namespace Client
{
    internal class Program
    {
        static string username = "demo_user";
        static string accessKey = "8370921743021";
        static string secret = "321094343143";
        static string baseUrl = @"https://publicapi.stage.nt.cloud.bewotec.de";
        private class Content
        {
            public string Prop { get; set; }
        }

        static void Main(string[] args)
        {
           GetRequest();
           PostRequest();
        }

        static void GetRequest()
        {
            string httpVerb = "GET";
            string path = "/td/travel-infos/4711";
            string query = "?q=100";
            Send(httpVerb, path, query, null, false);
        }

        static void PostRequest()
        {
            string httpVerb = "POST";
            string path = "/td/booking-documents/1";
            string query = "";
            Content content = new Content
            {
                Prop = "value"
            };
            Send(httpVerb, path, query, content, true);
        }
     
        static void Send(string httpVerb, string path, string query, object content, bool includePayload)
        {
            using (var client = new System.Net.Http.HttpClient())
            {
                client.BaseAddress = new System.Uri(baseUrl + path + query);
                using (var request = new System.Net.Http.HttpRequestMessage())
                {
                    request.Method = new System.Net.Http.HttpMethod(httpVerb);
                    request.Headers.Accept.Add(System.Net.Http.Headers.MediaTypeWithQualityHeaderValue.Parse("application/json"));

                    string bodyHash = string.Empty;

                    if (content != null)
                    {
                        var content_ = new System.Net.Http.StringContent(System.Text.Json.JsonSerializer.Serialize(content));
                        content_.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse("application/json");
                        request.Content = content_;
                       
                        if (includePayload)
                        {
                            request.Headers.TryAddWithoutValidation("x-nt-content-sha256", "true");
                            using (var sha256Hash = System.Security.Cryptography.SHA256.Create())
                            {
                                byte[] bodyBytes = content_.ReadAsByteArrayAsync().Result;
                                var hash = sha256Hash.ComputeHash(bodyBytes);
                                bodyHash = System.Convert.ToBase64String(hash);
                            }
                        }
                    }

                    string utcDate = System.DateTime.UtcNow.ToString("yyyyMMddHHmmss"); //20210118093334
                    string pathAndQueryString = path + query;
                    string assembleUpper = string.Concat(utcDate, httpVerb.ToUpper(), pathAndQueryString.ToUpper(), bodyHash);//20210118093334GET/TD/TRAVEL-INFOS/4711?Q=100

                    System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
                    byte[] textBytes = encoding.GetBytes(assembleUpper);
                    byte[] keyBytes = encoding.GetBytes(secret);
                    byte[] hashBytes;
                    using (var hash = new System.Security.Cryptography.HMACSHA256(keyBytes))
                    {
                        hashBytes = hash.ComputeHash(textBytes);
                    }
                    string signature = System.Convert.ToBase64String(hashBytes);//C8P/6j4En8+pqLA9gcQmih7rU119s/F9iMCHZMBxPOc=

                    string authorization = string.Format(@"DirectGrant {0} {1} {2} {3}", username, accessKey, utcDate, signature);//DirectGrant test@davincint-test.de public1234 20210118093334 C8P/6j4En8+pqLA9gcQmih7rU119s/F9iMCHZMBxPOc=

                    request.Headers.Add("Authorization", authorization);
                    
                    using (var response = client.Send(request))
                    {

                    }
                }
            }
        }
    }
}