import 'dart:io';
import 'dart:math';

import 'package:easy_debounce/easy_debounce.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/chat_room_cubit/chat_room_cubit.dart';
import 'package:eatvio_app/features/chat/presentation/bloc/chat_room_cubit/chat_room_state.dart';
import 'package:eatvio_app/features/chat/presentation/bloc/chats_cubit/chats_cubit.dart';
import 'package:eatvio_app/features/chat/presentation/widgets/chat_bubble_widget.dart';
import 'package:eatvio_app/core/locator_service.dart';
import 'package:eatvio_app/core/theme/custom_text_style.dart';
import 'package:eatvio_app/core/theme/theme_helper.dart';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:intl/intl.dart';
import 'package:visibility_detector/visibility_detector.dart';

class ChatScreen extends StatefulWidget {
  final String chatId;
  final ChatsCubit chatsCubit;
  const ChatScreen({
    required this.chatId,
    required this.chatsCubit,
    super.key,
  });

  @override
  State<ChatScreen> createState() => _ChatScreenState();
}

class _ChatScreenState extends State<ChatScreen> {
  final scrollController = ScrollController();
  final TextEditingController textEditingController = TextEditingController();
  final ChatRoomCubit chatRoomCubit = sl<ChatRoomCubit>();
  final List<({int id, int index})> unreadMessagesIds = [];
  final List<({int id, int index})> unreadMessagesIdsCopy = [];

  @override
  void initState() {
    super.initState();
    scrollController.addListener(_onScroll);
    chatRoomCubit.initChat(widget.chatId);
  }

  _onScroll() {
    if (scrollController.offset >= scrollController.position.maxScrollExtent && !scrollController.position.outOfRange) {
      chatRoomCubit.loadNextPage(widget.chatId);
    }
  }

  @override
  void dispose() {
    scrollController.dispose();
    super.dispose();
  }

  Widget build(BuildContext context) {
    return BlocProvider<ChatRoomCubit>(
      create: (BuildContext context) => chatRoomCubit,
      child: BlocBuilder<ChatRoomCubit, ChatRoomState>(
        bloc: chatRoomCubit,
        builder: (context, state) {
          if (state is ChatRoomStateLoaded) {
            return _buildChat(context, state);
          } else if (state is ChatRoomStateError) {
            return Scaffold(
              appBar: AppBar(),
              body: DataErrorWidget(onReload: () => chatRoomCubit.initChat(widget.chatId)),
            );
          } else {
            return Scaffold(
              body: const Loader(),
            );
          }
        },
      ),
    );
  }

