using System;

using System.Web.Mvc;

using System.Collections.Generic;

using System.Security.Cryptography;

using System.Text;

using Newtonsoft.Json;

using Newtonsoft.Json.Converters;

using System.Net.Http;

using System.Threading.Tasks;

using System.Net.Http.Headers;

​

namespace HelloWorldMvcApp

{

    public class HomeController : Controller

    {

        [HttpGet]

        public ActionResult Index()

        {

            return View(new SampleViewModel());

        }

​

        [HttpPost]

        public JsonResult GetAnswer(string question)

        {

            // Initialize authentication code

            var authCode = string.Empty;

            // Pre-generated access/secret keys. TG to provide to every client.

            var accessKey = "W+3SqwgA2gwSxlk/0PAz";

            var secretKey = "z1+DK1IEdNycYT6wBuBAaav51lCdnCFzUQJce4bt";

            // Api to call to retrieve asset infomation 

            var endpoint = "https://api-delivery-connect.tunedglobal.com/api/v3/play/logplay";

            //STEP 1: Generate nonce and timestamp

            // Nonce 

            string nonce = Guid.NewGuid().ToString("N");

            // Timestamp using unix time

            DateTime epochStart = new DateTime(1970, 01, 01, 0, 0, 0, 0, DateTimeKind.Utc);

            TimeSpan timeSpan = DateTime.UtcNow - epochStart;

            string requestTimeStamp = Convert.ToUInt64(timeSpan.TotalSeconds).ToString();

            // STEP 2: Encode request url using UTF8 encoding

            var uri = System.Web.HttpUtility.UrlEncode(endpoint, Encoding.UTF8);

            // STEP 3: Serialize Json object / payload

            // Sample Json object / payload

            var data = new SampleRequestPayload {TrackId=12345,Country="US",LogPlayType="Start",Seconds=0,PlayType="Preview",SourceId=0,Guid="47fb4874-6311-45df-91e3-6faa552b3331"};

            //Serialize to string

            string serializedData = JsonConvert.SerializeObject(data);

            // STEP 4: Convert serialized payload to bytes using UTF8 encoding table

            byte[] content = Encoding.UTF8.GetBytes(serializedData);

            // STEP 5: Hash the request body using MD5 hashing algorithm

            MD5 md5 = MD5.Create();

            byte[] requestContentHash = md5.ComputeHash(content);

            //  Convert hashed data to base 64 string

            string requestContentBase64String = Convert.ToBase64String(requestContentHash);

            // STEP 3: Create Raw signature string. Format: {your-access-key}{http-method}{request-url}{request-body-base64-string}{nonce}{timestamp}

            string signatureRawData = String.Format("{0}{1}{2}{3}{4}{5}", accessKey, "POST", uri, requestContentBase64String, nonce, requestTimeStamp);

            // STEP 4: Convert formatted signature raw string to bytes

            byte[] signature = Encoding.UTF8.GetBytes(signatureRawData);

            // STEP 5: Coverty secret key to byte array

            var secretKeyByteArray = Convert.FromBase64String(secretKey);

            //STEP 6: Create HMAC for signature string using secret key byte array

            using (HMACSHA256 sha = new HMACSHA256(secretKeyByteArray))

            {

                // Sign the request

                byte[] signatureBytes = sha.ComputeHash(signature);

                // STEP 7: Convert the signatureBytes result to base64 string

                string requestSignatureBase64String = Convert.ToBase64String(signatureBytes);

                //STEP 8: Generate authentication code. Format: {your-access-key}:{signature}:{nonce}:{timestamp}

                //This is the file signature string that needs to be sent in Tuned-HMAC auth header

                authCode = string.Format("{0}:{1}:{2}:{3}", accessKey, requestSignatureBase64String, nonce, requestTimeStamp);

            }

​

            return Json(authCode);

        }

    }

​

    public class SampleRequestPayload

    {

        public int TrackId { get; set; }

        public string Country { get; set; }

        public string LogPlayType { get; set; }

        public int? Seconds { get; set; }

​

        public string PlayType { get; set; }

        public int SourceId { get; set; }

        public string Guid { get; set; }    

    }

}