/// <summary>
        /// Validates Endpoints
        /// </summary>
        /// <param name="json">json</param>
        /// <param name="policy">policy</param>
        /// <returns>bool</returns>
        public string ValidateEndpoints(JObject json, DiscoveryPolicy policy)
        {
            //var authorityHost = new Uri(policy.Authority).Authority;

            foreach (var element in json)
            {
                if (element.Key.EndsWith("Endpoint", StringComparison.OrdinalIgnoreCase) ||
                    element.Key.Equals(OidcConstants.Discovery.JwksUri, StringComparison.OrdinalIgnoreCase))
                {
                    var endpoint = element.Value.ToString();
                    Uri uri;

                    var isValidUri = Uri.TryCreate(endpoint, UriKind.Absolute, out uri);
                    if (!isValidUri)//Uri not valid
                    {
                        return($"Malformed endpoint: {endpoint}");
                    }

                    if (!DiscoveryUrlHelper.IsValidScheme(uri))//Scheme not valid
                    {
                        return($"Malformed endpoint: {endpoint}");
                    }

                    if (!DiscoveryUrlHelper.IsSecureScheme(uri, policy))//Scheme not secure
                    {
                        return($"Endpoint does not use HTTPS: {endpoint}");
                    }
                }
            }


            return(string.Empty);
        }
        public DiscoveryClient(string authority, HttpMessageHandler innerHandler = null)
        {
            var handler = innerHandler ?? new HttpClientHandler();

            Uri uri;
            var success = Uri.TryCreate(authority, UriKind.Absolute, out uri);

            if (success == false)
            {
                throw new InvalidOperationException("Malformed authority URL");
            }

            if (!DiscoveryUrlHelper.IsValidScheme(uri))
            {
                throw new InvalidOperationException("Malformed authority URL");
            }

            var url = authority.RemoveTrailingSlash();

            if (url.EndsWith(OidcConstants.Discovery.ProdDiscoveryEndpoint, StringComparison.OrdinalIgnoreCase))
            {
                Url       = url;
                Authority = url.Substring(0, url.Length - OidcConstants.Discovery.ProdDiscoveryEndpoint.Length - 1);
            }
            else if (url.EndsWith(OidcConstants.Discovery.SandboxDiscoveryEndpoint, StringComparison.OrdinalIgnoreCase))
            {
                Url       = url;
                Authority = url.Substring(0, url.Length - OidcConstants.Discovery.SandboxDiscoveryEndpoint.Length - 1);
            }
            else
            {
                Authority = url;
                Url       = url.EnsureTrailingSlash() + OidcConstants.Discovery.ProdDiscoveryEndpoint;
            }

            _client = new HttpClient(handler);
        }
        public async Task <DiscoveryResponse> GetAsync(CancellationToken cancellationToken = default(CancellationToken))
        {
            //Policy.Authority = Authority;
            string jwkUrl = "";

            if (!DiscoveryUrlHelper.IsSecureScheme(new Uri(Url), Policy))
            {
                return(new DiscoveryResponse(new InvalidOperationException("HTTPS required"), $"Error connecting to {Url}"));
            }

            try
            {
                var response = await _client.GetAsync(Url, cancellationToken).ConfigureAwait(false);

                if (!response.IsSuccessStatusCode)
                {
                    string errorDetail = "";

                    HttpResponseHeaders headers = response.Headers;
                    if (headers.WwwAuthenticate != null)
                    {
                        errorDetail = headers.WwwAuthenticate.ToString();
                    }


                    if (errorDetail != null && errorDetail != "")
                    {
                        return(new DiscoveryResponse(response.StatusCode, $"Error connecting to {Url}: {response.ReasonPhrase}: { errorDetail}"));
                    }
                    else
                    {
                        return(new DiscoveryResponse(response.StatusCode, $"Error connecting to {Url}: {response.ReasonPhrase}"));
                    }
                }

                var disco = new DiscoveryResponse(await response.Content.ReadAsStringAsync().ConfigureAwait(false), Policy);
                if (disco.IsError)
                {
                    return(disco);
                }


                try
                {
                    jwkUrl = disco.JwksUri;
                    if (jwkUrl != null)
                    {
                        response = await _client.GetAsync(jwkUrl, cancellationToken).ConfigureAwait(false);

                        if (!response.IsSuccessStatusCode)
                        {
                            return(new DiscoveryResponse(response.StatusCode, $"Error connecting to {jwkUrl}: {response.ReasonPhrase}"));
                        }

                        var jwk = await response.Content.ReadAsStringAsync().ConfigureAwait(false);

                        disco.KeySet = new JsonWebKeySet(jwk);
                    }

                    return(disco);
                }
                catch (Exception ex)
                {
                    return(new DiscoveryResponse(ex, $"Error connecting to {jwkUrl}"));
                }
            }
            catch (Exception ex)
            {
                return(new DiscoveryResponse(ex, $"Error connecting to {Url}"));
            }
        }