eatvio_app/lib/features/chat/presentation/pages/chats_screen.dart

import 'package:easy_debounce/easy_debounce.dart';
import 'package:eatvio_app/core/enums/base_state.dart';
import 'package:eatvio_app/core/utils/pagination_utils.dart';
import 'package:eatvio_app/core/widgets/data_error_widget.dart';
import 'package:eatvio_app/core/widgets/loader.dart';
import 'package:eatvio_app/features/chat/presentation/bloc/chats_cubit/chats_cubit.dart';
import 'package:eatvio_app/features/chat/presentation/bloc/chats_cubit/chats_state.dart';
import 'package:eatvio_app/features/chat/presentation/widgets/chat_entry_widget.dart';
import 'package:eatvio_app/features/chat/presentation/widgets/chat_search_bar_widget.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

class ChatsScreen extends StatefulWidget {
  const ChatsScreen({super.key, this.initialSearchQuery});

  /// When set (e.g. from notification tap), the search field is pre-filled
  /// and chat list is filtered by this query.
  final String? initialSearchQuery;

  @override
  State<ChatsScreen> createState() => _ChatsScreenState();
}

class _ChatsScreenState extends State<ChatsScreen> {
  final searchController = TextEditingController();

  @override
  void initState() {
    super.initState();
    final query = widget.initialSearchQuery?.trim();
    if (query != null && query.isNotEmpty) {
      searchController.text = query;
    }
    WidgetsBinding.instance.addPostFrameCallback((_) {
      final cubit = context.read<ChatsCubit>();
      final state = cubit.state;
      if (state.state == BaseState.initial) {
        cubit.getChatRoomsWithLoading(query: query?.isNotEmpty == true ? query : null);
      } else if (query != null && query.isNotEmpty) {
        cubit.getChatRooms(query: query);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<ChatsCubit, ChatsState>(
      builder: (context, state) {
        return Scaffold(
          appBar: AppBar(
            backgroundColor: Colors.white,
            toolbarHeight: 0,
          ),
          body: NestedScrollView(
            headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
              return [
                SliverPadding(
                  padding: const EdgeInsets.only(top: 8),
                  sliver: SliverAppBar(
                    automaticallyImplyLeading: false,
                    stretchTriggerOffset: 1,
                    scrolledUnderElevation: 0,
                    floating: true,
                    snap: true,
                    title: Padding(
                      padding: const EdgeInsets.only(top: 8),
                      child: ChatSearchBarWidget(
                        onSuffixIconTap: () => context.read<ChatsCubit>().getChatRooms(),
                        onChanged: (query) {
                          if (query.length > 2) {
                            EasyDebounce.debounce(
                              'searchChatRoom',
                              const Duration(milliseconds: 300),
                              () => context.read<ChatsCubit>().getChatRooms(query: query),
                            );
                          } else {
                            context.read<ChatsCubit>().getChatRooms();
                          }
                        },
                        controller: searchController,
                        fillColor: const Color(0xFFF0F2F5),
                        hintText: "Поиск",
                        hintStyle: const TextStyle(
                          color: Color(0xFF7B8794),
                        ),
                      ),
                    ),
                  ),
                ),
              ];
            },
            body: RefreshIndicator(
              child: switch (state.state) {
                BaseState.error => DataErrorWidget(onReload: () => context.read<ChatsCubit>().getChatRooms()),
                BaseState.success => _buildChatList(context, state),
                _ => const Loader(),
              },
              onRefresh: () async {
                await context.read<ChatsCubit>().getChatRooms();
              },
            ),
          ),
        );
      },
    );
  }

  NotificationListener<ScrollNotification> _buildChatList(BuildContext context, ChatsState state) {
    return NotificationListener<ScrollNotification>(
      onNotification: (notification) {
        loadNewContent(notification, context.read<ChatsCubit>().loadMoreChatRooms);
        return false;
      },
      child: ListView.separated(
        padding: const EdgeInsets.all(16),
        shrinkWrap: true,
        physics: const NeverScrollableScrollPhysics(),
        separatorBuilder: (context, index) {
          return const SizedBox(
            height: 8,
          );
        },
        itemCount: state.isLoadingMoreChats ? state.chatRooms.length + 1 : state.chatRooms.length,
        itemBuilder: (context, index) {
          if (index == state.chatRooms.length) {
            return const Center(child: Loader());
          }
          return ChatEntryWidget(chatRoom: state.chatRooms[index]);
        },
      ),
    );
  }
}