// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using MQTTnet.Diagnostics.Logger;
using MQTTnet.Internal;
using MQTTnet.Protocol;
using MQTTnet.Server;
using Newtonsoft.Json;

namespace MQTTnet.TestApp;

public static class ServerTest
{
    public static void RunEmptyServer()
    {
        var mqttServer = new MqttServerFactory().CreateMqttServer(new MqttServerOptions());
        mqttServer.StartAsync().GetAwaiter().GetResult();

        Console.WriteLine("Press any key to exit.");
        Console.ReadLine();
    }

    public static void RunEmptyServerWithLogging()
    {
        var logger = new MqttNetEventLogger();
        MqttNetConsoleLogger.ForwardToConsole(logger);

        var mqttServerFactory = new MqttServerFactory(logger);
        var mqttServer = mqttServerFactory.CreateMqttServer(new MqttServerOptions());
        mqttServer.StartAsync().GetAwaiter().GetResult();

        Console.WriteLine("Press any key to exit.");
        Console.ReadLine();
    }

    public static async Task RunAsync()
    {
        try
        {
            var options = new MqttServerOptionsBuilder()
                .WithDefaultEndpoint()
                .Build();

            // Extend the timestamp for all messages from clients.
            // Protect several topics from being subscribed from every client.

            //var certificate = new X509Certificate(@"C:\certs\test\test.cer", "");
            //options.TlsEndpointOptions.Certificate = certificate.Export(X509ContentType.Cert);
            //options.ConnectionBacklog = 5;
            //options.DefaultEndpointOptions.IsEnabled = true;
            //options.TlsEndpointOptions.IsEnabled = false;

            var mqttServer = new MqttServerFactory().CreateMqttServer(options);

            const string filename = @"C:\MQTT\RetainedMessages.json";

            mqttServer.RetainedMessageChangedAsync += e =>
            {
                var directory = Path.GetDirectoryName(filename);
                if (!Directory.Exists(directory))
                {
                    Directory.CreateDirectory(directory!);
                }

                File.WriteAllText(filename, JsonConvert.SerializeObject(e.StoredRetainedMessages));
                return CompletedTask.Instance;
            };

            mqttServer.RetainedMessagesClearedAsync += _ =>
            {
                File.Delete(filename);
                return CompletedTask.Instance;
            };

            mqttServer.LoadingRetainedMessageAsync += e =>
            {
                List<MqttApplicationMessage> retainedMessages;
                if (File.Exists(filename))
                {
                    var json = File.ReadAllText(filename);
                    retainedMessages = JsonConvert.DeserializeObject<List<MqttApplicationMessage>>(json);
                }
                else
                {
                    retainedMessages = new List<MqttApplicationMessage>();
                }

                e.LoadedRetainedMessages = retainedMessages;

                return CompletedTask.Instance;
            };

            mqttServer.InterceptingPublishAsync += e =>
            {
                if (MqttTopicFilterComparer.Compare(e.ApplicationMessage.Topic, "/myTopic/WithTimestamp/#") == MqttTopicFilterCompareResult.IsMatch)
                {
                    // Replace the payload with the timestamp. But also extending a JSON
                    // based payload with the timestamp is a suitable use case.
                    e.ApplicationMessage.PayloadSegment = new ArraySegment<byte>(Encoding.UTF8.GetBytes(DateTime.Now.ToString("O")));
                }

                if (e.ApplicationMessage.Topic == "not_allowed_topic")
                {
                    e.ProcessPublish = false;
                    e.CloseConnection = true;
                }

                return CompletedTask.Instance;
            };

            mqttServer.ValidatingConnectionAsync += e =>
            {
                if (e.ClientId == "SpecialClient")
                {
                    if (e.UserName != "USER" || e.Password != "PASS")
                    {
                        e.ReasonCode = MqttConnectReasonCode.BadUserNameOrPassword;
                    }
                }

                return CompletedTask.Instance;
            };

            mqttServer.InterceptingSubscriptionAsync += e =>
            {
                if (e.TopicFilter.Topic.StartsWith("admin/foo/bar", StringComparison.InvariantCulture) && e.ClientId != "theAdmin")
                {
                    e.Response.ReasonCode = MqttSubscribeReasonCode.ImplementationSpecificError;
                }

                if (e.TopicFilter.Topic.StartsWith("the/secret/stuff", StringComparison.InvariantCulture) && e.ClientId != "Imperator")
                {
                    e.Response.ReasonCode = MqttSubscribeReasonCode.ImplementationSpecificError;
                    e.CloseConnection = true;
                }

                return CompletedTask.Instance;
            };

            mqttServer.InterceptingPublishAsync += e =>
            {
                var payloadText = string.Empty;
                if (e.ApplicationMessage.Payload.Length > 0)
                {
                    payloadText = Encoding.UTF8.GetString(e.ApplicationMessage.Payload);
                }

                MqttNetConsoleLogger.PrintToConsole($"'{e.ClientId}' reported '{e.ApplicationMessage.Topic}' > '{payloadText}'", ConsoleColor.Magenta);
                return CompletedTask.Instance;
            };

            //options.ApplicationMessageInterceptor = c =>
            //{
            //    if (c.ApplicationMessage.Payload == null || c.ApplicationMessage.Payload.Length == 0)
            //    {
            //        return;
            //    }

            //    try
            //    {
            //        var content = JObject.Parse(Encoding.UTF8.GetString(c.ApplicationMessage.Payload));
            //        var timestampProperty = content.Property("timestamp");
            //        if (timestampProperty != null && timestampProperty.Value.Type == JTokenType.Null)
            //        {
            //            timestampProperty.Value = DateTime.Now.ToString("O");
            //            c.ApplicationMessage.Payload = Encoding.UTF8.GetBytes(content.ToString());
            //        }
            //    }
            //    catch (Exception)
            //    {
            //    }
            //};

            mqttServer.ClientConnectedAsync += _ =>
            {
                Console.Write("Client disconnected event fired.");
                return CompletedTask.Instance;
            };

            await mqttServer.StartAsync();

            Console.WriteLine("Press any key to exit.");
            Console.ReadLine();

            await mqttServer.StopAsync();
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }

        Console.ReadLine();
    }
}