diff --git a/CHANGELOG.md b/CHANGELOG.md
index 502c4a057..6d427e653 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
+### Added
+- Collection / Albums / Countries / Tags: added label when dragging scrollbar thumb
+
 ### Changed
 - Upgraded Flutter to beta v2.1.0-12.2.pre
 
diff --git a/lib/l10n/app_en.arb b/lib/l10n/app_en.arb
index e1b873657..a245d94a4 100644
--- a/lib/l10n/app_en.arb
+++ b/lib/l10n/app_en.arb
@@ -7,6 +7,12 @@
   "@welcomeAnalyticsToggle": {},
   "welcomeTermsToggle": "I agree to the terms and conditions",
   "@welcomeTermsToggle": {},
+  "itemCount": "{count, plural, =1{1 item} other{{count} items}}",
+  "@itemCount": {
+    "placeholders": {
+      "count": {}
+    }
+  },
 
   "applyButtonLabel": "APPLY",
   "@applyButtonLabel": {},
diff --git a/lib/l10n/app_ko.arb b/lib/l10n/app_ko.arb
index c53f3385b..eca076e12 100644
--- a/lib/l10n/app_ko.arb
+++ b/lib/l10n/app_ko.arb
@@ -3,6 +3,7 @@
   "welcomeMessage": "아베스 사용을 환영합니다",
   "welcomeAnalyticsToggle": "진단 데이터를 보내는 것에 동의합니다 (선택)",
   "welcomeTermsToggle": "이용약관에 동의합니다",
+  "itemCount": "{count, plural, other{{count}개}}",
 
   "applyButtonLabel": "확인",
   "deleteButtonLabel": "삭제",
diff --git a/lib/theme/durations.dart b/lib/theme/durations.dart
index f0c590209..55f5a0928 100644
--- a/lib/theme/durations.dart
+++ b/lib/theme/durations.dart
@@ -9,6 +9,7 @@ class Durations {
   static const dialogTransitionAnimation = Duration(milliseconds: 150); // ref `transitionDuration` in `showDialog()`
 
   static const staggeredAnimation = Duration(milliseconds: 375);
+  static const staggeredAnimationPageTarget = Duration(milliseconds: 900);
   static const dialogFieldReachAnimation = Duration(milliseconds: 300);
 
   static const appBarTitleAnimation = Duration(milliseconds: 300);
diff --git a/lib/widgets/collection/collection_grid.dart b/lib/widgets/collection/collection_grid.dart
index 2c0ebb4f7..fba492c3a 100644
--- a/lib/widgets/collection/collection_grid.dart
+++ b/lib/widgets/collection/collection_grid.dart
@@ -11,6 +11,7 @@ import 'package:aves/ref/mime_types.dart';
 import 'package:aves/theme/durations.dart';
 import 'package:aves/theme/icons.dart';
 import 'package:aves/widgets/collection/app_bar.dart';
+import 'package:aves/widgets/collection/draggable_thumb_label.dart';
 import 'package:aves/widgets/collection/grid/section_layout.dart';
 import 'package:aves/widgets/collection/grid/selector.dart';
 import 'package:aves/widgets/collection/grid/thumbnail.dart';
@@ -29,9 +30,9 @@ import 'package:aves/widgets/common/providers/tile_extent_controller_provider.da
 import 'package:aves/widgets/common/scaling.dart';
 import 'package:aves/widgets/common/tile_extent_controller.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/rendering.dart';
 import 'package:flutter_staggered_animations/flutter_staggered_animations.dart';
 import 'package:provider/provider.dart';
+import 'package:tuple/tuple.dart';
 
 class CollectionGrid extends StatefulWidget {
   final String settingsRouteKey;
@@ -74,23 +75,34 @@ class _CollectionGridContent extends StatelessWidget {
           builder: (context, tileExtent, child) {
             return ThumbnailTheme(
               extent: tileExtent,
-              child: SectionedEntryListLayoutProvider(
-                collection: collection,
-                scrollableWidth: context.select<TileExtentController, double>((controller) => controller.viewportSize.width),
-                tileExtent: tileExtent,
-                columnCount: context.select<TileExtentController, int>((controller) => controller.getEffectiveColumnCountForExtent(tileExtent)),
-                tileBuilder: (entry) => InteractiveThumbnail(
-                  key: ValueKey(entry.contentId),
-                  collection: collection,
-                  entry: entry,
-                  tileExtent: tileExtent,
-                  isScrollingNotifier: _isScrollingNotifier,
-                ),
-                child: _CollectionSectionedContent(
-                  collection: collection,
-                  isScrollingNotifier: _isScrollingNotifier,
-                  scrollController: PrimaryScrollController.of(context),
-                ),
+              child: Selector<TileExtentController, Tuple2<double, int>>(
+                selector: (context, c) => Tuple2(c.viewportSize.width, c.columnCount),
+                builder: (context, c, child) {
+                  final scrollableWidth = c.item1;
+                  final columnCount = c.item2;
+                  // do not listen for animation delay change
+                  final controller = Provider.of<TileExtentController>(context, listen: false);
+                  final tileAnimationDelay = controller.getTileAnimationDelay(Durations.staggeredAnimationPageTarget);
+                  return SectionedEntryListLayoutProvider(
+                    collection: collection,
+                    scrollableWidth: scrollableWidth,
+                    tileExtent: tileExtent,
+                    columnCount: columnCount,
+                    tileBuilder: (entry) => InteractiveThumbnail(
+                      key: ValueKey(entry.contentId),
+                      collection: collection,
+                      entry: entry,
+                      tileExtent: tileExtent,
+                      isScrollingNotifier: _isScrollingNotifier,
+                    ),
+                    tileAnimationDelay: tileAnimationDelay,
+                    child: _CollectionSectionedContent(
+                      collection: collection,
+                      isScrollingNotifier: _isScrollingNotifier,
+                      scrollController: PrimaryScrollController.of(context),
+                    ),
+                  );
+                },
               ),
             );
           },
@@ -266,10 +278,10 @@ class _CollectionScrollViewState extends State<_CollectionScrollView> {
   @override
   Widget build(BuildContext context) {
     final scrollView = _buildScrollView(widget.appBar, widget.collection);
-    return _buildDraggableScrollView(scrollView);
+    return _buildDraggableScrollView(scrollView, widget.collection);
   }
 
