using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;


namespace Aitex.Core.Utilities
{
    public static class Network
    {
        const string IpPrefix = "192.18.";

        static string _localIP;
        public static string LocalIP
        {
            get
            {
                if (string.IsNullOrWhiteSpace(_localIP))
                {
                    string hostName = Dns.GetHostName();
                    IPHostEntry me = Dns.GetHostEntry(hostName);
                    IPAddress[] ips = me.AddressList;

                    Func<IPAddress, bool> predicateIPV4 = ip => ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork;
                    Func<IPAddress, bool> predicate192 = ip => predicateIPV4(ip) && ip.ToString().StartsWith(IpPrefix);

                    _localIP = ips.Any(predicate192) ? ips.First(predicate192).ToString()
                        : ips.Any(predicateIPV4) ? ips.First(predicateIPV4).ToString()
                        : (ips.Length > 0 ? ips[0]: new IPAddress(0x0)).ToString();
                }
                return _localIP;
            }
        }
    }
}