changed advance filter

Author: Sayak Ghosh

frontend/appflowy_flutter/lib/plugins/database/application/field/filter_entities.dart

@@ -27,6 +27,19 @@ abstract class DatabaseFilter extends Equatable {
   });
 
   factory DatabaseFilter.fromPB(FilterPB filterPB) {
+    if (filterPB.filterType == FilterType.And ||
+        filterPB.filterType == FilterType.Or) {
+      return GroupFilter(
+        filterId: filterPB.id,
+        filterType: filterPB.filterType,
+        children: filterPB.children.map(DatabaseFilter.fromPB).toList(),
+      );
+    }
+
+    if (!filterPB.hasData()) {
+      return PlaceholderFilter(filterId: filterPB.id);
+    }
+
     final FilterDataPB(:fieldId, :fieldType) = filterPB.data;
     switch (fieldType) {
       case FieldType.RichText:
@@ -88,7 +101,7 @@ abstract class DatabaseFilter extends Equatable {
           end: data.hasEnd() ? data.end.toDateTime() : null,
         );
       default:
-        throw ArgumentError();
+        return PlaceholderFilter(filterId: filterPB.id);
     }
   }
 
@@ -746,3 +759,49 @@ final class TimeFilter extends DatabaseFilter {
   @override
   List<Object?> get props => [filterId, fieldId, condition, content];
 }
+
+final class PlaceholderFilter extends DatabaseFilter {
+  const PlaceholderFilter({required super.filterId})
+      : super(fieldId: '', fieldType: FieldType.RichText);
+
+  @override
+  String get conditionName => "";
+
+  @override
+  bool get canAttachContent => false;
+
+  @override
+  String getContentDescription(FieldInfo field) => "";
+
+  @override
+  Uint8List writeToBuffer() => Uint8List(0);
+
+  @override
+  List<Object?> get props => [filterId];
+}
+
+final class GroupFilter extends DatabaseFilter {
+  const GroupFilter({
+    required super.filterId,
+    required this.filterType,
+    required this.children,
+  }) : super(fieldId: '', fieldType: FieldType.RichText);
+
+  final FilterType filterType;
+  final List<DatabaseFilter> children;
+
+  @override
+  String get conditionName => filterType == FilterType.And ? "And" : "Or";
+
+  @override
+  bool get canAttachContent => false;
+
+  @override
+  String getContentDescription(FieldInfo field) => "";
+
+  @override
+  Uint8List writeToBuffer() => Uint8List(0);
+
+  @override
+  List<Object?> get props => [filterId, filterType, children];
+}

frontend/appflowy_flutter/lib/plugins/database/grid/presentation/widgets/filter/filter_menu.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:appflowy/generated/flowy_svgs.g.dart';
 import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/database/application/field/field_controller.dart';
@@ -35,21 +36,28 @@ class FilterMenu extends StatelessWidget {
         },
         builder: (context, state) {
           final List<Widget> children = [];
-          children.addAll(
-            state.filters
-                .map(
-                  (filter) => FilterMenuItem(
-                    key: ValueKey(filter.filterId),
-                    filterId: filter.filterId,
-                    fieldType: state.fields
-                        .firstWhere(
-                          (element) => element.id == filter.fieldId,
-                        )
-                        .fieldType,
-                  ),
-                )
-                .toList(),
-          );
+          void addFilters(List<DatabaseFilter> filters) {
+            for (final filter in filters) {
+              if (filter is GroupFilter) {
+                addFilters(filter.children);
+              } else {
+                final field = state.fields.firstWhereOrNull(
+                  (element) => element.id == filter.fieldId,
+                );
+                if (field != null) {
+                  children.add(
+                    FilterMenuItem(
+                      key: ValueKey(filter.filterId),
+                      filterId: filter.filterId,
+                      fieldType: field.fieldType,
+                    ),
+                  );
+                }
+              }
+            }
+          }
+
+          addFilters(state.filters);
 
           if (state.fields.isNotEmpty) {
             children.add(