 条跳过${errors.isNotEmpty ? '，${errors.length} 条失败' : ''}'),
-        backgroundColor: errors.isEmpty ? Colors.green : AppTheme.accent,
-        duration: const Duration(seconds: 4),
-      ));
-      ref.read(inventoryListProvider.notifier).reload();
+      final resp = await dio.post(
+        '/import/inventory',
+        data: formData,
+        onSendProgress: (sent, total) {
+          if (total <= 0) return;
+          if (sent >= total && !uploadDone) {
+            uploadDone = true;
+            elapsed = 0;
+            stateNotifier.value = const _ImportState(
+              stage: _ImportStage.processing, uploadPercent: 100, processingSeconds: 0,
+            );
+            processingTimer = Timer.periodic(const Duration(seconds: 1), (_) {
+              elapsed++;
+              stateNotifier.value = _ImportState(
+                stage: _ImportStage.processing, uploadPercent: 100, processingSeconds: elapsed,
+              );
+            });
+          } else if (!uploadDone) {
+            final pct = (sent / total * 100).round().clamp(0, 99);
+            stateNotifier.value = _ImportState(stage: _ImportStage.uploading, uploadPercent: pct);
+          }
+        },
+      );
+
+      processingTimer?.cancel();
+      final data = resp.data as Map<String, dynamic>;
+      stateNotifier.value = _ImportState(
+        stage: _ImportStage.done,
+        uploadPercent: 100,
+        imported: data['imported'] ?? 0,
+        updated: data['updated'] ?? 0,
+        skipped: data['skipped'] ?? 0,
+        errors: (data['errors'] as List?)?.cast<String>() ?? [],
+      );
+
+      await Future.delayed(const Duration(seconds: 2));
+      closeDialog();
+      if (context.mounted) ref.read(inventoryListProvider.notifier).reload();
     } on DioException catch (e) {
-      final msg = (e.response?.data is Map ? e.response!.data['error'] : null) ?? e.message ?? '未知错误';
-      if (!context.mounted) return;
-      ScaffoldMessenger.of(context).hideCurrentSnackBar();
-      ScaffoldMessenger.of(context).showSnackBar(SnackBar(
-        content: Text('导入失败：$msg'),
-        backgroundColor: AppTheme.danger,
-      ));
+      processingTimer?.cancel();
+      final msg = (e.response?.data is Map ? e.response!.data['error'] : null)
+          ?? e.message ?? '未知错误';
+      stateNotifier.value = _ImportState(
+        stage: _ImportStage.error, uploadPercent: 0, errorMsg: msg,
+      );
     }
   }
 
