import 'dart:async';
import 'dart:convert';
import 'dart:typed_data';
import 'package:flutter/foundation.dart';
import 'package:web_socket_channel/web_socket_channel.dart';
import '../models/message.dart';

enum ConnectionState { disconnected, connecting, connected }

class ConnectionService extends ChangeNotifier {
  WebSocketChannel? _channel;
  ConnectionState _state = ConnectionState.disconnected;
  String _serverUrl = 'ws://localhost:8443/ws';
  String? _userId;
  String? _username;
  String? _token;
  Timer? _heartbeatTimer;
  int _seq = 0;

  final StreamController<Map<String, dynamic>> _messageController =
      StreamController<Map<String, dynamic>>.broadcast();

  Stream<Map<String, dynamic>> get messageStream => _messageController.stream;

  ConnectionState get state => _state;
  String? get userId => _userId;
  String? get username => _username;
  String? get token => _token;
  bool get isConnected => _state == ConnectionState.connected;

  String get serverUrl => _serverUrl;
  set serverUrl(String url) {
    _serverUrl = url;
    notifyListeners();
  }

  @override
  void dispose() {
    disconnect();
    _messageController.close();
    super.dispose();
  }

  void init() {
    notifyListeners();
  }

  Future<void> connect() async {
    _state = ConnectionState.connecting;
    notifyListeners();

    try {
      _channel = WebSocketChannel.connect(Uri.parse(_serverUrl));
      await _channel!.ready;

      _channel!.stream.listen(
        (data) {
          _handleMessage(data);
        },
        onError: (error) {
          _state = ConnectionState.disconnected;
          notifyListeners();
        },
        onDone: () {
          _state = ConnectionState.disconnected;
          _heartbeatTimer?.cancel();
          notifyListeners();
        },
      );

      _state = ConnectionState.connected;
      _startHeartbeat();
      notifyListeners();
    } catch (e) {
      _state = ConnectionState.disconnected;
      notifyListeners();
      rethrow;
    }
  }

  void disconnect() {
    _heartbeatTimer?.cancel();
    _channel?.sink.close();
    _channel = null;
    _state = ConnectionState.disconnected;
    notifyListeners();
  }

  void _startHeartbeat() {
    _heartbeatTimer = Timer.periodic(const Duration(seconds: 30), (_) {
      send({'op': 0});
    });
  }

  void _handleMessage(dynamic data) {
    try {
      final Map<String, dynamic> packet = jsonDecode(data as String);
      final int op = packet['op'] as int;

      switch (op) {
        case 1: // Hello
          break;
        case 3: // Authenticated
          final d = packet['d'] as Map<String, dynamic>;
          _userId = d['user_id'] as String?;
          _username = d['username'] as String?;
          _token = d['token'] as String?;
          notifyListeners();
          break;
        case 10: // MessageCreate
          _messageController.add(packet['d'] as Map<String, dynamic>);
          break;
        case 13: // Reaction
          _messageController.add(packet['d'] as Map<String, dynamic>);
          break;
        case 40: // VoiceState
          _messageController.add(packet['d'] as Map<String, dynamic>);
          break;
        case 60: // Typing
          _messageController.add(packet['d'] as Map<String, dynamic>);
          break;
      }
    } catch (e) {
      debugPrint('Failed to handle message: $e');
    }
  }

  void send(Map<String, dynamic> packet) {
    if (_channel == null) return;
    packet['s'] = ++_seq;
    _channel!.sink.add(jsonEncode(packet));
  }

  void authenticate({String? token, String? username}) {
    send({
      'op': 2,
      'd': {
        if (token != null) 'token': token,
        if (username != null) 'username': username,
      },
    });
  }

  void sendMessage({
    required String channelId,
    required Uint8List content,
    bool encrypted = false,
    Uint8List? nonce,
    String messageType = 'text',
    String? replyTo,
  }) {
    send({
      'op': 10,
      'd': {
        'channel_id': channelId,
        'content': content.toList(),
        'encrypted': encrypted,
        if (nonce != null) 'nonce': nonce.toList(),
        'message_type': messageType,
        if (replyTo != null) 'reply_to': replyTo,
      },
    });
  }

  void sendReaction(String messageId, String emoji, {bool add = true}) {
    send({
      'op': 13,
      'd': {
        'message_id': messageId,
        'emoji': emoji,
        'add': add,
      },
    });
  }

  void updateVoiceState({
    required String guildId,
    String? channelId,
    bool muted = false,
    bool deafened = false,
  }) {
    send({
      'op': 40,
      'd': {
        'guild_id': guildId,
        'channel_id': channelId ?? '',
        'muted': muted,
        'deafened': deafened,
      },
    });
  }

  void sendTyping(String channelId) {
    send({
      'op': 60,
      'd': {'channel_id': channelId},
    });
  }
}