using Edge.Core.Processor;
using Edge.Core.IndustryStandardInterface.Pump;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using MQTTnet;
using MQTTnet.Client;
using SimpleScanner.MessageEntity;
using System;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SimpleScanner
{
    public class Handler : IDeviceHandler<byte[], ScannerMessage>
    {
        private IMqttClient mqttClient;

        private string mqttServerUrl;
        private int mqttServerPort;
        private string mqttClientId;
        private string mqttClientUsername;
        private string mqttClientPassword;

        private string topic_ScannerRequest;
        private string topic_ScannerRequestReply;

        private ILogger logger = NullLogger.Instance;
        private bool shouldReconnect = true;

        public Handler(string mqttServerUrl, int mqttServerPort, string mqttClientId,
            string mqttClientUsername, string mqttClientPassword,
            string topic_ScannerRequest, string topic_ScannerRequestReply,
            IServiceProvider services)
        {
            var loggerFactory = services.GetRequiredService<ILoggerFactory>();
            this.logger = loggerFactory.CreateLogger("Application");

            this.mqttServerUrl = mqttServerUrl;
            this.mqttServerPort = mqttServerPort;
            this.mqttClientId = mqttClientId;
            this.mqttClientUsername = mqttClientUsername;
            this.mqttClientPassword = mqttClientPassword;

            this.topic_ScannerRequest = topic_ScannerRequest;
            this.topic_ScannerRequestReply = topic_ScannerRequestReply;
        }

        public async void Init(IContext<byte[], ScannerMessage> context)
        {
            //MqttNetGlobalLogger.LogMessagePublished += (s, e) =>
            //{
            //    //var trace = $">> [{e.TraceMessage.ThreadId}] [{e.TraceMessage.Source}] [{e.TraceMessage.Level}]: {e.TraceMessage.Message}";
            //    if (this.logger.IsEnabled(LogLevel.Trace))
            //    {
            //        var trace = $"MQTTnet - {e.TraceMessage.Message}";
            //        if (e.TraceMessage.Exception != null)
            //            trace += Environment.NewLine + e.TraceMessage.Exception.ToString();
            //        this.logger.LogTrace(trace);
            //    }
            //};
            // Create a new MQTT client.
            var factory = new MqttFactory();
            this.mqttClient = factory.CreateMqttClient();
            this.mqttClient.ApplicationMessageReceivedAsync += e =>
            {
                if (this.logger.IsEnabled(LogLevel.Trace))
                {
                    this.logger.LogTrace("### Received Messages from Topic ###");
                    this.logger.LogTrace($"     Topic = {e.ApplicationMessage.Topic}");
                    this.logger.LogTrace($"     Payload = {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
                    this.logger.LogTrace($"     QoS = {e.ApplicationMessage.QualityOfServiceLevel}");
                    this.logger.LogTrace($"     Retain = {e.ApplicationMessage.Retain}");
                }

                if (e.ApplicationMessage.Topic == this.topic_ScannerRequestReply)
                {
                    try
                    {
                        // the device could not be capable to receive any data
                        logger.LogInformation("how mqtt server send data to this device " +
                                "which is not capable for receive any command, send it anyway: " +
                                Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
                        context.Outgoing.Write(new ScannerMessage()
                        {
                            RawContent = this.ParseFormatDataToDeviceData(e.ApplicationMessage.Payload)
                        });
                    }
                    catch (Exception eeee)
                    {
                        logger.LogInformation("handle mqtt server incoming msg received from topic: " +
                            (this.topic_ScannerRequestReply ?? "")
                            + ", exceptioned: " + eeee);
                    }
                }
                return Task.CompletedTask;
            };
            this.mqttClient.DisconnectedAsync += arg =>
            {
                this.shouldReconnect = true;
                this.logger.LogInformation("    Mqtt connection disconnected, " +
                    "AuthenticateResult: " + (arg.ReasonString ?? "") +
                    ", ClientWasConnected: " + arg.ClientWasConnected +
                    ", exception: " + arg.Exception);
                return Task.CompletedTask;
            };

            // Create TCP based options using the builder.
            var options = new MqttClientOptionsBuilder()
                .WithClientId(this.mqttClientId)
                .WithTcpServer(this.mqttServerUrl, this.mqttServerPort)
                .WithCredentials(this.mqttClientUsername, this.mqttClientPassword)
                .WithKeepAlivePeriod(new TimeSpan(0, 0, 30))
                .WithCleanSession(true)
                .Build();
            await Task.Run(async () =>
            {
                while (true)
                {
                    if (!this.shouldReconnect) { await Task.Delay(30000); continue; }
                    this.logger.LogDebug("Connecting to mqtt server...");
                    try
                    {
                        try
                        {
                            // always try to close previous conn.
                            await mqttClient.DisconnectAsync();
                        }
                        catch { }

                        var result = await mqttClient.ConnectAsync(options);
                        if (result.ResultCode == MqttClientConnectResultCode.Success)
                        {
                            this.logger.LogInformation("    Successfully connected to mqtt server.");
                            if (string.IsNullOrEmpty(this.topic_ScannerRequestReply))
                            {
                                this.shouldReconnect = false;
                                return;
                            }

                            var subResult = await this.mqttClient.SubscribeAsync(this.topic_ScannerRequestReply,
                                MQTTnet.Protocol.MqttQualityOfServiceLevel.AtMostOnce);
                            if (subResult.Items.Any())
                            {
                                if ((int)(subResult.Items.First().ResultCode) <= 2)
                                {
                                    this.logger.LogInformation("    Successfully subscribed on topic.");
                                    this.shouldReconnect = false;
                                }
                                else
                                {
                                    this.logger.LogInformation("    Failed on subscribe on topic with Sub resultCode: "
                                        + subResult.Items.First().ResultCode);
                                }
                            }
                            else
                                this.logger.LogInformation("    Failed on subscribe on topic by generic error.");
                        }
                        else
                        {
                            this.logger.LogInformation("    Failed connecting to mqtt server with returned ResultCode: "
                                + result.ResultCode
                                + ", ReasonString:" + (result.ReasonString ?? ""));
                        }
                    }
                    catch (Exception exx)
                    {
                        this.logger.LogError("  Connecting to mqtt server exceptioned: " + exx);
                    }

                    // keep retry...
                    await Task.Delay(30000);
                }
            });
        }

        public Task Process(IContext<byte[], ScannerMessage> context)
        {
            if (context.Incoming.Message.RawContent == null || !context.Incoming.Message.RawContent.Any())
            { logger.LogDebug("Incoming an null or empty Scanner Msg."); return Task.CompletedTask; }
            logger.LogDebug("Incoming Scanner msg: "
                + context.Incoming.Message.RawContent.Select(b => b.ToString("X2")).Aggregate((acc, n) => acc + " " + n)
                + " (" + Encoding.UTF8.GetString(context.Incoming.Message.RawContent) + ")");
            if (!string.IsNullOrEmpty(this.topic_ScannerRequest))
                this.mqttClient.PublishAsync(new MqttApplicationMessage()
                {
                    Topic = this.topic_ScannerRequest,
                    Payload = context.Incoming.Message.RawContent
                });
            return Task.CompletedTask;
        }

        /// <summary>
        /// </summary>
        /// <param name="rawContent"></param>
        /// <returns>bytes that the device can read and operate</returns>
        private byte[] ParseFormatDataToDeviceData(byte[] rawContent)
        {
            return rawContent;
        }
    }
}