@@ -865,3 +917,149 @@ class _DirectionBadge extends StatelessWidget {
     );
   }
 }
+
+// ── 导入进度对话框 ──────────────────────────────────────────
+
+enum _ImportStage { uploading, processing, done, error }
+
+class _ImportState {
+  final _ImportStage stage;
+  final int uploadPercent;
+  final int processingSeconds;
+  final int imported;
+  final int updated;
+  final int skipped;
+  final List<String> errors;
+  final String? errorMsg;
+
+  const _ImportState({
+    required this.stage,
+    required this.uploadPercent,
+    this.processingSeconds = 0,
+    this.imported = 0,
+    this.updated = 0,
+    this.skipped = 0,
+    this.errors = const [],
+    this.errorMsg,
+  });
+}
+
+class _ImportProgressDialog extends StatelessWidget {
+  final ValueNotifier<_ImportState> stateNotifier;
+  const _ImportProgressDialog({required this.stateNotifier});
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const Text('导入库存'),
+      content: ValueListenableBuilder<_ImportState>(
+        valueListenable: stateNotifier,
+        builder: (_, state, __) => SizedBox(
+          width: 320,
+          child: _buildContent(context, state),
+        ),
+      ),
+      actions: [
+        ValueListenableBuilder<_ImportState>(
+          valueListenable: stateNotifier,
+          builder: (ctx, state, __) {
+            if (state.stage == _ImportStage.done || state.stage == _ImportStage.error) {
+              return TextButton(
+                onPressed: () => Navigator.of(ctx).pop(),
+                child: const Text('关闭'),
+              );
+            }
+            return const SizedBox.shrink();
+          },
+        ),
+      ],
+    );
+  }
+
+  Widget _buildContent(BuildContext context, _ImportState state) {
+    switch (state.stage) {
+      case _ImportStage.uploading:
+        return Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            const Text('上传文件...', style: TextStyle(fontSize: 14)),
+            const SizedBox(height: 12),
+            LinearProgressIndicator(
+              value: state.uploadPercent / 100,
+              backgroundColor: Colors.grey[200],
+              valueColor: AlwaysStoppedAnimation<Color>(AppTheme.primary),
+            ),
+            const SizedBox(height: 6),
+            Text('${state.uploadPercent}%',
+                style: TextStyle(fontSize: 12, color: Colors.grey[600])),
+          ],
+        );
+
+      case _ImportStage.processing:
+        return Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Row(children: [
+              SizedBox(
+                width: 16, height: 16,
+                child: CircularProgressIndicator(
+                  strokeWidth: 2,
+                  valueColor: AlwaysStoppedAnimation<Color>(AppTheme.primary),
+                ),
+              ),
+              const SizedBox(width: 10),
+              Text(
+                '导入数据中...${state.processingSeconds > 0 ? "（${state.processingSeconds}秒）" : ""}',
+                style: const TextStyle(fontSize: 14),
+              ),
+            ]),
+            const SizedBox(height: 8),
+            LinearProgressIndicator(
+              backgroundColor: Colors.grey[200],
+              valueColor: AlwaysStoppedAnimation<Color>(AppTheme.primary),
+            ),
+          ],
+        );
+
+      case _ImportStage.done:
+        return Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Row(children: [
+              Icon(Icons.check_circle, color: AppTheme.success, size: 20),
+              const SizedBox(width: 8),
+              const Text('导入成功', style: TextStyle(fontSize: 14, fontWeight: FontWeight.w500)),
+            ]),
+            const SizedBox(height: 10),
+            Text('新增：${state.imported} 条', style: const TextStyle(fontSize: 13)),
+            if (state.updated > 0)
+              Text('更新：${state.updated} 条', style: const TextStyle(fontSize: 13)),
+            if (state.skipped > 0)
+              Text('跳过：${state.skipped} 条',
+                  style: TextStyle(fontSize: 13, color: Colors.grey[600])),
+            if (state.errors.isNotEmpty)
+              Text('失败：${state.errors.length} 条',
+                  style: TextStyle(fontSize: 13, color: AppTheme.danger)),
+          ],
+        );
+
+      case _ImportStage.error:
+        return Row(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Icon(Icons.error_outline, color: AppTheme.danger, size: 20),
+            const SizedBox(width: 8),
+            Expanded(
+              child: Text(
+                '导入失败：${state.errorMsg}',
+                style: TextStyle(fontSize: 13, color: AppTheme.danger),
+              ),
+            ),
+          ],
+        );
+    }
+  }
+}

client/lib/screens/settings/settings_screen.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import '../../core/utils/dialog_util.dart';
 import 'package:dio/dio.dart';
 import 'package:file_picker/file_picker.dart';
@@ -1524,10 +1525,22 @@ class _ImportSlot {
   int total = 0;
   int imported = 0;
   int skipped = 0;
+  // 进度
+  int uploadPercent = 0;
+  bool isProcessing = false;
+  int processingSeconds = 0;
 
   _ImportSlot(this.title, this.endpoint, this.hint);
 
   bool get hasResult => success != null;
+
+  void resetProgress() {
+    uploadPercent = 0;
+    isProcessing = false;
+    processingSeconds = 0;
+    success = null;
+    error = null;
+  }
 }
 
 class _BatchImportWidget extends ConsumerStatefulWidget {
@@ -1657,14 +1670,15 @@ class _BatchImportWidgetState extends ConsumerState<_BatchImportWidget> {
     setState(() {
       _loading = true;
       for (final s in _slots) {
-        if (s.file != null) {
-          s.success = null;
-          s.error = null;
-        }
+        if (s.file != null) s.resetProgress();
       }
     });
 