-  Widget _buildDraggableScrollView(ScrollView scrollView) {
+  Widget _buildDraggableScrollView(ScrollView scrollView, CollectionLens collection) {
     return ValueListenableBuilder<double>(
       valueListenable: widget.appBarHeightNotifier,
       builder: (context, appBarHeight, child) => Selector<MediaQueryData, double>(
@@ -287,6 +299,10 @@ class _CollectionScrollViewState extends State<_CollectionScrollView> {
             top: appBarHeight,
             bottom: mqPaddingBottom,
           ),
+          labelTextBuilder: (offsetY) => CollectionDraggableThumbLabel(
+            collection: collection,
+            offsetY: offsetY,
+          ),
           child: scrollView,
         ),
         child: child,
diff --git a/lib/widgets/collection/draggable_thumb_label.dart b/lib/widgets/collection/draggable_thumb_label.dart
new file mode 100644
index 000000000..df13fb0a2
--- /dev/null
+++ b/lib/widgets/collection/draggable_thumb_label.dart
@@ -0,0 +1,60 @@
+import 'package:aves/model/entry.dart';
+import 'package:aves/model/source/collection_lens.dart';
+import 'package:aves/model/source/collection_source.dart';
+import 'package:aves/model/source/enums.dart';
+import 'package:aves/utils/file_utils.dart';
+import 'package:aves/widgets/common/grid/draggable_thumb_label.dart';
+import 'package:aves/widgets/common/grid/section_layout.dart';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+class CollectionDraggableThumbLabel extends StatelessWidget {
+  final CollectionLens collection;
+  final double offsetY;
+
+  const CollectionDraggableThumbLabel({
+    @required this.collection,
+    @required this.offsetY,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return DraggableThumbLabel<AvesEntry>(
+      offsetY: offsetY,
+      lineBuilder: (context, entry) {
+        switch (collection.sortFactor) {
+          case EntrySortFactor.date:
+            switch (collection.groupFactor) {
+              case EntryGroupFactor.album:
+                return [
+                  DraggableThumbLabel.formatMonthThumbLabel(context, entry.bestDate),
+                  if (_hasMultipleSections(context)) context.read<CollectionSource>().getUniqueAlbumName(context, entry.directory),
+                ];
+              case EntryGroupFactor.month:
+              case EntryGroupFactor.none:
+                return [
+                  DraggableThumbLabel.formatMonthThumbLabel(context, entry.bestDate),
+                ];
+              case EntryGroupFactor.day:
+                return [
+                  DraggableThumbLabel.formatDayThumbLabel(context, entry.bestDate),
+                ];
+            }
+            break;
+          case EntrySortFactor.name:
+            return [
+              if (_hasMultipleSections(context)) context.read<CollectionSource>().getUniqueAlbumName(context, entry.directory),
+              entry.bestTitle,
+            ];
+          case EntrySortFactor.size:
+            return [
+              formatFilesize(entry.sizeBytes, round: 0),
+            ];
+        }
+        return [];
+      },
+    );
+  }
+
+  bool _hasMultipleSections(BuildContext context) => context.read<SectionedListLayout<AvesEntry>>().sections.length > 1;
+}
diff --git a/lib/widgets/collection/grid/section_layout.dart b/lib/widgets/collection/grid/section_layout.dart
index c481e2ce1..33597cbd5 100644
--- a/lib/widgets/collection/grid/section_layout.dart
+++ b/lib/widgets/collection/grid/section_layout.dart
@@ -15,12 +15,14 @@ class SectionedEntryListLayoutProvider extends SectionedListLayoutProvider<AvesE
     @required int columnCount,
     @required double tileExtent,
     @required Widget Function(AvesEntry entry) tileBuilder,
+    @required Duration tileAnimationDelay,
     @required Widget child,
   }) : super(
           scrollableWidth: scrollableWidth,
           columnCount: columnCount,
           tileExtent: tileExtent,
           tileBuilder: tileBuilder,
+          tileAnimationDelay: tileAnimationDelay,
           child: child,
         );
 
