using System.Security.Cryptography;
using System.Text.Json;
using System.Text;
using MQTTnet;
using MQTTnet.Protocol;
using Newtonsoft.Json;
using System.Collections.Concurrent;

namespace SimulatedTrackingDevice
{
    internal class Program
    {
        private static readonly string BrokerIp = "127.0.0.1";
        //private static readonly string BrokerIp = "localhost";
        private static readonly int BrokerPort = 1883;
        private static readonly string Username = "emqxdevice";
        private static readonly string Password = "sivan@123";
        private static readonly string DevicePasswordSalt = "navis@salt";
        private static readonly int secondsToReconnect = 2000;
        private static readonly int secondsToHealthcheck = 10000;

        //private static readonly int DeviceCount = 1000;

        private static readonly string UpdatePVTTopic = "iot/device/update_pvt";
        private static readonly ConcurrentDictionary<string, string> deviceTokens = new();
        private static readonly ConcurrentDictionary<string, SemaphoreSlim> deviceSemaphores = new();

        static async Task Main(string[] args)
        {
            List<Task> deviceTasks = new();
            for (int i = 1; i <= 1; i++)
            {
                string localMacAddress = $"DeviceTest{i:0000}";
                deviceSemaphores[localMacAddress] = new SemaphoreSlim(1, 1); // Tạo semaphore riêng cho từng thiết bị
                //deviceTasks.Add(AllDevicePublish(macAddress, i));
                deviceTasks.Add(SimulateDevice(localMacAddress));

                await Task.Delay(50); // Tránh quá tải khi tạo quá nhiều thiết bị cùng lúc
            }
            await Task.WhenAll(deviceTasks);
        }

        private static async Task SimulateDevice(string localMacAddress)
        {
            try
            {
                var factory = new MqttClientFactory();
                var mqttClient = factory.CreateMqttClient();
                string token = "";

                var options = new MqttClientOptionsBuilder()
                    .WithClientId(localMacAddress)
                    .WithTcpServer(BrokerIp, BrokerPort)
                    .WithCredentials(Username, Password)
                    .WithCleanSession()
                    .Build();

                mqttClient.ApplicationMessageReceivedAsync += async e =>
                {
                    var macAddressProperty = e.ApplicationMessage.UserProperties
                                                .FirstOrDefault(p => p.Name == "MacAddress")?.Value;
                    if (macAddressProperty == localMacAddress)
                    {
                        var commandTopic = "iot/server/" + localMacAddress + "/command";
                        string topic = e.ApplicationMessage.Topic;
                        string payload = Encoding.UTF8.GetString(e.ApplicationMessage.Payload);

                        if (topic == ResponseTopic)
                        {
                            if (!string.IsNullOrEmpty(payload))
                            {
                                var response = System.Text.Json.JsonSerializer.Deserialize<DeviceRegisterResponse>(payload);
                                token = response.AccessToken;

                                // Unsubscribe khỏi topic response sau khi nhận token
                                await mqttClient.UnsubscribeAsync(ResponseTopic);
                                Console.WriteLine(localMacAddress + ": Unsubscribed from response topic");

                                // log file
                                Log2File("./LogFiles/" + localMacAddress + ".txt", DateTime.UtcNow.AddHours(7).ToString("yyyy/MM/dd HH:mm:ss") + " - Received: " + payload);
                            }
                        }
                        else if (topic == commandTopic)
                        {
                            // xu ly lenh gui tu server
                            Console.WriteLine(localMacAddress + ": " + payload);
                            // log file
                            Log2File("./LogFiles/" + localMacAddress + ".txt", DateTime.UtcNow.AddHours(7).ToString("yyyy/MM/dd HH:mm:ss") + " - Received: " + payload);
                        }
                    }
                };

                await mqttClient.ConnectAsync(options, CancellationToken.None);
                await mqttClient.SubscribeAsync(ResponseTopic, MqttQualityOfServiceLevel.AtLeastOnce);
                await SendRegistrationRequest(mqttClient, localMacAddress);

                while (string.IsNullOrEmpty(token))
                {
                    await Task.Delay(1000);
                }

                var _factory = new MqttClientFactory();
                var _mqttClient = _factory.CreateMqttClient();
                var _options = new MqttClientOptionsBuilder()
                    .WithClientId(localMacAddress)
                    .WithTcpServer(BrokerIp, BrokerPort)
                    .WithCredentials(localMacAddress, token)
                    .WithCleanSession()
                    .Build();

                _mqttClient.DisconnectedAsync += async (e) =>
                {
                    Console.WriteLine($"MQTT Disconnected. Reason: {e.ToString()}");

                    // Nếu lỗi có thể do token hết hạn, gửi lại request đăng ký
                    if (e.Reason == MqttClientDisconnectReason.NotAuthorized)
                    {
                        Console.WriteLine("Token might be expired. Sending Register...");
                    }
                };

                await _mqttClient.ConnectAsync(_options, CancellationToken.None);

                while (true)
                {
                    await SendHealthData(_mqttClient, localMacAddress, token);
                    await Task.Delay(10000);
                }
            }
            catch (Exception ex)
            {
                // log file
                Log2File("./LogFiles/Exceptions.txt", DateTime.UtcNow.AddHours(7).ToString("yyyy/MM/dd HH:mm:ss") + "- User: " + Username + " - " + localMacAddress + ": " + ex.ToString());
            }
        }

        public static void Log2File(string filePath, string data)
        {
            try
            {
                FileInfo info = new FileInfo(filePath);
                try
                {
                    if (info.Exists && info.Length > 10000000) // delete the file first if 10 MB
                    {
                        File.Delete(filePath);
                    }
                }
                catch (Exception ex)
                {

                }
                using (var fs = File.Open(filePath, FileMode.Append))
                {
                    using (var sw = new StreamWriter(fs))
                    {
                        sw.WriteLine(data);
                    }
                }
            }
            catch (Exception ex)
            {
            }
        }
    }
   
}