OpenContacts/lib/widgets/friends/friends_list.dart

import 'package:contacts_plus_plus/clients/messaging_client.dart';
import 'package:contacts_plus_plus/widgets/default_error_widget.dart';
import 'package:contacts_plus_plus/widgets/friends/expanding_input_fab.dart';
import 'package:contacts_plus_plus/widgets/friends/friend_list_tile.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';


class FriendsList extends StatefulWidget {
  const FriendsList({super.key});

  @override
  State<FriendsList> createState() => _FriendsListState();
}

class _FriendsListState extends State<FriendsList> with AutomaticKeepAliveClientMixin {
  String _searchFilter = "";

  @override
  Widget build(BuildContext context) {
    super.build(context);
    return ChangeNotifierProvider.value(
      value: Provider.of<MessagingClient>(context, listen: false),
      child: Stack(
          alignment: Alignment.topCenter,
          children: [
            Consumer<MessagingClient>(builder: (context, mClient, _) {
              if (mClient.initStatus == null) {
                return const LinearProgressIndicator();
              } else if (mClient.initStatus!.isNotEmpty) {
                return Column(
                  children: [
                    Expanded(
                      child: DefaultErrorWidget(
                        message: mClient.initStatus,
                        onRetry: () async {
                          mClient.resetInitStatus();
                          mClient.refreshFriendsListWithErrorHandler();
                        },
                      ),
                    ),
                  ],
                );
              } else {
                var friends = List.from(mClient.cachedFriends); // Explicit copy.
                if (_searchFilter.isNotEmpty) {
                  friends = friends
                      .where((element) => element.username.toLowerCase().contains(_searchFilter.toLowerCase()))
                      .toList();
                  friends.sort((a, b) => a.username.length.compareTo(b.username.length));
                }
                return ListView.builder(
                  physics: const BouncingScrollPhysics(decelerationRate: ScrollDecelerationRate.fast),
                  itemCount: friends.length,
                  itemBuilder: (context, index) {
                    final friend = friends[index];
                    final unreads = mClient.getUnreadsForFriend(friend);
                    return FriendListTile(
                      friend: friend,
                      unreads: unreads.length,
                    );
                  },
                );
              }
            }),
            Align(
              alignment: Alignment.bottomCenter,
              child: ExpandingInputFab(
                onInputChanged: (String text) {
                  setState(() {
                    _searchFilter = text;
                  });
                },
                onExpansionChanged: (expanded) {
                  if (!expanded) {
                    setState(() {
                      _searchFilter = "";
                    });
                  }
                },
              ),
            ),
          ],
        ),
    );
  }

  @override
  bool get wantKeepAlive => true;
}