aves/lib/widgets/collection/search/search_delegate.dart

import 'package:aves/model/filters/album.dart';
import 'package:aves/model/filters/favourite.dart';
import 'package:aves/model/filters/filters.dart';
import 'package:aves/model/filters/location.dart';
import 'package:aves/model/filters/mime.dart';
import 'package:aves/model/filters/query.dart';
import 'package:aves/model/filters/tag.dart';
import 'package:aves/model/mime_types.dart';
import 'package:aves/model/source/album.dart';
import 'package:aves/model/source/collection_source.dart';
import 'package:aves/model/source/location.dart';
import 'package:aves/model/source/tag.dart';
import 'package:aves/widgets/collection/search/expandable_filter_row.dart';
import 'package:aves/widgets/common/aves_filter_chip.dart';
import 'package:aves/widgets/common/icons.dart';
import 'package:flutter/material.dart';

class ImageSearchDelegate extends SearchDelegate<CollectionFilter> {
  final CollectionSource source;
  final ValueNotifier<String> expandedSectionNotifier = ValueNotifier(null);
  final FilterCallback onSelection;

  ImageSearchDelegate(this.source, this.onSelection);

  @override
  ThemeData appBarTheme(BuildContext context) {
    return Theme.of(context);
  }

  @override
  Widget buildLeading(BuildContext context) {
    return IconButton(
      icon: AnimatedIcon(
        icon: AnimatedIcons.menu_arrow,
        progress: transitionAnimation,
      ),
      onPressed: () => _select(context, null),
      tooltip: 'Back',
    );
  }

  @override
  List<Widget> buildActions(BuildContext context) {
    return [
      if (query.isNotEmpty)
        IconButton(
          icon: Icon(AIcons.clear),
          onPressed: () {
            query = '';
            showSuggestions(context);
          },
          tooltip: 'Clear',
        ),
    ];
  }

  @override
  Widget buildSuggestions(BuildContext context) {
    final upQuery = query.trim().toUpperCase();
    bool containQuery(String s) => s.toUpperCase().contains(upQuery);
    return SafeArea(
      child: ValueListenableBuilder<String>(
          valueListenable: expandedSectionNotifier,
          builder: (context, expandedSection, child) {
            var queryFilter = _buildQueryFilter(false);
            return ListView(
              padding: EdgeInsets.only(top: 8),
              children: [
                _buildFilterRow(
                  context: context,
                  filters: [
                    queryFilter,
                    FavouriteFilter(),
                    MimeFilter(MimeTypes.anyImage),
                    MimeFilter(MimeTypes.anyVideo),
                    MimeFilter(MimeFilter.animated),
                    MimeFilter(MimeTypes.svg),
                  ].where((f) => f != null && containQuery(f.label)),
                  // usually perform hero animation only on tapped chips,
                  // but we also need to animate the query chip when it is selected by submitting the search query
                  heroTypeBuilder: (filter) => filter == queryFilter ? HeroType.always : HeroType.onTap,
                ),
                StreamBuilder(
                    stream: source.eventBus.on<AlbumsChangedEvent>(),
                    builder: (context, snapshot) {
                      return _buildFilterRow(
                        context: context,
                        title: 'Albums',
                        filters: source.sortedAlbums.where(containQuery).map((s) => AlbumFilter(s, source.getUniqueAlbumName(s))).where((f) => containQuery(f.uniqueName)),
                      );
                    }),
                StreamBuilder(
                    stream: source.eventBus.on<LocationsChangedEvent>(),
                    builder: (context, snapshot) {
                      return _buildFilterRow(
                        context: context,
                        title: 'Countries',
                        filters: source.sortedCountries.where(containQuery).map((s) => LocationFilter(LocationLevel.country, s)),
                      );
                    }),
                StreamBuilder(
                    stream: source.eventBus.on<LocationsChangedEvent>(),
                    builder: (context, snapshot) {
                      return _buildFilterRow(
                        context: context,
                        title: 'Places',
                        filters: source.sortedPlaces.where(containQuery).map((s) => LocationFilter(LocationLevel.place, s)),
                      );
                    }),
                StreamBuilder(
                    stream: source.eventBus.on<TagsChangedEvent>(),
                    builder: (context, snapshot) {
                      return _buildFilterRow(
                        context: context,
                        title: 'Tags',
                        filters: source.sortedTags.where(containQuery).map((s) => TagFilter(s)),
                      );
                    }),
              ],
            );
          }),
    );
  }

  Widget _buildFilterRow({
    @required BuildContext context,
    String title,
    @required Iterable<CollectionFilter> filters,
    HeroType Function(CollectionFilter filter) heroTypeBuilder,
  }) {
    return ExpandableFilterRow(
      title: title,
      filters: filters,
      expandedNotifier: expandedSectionNotifier,
      heroTypeBuilder: heroTypeBuilder,
      onPressed: (filter) => _select(context, filter is QueryFilter ? QueryFilter(filter.query) : filter),
    );
  }

  @override
  Widget buildResults(BuildContext context) {
    WidgetsBinding.instance.addPostFrameCallback((_) {
      // `buildResults` is called in the build phase,
      // so we post the call that will filter the collection
      // and possibly trigger a rebuild here
      _select(context, _buildQueryFilter(true));
    });
    return SizedBox.shrink();
  }

  QueryFilter _buildQueryFilter(bool colorful) {
    final cleanQuery = query.trim();
    return cleanQuery.isNotEmpty ? QueryFilter(cleanQuery, colorful: colorful) : null;
  }

  void _select(BuildContext context, CollectionFilter filter) {
    if (filter != null) {
      onSelection(filter);
    }
    // we post closing the search page after applying the filter selection
    // so that hero animation target is ready in the `FilterBar`,
    // even when the target is a child of an `AnimatedList`
    WidgetsBinding.instance.addPostFrameCallback((_) {
      close(context, null);
    });
  }
}