-    final dio = Dio(BaseOptions(baseUrl: AppConfig.apiBaseUrl));
+    final dio = Dio(BaseOptions(
+      baseUrl: AppConfig.apiBaseUrl,
+      sendTimeout: const Duration(seconds: 120),
+      receiveTimeout: const Duration(seconds: 300),
+    ));
     dio.options.headers['Authorization'] = 'Bearer $token';
 
     for (final slot in _slots) {
@@ -1674,29 +1688,56 @@ class _BatchImportWidgetState extends ConsumerState<_BatchImportWidget> {
         if (mounted) setState(() { slot.success = false; slot.error = '无法读取文件'; });
         continue;
       }
+
+      Timer? processingTimer;
+      bool uploadDone = false;
+
       try {
         final formData = FormData.fromMap({
           'file': MultipartFile.fromBytes(bytes, filename: slot.file!.name),
         });
-        final resp = await dio.post(slot.endpoint, data: formData);
+        final resp = await dio.post(
+          slot.endpoint,
+          data: formData,
+          onSendProgress: (sent, total) {
+            if (total <= 0 || !mounted) return;
+            if (sent >= total && !uploadDone) {
+              uploadDone = true;
+              setState(() { slot.isProcessing = true; slot.processingSeconds = 0; });
+              processingTimer = Timer.periodic(const Duration(seconds: 1), (_) {
+                if (!mounted) return;
+                setState(() => slot.processingSeconds++);
+              });
+            } else if (!uploadDone) {
+              final pct = (sent / total * 100).round().clamp(0, 99);
+              if (mounted) setState(() => slot.uploadPercent = pct);
+            }
+          },
+        );
+        processingTimer?.cancel();
         final data = (resp.data is Map) ? resp.data as Map<String, dynamic> : <String, dynamic>{};
         if (mounted) setState(() {
           slot.success = true;
           slot.total = (data['total'] ?? data['imported'] ?? 0) as int;
           slot.imported = (data['imported'] ?? 0) as int;
           slot.skipped = (data['skipped'] ?? 0) as int;
+          slot.isProcessing = false;
         });
       } on DioException catch (e) {
+        processingTimer?.cancel();
         final raw = e.response?.data;
         final msg = (raw is Map ? raw['error'] : null) ?? e.message ?? '未知错误';
         if (mounted) setState(() {
           slot.success = false;
           slot.error = msg.toString();
+          slot.isProcessing = false;
         });
       } catch (e) {
+        processingTimer?.cancel();
         if (mounted) setState(() {
           slot.success = false;
           slot.error = e.toString();
+          slot.isProcessing = false;
         });
       }
     }
@@ -2047,10 +2088,42 @@ class _BatchImportWidgetState extends ConsumerState<_BatchImportWidget> {
         );
       }
     } else if (_loading && slot.file != null) {
-      statusWidget = const SizedBox(
-        width: 14, height: 14,
-        child: CircularProgressIndicator(strokeWidth: 2),
-      );
+      if (slot.isProcessing) {
+        statusWidget = Row(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            SizedBox(
+              width: 12, height: 12,
+              child: CircularProgressIndicator(strokeWidth: 2, color: AppTheme.primary),
+            ),
+            const SizedBox(width: 6),
+            Text(
+              '导入数据${slot.processingSeconds > 0 ? "（${slot.processingSeconds}秒）" : ""}',
+              style: const TextStyle(fontSize: 13, color: AppTheme.textSecondary),
+            ),
+          ],
+        );
+      } else {
+        statusWidget = Row(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            SizedBox(
+              width: 80,
+              child: LinearProgressIndicator(
+                value: slot.uploadPercent / 100,
+                backgroundColor: Colors.grey[200],
+                valueColor: AlwaysStoppedAnimation<Color>(AppTheme.primary),
+                minHeight: 6,
+              ),
+            ),
+            const SizedBox(width: 6),
+            Text(
+              '上传 ${slot.uploadPercent}%',
+              style: const TextStyle(fontSize: 12, color: AppTheme.textSecondary),
+            ),
+          ],
+        );
+      }
     }
 
     return Padding(