Add file sync util for the day Flutter makes using isolate less painful

lib/utils/file_sync_util.dart

@@ -0,0 +1,66 @@
+import 'dart:math';
+
+import 'package:photo_manager/photo_manager.dart';
+import 'package:photos/models/file.dart';
+
+Future<List<File>> getDeviceFiles(Map<String, dynamic> params) async {
+  final lastDBUpdationTime = params["lastDBUpdationTime"];
+  final syncStartTime = params["syncStartTime"];
+  final pathEntities = await _getGalleryList(lastDBUpdationTime, syncStartTime);
+  final files = List<File>();
+  AssetPathEntity recents;
+  for (AssetPathEntity pathEntity in pathEntities) {
+    if (pathEntity.name == "Recent" || pathEntity.name == "Recents") {
+      recents = pathEntity;
+    } else {
+      await _addToPhotos(pathEntity, lastDBUpdationTime, files);
+    }
+  }
+  if (recents != null) {
+    await _addToPhotos(recents, lastDBUpdationTime, files);
+  }
+  files.sort(
+      (first, second) => first.creationTime.compareTo(second.creationTime));
+  return files;
+}
+
+Future<List<AssetPathEntity>> _getGalleryList(
+    final int fromTimestamp, final int toTimestamp) async {
+  final filterOptionGroup = FilterOptionGroup();
+  filterOptionGroup.setOption(AssetType.image, FilterOption(needTitle: true));
+  filterOptionGroup.setOption(AssetType.video, FilterOption(needTitle: true));
+  filterOptionGroup.dateTimeCond = DateTimeCond(
+    min: DateTime.fromMicrosecondsSinceEpoch(fromTimestamp),
+    max: DateTime.fromMicrosecondsSinceEpoch(toTimestamp),
+  );
+  final galleryList = await PhotoManager.getAssetPathList(
+    hasAll: true,
+    type: RequestType.common,
+    filterOption: filterOptionGroup,
+  );
+
+  galleryList.sort((s1, s2) {
+    return s2.assetCount.compareTo(s1.assetCount);
+  });
+
+  return galleryList;
+}
+
+Future _addToPhotos(AssetPathEntity pathEntity, int lastDBUpdationTime,
+    List<File> files) async {
+  final assetList = await pathEntity.assetList;
+  for (AssetEntity entity in assetList) {
+    if (max(entity.createDateTime.microsecondsSinceEpoch,
+            entity.modifiedDateTime.microsecondsSinceEpoch) >
+        lastDBUpdationTime) {
+      try {
+        final file = await File.fromAsset(pathEntity, entity);
+        if (!files.contains(file)) {
+          files.add(file);
+        }
+      } catch (e) {
+        // _logger.severe(e);
+      }
+    }
+  }
+}