import 'dart:convert';
import 'dart:typed_data';

import 'package:mqtt5_client/mqtt5_client.dart';
import 'package:mqtt5_client/mqtt5_server_client.dart';
import 'package:typed_data/src/typed_buffer.dart';

class Mqtt {
  final MqttConfig _config;
  MqttClient? _client;
  //标记是否自动重连
  bool reconnect = true;
  //缓存自定义主题订阅信息
  Map<String, int> topicCache = {};

  Mqtt(this._config) {
    _client = MqttServerClient.withPort(
        _config.host,
        "${_config.clientId}_${DateTime.now().millisecondsSinceEpoch}",
        _config.port)
      ..useWebSocket =
          _config.host.startsWith("ws") || _config.host.startsWith("wss");
    _client?.keepAlivePeriod = _config.keepAlive;
    _client?.connectionMessage =
        MqttConnectMessage().keepAliveFor(_config.keepAlive);
    // _client?.autoReconnect = true;
    _client?.onConnected = () {
      // print("aa:mqtt服务器连接成功");
      print("mqtt服务器: ${_config.host} 连接成功");
    };
    _client?.onDisconnected = () {
      // print("aa:mqtt服务器连接断开");
      print("mqtt服务器: ${_config.host} 连接断开");
      //执行重连操作
      if (reconnect) {
        connect(reconnect: true);
      }
    };
  }

  static late Mqtt _mqtt;

  static Mqtt getInstance() {
    return _mqtt;
  }

  static void setInstance(Mqtt server) {
    _mqtt = server;
  }

  Future<bool> connect({bool reconnect = false}) async {
    if (reconnect) {
      //限制重连速率
      await Future.delayed(Duration(seconds: 1));
      print("mqtt服务器: ${_config.host} 尝试重连");
    }
    MqttConnectionStatus? state;
    try {
      state = await _client?.connect(_config.username, _config.password);
    } catch (e) {
      //连接错误
      print("mqtt连接失败: 地址:${_config.host} 原因:$e");
      return connect(reconnect: this.reconnect);
    }
    if (state == null || state.state != MqttConnectionState.connected) {
      //连接失败
      print("mqtt连接失败-1: 地址:${_config.host} 原因:$state");
      return connect(reconnect: this.reconnect);
    }
    // print("mqtt服务器: ${_config.host} 连接成功");

    _client?.updates.listen((List<MqttReceivedMessage<MqttMessage>> message) {
      final recMess = message[0].payload as MqttPublishMessage;
      try {
        if (_config.messgae != null) {
          final payload = Utf8Decoder().convert(recMess.payload.message!);
          // final payload =
          // MqttUtilities.bytesToStringAsString(recMess.payload.message!);
          _config.messgae!(message[0].topic!, payload);
        } else if (_config.buffMessage != null) {
          _config.buffMessage!(
              message[0].topic!, recMess.payload.message!.buffer.asUint8List());
        }
      } catch (e) {
        //转字符串失败
        print(e);
      }
    });
    _config.topic?.forEach((topic) {
      subscribe(topic, _config.qos, cache: false);
    });
    topicCache.forEach((t, q) {
      subscribe(t, q, cache: false);
    });

    return true;
  }

  void disconnect() {
    _client?.disconnect();
    reconnect = false;
    // _client = null;
  }

  void subscribe(String topic, int qos, {bool cache = true}) {
    if (cache) {
      topicCache[topic] = qos;
    }
    _client?.subscribe(topic, MqttUtilities.getQosLevel(qos));
  }

  void unSubscribe(String topic) {
    topicCache.remove(topic);
    _client?.unsubscribeStringTopic(topic);
  }

  Future<bool> publish(String topic, String msg, {int qos = 0}) async {
    try {
      var payload = MqttPayloadBuilder();
      payload.addUTF8String(msg);
      _client?.publishMessage(
          topic, MqttUtilities.getQosLevel(qos), payload.payload!);
      return true;
    } catch (e) {
      print(e);
      return false;
    }
  }

  Future<bool> publishBuff(String topic, Uint8List data, {int qos = 0}) async {
    try {
      var payload = MqttPayloadBuilder();
      // data.buffer
      payload.addBuffer(Uint8Buffer()..addAll(data));

      _client?.publishMessage(
          topic, MqttUtilities.getQosLevel(qos), payload.payload!);
      return true;
    } catch (e) {
      print(e);
      return false;
    }
  }
}

class MqttConfig {
  final String host;
  final int port;
  final String clientId;
  String? username;
  String? password;
  List<String>? topic;
  int keepAlive;
  int qos;
  //文本消息
  Function(String topic, String message)? messgae;
  //二进制消息
  Function(String topic, Uint8List buff)? buffMessage;

  MqttConfig(
      {required this.host,
      this.port = 1883,
      required this.clientId,
      this.messgae,
      this.buffMessage,
      this.topic,
      this.qos = 0,
      this.username,
      this.password,
      this.keepAlive = 60});
}