diff --git a/lib/widgets/common/basic/draggable_scrollbar.dart b/lib/widgets/common/basic/draggable_scrollbar.dart
index aea685017..6cf73dbe6 100644
--- a/lib/widgets/common/basic/draggable_scrollbar.dart
+++ b/lib/widgets/common/basic/draggable_scrollbar.dart
@@ -62,7 +62,7 @@ class DraggableScrollbar extends StatefulWidget {
     @required this.controller,
     this.padding,
     this.scrollbarAnimationDuration = const Duration(milliseconds: 300),
-    this.scrollbarTimeToFade = const Duration(milliseconds: 600),
+    this.scrollbarTimeToFade = const Duration(milliseconds: 1000),
     this.labelTextBuilder,
     @required this.child,
   })  : assert(controller != null),
@@ -91,6 +91,7 @@ class DraggableScrollbar extends StatefulWidget {
                 backgroundColor: backgroundColor,
                 child: labelText,
               ),
+              SizedBox(width: 24),
               scrollThumb,
             ],
           );
@@ -133,6 +134,7 @@ class ScrollLabel extends StatelessWidget {
 class _DraggableScrollbarState extends State<DraggableScrollbar> with TickerProviderStateMixin {
   final ValueNotifier<double> _thumbOffsetNotifier = ValueNotifier(0), _viewOffsetNotifier = ValueNotifier(0);
   bool _isDragInProcess = false;
+  Offset _longPressLastGlobalPosition;
 
   AnimationController _thumbAnimationController;
   Animation<double> _thumbAnimation;
@@ -193,9 +195,19 @@ class _DraggableScrollbarState extends State<DraggableScrollbar> with TickerProv
           ),
           RepaintBoundary(
             child: GestureDetector(
-              onVerticalDragStart: _onVerticalDragStart,
-              onVerticalDragUpdate: _onVerticalDragUpdate,
-              onVerticalDragEnd: _onVerticalDragEnd,
+              onLongPressStart: (details) {
+                _longPressLastGlobalPosition = details.globalPosition;
+                _onVerticalDragStart();
+              },
+              onLongPressMoveUpdate: (details) {
+                final dy = (details.globalPosition - _longPressLastGlobalPosition).dy;
+                _longPressLastGlobalPosition = details.globalPosition;
+                _onVerticalDragUpdate(dy);
+              },
+              onLongPressEnd: (_) => _onVerticalDragEnd(),
+              onVerticalDragStart: (_) => _onVerticalDragStart(),
+              onVerticalDragUpdate: (details) => _onVerticalDragUpdate(details.delta.dy),
+              onVerticalDragEnd: (_) => _onVerticalDragEnd(),
               child: ValueListenableBuilder(
                 valueListenable: _thumbOffsetNotifier,
                 builder: (context, thumbOffset, child) => Container(
@@ -244,17 +256,18 @@ class _DraggableScrollbarState extends State<DraggableScrollbar> with TickerProv
     }
   }
 
-  void _onVerticalDragStart(DragStartDetails details) {
+  void _onVerticalDragStart() {
     _labelAnimationController.forward();
     _fadeoutTimer?.cancel();
+    _showThumb();
     setState(() => _isDragInProcess = true);
   }
 
-  void _onVerticalDragUpdate(DragUpdateDetails details) {
+  void _onVerticalDragUpdate(double deltaY) {
     _showThumb();
     if (_isDragInProcess) {
       // thumb offset
-      _thumbOffsetNotifier.value = (_thumbOffsetNotifier.value + details.delta.dy).clamp(thumbMinScrollExtent, thumbMaxScrollExtent);
+      _thumbOffsetNotifier.value = (_thumbOffsetNotifier.value + deltaY).clamp(thumbMinScrollExtent, thumbMaxScrollExtent);
 
       // scroll offset
       final min = controller.position.minScrollExtent;
@@ -263,7 +276,7 @@ class _DraggableScrollbarState extends State<DraggableScrollbar> with TickerProv
     }
   }
 