  _buildChat(BuildContext context, ChatRoomStateLoaded state) {
    return Scaffold(
      resizeToAvoidBottomInset: true,
      appBar: AppBar(
        titleSpacing: 0,
        backgroundColor: appTheme.gray100,
        centerTitle: false,
        title: Row(
          children: [
            if (state.chatRoom.users['to_chat_user']!.profilePhotoUrl != null)
              CircleAvatar(
                radius: 20,
                foregroundImage: NetworkImage(state.chatRoom.users['to_chat_user']!.profilePhotoUrl!),
              ),
            if (state.chatRoom.users['to_chat_user']!.profilePhotoUrl == null)
              Container(
                width: 40,
                height: 40,
                alignment: Alignment.center,
                decoration: BoxDecoration(
                  color: Color(0xFFEBF4FF),
                  shape: BoxShape.circle,
                ),
                child: Text(
                  state.chatRoom.users['to_chat_user']!.name.split(' ').first[0] + state.chatRoom.users['to_chat_user']!.name.split(' ')[1][0],
                  style: TextStyle(
                    color: Color(0xFF7F9CF5),
                    fontWeight: FontWeight.w400,
                    fontSize: 20,
                  ),
                ),
              ),
            SizedBox(width: 16),
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  state.chatRoom.users['to_chat_user']!.name,
                  style: CustomTextStyles.titleSmallBold.copyWith(
                    color: PrimaryColors().black,
                  ),
                ),
                AnimatedCrossFade(
                  firstChild: Text(
                    'Печатает...',
                    style: CustomTextStyles.bodySmallMulishPrimary,
                  ),
                  firstCurve: Curves.easeIn,
                  secondCurve: Curves.easeOut,
                  secondChild: const SizedBox.shrink(),
                  crossFadeState: state.isTyping ? CrossFadeState.showFirst : CrossFadeState.showSecond,
                  duration: Duration(milliseconds: 150),
                ),
              ],
            ),
          ],
        ),
      ),
      body: SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Expanded(
              child: Container(
                color: appTheme.whiteA700,
                width: double.maxFinite,
                child: CustomScrollView(
                  physics: BouncingScrollPhysics(),
                  controller: scrollController,
                  reverse: true,
                  slivers: [
                    SliverPadding(
                      padding: EdgeInsets.symmetric(vertical: 16),
                      sliver: SliverList(
                        delegate: SliverChildBuilderDelegate(
                          (context, index) {
                            if (index < state.chatMessages.length) {
                              if ((index + 1 != state.chatMessages.length &&
                                      state.chatMessages[index].updatedAt.day != state.chatMessages[index + 1].updatedAt.day) ||
                                  index + 1 == state.chatMessages.length) {
                                final isCurrentUserAuthor = state.chatRoom.users['to_chat_user']!.id != state.chatMessages[index].authorId;
                                return Column(
                                  children: [
                                    _messageDate(state.chatMessages[index].updatedAt),
                                    VisibilityDetector(
                                      key: Key(state.chatMessages[index].id.toString()),
                                      onVisibilityChanged: (VisibilityInfo info) {
                                        if (!state.chatMessages[index].isRead && !isCurrentUserAuthor && info.visibleFraction > 0) {
                                          unreadMessagesIdsCopy.add((id: state.chatMessages[index].id, index: index));
                                          EasyDebounce.debounce(
                                            'mark_as_read',
                                            Duration(milliseconds: 500),
                                            () async {
                                              final result = await context.read<ChatRoomCubit>().markMessagesAsRead(state.chatRoom.id, unreadMessagesIdsCopy);
                                              if (!result) return;
                                              widget.chatsCubit.reduceUnreadMessagesCount(chatId: state.chatRoom.id, count: unreadMessagesIdsCopy.length);
                                              unreadMessagesIdsCopy.clear();
                                            },
                                          );
                                        }
                                      },
                                      child: ChatBubbleWidget(
                                        isRead: state.chatMessages[index].isRead,
                                        sendTime: state.chatMessages[index].updatedAt,
                                        text: state.chatMessages[index].data.trim(),
                                        isCurrentUser: isCurrentUserAuthor,
                                        mediaData: state.chatMessages[index].mediaData ?? [],
                                      ),
                                    ),
                                  ],
                                );
                              }
                              final isCurrentUserAuthor = state.chatRoom.users['to_chat_user']!.id != state.chatMessages[index].authorId;
                              return VisibilityDetector(
                                key: Key(state.chatMessages[index].id.toString()),
                                onVisibilityChanged: (VisibilityInfo info) {
                                  if (!state.chatMessages[index].isRead && !isCurrentUserAuthor && info.visibleFraction > 0) {
                                    unreadMessagesIds.add((id: state.chatMessages[index].id, index: index));
                                    EasyDebounce.debounce(
                                      'mark_as_read',
                                      Duration(milliseconds: 500),
                                      () async {
                                        final result = await context.read<ChatRoomCubit>().markMessagesAsRead(state.chatRoom.id, unreadMessagesIds);
                                        if (!result) return;
                                        widget.chatsCubit.reduceUnreadMessagesCount(chatId: state.chatRoom.id, count: unreadMessagesIds.length);
                                        unreadMessagesIds.clear();
                                      },
                                    );
                                  }
                                },
                                child: ChatBubbleWidget(
                                  isRead: state.chatMessages[index].isRead,
                                  sendTime: state.chatMessages[index].updatedAt,
                                  text: state.chatMessages[index].data.trim(),
                                  isCurrentUser: isCurrentUserAuthor,
                                  mediaData: state.chatMessages[index].mediaData ?? [],
                                ),
                              );
                            } else {
                              return Padding(
                                padding: const EdgeInsets.all(8),
                                child: const Loader(),
                              );
                            }
                          },
                          childCount: state.chatMessages.length + (state.isLoading ? 1 : 0),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
            Container(
              padding: EdgeInsets.symmetric(vertical: 8),
              child: Row(
                crossAxisAlignment: CrossAxisAlignment.end,
                children: [
                  SizedBox(width: 8),
                  InkWell(
                    onTap: () async {
                      FilePickerResult? result = await FilePicker.platform.pickFiles(
                        allowMultiple: true,
                        type: FileType.custom,
                        allowedExtensions: [
                          'pdf',
                          'doc',
                          'docx',
                          'json',
                          'ppt',
                          'pptx',
                          'rtf',
                          'txt',
                          'xls',
                          'xlsx',
                          'csv',
                          'jpeg',
                          'jpg',
                          'png',
                          'gif',
                          'svg',
                          'xml',
                          'webp',
                        ],
                      );

