feat(mobile): fallback to computed checksum for timeline match

- hash local asset on-demand when checksum missing
- search main timeline by localId or checksum before standalone viewer
- persist computed hash into local_asset_entity

mobile/lib/providers/asset_viewer/view_intent_handler.provider.dart

@@ -1,15 +1,18 @@
 import 'dart:async';
 
 import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:immich_mobile/constants/constants.dart';
 import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
 import 'package:immich_mobile/domain/services/timeline.service.dart';
 import 'package:immich_mobile/infrastructure/repositories/local_asset.repository.dart';
 import 'package:immich_mobile/models/view_intent/view_intent_attachment.model.dart';
+import 'package:immich_mobile/platform/native_sync_api.g.dart';
 import 'package:immich_mobile/presentation/widgets/asset_viewer/asset_viewer.state.dart';
 import 'package:immich_mobile/providers/asset_viewer/video_player_controls_provider.dart';
 import 'package:immich_mobile/providers/asset_viewer/video_player_value_provider.dart';
 import 'package:immich_mobile/providers/infrastructure/asset.provider.dart';
 import 'package:immich_mobile/providers/infrastructure/asset_viewer/current_asset.provider.dart';
+import 'package:immich_mobile/providers/infrastructure/platform.provider.dart';
 import 'package:immich_mobile/providers/infrastructure/timeline.provider.dart';
 import 'package:immich_mobile/providers/user.provider.dart';
 import 'package:immich_mobile/routing/router.dart';
@@ -21,6 +24,7 @@ final viewIntentHandlerProvider = Provider<ViewIntentHandler>(
     ref.read(viewIntentServiceProvider),
     ref.watch(appRouterProvider),
     ref.read(localAssetRepository),
+    ref.read(nativeSyncApiProvider),
     ref.read(timelineFactoryProvider),
   ),
 );
@@ -30,6 +34,7 @@ class ViewIntentHandler {
   final ViewIntentService _viewIntentService;
   final AppRouter _router;
   final DriftLocalAssetRepository _localAssetRepository;
+  final NativeSyncApi _nativeSyncApi;
   final TimelineFactory _timelineFactory;
 
   const ViewIntentHandler(
@@ -37,6 +42,7 @@ class ViewIntentHandler {
     this._viewIntentService,
     this._router,
     this._localAssetRepository,
+    this._nativeSyncApi,
     this._timelineFactory,
   );
 
@@ -63,7 +69,19 @@ class ViewIntentHandler {
     if (localAssetId != null) {
       final localAsset = await _localAssetRepository.getById(localAssetId);
       if (localAsset != null) {
-        _openAssetViewer(localAsset);
+        var checksum = localAsset.checksum;
+        if (checksum == null) {
+          checksum = await _computeChecksum(localAssetId);
+          if (checksum != null) {
+            await _localAssetRepository.updateHashes({localAssetId: checksum});
+          }
+        }
+        //todo clarify logic for assets not presented into MainTimeline (locked folder, deleted etc)
+        final timelineMatch = await _openFromMainTimeline(localAssetId, checksum: checksum);
+        if (timelineMatch) {
+          return;
+        }
+        _openAssetViewer(localAsset, _timelineFactory.fromAssets([localAsset], TimelineOrigin.deepLink), 0);
         return;
       }
     }
@@ -71,7 +89,44 @@ class ViewIntentHandler {
     await _router.push(ExternalMediaViewerRoute(attachment: attachment));
   }
 
-  void _openAssetViewer(LocalAsset asset) {
+  Future<bool> _openFromMainTimeline(String localAssetId, {String? checksum}) async {
+    final timelineService = _ref.read(timelineServiceProvider);
+    if (timelineService.totalAssets == 0) {
+      try {
+        await timelineService.watchBuckets().first.timeout(const Duration(seconds: 2));
+      } catch (_) {
+        // Ignore and fallback.
+      }
+    }
+
+    final totalAssets = timelineService.totalAssets;
+    if (totalAssets == 0) {
+      return false;
+    }
+
+    final batchSize = kTimelineAssetLoadBatchSize;
+    for (var offset = 0; offset < totalAssets; offset += batchSize) {
+      final count = (offset + batchSize > totalAssets) ? totalAssets - offset : batchSize;
+      final assets = await timelineService.loadAssets(offset, count);
+      final indexInBatch = assets.indexWhere((asset) {
+        if (asset.localId == localAssetId) {
+          return true;
+        }
+        if (checksum != null && asset.checksum == checksum) {
+          return true;
+        }
+        return false;
+      });
+      if (indexInBatch >= 0) {
+        final asset = assets[indexInBatch];
+        _openAssetViewer(asset, timelineService, offset + indexInBatch);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  void _openAssetViewer(BaseAsset asset, TimelineService timelineService, int initialIndex) {
     _ref.read(assetViewerProvider.notifier).reset();
     _ref.read(assetViewerProvider.notifier).setAsset(asset);
     _ref.read(currentAssetNotifier.notifier).setAsset(asset);
@@ -83,11 +138,18 @@ class ViewIntentHandler {
       _ref.read(assetViewerProvider.notifier).setControls(false);
     }
 
-    _router.push(
-      AssetViewerRoute(
-        initialIndex: 0,
-        timelineService: _timelineFactory.fromAssets([asset], TimelineOrigin.deepLink),
-      ),
-    );
+    _router.push(AssetViewerRoute(initialIndex: initialIndex, timelineService: timelineService));
+  }
+
+  Future<String?> _computeChecksum(String localAssetId) async {
+    try {
+      final hashResults = await _nativeSyncApi.hashAssets([localAssetId]);
+      if (hashResults.isEmpty) {
+        return null;
+      }
+      return hashResults.first.hash;
+    } catch (_) {
+      return null;
+    }
   }
 }