-  void _onVerticalDragEnd(DragEndDetails details) {
+  void _onVerticalDragEnd() {
     _scheduleFadeout();
     setState(() => _isDragInProcess = false);
   }
diff --git a/lib/widgets/common/grid/draggable_thumb_label.dart b/lib/widgets/common/grid/draggable_thumb_label.dart
new file mode 100644
index 000000000..515039299
--- /dev/null
+++ b/lib/widgets/common/grid/draggable_thumb_label.dart
@@ -0,0 +1,67 @@
+import 'package:aves/widgets/common/extensions/build_context.dart';
+import 'package:aves/widgets/common/grid/section_layout.dart';
+import 'package:flutter/material.dart';
+import 'package:intl/intl.dart';
+import 'package:provider/provider.dart';
+
+class DraggableThumbLabel<T> extends StatelessWidget {
+  final double offsetY;
+  final List<String> Function(BuildContext context, T item) lineBuilder;
+
+  const DraggableThumbLabel({
+    @required this.offsetY,
+    @required this.lineBuilder,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final sll = context.read<SectionedListLayout<T>>();
+    final sectionLayout = sll.getSectionAt(offsetY);
+    if (sectionLayout == null) return null;
+
+    final section = sll.sections[sectionLayout.sectionKey];
+    final dy = offsetY - (sectionLayout.minOffset + sectionLayout.headerExtent);
+    final itemIndex = dy < 0 ? 0 : (dy ~/ (sll.tileExtent + sll.spacing)) * sll.columnCount;
+    final item = section[itemIndex];
+    if (item == null) return SizedBox();
+
+    final lines = lineBuilder(context, item);
+    if (lines.isEmpty) return SizedBox();
+
+    return ConstrainedBox(
+      constraints: BoxConstraints(maxWidth: 140),
+      child: Padding(
+        padding: EdgeInsets.symmetric(vertical: 4, horizontal: 8),
+        child: lines.length > 1
+            ? Column(
+                mainAxisSize: MainAxisSize.min,
+                crossAxisAlignment: CrossAxisAlignment.end,
+                children: lines.map(_buildText).toList(),
+              )
+            : _buildText(lines.first),
+      ),
+    );
+  }
+
+  Widget _buildText(String text) => Text(
+        text,
+        style: TextStyle(
+          color: Colors.black,
+        ),
+        softWrap: false,
+        overflow: TextOverflow.fade,
+        maxLines: 1,
+      );
+
+  static String formatMonthThumbLabel(BuildContext context, DateTime date) {
+    final l10n = context.l10n;
+    if (date == null) return l10n.sectionUnknown;
+    return DateFormat.yMMM(l10n.localeName).format(date);
+  }
+
+  static String formatDayThumbLabel(BuildContext context, DateTime date) {
+    final l10n = context.l10n;
+    if (date == null) return l10n.sectionUnknown;
+    return DateFormat.yMMMd(l10n.localeName).format(date);
+  }
+}
diff --git a/lib/widgets/common/grid/section_layout.dart b/lib/widgets/common/grid/section_layout.dart
index b1a6f1657..329ec9c58 100644
--- a/lib/widgets/common/grid/section_layout.dart
+++ b/lib/widgets/common/grid/section_layout.dart
@@ -12,6 +12,7 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
   final int columnCount;
   final double spacing, tileExtent;
   final Widget Function(T item) tileBuilder;
+  final Duration tileAnimationDelay;
   final Widget child;
 
   const SectionedListLayoutProvider({
@@ -20,6 +21,7 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
     this.spacing = 0,
     @required this.tileExtent,
     @required this.tileBuilder,
+    this.tileAnimationDelay,
     @required this.child,
   }) : assert(scrollableWidth != 0);
 
@@ -40,6 +42,7 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
     final _showHeaders = showHeaders;
     final _sections = sections;
     final sectionKeys = _sections.keys.toList();
+    final animate = tileAnimationDelay > Duration.zero;
 
     final sectionLayouts = <SectionLayout>[];
     var currentIndex = 0, currentOffset = 0.0;
@@ -76,6 +79,7 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
             listIndex - sectionFirstIndex,
             sectionKey,
             headerExtent,
+            animate,
           ),
         ),
       );
@@ -97,10 +101,11 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
     int sectionChildIndex,
     SectionKey sectionKey,
     double headerExtent,
+    bool animate,
   ) {
     if (sectionChildIndex == 0) {
       final header = headerExtent > 0 ? buildHeader(context, sectionKey, headerExtent) : SizedBox.shrink();
-      return _buildAnimation(sectionGridIndex, header);
+      return animate ? _buildAnimation(sectionGridIndex, header) : header;
     }
     sectionChildIndex--;
 
@@ -113,7 +118,7 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
       final itemGridIndex = sectionGridIndex + i - minItemIndex;
       final item = tileBuilder(section[i]);
       if (i != minItemIndex) children.add(SizedBox(width: spacing));
-      children.add(_buildAnimation(itemGridIndex, item));
+      children.add(animate ? _buildAnimation(itemGridIndex, item) : item);
     }
     return Row(
       mainAxisSize: MainAxisSize.min,
@@ -126,7 +131,7 @@ abstract class SectionedListLayoutProvider<T> extends StatelessWidget {
       position: index,
       columnCount: columnCount,
       duration: Durations.staggeredAnimation,
-      delay: Durations.staggeredAnimationDelay,
+      delay: tileAnimationDelay ?? Durations.staggeredAnimationDelay,
       child: SlideAnimation(
         verticalOffset: 50.0,
         child: FadeInAnimation(
@@ -189,9 +194,11 @@ class SectionedListLayout<T> {
     return Rect.fromLTWH(left, top, tileExtent, tileExtent);
   }
 