                      if (result != null) {
                        List<File> files = result.paths.map((path) => File(path!)).toList();
                        await chatRoomCubit.sendMessage(
                          chatId: widget.chatId,
                          files: files,
                        );
                      } else {
                        // User canceled the picker
                      }
                    },
                    customBorder: CircleBorder(),
                    child: Ink(
                      height: 40,
                      width: 40,
                      child: Transform.rotate(
                        angle: pi / 4,
                        child: Icon(
                          Icons.attach_file_rounded,
                          size: 30,
                          color: Color(0xFF858E99),
                        ),
                      ),
                    ),
                  ),
                  SizedBox(width: 8),
                  Expanded(
                    child: SizedBox(
                      height: 40,
                      child: TextFormField(
                        expands: true,
                        controller: textEditingController,
                        maxLines: null,
                        minLines: null,
                        keyboardType: TextInputType.multiline,
                        style: TextStyle(fontSize: 16, fontWeight: FontWeight.w400, color: Colors.black, height: 1),
                        decoration: InputDecoration(
                          isDense: true,
                          contentPadding: EdgeInsets.symmetric(horizontal: 16, vertical: 10),
                          hintText: 'Сообщение',
                          hintStyle: TextStyle(
                            fontSize: 14,
                            fontWeight: FontWeight.w400,
                            height: 1,
                            color: Color(0xFFAEAEB2),
                          ),
                          filled: true,
                          border: OutlineInputBorder(
                            borderRadius: BorderRadius.circular(100),
                            borderSide: BorderSide(
                              color: Color(0xFFD1D1D6),
                              width: 1,
                            ),
                          ),
                          enabledBorder: OutlineInputBorder(
                            borderRadius: BorderRadius.circular(100),
                            borderSide: BorderSide(
                              color: Color(0xFFD1D1D6),
                              width: 1,
                            ),
                          ),
                          focusedBorder: OutlineInputBorder(
                            borderRadius: BorderRadius.circular(100),
                            borderSide: BorderSide(
                              color: Color(0xFFD1D1D6),
                              width: 1,
                            ),
                          ),
                        ),
                      ),
                    ),
                  ),
                  SizedBox(width: 8),
                  InkWell(
                    customBorder: CircleBorder(),
                    onTap: () {
                      if (textEditingController.text.isNotEmpty) {
                        chatRoomCubit.sendMessage(
                          chatId: widget.chatId,
                          data: textEditingController.text.trim(),
                        );
                        setState(() {
                          textEditingController.clear();
                        });
                      }
                    },
                    child: Ink(
                      decoration: BoxDecoration(
                        color: appTheme.blueA400,
                        shape: BoxShape.circle,
                      ),
                      height: 40,
                      width: 40,
                      child: Icon(
                        Icons.arrow_upward_rounded,
                        size: 24,
                        color: Colors.white,
                      ),
                    ),
                  ),
                  SizedBox(width: 8),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  _messageDate(DateTime date) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.only(top: 32),
        child: Text(
          DateFormat.yMMMMd('RU').format(
            date,
          ),
          style: const TextStyle(
            height: 1,
            color: Color(0xFF8393A1),
            fontWeight: FontWeight.w500,
          ),
        ),
      ),
    );
  }
}