// Copyright (c) 2004, 2021, Oracle and/or its affiliates.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
// This program is also distributed with certain software (including
// but not limited to OpenSSL) that is licensed under separate terms,
// as designated in a particular file or component or in included license
// documentation.  The authors of MySQL hereby grant you an
// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Connector/NET, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License, version 2.0, for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using MySql.Data.MySqlClient;
using MySql.Data.MySqlClient.Common;
using System;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Threading.Tasks;
using Sog.Properties;

namespace MySql.Data.Common
{
    /// <summary>
    /// Summary description for StreamCreator.
    /// </summary>
    internal class StreamCreator
    {
        readonly string _hostList;
        uint _port;
        string pipeName;
        uint keepalive;
        DBVersion driverVersion;

        public StreamCreator(string hosts, uint port, string pipeName, uint keepalive, DBVersion driverVersion)
        {
            this._hostList = hosts;
            if (string.IsNullOrEmpty(this._hostList))
            {
                this._hostList = "localhost";
            }

            this._port = port;
            this.pipeName = pipeName;
            this.keepalive = keepalive;
            this.driverVersion = driverVersion;
        }

        public static Stream GetStream(string server, uint port, string pipename, uint keepalive, DBVersion v, uint timeout)
        {
            MySqlConnectionStringBuilder settings = new MySqlConnectionStringBuilder
            {
                Server = server,
                Port = port,
                PipeName = pipename,
                Keepalive = keepalive,
                ConnectionTimeout = timeout
            };
            MyNetworkStream networkStream = null;
            return GetStream(settings, ref networkStream);
        }

        public static Stream GetStream(MySqlConnectionStringBuilder settings, ref MyNetworkStream networkStream)
        {
            switch (settings.ConnectionProtocol)
            {
                case MySqlConnectionProtocol.Tcp: return GetTcpStream(settings, ref networkStream);
                case MySqlConnectionProtocol.UnixSocket: return GetUnixSocketStream(settings, ref networkStream);
                case MySqlConnectionProtocol.SharedMemory: return GetSharedMemoryStream(settings);
                case MySqlConnectionProtocol.NamedPipe: return GetNamedPipeStream(settings);
            }

            throw new InvalidOperationException(Resources.UnknownConnectionProtocol);
        }

        private static Stream GetTcpStream(MySqlConnectionStringBuilder settings, ref MyNetworkStream networkStream)
        {
            Task<IPAddress[]> dnsTask = Dns.GetHostAddressesAsync(settings.Server);
            dnsTask.Wait();
            if (dnsTask.Result == null || dnsTask.Result.Length == 0)
            {
                throw new ArgumentException(Resources.InvalidHostNameOrAddress);
            }

            IPAddress addr = dnsTask.Result.FirstOrDefault(c => c.AddressFamily == AddressFamily.InterNetwork);
            if (addr == null)
            {
                addr = dnsTask.Result[0];
            }

            TcpClient client = new TcpClient(addr.AddressFamily);
            Task task = client.ConnectAsync(settings.Server, (int)settings.Port);

            if (!task.Wait(((int)settings.ConnectionTimeout * 1000)))
            {
                throw new MySqlException(Resources.Timeout);
            }

            if (settings.Keepalive > 0)
            {
                SetKeepAlive(client.Client, settings.Keepalive);
            }

            networkStream = new MyNetworkStream(client.Client, true);
            var result = client.GetStream();
            GC.SuppressFinalize(result);

            return result;
        }

        internal static Stream GetUnixSocketStream(MySqlConnectionStringBuilder settings, ref MyNetworkStream networkStream)
        {
            try
            {
                networkStream = new MyNetworkStream(GetUnixSocket(settings.Server, settings.ConnectionTimeout, settings.Keepalive), true);
                return new NetworkStream(networkStream.Socket, true);
            }
            catch (Exception)
            {
                throw;
            }
        }

        internal static Socket GetUnixSocket(string server, uint connectionTimeout, uint keepAlive)
        {
            if (Platform.IsWindows())
            {
                throw new InvalidOperationException(Resources.NoUnixSocketsOnWindows);
            }

            EndPoint endPoint = new UnixEndPoint(server);
            Socket socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.IP);
            if (keepAlive > 0)
            {
                SetKeepAlive(socket, keepAlive);
            }

            try
            {
                socket.ReceiveTimeout = (int)connectionTimeout * 1000;
                socket.Connect(endPoint);
                return socket;
            }
            catch (Exception)
            {
                socket.Dispose();
                throw;
            }
        }

        private static Stream GetSharedMemoryStream(MySqlConnectionStringBuilder settings)
        {
            SharedMemoryStream str = new SharedMemoryStream(settings.SharedMemoryName);
            str.Open(settings.ConnectionTimeout);
            return str;
        }

        private static Stream GetNamedPipeStream(MySqlConnectionStringBuilder settings)
        {
            Stream stream = NamedPipeStream.Create(settings.PipeName, settings.Server, settings.ConnectionTimeout);
            return stream;
        }

        /// <summary>
        /// Set the keepalive timeout on the socket.
        /// </summary>
        /// <param name="s">The socket object.</param>
        /// <param name="time">The keepalive timeout, in seconds.</param>
        internal static void SetKeepAlive(Socket s, uint time)
        {
            uint on = 1;
            uint interval = 1000; // default interval = 1 sec

            uint timeMilliseconds;
            if (time > UInt32.MaxValue / 1000)
            {
                timeMilliseconds = UInt32.MaxValue;
            }
            else
            {
                timeMilliseconds = time * 1000;
            }

            // Use Socket.IOControl to implement equivalent of
            // WSAIoctl with  SOL_KEEPALIVE_VALS 

            // the native structure passed to WSAIoctl is
            // struct tcp_keepalive {
            //    ULONG onoff;
            //    ULONG keepalivetime;
            //    ULONG keepaliveinterval;
            // };
            // marshal the equivalent of the native structure into a byte array

            byte[] inOptionValues = new byte[12];
            BitConverter.GetBytes(on).CopyTo(inOptionValues, 0);
            BitConverter.GetBytes(timeMilliseconds).CopyTo(inOptionValues, 4);
            BitConverter.GetBytes(interval).CopyTo(inOptionValues, 8);
            try
            {
                // call WSAIoctl via IOControl
                s.IOControl(IOControlCode.KeepAliveValues, inOptionValues, null);
                return;
            }
            catch (NotImplementedException)
            {
                // Mono throws not implemented currently
            }

            // Fallback if Socket.IOControl is not available ( Compact Framework )
            // or not implemented ( Mono ). Keepalive option will still be set, but
            // with timeout is kept default.
            s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, 1);
        }
    }
}