+  SectionLayout getSectionAt(double offsetY) => sectionLayouts.firstWhere((sl) => offsetY < sl.maxOffset, orElse: () => null);
+
   T getItemAt(Offset position) {
     var dy = position.dy;
-    final sectionLayout = sectionLayouts.firstWhere((sl) => dy < sl.maxOffset, orElse: () => null);
+    final sectionLayout = getSectionAt(dy);
     if (sectionLayout == null) return null;
 
     final section = sections[sectionLayout.sectionKey];
diff --git a/lib/widgets/common/tile_extent_controller.dart b/lib/widgets/common/tile_extent_controller.dart
index fa782e058..9500d1641 100644
--- a/lib/widgets/common/tile_extent_controller.dart
+++ b/lib/widgets/common/tile_extent_controller.dart
@@ -1,6 +1,7 @@
 import 'dart:math';
 
 import 'package:aves/model/settings/settings.dart';
+import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';
 
 class TileExtentController {
@@ -45,7 +46,7 @@ class TileExtentController {
             ? oldUserPreferredExtent
             : currentExtent;
 
-    final columnCount = getEffectiveColumnCountForExtent(targetExtent);
+    final columnCount = _effectiveColumnCountForExtent(targetExtent);
     final newExtent = _extentForColumnCount(columnCount);
 
     if (userPreferredExtent > 0 || oldUserPreferredExtent == 0) {
@@ -67,15 +68,24 @@ class TileExtentController {
 
   int _effectiveColumnCountMax() => _columnCountForExtent(extentMin).floor();
 
-  double get effectiveExtentMin => _extentForColumnCount(_effectiveColumnCountMax());
-
-  double get effectiveExtentMax => _extentForColumnCount(_effectiveColumnCountMin());
-
-  int getEffectiveColumnCountForExtent(double extent) {
+  int _effectiveColumnCountForExtent(double extent) {
     if (extent > 0) {
       final columnCount = _columnCountForExtent(extent);
       return columnCount.clamp(_effectiveColumnCountMin(), _effectiveColumnCountMax()).round();
     }
     return columnCountDefault;
   }
+
+  double get effectiveExtentMin => _extentForColumnCount(_effectiveColumnCountMax());
+
+  double get effectiveExtentMax => _extentForColumnCount(_effectiveColumnCountMin());
+
+  int get columnCount => _effectiveColumnCountForExtent(extentNotifier.value);
+
+  Duration getTileAnimationDelay(Duration pageTarget) {
+    final extent = extentNotifier.value;
+    final columnCount = ((viewportSize.width + spacing) / (extent + spacing)).round();
+    final rowCount = (viewportSize.height + spacing) ~/ (extent + spacing);
+    return pageTarget ~/ (columnCount + rowCount) * timeDilation;
+  }
 }
diff --git a/lib/widgets/filter_grids/album_pick.dart b/lib/widgets/filter_grids/album_pick.dart
index f53813f83..88661bb57 100644
--- a/lib/widgets/filter_grids/album_pick.dart
+++ b/lib/widgets/filter_grids/album_pick.dart
@@ -62,6 +62,7 @@ class _AlbumPickPageState extends State<AlbumPickPage> {
             appBar: appBar,
             appBarHeight: AlbumPickAppBar.preferredHeight,
             filterSections: AlbumListPage.getAlbumEntries(context, source),
+            sortFactor: settings.albumSortFactor,
             showHeaders: settings.albumGroupFactor != AlbumChipGroupFactor.none,
             queryNotifier: _queryNotifier,
             applyQuery: (filters, query) {
diff --git a/lib/widgets/filter_grids/albums_page.dart b/lib/widgets/filter_grids/albums_page.dart
index 5b4df6a3e..328762240 100644
--- a/lib/widgets/filter_grids/albums_page.dart
+++ b/lib/widgets/filter_grids/albums_page.dart
@@ -34,6 +34,7 @@ class AlbumListPage extends StatelessWidget {
             builder: (context, snapshot) => FilterNavigationPage<AlbumFilter>(
               source: source,
               title: context.l10n.albumPageTitle,
+              sortFactor: settings.albumSortFactor,
               groupable: true,
               showHeaders: settings.albumGroupFactor != AlbumChipGroupFactor.none,
               chipSetActionDelegate: AlbumChipSetActionDelegate(),
diff --git a/lib/widgets/filter_grids/common/draggable_thumb_label.dart b/lib/widgets/filter_grids/common/draggable_thumb_label.dart
new file mode 100644
index 000000000..ba1dab337
--- /dev/null
+++ b/lib/widgets/filter_grids/common/draggable_thumb_label.dart
@@ -0,0 +1,42 @@
+import 'package:aves/model/filters/filters.dart';
+import 'package:aves/model/source/collection_source.dart';
+import 'package:aves/model/source/enums.dart';
+import 'package:aves/widgets/common/extensions/build_context.dart';
+import 'package:aves/widgets/common/grid/draggable_thumb_label.dart';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+class FilterDraggableThumbLabel<T extends CollectionFilter> extends StatelessWidget {
+  final ChipSortFactor sortFactor;
+  final double offsetY;
+
+  const FilterDraggableThumbLabel({
+    @required this.sortFactor,
+    @required this.offsetY,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return DraggableThumbLabel<FilterGridItem<T>>(
+      offsetY: offsetY,
+      lineBuilder: (context, filterGridItem) {
+        switch (sortFactor) {
+          case ChipSortFactor.count:
+            return [
+              context.l10n.itemCount(context.read<CollectionSource>().count(filterGridItem.filter)),
+            ];
+            break;
+          case ChipSortFactor.date:
+            return [
+              DraggableThumbLabel.formatMonthThumbLabel(context, filterGridItem.entry.bestDate),
+            ];
+          case ChipSortFactor.name:
+            return [
+              filterGridItem.filter.getLabel(context),
+            ];
+        }
+        return [];
+      },
+    );
+  }
+}
diff --git a/lib/widgets/filter_grids/common/filter_grid_page.dart b/lib/widgets/filter_grids/common/filter_grid_page.dart
index 65833b2ba..af4f98381 100644
--- a/lib/widgets/filter_grids/common/filter_grid_page.dart
+++ b/lib/widgets/filter_grids/common/filter_grid_page.dart
@@ -4,6 +4,7 @@ import 'package:aves/model/covers.dart';
 import 'package:aves/model/filters/filters.dart';
 import 'package:aves/model/highlight.dart';
 import 'package:aves/model/settings/settings.dart';
+import 'package:aves/model/source/enums.dart';
 import 'package:aves/theme/durations.dart';
 import 'package:aves/widgets/common/basic/draggable_scrollbar.dart';
 import 'package:aves/widgets/common/basic/insets.dart';
@@ -20,12 +21,14 @@ import 'package:aves/widgets/common/scaling.dart';
 import 'package:aves/widgets/common/tile_extent_controller.dart';
 import 'package:aves/widgets/drawer/app_drawer.dart';
 import 'package:aves/widgets/filter_grids/common/decorated_filter_chip.dart';
+import 'package:aves/widgets/filter_grids/common/draggable_thumb_label.dart';
 import 'package:aves/widgets/filter_grids/common/section_keys.dart';
 import 'package:aves/widgets/filter_grids/common/section_layout.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_staggered_animations/flutter_staggered_animations.dart';
 import 'package:provider/provider.dart';
+import 'package:tuple/tuple.dart';
 
