using Microsoft.Data.Tools.TdsLib;
using Microsoft.Data.Tools.TdsLib.IO.Connection.Tcp;
using Microsoft.Data.Tools.TdsLib.Messages;
using Microsoft.Data.Tools.TdsLib.Packets;
using Microsoft.Data.Tools.TdsLib.Payloads.Login7;
using Microsoft.Data.Tools.TdsLib.Payloads.PreLogin;
using Microsoft.Data.Tools.TdsLib.Tokens.Error;

string hostname = "sqlserver.contoso.net";
int port = 1433;

using TdsClient client = new TdsClient(new TcpServerEndpoint(hostname, port));

// Send PreLogin message
await client.MessageHandler.SendMessage(new Message(PacketType.PreLogin)
{
    Payload = new PreLoginPayload(encrypt: true)
});

// Receive PreLogin message
var preLoginResponseMessage = await client.MessageHandler.ReceiveMessage(b => new PreLoginPayload(b));

// Perform TLS handshake
await client.PerformTlsHandshake();

// Prepare Login7 message
Login7Payload login7Payload = new Login7Payload()
{
    Hostname = hostname,
    ServerName = "MyServerName",
    AppName = "MyAppName",
    Language = "us_english",
    Database = "MyDatabaseName",
    //Username,
    //Password
};

login7Payload.TypeFlags.AccessIntent = OptionAccessIntent.ReadWrite;

Message login7Message = new Message(PacketType.Login7) { Payload = login7Payload };

// Send Login7 message
await client.MessageHandler.SendMessage(login7Message);

// Receive Login response tokens
await client.TokenStreamHandler.ReceiveTokensAsync(tokenEvent =>
{
    if (tokenEvent.Token is ErrorToken errorToken)
    {
        // Error was received from the server
    }
});

// If no error token was received, and SQL server did not close the connection, then the connection to the server is now established and the user is logged in.