From 1424857327981f8f1d01794dbd8f44ffe124ec49 Mon Sep 17 00:00:00 2001
From: Thomas Way <thomas@6f.io>
Date: Fri, 30 Jan 2026 16:14:41 +0000
Subject: [PATCH] fix(mobile): reset asset index on timeline refresh

The current asset changes when the timeline refreshes, which can be
quite jarring. Assets are tracked by their index, and that index becomes
stale when the timeline refreshes. This can be resolved by updating the
index of asset based on a unique identifier (like the hero tag).
---
 .../lib/domain/services/timeline.service.dart |  7 +++++++
 .../asset_viewer/asset_viewer.page.dart       | 20 ++++++++++++++-----
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/mobile/lib/domain/services/timeline.service.dart b/mobile/lib/domain/services/timeline.service.dart
index 61e114762c..bd36d0b569 100644
--- a/mobile/lib/domain/services/timeline.service.dart
+++ b/mobile/lib/domain/services/timeline.service.dart
@@ -227,6 +227,13 @@ class TimelineService {
     return _buffer.elementAt(index - _bufferOffset);
   }
 
+  /// Finds the index of an asset by its heroTag within the current buffer.
+  /// Returns null if the asset is not found in the buffer.
+  int? getIndex(String heroTag) {
+    final index = _buffer.indexWhere((a) => a.heroTag == heroTag);
+    return index >= 0 ? _bufferOffset + index : null;
+  }
+
   Future<void> dispose() async {
     await _bucketSubscription?.cancel();
     _bucketSubscription = null;
diff --git a/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart b/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart
index 2be2bdf765..9129d998e6 100644
--- a/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart
+++ b/mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart
@@ -451,21 +451,31 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
   }
 
   void _onTimelineReloadEvent() {
-    totalAssets = ref.read(timelineServiceProvider).totalAssets;
+    final timelineService = ref.read(timelineServiceProvider);
+    totalAssets = timelineService.totalAssets;
+
     if (totalAssets == 0) {
       context.maybePop();
       return;
     }
 
+    var index = pageController.page?.round() ?? 0;
+    final currentAsset = ref.read(currentAssetNotifier);
+    if (currentAsset != null) {
+      final newIndex = timelineService.getIndex(currentAsset.heroTag);
+      if (newIndex != null && newIndex != index) {
+        index = newIndex;
+        pageController.jumpToPage(index);
+      }
+    }
+
     if (assetReloadRequested) {
       assetReloadRequested = false;
-      _onAssetReloadEvent();
-      return;
+      _onAssetReloadEvent(index);
     }
   }
 
-  void _onAssetReloadEvent() async {
-    final index = pageController.page?.round() ?? 0;
+  void _onAssetReloadEvent(int index) async {
     final timelineService = ref.read(timelineServiceProvider);
     final newAsset = await timelineService.getAssetAsync(index);