feat(mobile): Improve timeline performance on mobile - experimental (#710)

mobile/lib/modules/home/providers/home_page_render_list_provider.dart

@@ -0,0 +1,91 @@
+import 'dart:math';
+
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:immich_mobile/modules/settings/providers/app_settings.provider.dart';
+import 'package:immich_mobile/modules/settings/services/app_settings.service.dart';
+import 'package:immich_mobile/shared/providers/asset.provider.dart';
+import 'package:openapi/api.dart';
+
+enum RenderAssetGridElementType {
+  assetRow,
+  dayTitle,
+  monthTitle;
+}
+
+class RenderAssetGridRow {
+  final List<AssetResponseDto> assets;
+
+  RenderAssetGridRow(this.assets);
+}
+
+class RenderAssetGridElement {
+  final RenderAssetGridElementType type;
+  final RenderAssetGridRow? assetRow;
+  final String? title;
+  final int? month;
+  final int? year;
+  final List<AssetResponseDto>? relatedAssetList;
+
+  RenderAssetGridElement(
+    this.type, {
+    this.assetRow,
+    this.title,
+    this.month,
+    this.year,
+    this.relatedAssetList,
+  });
+}
+
+final renderListProvider = StateProvider((ref) {
+  var assetGroups = ref.watch(assetGroupByDateTimeProvider);
+  var settings = ref.watch(appSettingsServiceProvider);
+
+  final assetsPerRow = settings.getSetting(AppSettingsEnum.tilesPerRow);
+
+  List<RenderAssetGridElement> elements = [];
+  DateTime? lastDate;
+
+  assetGroups.forEach((groupName, assets) {
+    final date = DateTime.parse(groupName);
+
+    if (lastDate == null || lastDate!.month != date.month) {
+      elements.add(
+        RenderAssetGridElement(RenderAssetGridElementType.monthTitle,
+            title: groupName, month: date.month, year: date.year),
+      );
+    }
+
+    // Add group title
+    elements.add(
+      RenderAssetGridElement(
+        RenderAssetGridElementType.dayTitle,
+        title: groupName,
+        month: date.month,
+        year: date.year,
+        relatedAssetList: assets,
+      ),
+    );
+
+    // Add rows
+    int cursor = 0;
+    while (cursor < assets.length) {
+      int rowElements = min(assets.length - cursor, assetsPerRow);
+
+      final rowElement = RenderAssetGridElement(
+        RenderAssetGridElementType.assetRow,
+        month: date.month,
+        year: date.year,
+        assetRow: RenderAssetGridRow(
+          assets.sublist(cursor, cursor + rowElements),
+        ),
+      );
+
+      elements.add(rowElement);
+      cursor += rowElements;
+    }
+
+    lastDate = date;
+  });
+
+  return elements;
+});