 typedef QueryTest<T extends CollectionFilter> = Iterable<FilterGridItem<T>> Function(Iterable<FilterGridItem<T>> filters, String query);
 
@@ -34,6 +37,7 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
   final Widget appBar;
   final double appBarHeight;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> filterSections;
+  final ChipSortFactor sortFactor;
   final bool showHeaders;
   final ValueNotifier<String> queryNotifier;
   final QueryTest<T> applyQuery;
@@ -47,6 +51,7 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
     @required this.appBar,
     this.appBarHeight = kToolbarHeight,
     @required this.filterSections,
+    @required this.sortFactor,
     @required this.showHeaders,
     @required this.queryNotifier,
     this.applyQuery,
@@ -72,6 +77,7 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
                   appBar: appBar,
                   appBarHeight: appBarHeight,
                   filterSections: filterSections,
+                  sortFactor: sortFactor,
                   showHeaders: showHeaders,
                   queryNotifier: queryNotifier,
                   applyQuery: applyQuery,
@@ -95,6 +101,7 @@ class FilterGrid<T extends CollectionFilter> extends StatefulWidget {
   final Widget appBar;
   final double appBarHeight;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> filterSections;
+  final ChipSortFactor sortFactor;
   final bool showHeaders;
   final ValueNotifier<String> queryNotifier;
   final QueryTest<T> applyQuery;
@@ -108,6 +115,7 @@ class FilterGrid<T extends CollectionFilter> extends StatefulWidget {
     @required this.appBar,
     @required this.appBarHeight,
     @required this.filterSections,
+    @required this.sortFactor,
     @required this.showHeaders,
     @required this.queryNotifier,
     @required this.applyQuery,
@@ -137,6 +145,7 @@ class _FilterGridState<T extends CollectionFilter> extends State<FilterGrid<T>>
         appBar: widget.appBar,
         appBarHeight: widget.appBarHeight,
         filterSections: widget.filterSections,
+        sortFactor: widget.sortFactor,
         showHeaders: widget.showHeaders,
         queryNotifier: widget.queryNotifier,
         applyQuery: widget.applyQuery,
@@ -151,6 +160,7 @@ class _FilterGridState<T extends CollectionFilter> extends State<FilterGrid<T>>
 class _FilterGridContent<T extends CollectionFilter> extends StatelessWidget {
   final Widget appBar;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> filterSections;
+  final ChipSortFactor sortFactor;
   final bool showHeaders;
   final ValueNotifier<String> queryNotifier;
   final Widget Function() emptyBuilder;
@@ -165,6 +175,7 @@ class _FilterGridContent<T extends CollectionFilter> extends StatelessWidget {
     @required this.appBar,
     @required double appBarHeight,
     @required this.filterSections,
+    @required this.sortFactor,
     @required this.showHeaders,
     @required this.queryNotifier,
     @required this.applyQuery,
@@ -197,38 +208,48 @@ class _FilterGridContent<T extends CollectionFilter> extends StatelessWidget {
         final sectionedListLayoutProvider = ValueListenableBuilder<double>(
           valueListenable: context.select<TileExtentController, ValueNotifier<double>>((controller) => controller.extentNotifier),
           builder: (context, tileExtent, child) {
-            final columnCount = context.select<TileExtentController, int>((controller) => controller.getEffectiveColumnCountForExtent(tileExtent));
-            final tileSpacing = context.select<TileExtentController, double>((controller) => controller.spacing);
-            return SectionedFilterListLayoutProvider<T>(
-              sections: visibleFilterSections,
-              showHeaders: showHeaders,
-              scrollableWidth: context.select<TileExtentController, double>((controller) => controller.viewportSize.width),
-              tileExtent: tileExtent,
-              columnCount: columnCount,
-              spacing: tileSpacing,
-              tileBuilder: (gridItem) {
-                final filter = gridItem.filter;
-                final entry = gridItem.entry;
-                return MetaData(
-                  metaData: ScalerMetadata(FilterGridItem<T>(filter, entry)),
-                  child: DecoratedFilterChip(
-                    key: Key(filter.key),
