using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using AWSSignatureV4_S3_Sample.Signers;
using AWSSignatureV4_S3_Sample.Util;
using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Serializer;

namespace MySecondWebsocket
{
    class Program
    {
        static private string presignedURl;
        static void Main(string[] args)
        {
            var endpoint = "wss://<AWS_Account>.iot.us-east-1.amazonaws.com/mqtt";
            var queryParams = new StringBuilder();
            var expiresOn = DateTime.UtcNow.AddDays(2);
            var period = Convert.ToInt64((expiresOn.ToUniversalTime() - DateTime.UtcNow).TotalSeconds);
            queryParams.AppendFormat("{0}={1}", AWS4SignerBase.X_Amz_Expires, HttpHelpers.UrlEncode(period.ToString()));

            var headers = new Dictionary<string, string>();

            var signer = new AWS4SignerForQueryParameterAuth()
            {
                EndpointUri = new Uri(endpoint),
                HttpMethod = "GET",
                Region = "us-east-1",
                Service = "iotdevicegateway"
            };

            var authorization = signer.ComputeSignature(headers,
                queryParams.ToString(),
                "UNSIGNED-PAYLOAD",
                "<Access>",
                "<Secret>");
            // build the presigned url to incorporate the authorization element
            var urlBuilder = new StringBuilder(endpoint.ToString());

            // add our query params
            urlBuilder.AppendFormat("?{0}", queryParams.ToString());

            // and finally the Signature V4 authorization string components
            urlBuilder.AppendFormat("&{0}", authorization);

            var presignedUrl = urlBuilder.ToString();
            Console.WriteLine(presignedUrl);
            Task.Run(()=>Connect(presignedUrl));
            Console.ReadLine();
        }

        public static async void Connect(string presignedurl)
        {
            string CLIENT_ID = "12345;
            var client = new MqttFactory().CreateMqttClient();
            var options = new MqttClientOptionsBuilder()
                .WithWebSocketServer(presignedurl)
                .WithClientId(CLIENT_ID)
                .Build();
            (options.ChannelOptions as MqttClientWebSocketOptions).SubProtocols = new List<string>();
            (options.ChannelOptions as MqttClientWebSocketOptions).SubProtocols.Add("mqtt");

            MqttClientConnectResult res = await client.ConnectAsync(options);
            Console.WriteLine(res.IsSessionPresent);
        }
    }
}