From 36dc258224a4ee71c045dffe294ea6973cfc21ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E6=96=8C?= <259278618@qq.com>
Date: Mon, 31 Aug 2026 16:49:55 +0800
Subject: [PATCH] =?UTF-8?q?fix(app):=20downloadModel=20=E5=B9=B6=E5=8F=91?=
 =?UTF-8?q?=E4=B8=8B=E8=BD=BD=E7=9F=AD=E8=B7=AF=20+=20=E9=9D=9E200=20?=
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---
 flutter_app/lib/models/model_manager.dart | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/flutter_app/lib/models/model_manager.dart b/flutter_app/lib/models/model_manager.dart
index 08241ed..ddccbdd 100644
--- a/flutter_app/lib/models/model_manager.dart
+++ b/flutter_app/lib/models/model_manager.dart
@@ -123,7 +123,7 @@ class ModelManager extends ChangeNotifier {
   /// 是否成功拉取过目录（即使下载失败也为 true，用于区分"从未联网"与"目录为空"）
   bool get ready => _ready;
 
-  /// 最近一次同步的错误信息（下载失败/校验失败等；目录为空不算错误）
+  /// 模型目录拉取失败的错误信息（仅目录级；下载/校验失败见 errorOf）
   String? get error => _error;
 
   bool get refreshing => _refreshing;
@@ -206,6 +206,10 @@ class ModelManager extends ChangeNotifier {
   /// 成功自动加入激活集（下载完成即使用）。失败重试一次并记录错误。
   Future<bool> downloadModel(ModelCatalogItem item,
       {void Function(int received, int total)? onProgress}) async {
+    // 并发保护：同一数据集已有进行中的下载则直接短路（预置 0 先占位，
+    // 使 onProgress 首次回调前的双击/refresh 交错也被 containsKey 拦下）
+    if (_progress.containsKey(item.datasetId)) return false;
+    _progress[item.datasetId] = 0;
     final dir = await _modelDir(item.datasetId);
     final file = File('${dir.path}/model.tflite');
     try {
@@ -252,7 +256,10 @@ class ModelManager extends ChangeNotifier {
       final res = await _client
           .send(http.Request('GET', Uri.parse('$baseUrl${item.downloadUrl}')))
           .timeout(const Duration(minutes: 3));
-      if (res.statusCode != 200) return false;
+      if (res.statusCode != 200) {
+        await sink.close();
+        return false;
+      }
       final total = res.contentLength ?? item.sizeBytes;
       await for (final chunk in res.stream) {
         sink.add(chunk);