-                    filter: filter,
-                    extent: tileExtent,
-                    pinned: pinnedFilters.contains(filter),
-                    onTap: onTap,
-                    onLongPress: onLongPress,
-                  ),
-                );
-              },
-              child: _FilterSectionedContent<T>(
-                appBar: appBar,
-                appBarHeightNotifier: _appBarHeightNotifier,
-                visibleFilterSections: visibleFilterSections,
-                emptyBuilder: emptyBuilder,
-                scrollController: PrimaryScrollController.of(context),
-              ),
-            );
+            return Selector<TileExtentController, Tuple3<double, int, double>>(
+                selector: (context, c) => Tuple3(c.viewportSize.width, c.columnCount, c.spacing),
+                builder: (context, c, child) {
+                  final scrollableWidth = c.item1;
+                  final columnCount = c.item2;
+                  final tileSpacing = c.item3;
+                  // do not listen for animation delay change
+                  final controller = Provider.of<TileExtentController>(context, listen: false);
+                  final tileAnimationDelay = controller.getTileAnimationDelay(Durations.staggeredAnimationPageTarget);
+                  return SectionedFilterListLayoutProvider<T>(
+                    sections: visibleFilterSections,
+                    showHeaders: showHeaders,
+                    scrollableWidth: scrollableWidth,
+                    tileExtent: tileExtent,
+                    columnCount: columnCount,
+                    spacing: tileSpacing,
+                    tileBuilder: (gridItem) {
+                      final filter = gridItem.filter;
+                      final entry = gridItem.entry;
+                      return MetaData(
+                        metaData: ScalerMetadata(FilterGridItem<T>(filter, entry)),
+                        child: DecoratedFilterChip(
+                          key: Key(filter.key),
+                          filter: filter,
+                          extent: tileExtent,
+                          pinned: pinnedFilters.contains(filter),
+                          onTap: onTap,
+                          onLongPress: onLongPress,
+                        ),
+                      );
+                    },
+                    tileAnimationDelay: tileAnimationDelay,
+                    child: _FilterSectionedContent<T>(
+                      appBar: appBar,
+                      appBarHeightNotifier: _appBarHeightNotifier,
+                      visibleFilterSections: visibleFilterSections,
+                      sortFactor: sortFactor,
+                      emptyBuilder: emptyBuilder,
+                      scrollController: PrimaryScrollController.of(context),
+                    ),
+                  );
+                });
           },
         );
         return sectionedListLayoutProvider;
@@ -241,6 +262,7 @@ class _FilterSectionedContent<T extends CollectionFilter> extends StatefulWidget
   final Widget appBar;
   final ValueNotifier<double> appBarHeightNotifier;
   final Map<ChipSectionKey, List<FilterGridItem<T>>> visibleFilterSections;
+  final ChipSortFactor sortFactor;
   final Widget Function() emptyBuilder;
   final ScrollController scrollController;
 
@@ -248,6 +270,7 @@ class _FilterSectionedContent<T extends CollectionFilter> extends StatefulWidget
     @required this.appBar,
     @required this.appBarHeightNotifier,
     @required this.visibleFilterSections,
+    @required this.sortFactor,
     @required this.emptyBuilder,
     @required this.scrollController,
   });
@@ -282,6 +305,7 @@ class _FilterSectionedContentState<T extends CollectionFilter> extends State<_Fi
         scrollableKey: _scrollableKey,
         appBar: appBar,
         appBarHeightNotifier: appBarHeightNotifier,
+        sortFactor: widget.sortFactor,
         emptyBuilder: emptyBuilder,
         scrollController: scrollController,
       ),
@@ -380,6 +404,7 @@ class _FilterScrollView<T extends CollectionFilter> extends StatelessWidget {
   final GlobalKey scrollableKey;
   final Widget appBar;
   final ValueNotifier<double> appBarHeightNotifier;
+  final ChipSortFactor sortFactor;
   final Widget Function() emptyBuilder;
   final ScrollController scrollController;
 
