fix(mobile): proper syncing with Recents album on iOS (#2020)

* fix(mobile): deal with Recents album on iOS

* feature(mobile): local asset sync logging

* add comments

* delete ExifInfo when deleting Asset

---------

Co-authored-by: Fynn Petersen-Frey <zoodyy@users.noreply.github.com>

mobile/lib/modules/album/services/album.service.dart

@@ -1,4 +1,6 @@
 import 'dart:async';
+import 'dart:collection';
+import 'dart:io';
 
 import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
@@ -15,6 +17,7 @@ import 'package:immich_mobile/shared/services/api.service.dart';
 import 'package:immich_mobile/shared/services/sync.service.dart';
 import 'package:immich_mobile/shared/services/user.service.dart';
 import 'package:isar/isar.dart';
+import 'package:logging/logging.dart';
 import 'package:openapi/api.dart';
 import 'package:photo_manager/photo_manager.dart';
 
@@ -34,6 +37,7 @@ class AlbumService {
   final SyncService _syncService;
   final Isar _db;
   final BackupService _backupService;
+  final Logger _log = Logger('AlbumService');
   Completer<bool> _localCompleter = Completer()..complete(false);
   Completer<bool> _remoteCompleter = Completer()..complete(false);
 
@@ -50,6 +54,7 @@ class AlbumService {
   Future<bool> refreshDeviceAlbums() async {
     if (!_localCompleter.isCompleted) {
       // guard against concurrent calls
+      _log.info("refreshDeviceAlbums is already in progress");
       return _localCompleter.future;
     }
     _localCompleter = Completer();
@@ -68,22 +73,45 @@ class AlbumService {
         hasAll: true,
         filterOption: FilterOptionGroup(containsPathModified: true),
       );
+      _log.info("Found ${onDevice.length} device albums");
+      Set<String>? excludedAssets;
       if (excludedIds.isNotEmpty) {
+        if (Platform.isIOS) {
+          // iOS and Android device album working principle differ significantly
+          // on iOS, an asset can be in multiple albums
+          // on Android, an asset can only be in exactly one album (folder!) at the same time
+          // thus, on Android, excluding an album can be done by ignoring that album
+          // however, on iOS, it it necessary to load the assets from all excluded
+          // albums and check every asset from any selected album against the set
+          // of excluded assets
+          excludedAssets = await _loadExcludedAssetIds(onDevice, excludedIds);
+          _log.info("Found ${excludedAssets.length} assets to exclude");
+        }
         // remove all excluded albums
         onDevice.removeWhere((e) => excludedIds.contains(e.id));
+        _log.info(
+          "Ignoring ${excludedIds.length} excluded albums resulting in ${onDevice.length} device albums",
+        );
       }
       final hasAll = selectedIds
           .map((id) => onDevice.firstWhereOrNull((a) => a.id == id))
           .whereNotNull()
           .any((a) => a.isAll);
       if (hasAll) {
-        // remove the virtual "Recents" album and keep and individual albums
-        onDevice.removeWhere((e) => e.isAll);
+        if (Platform.isAndroid) {
+          // remove the virtual "Recent" album and keep and individual albums
+          // on Android, the virtual "Recent" `lastModified` value is always null
+          onDevice.removeWhere((e) => e.isAll);
+          _log.info("'Recents' is selected, keeping all individual albums");
+        }
       } else {
         // keep only the explicitly selected albums
         onDevice.removeWhere((e) => !selectedIds.contains(e.id));
+        _log.info("'Recents' is not selected, keeping only selected albums");
       }
-      changes = await _syncService.syncLocalAlbumAssetsToDb(onDevice);
+      changes =
+          await _syncService.syncLocalAlbumAssetsToDb(onDevice, excludedAssets);
+      _log.info("Syncing completed. Changes: $changes");
     } finally {
       _localCompleter.complete(changes);
     }
@@ -91,6 +119,21 @@ class AlbumService {
     return changes;
   }
 
+  Future<Set<String>> _loadExcludedAssetIds(
+    List<AssetPathEntity> albums,
+    List<String> excludedAlbumIds,
+  ) async {
+    final Set<String> result = HashSet<String>();
+    for (AssetPathEntity a in albums) {
+      if (excludedAlbumIds.contains(a.id)) {
+        final List<AssetEntity> assets =
+            await a.getAssetListRange(start: 0, end: 0x7fffffffffffffff);
+        result.addAll(assets.map((e) => e.id));
+      }
+    }
+    return result;
+  }
+
   /// Checks remote albums (owned if `isShared` is false) for changes,
   /// updates the local database and returns `true` if there were any changes
   Future<bool> refreshRemoteAlbums({required bool isShared}) async {