//
// MonoTlsStream.cs
//
// Author:
//       Martin Baulig <martin.baulig@xamarin.com>
//
// Copyright (c) 2015 Xamarin, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#if SECURITY_DEP
#if MONO_SECURITY_ALIAS
extern alias MonoSecurity;
#endif

#if MONO_SECURITY_ALIAS
using MonoSecurity::Mono.Security.Interface;
#else
using Mono.Security.Interface;
#endif
#endif

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Net.Security;
using System.Threading;
using System.Threading.Tasks;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Security.Principal;
using System.Security.Cryptography;

namespace Mono.Net.Security
{
	class MonoTlsStream : IDisposable
	{
#if SECURITY_DEP
		readonly MonoTlsProvider provider;
		readonly NetworkStream networkStream;		
		readonly HttpWebRequest request;

		readonly MonoTlsSettings settings;

		internal HttpWebRequest Request {
			get { return request; }
		}

		IMonoSslStream sslStream;

		internal IMonoSslStream SslStream {
			get { return sslStream; }
		}
#else
		const string EXCEPTION_MESSAGE = "System.Net.Security.SslStream is not supported on the current platform.";
#endif

		WebExceptionStatus status;

		internal WebExceptionStatus ExceptionStatus {
			get { return status; }
		}

		internal bool CertificateValidationFailed {
			get; set;
		}

		public MonoTlsStream (HttpWebRequest request, NetworkStream networkStream)
		{
#if SECURITY_DEP
			this.request = request;
			this.networkStream = networkStream;

			settings = request.TlsSettings;
			provider = request.TlsProvider ?? MonoTlsProviderFactory.GetProviderInternal ();
			status = WebExceptionStatus.SecureChannelFailure;

			ChainValidationHelper.Create (provider, ref settings, this);
#else
			status = WebExceptionStatus.SecureChannelFailure;
			throw new PlatformNotSupportedException (EXCEPTION_MESSAGE);
#endif
		}

		internal async Task<Stream> CreateStream (WebConnectionTunnel tunnel, CancellationToken cancellationToken)
		{
#if SECURITY_DEP
			var socket = networkStream.InternalSocket;
			WebConnection.Debug ($"MONO TLS STREAM CREATE STREAM: {socket.ID}");
			sslStream = provider.CreateSslStream (networkStream, false, settings);

			try {
				var host = request.Host;
				if (!string.IsNullOrEmpty (host)) {
					var pos = host.IndexOf (':');
					if (pos > 0)
						host = host.Substring (0, pos);
				}

				await sslStream.AuthenticateAsClientAsync (
					host, request.ClientCertificates,
					(SslProtocols)ServicePointManager.SecurityProtocol,
					ServicePointManager.CheckCertificateRevocationList).ConfigureAwait (false);

				status = WebExceptionStatus.Success;
			} catch (Exception ex) {
				WebConnection.Debug ($"MONO TLS STREAM ERROR: {socket.ID} {socket.CleanedUp} {ex.Message}");
				if (socket.CleanedUp)
					status = WebExceptionStatus.RequestCanceled;
				else
					status = WebExceptionStatus.SecureChannelFailure;
				throw;
			} finally {
				WebConnection.Debug ($"MONO TLS STREAM CREATE STREAM DONE: {socket.ID} {socket.CleanedUp}");
				if (CertificateValidationFailed)
					status = WebExceptionStatus.TrustFailure;

				if (status == WebExceptionStatus.Success)
					request.ServicePoint.UpdateClientCertificate (sslStream.InternalLocalCertificate);
				else {
					request.ServicePoint.UpdateClientCertificate (null);
					sslStream.Dispose ();
					sslStream = null;
				}
			}

			try {
				if (tunnel?.Data != null)
					await sslStream.WriteAsync (tunnel.Data, 0, tunnel.Data.Length, cancellationToken).ConfigureAwait (false);
			} catch {
				status = WebExceptionStatus.SendFailure;
				sslStream = null;
				throw;
			}

			return sslStream.AuthenticatedStream;
#else
			throw new PlatformNotSupportedException (EXCEPTION_MESSAGE);
#endif
		}

		public void Dispose ()
		{
			if (sslStream != null) {
				sslStream.Dispose ();
				sslStream = null;
			}
		}
	}
}