using System;
using System.Collections.Generic;
using System.Linq;
using System.Timers;
using System.Threading.Tasks;
using System.Configuration;

using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Client.Connecting;
using MQTTnet.Client.Disconnecting;
using MQTTnet.Client.Options;
using MQTTnet.Client.Receiving;
using MQTTnet.Extensions.ManagedClient;
using MQTTnet.Formatter;
using MQTTnet.Protocol;
using MQTTnet.Server;

namespace MQTTClientTest
{
    class MultiClients
    {
        //private List<IManagedMqttClient> _mClientList = new List<IManagedMqttClient>();
        private List<IMqttClient> _mClientList = new List<IMqttClient>();
        private Timer _timer = new Timer();
        private Int32 _connectedCount = 0;
        private object _lock = new object();

        string serverIP = ConfigurationManager.AppSettings["MQTTServer.Addr"];
        string serverPort = ConfigurationManager.AppSettings["MQTTServer.Port"];
        string serverUserId = ConfigurationManager.AppSettings["MQTTServer.UserId"];
        string serverPasswd = ConfigurationManager.AppSettings["MQTTServer.Passwd"];
        string serverTopic = ConfigurationManager.AppSettings["MQTTServer.Topic"];

        // start multiple clients
        public async void start(int clientsCount)
        {
            await Task.Factory.StartNew(async () =>
            {
                for (int i = 0; i < clientsCount; i++)
                {
                    //var c = new MqttFactory().CreateManagedMqttClient();
                    var c = new MqttFactory().CreateMqttClient();

                    c.ConnectedHandler = new MqttClientConnectedHandlerDelegate(arg =>
                    {
                        ChangeCount(1);
                        System.Console.WriteLine("Client Connected, connectedCount = " + _connectedCount.ToString());
                    });
                    c.DisconnectedHandler = new MqttClientDisconnectedHandlerDelegate(arg =>
                    {
                        ChangeCount(-1);
                        string strMsg = "Client disconnected, ";
                        if (arg.Exception != null)
                            strMsg = strMsg + "exception=" + arg.Exception.Message.ToString();
                        if (arg.AuthenticateResult != null)
                            strMsg = strMsg + "authReason=" + arg.AuthenticateResult.ReasonString;
                        System.Console.WriteLine(strMsg + ", connectedCount=" + _connectedCount.ToString());
                    });
                    c.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(arg =>
                    {
                        string payload = System.Text.Encoding.UTF8.GetString(arg.ApplicationMessage.Payload);
                        System.Console.WriteLine("Message received, topic [" + arg.ApplicationMessage.Topic + "], payload [" + payload + "], connectedCount=" + _connectedCount.ToString());
                    });


                    string clientId = serverUserId; // Guid.NewGuid().ToString();
                    /*var options = new ManagedMqttClientOptionsBuilder()
                     .WithAutoReconnectDelay(TimeSpan.FromSeconds(5))
                     .WithClientOptions(new MqttClientOptionsBuilder()
                         .WithClientId(clientId)
                         .WithCleanSession(true)
                         .WithTcpServer(serverIP, Convert.ToInt32(serverPort))
                         .WithCredentials(serverUserId, serverPasswd)
                         .Build()
                     )
                     .Build();
                    await c.SubscribeAsync(serverTopic, MqttQualityOfServiceLevel.AtLeastOnce);
                    await c.StartAsync(options);*/

                    var options = new MqttClientOptions() { ClientId = clientId };
                    options.ChannelOptions = new MqttClientTcpOptions()
                    {
                        Server = serverIP,
                        Port = Convert.ToInt32(serverPort)
                    };
                    options.Credentials = new MqttClientCredentials()
                    {
                        Username = serverUserId,
                        Password = System.Text.Encoding.Default.GetBytes(serverPasswd)
                    };
                    await c.ConnectAsync(options);
                    await c.SubscribeAsync(serverTopic, MqttQualityOfServiceLevel.AtLeastOnce);

                    _mClientList.Add(c);

                    System.Threading.Thread.Sleep(200);
                }//for
            });

            //_timer.Interval = 30000;
           // _timer.Elapsed += new ElapsedEventHandler(timer_elapsed);
            //_timer.Enabled = true;
        }//start

        public async void stop()
        {
            /*foreach(IManagedMqttClient c in _mClientList)
            {
                if (c.IsStarted)
                {
                    await c.StopAsync();
                }
            }*/
        }//stop

        private async void timer_elapsed(object sender, ElapsedEventArgs e)
        {
            if (_mClientList.Count < 1)
                return;

            string strPayload = DateTime.Now.ToString();
            IMqttClient c = _mClientList[0];
            await c.PublishAsync(serverTopic, strPayload);           
        }

        private void ChangeCount(Int16 chg)
        {
            lock(_lock)
            {
                _connectedCount += chg;
            }
        }
    }
}