import 'dart:async';

import 'package:flutter/material.dart';
import 'l10n/app_localizations.dart';
import 'models/chat.dart';
import 'services/chat_service.dart';
import 'widgets/offline_banner.dart';

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

  @override
  State<ChatsView> createState() => _ChatsViewState();
}

class _ChatsViewState extends State<ChatsView> {
  final ChatService _chatService = ChatService();
  List<Chat> _chats = const [];
  StreamSubscription<List<Chat>>? _chatSubscription;
  bool _isInitializing = true;

  @override
  void initState() {
    super.initState();
    _initializeChats();
  }

  Future<void> _initializeChats() async {
    await _chatService.initialize();
    if (!mounted) return;

    setState(() {
      _chats = _chatService.currentChats;
      _isInitializing = false;
    });

    _chatSubscription = _chatService.chatsStream.listen((chats) {
      if (!mounted) return;
      setState(() {
        _chats = chats;
      });
    });
  }

  @override
  void dispose() {
    _chatSubscription?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(AppLocalizations.of(context).chats),
        backgroundColor: Colors.deepPurple[100],
      ),
      body: Column(
        children: [
          const OfflineBanner(),
          Expanded(child: _buildBody()),
        ],
      ),
    );
  }

  Widget _buildBody() {
    if (_isInitializing) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_chats.isEmpty) {
      return const Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(Icons.chat_outlined, size: 64, color: Colors.grey),
            SizedBox(height: 16),
            Text(
              'Keine Chats verfügbar',
              style: TextStyle(fontSize: 16, color: Colors.grey),
            ),
          ],
        ),
      );
    }

    return ListView.builder(
      itemCount: _chats.length,
      itemBuilder: (context, index) {
        final chat = _chats[index];
        return _buildChatTile(chat);
      },
    );
  }

  Widget _buildChatTile(Chat chat) {
    final isJobChat = chat.type == ChatType.jobSpecific;
    final hasMessages = chat.messages.isNotEmpty;
    final previewText =
        hasMessages ? chat.lastMessagePreview : 'Noch keine Nachrichten';
    final timeLabel = hasMessages ? _formatTime(chat.lastMessageTime) : '--';
    final jobId = chat.jobId?.trim();
    final jobNumber = chat.jobNumber?.trim();
    final showJobId = isJobChat && jobId != null && jobId.isNotEmpty;

    return Card(
      margin: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      child: ListTile(
        leading: CircleAvatar(
          backgroundColor: isJobChat ? Colors.blue[100] : Colors.green[100],
          child: Icon(
            isJobChat ? Icons.work : Icons.support_agent,
            color: isJobChat ? Colors.blue[700] : Colors.green[700],
          ),
        ),
        title: Text(() {
          if (isJobChat) {
            if (jobNumber != null && jobNumber.isNotEmpty) {
              return 'Job $jobNumber';
            }
            if (showJobId) {
              return 'Job $jobId';
            }
          }
          return chat.type == ChatType.general
              ? 'Allgemeine Nachrichten'
              : chat.title;
        }(), style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 16)),
        subtitle: Text(
          previewText,
          maxLines: 1,
          overflow: TextOverflow.ellipsis,
          style: TextStyle(fontSize: 14, color: Colors.grey[700]),
        ),
        trailing: Column(
          crossAxisAlignment: CrossAxisAlignment.end,
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              timeLabel,
              style: TextStyle(fontSize: 12, color: Colors.grey[500]),
            ),
            const SizedBox(height: 4),
            Container(
              padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
              decoration: BoxDecoration(
                color: isJobChat ? Colors.blue[50] : Colors.green[50],
                borderRadius: BorderRadius.circular(10),
                border: Border.all(
                  color: isJobChat ? Colors.blue[200]! : Colors.green[200]!,
                ),
              ),
              child: Text(
                isJobChat ? 'JOB' : 'ALLG',
                style: TextStyle(
                  fontSize: 10,
                  fontWeight: FontWeight.w600,
                  color: isJobChat ? Colors.blue[700] : Colors.green[700],
                ),
              ),
            ),
          ],
        ),
        onTap: () {
          Navigator.of(context).pushNamed('/chat_details', arguments: chat);
        },
      ),
    );
  }

  String _formatTime(DateTime dateTime) {
    final now = DateTime.now();
    final difference = now.difference(dateTime);

    if (difference.inDays > 0) {
      return '${difference.inDays}T';
    } else if (difference.inHours > 0) {
      return '${difference.inHours}h';
    } else if (difference.inMinutes > 0) {
      return '${difference.inMinutes}m';
    } else {
      return 'jetzt';
    }
  }
}