@@ -387,6 +412,7 @@ class _FilterScrollView<T extends CollectionFilter> extends StatelessWidget {
     @required this.scrollableKey,
     @required this.appBar,
     @required this.appBarHeightNotifier,
+    @required this.sortFactor,
     @required this.emptyBuilder,
     @required this.scrollController,
   });
@@ -413,6 +439,10 @@ class _FilterScrollView<T extends CollectionFilter> extends StatelessWidget {
           top: appBarHeightNotifier.value,
           bottom: mqPaddingBottom,
         ),
+        labelTextBuilder: (offsetY) => FilterDraggableThumbLabel<T>(
+          sortFactor: sortFactor,
+          offsetY: offsetY,
+        ),
         child: scrollView,
       ),
     );
diff --git a/lib/widgets/filter_grids/common/filter_nav_page.dart b/lib/widgets/filter_grids/common/filter_nav_page.dart
index e85d4a88c..4c8a29fe6 100644
--- a/lib/widgets/filter_grids/common/filter_nav_page.dart
+++ b/lib/widgets/filter_grids/common/filter_nav_page.dart
@@ -28,6 +28,7 @@ class FilterNavigationPage<T extends CollectionFilter> extends StatelessWidget {
   final CollectionSource source;
   final String title;
   final ChipSetActionDelegate chipSetActionDelegate;
+  final ChipSortFactor sortFactor;
   final bool groupable, showHeaders;
   final ChipActionDelegate chipActionDelegate;
   final List<ChipAction> Function(T filter) chipActionsBuilder;
@@ -37,6 +38,7 @@ class FilterNavigationPage<T extends CollectionFilter> extends StatelessWidget {
   const FilterNavigationPage({
     @required this.source,
     @required this.title,
+    @required this.sortFactor,
     this.groupable = false,
     this.showHeaders = false,
     @required this.chipSetActionDelegate,
@@ -64,6 +66,7 @@ class FilterNavigationPage<T extends CollectionFilter> extends StatelessWidget {
         floating: true,
       ),
       filterSections: filterSections,
+      sortFactor: sortFactor,
       showHeaders: showHeaders,
       queryNotifier: ValueNotifier(''),
       emptyBuilder: () => ValueListenableBuilder<SourceState>(
diff --git a/lib/widgets/filter_grids/common/section_layout.dart b/lib/widgets/filter_grids/common/section_layout.dart
index 4c1d690a8..154bcc401 100644
--- a/lib/widgets/filter_grids/common/section_layout.dart
+++ b/lib/widgets/filter_grids/common/section_layout.dart
@@ -14,6 +14,7 @@ class SectionedFilterListLayoutProvider<T extends CollectionFilter> extends Sect
     double spacing = 0,
     @required double tileExtent,
     @required Widget Function(FilterGridItem<T> gridItem) tileBuilder,
+    @required Duration tileAnimationDelay,
     @required Widget child,
   }) : super(
           scrollableWidth: scrollableWidth,
@@ -21,6 +22,7 @@ class SectionedFilterListLayoutProvider<T extends CollectionFilter> extends Sect
           spacing: spacing,
           tileExtent: tileExtent,
           tileBuilder: tileBuilder,
+          tileAnimationDelay: tileAnimationDelay,
           child: child,
         );
 
diff --git a/lib/widgets/filter_grids/countries_page.dart b/lib/widgets/filter_grids/countries_page.dart
index 774f4899d..087e00c5e 100644
--- a/lib/widgets/filter_grids/countries_page.dart
+++ b/lib/widgets/filter_grids/countries_page.dart
@@ -31,6 +31,7 @@ class CountryListPage extends StatelessWidget {
           builder: (context, snapshot) => FilterNavigationPage<LocationFilter>(
             source: source,
             title: context.l10n.countryPageTitle,
+            sortFactor: settings.countrySortFactor,
             chipSetActionDelegate: CountryChipSetActionDelegate(),
             chipActionDelegate: ChipActionDelegate(),
             chipActionsBuilder: (filter) => [
diff --git a/lib/widgets/filter_grids/tags_page.dart b/lib/widgets/filter_grids/tags_page.dart
index faf4b7cbb..6b0f86520 100644
--- a/lib/widgets/filter_grids/tags_page.dart
+++ b/lib/widgets/filter_grids/tags_page.dart
@@ -31,6 +31,7 @@ class TagListPage extends StatelessWidget {
           builder: (context, snapshot) => FilterNavigationPage<TagFilter>(
             source: source,
             title: context.l10n.tagPageTitle,
+            sortFactor: settings.tagSortFactor,
             chipSetActionDelegate: TagChipSetActionDelegate(),
             chipActionDelegate: ChipActionDelegate(),
             chipActionsBuilder: (filter) => [