using System;

public class Program

{

    public static void Main()

    {

        string fullAddress = GetFullAddressFromHostAndPort("[1fff:0:a88:85a3::ac1f]",6000);

        Console.WriteLine(fullAddress);

        string host;    ushort port;

        bool res = GetHostAndPortFromFullAddress(fullAddress, out host, out port);

        Console.WriteLine("host: {0}, port: {1}", host, port);

    }

    /// <summary>

    ///     Build full address from HOST and PORT

    /// </summary>

    /// <remarks>

    ///     Possible formats of addresses:

    ///         domain_name:5000

    ///         192.168.1.1:5000

    ///         [1fff:0:a88:85a3::ac1f]:5000

    ///     The address always contains port number (5000 by default) and the host can be IPv4/v6 address or domain name.

    ///     If address is empty (e.g. in an intermediate stage), the <see cref="Target"/> address will contain just port number, e.g. ":5000"

    /// </remarks>

    /// <param name="host"> Host of the address. Can be domain name or IPv4/v6 address (needs brackets for IPv6) </param>

    /// <param name="portNum"> Port number from the address. By default it's 5000 </param>

    /// <returns> Address or null if an error occurs </returns>

    private static string GetFullAddressFromHostAndPort(string host, ushort portNum = 5000)

    {

        try

        {

            var uri = new Uri("http://" + host + ":" + portNum);

            // host:address without schema (e.g. 'http://')

            return uri.Authority;

        }

        catch (Exception)

        {

            return ":"+portNum;

        }

    }

    /// <summary>

    ///     Returns HOST and PORT from the <see cref="Target"/> address field

    /// </summary>

    /// <param name="fullAddress"> 

    ///     Full URI. Possible formats:

    ///         domain_name:5000

    ///         192.168.1.1:5000

    ///         [1fff:0:a88:85a3::ac1f]:5000

    ///     The address always contains port number (5000 by default) and the host can be IPv4/v6 address or domain name.

    ///     The address can't contain protocol (e.g. 'tcp://', 'http://', etc.)

    /// </param>

    /// <param name="host"> 

    ///     Host of the address. Can be domain name or IPv4/v6 address (no brackets for IPv6). It's empty if couldn't parse. 

    /// </param>

    /// <param name="portNum"> 

    ///     Port number from the address. By default it's 5000 if couldn't parse. 

    /// </param>

    /// <returns> True - parsing was successful, otherwise - False </returns>

    private static bool GetHostAndPortFromFullAddress(string fullAddress, out string host, out ushort portNum)

    {

        host = string.Empty;    portNum = 5000;

        try

        {

            // Use URI class for parsing only

            var uri = new Uri("http://" + fullAddress);

            // get host

            host = uri.DnsSafeHost;

            // get port

            portNum = (ushort)uri.Port;

            return true;

        }

        catch (Exception)

        {

            return false;

        }

    }

}